# Rainbow Documentation Home

Welcome to the Rainbow Documentation Hub—your go-to resource for everything related to our carbon registry: standard rules, procedures, and methodologies. Whether you are a project developer, partner, or carbon credit buyer, this platform is designed to provide you with all relevant information you might look in a efficient navigation system.

**Why this documentation?**

At Rainbow, we believe that consistency, transparency, and adherence to well-defined standards are the cornerstones of trustful and success Voluntary Carbon Markets.

Our documentation is providing detailed guidance, rules and structured approaches to all processes of our carbon standard and registry.

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:arrow\_heading\_down: Download any page as a PDF by clicking the dropdown next to **Copy** button at the top of the page :point\_up:, then **Export as PDF.**
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{% hint style="info" %}
:mag: Check out our [open public consultations](/rainbow-standard-documents/public-consultations) and give feedback :speech\_balloon:
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## Rainbow Standard Documents

Our Rainbow Standard Document section covers the essential rules and guidelines that govern our standard and registry across all methodologies and project types.

<table data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="files"></th></tr></thead><tbody><tr><td><a href="/pages/CRADNrj4mfS258PN3x7N"><strong>Rainbow Standard Rules</strong></a></td><td>Sets the general requirement for Project Developers for registering and operating Rainbow projects and issuing Rainbow Carbon Credits (RCC).</td><td></td><td><a href="/pages/CRADNrj4mfS258PN3x7N">/pages/CRADNrj4mfS258PN3x7N</a></td><td></td></tr><tr><td><a href="/pages/skPU8S5bIwMzBj9mtaHa"><strong>Rainbow Procedures Manual</strong></a></td><td>Describes the rules and procedures for documentation management, methodology development and updates, registering and operating carbon projects.</td><td></td><td><a href="/pages/skPU8S5bIwMzBj9mtaHa">/pages/skPU8S5bIwMzBj9mtaHa</a></td><td></td></tr></tbody></table>

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[Procedural templates](/rainbow-standard-documents/procedural-templates)
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***

## Rainbow Methodologies

Each methodology gives specific requirements and quantification methods per project types.

<table data-card-size="large" data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="image">Cover image</th></tr></thead><tbody><tr><td>Biogas from anaerobic digestion</td><td></td><td></td><td><a href="/pages/obRdXsWwQ3QKd33cPfRG">/pages/obRdXsWwQ3QKd33cPfRG</a></td><td><a href="/files/q6E23xtpYegumN0r1WTp">/files/q6E23xtpYegumN0r1WTp</a></td></tr><tr><td>Biomass carbon removal and storage (BiCRS)</td><td></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo">/pages/Jy6o8q5Q31d2U0OK7Yuo</a></td><td><a href="/files/4B3R2CjT9hA3bBYbzz1a">/files/4B3R2CjT9hA3bBYbzz1a</a></td></tr><tr><td>Refurbishing of electronic devices</td><td></td><td></td><td><a href="/pages/rqZzogSgVlIRAB55Oki1">/pages/rqZzogSgVlIRAB55Oki1</a></td><td><a href="/files/ZAxqYlP50vM4pzsvknrg">/files/ZAxqYlP50vM4pzsvknrg</a></td></tr><tr><td>Biobased construction materials</td><td></td><td></td><td><a href="/pages/RqfJGxwJIa5eql8owuF4">/pages/RqfJGxwJIa5eql8owuF4</a></td><td><a href="/files/f5cKAncYBa43GiMMU7HB">/files/f5cKAncYBa43GiMMU7HB</a></td></tr><tr><td>Battery second life</td><td></td><td></td><td><a href="/pages/h2OzRlsij4Sb7h6ufm2X">/pages/h2OzRlsij4Sb7h6ufm2X</a></td><td><a href="/files/eoFyTVMVVZVZgcowt7cX">/files/eoFyTVMVVZVZgcowt7cX</a></td></tr><tr><td>Mineralization of alkaline materials (ex situ)</td><td></td><td></td><td><a href="/pages/dWUzpkT7ZGzmw6bBk7m4">/pages/dWUzpkT7ZGzmw6bBk7m4</a></td><td><a href="/files/msi0QQdy9fGE46fIQeou">/files/msi0QQdy9fGE46fIQeou</a></td></tr><tr><td>Enhanced rock weathering</td><td></td><td></td><td><a href="/pages/IzD2vrA9ezW0AapQTp1l">/pages/IzD2vrA9ezW0AapQTp1l</a></td><td><a href="/files/UF1GBglM39hR3jIMKvUW">/files/UF1GBglM39hR3jIMKvUW</a></td></tr></tbody></table>

## Rainbow modules

General Rainbow modules cover parts of project life cycles that are repeated across many technology types and methodologies. They contain basic eligibility requirements and GHG quantification approaches, and are combined with Rainbow methodologies when needed.

<table data-card-size="large" data-view="cards"><thead><tr><th></th><th data-hidden data-card-cover data-type="image">Cover image</th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td>Transportation</td><td><a href="/files/XAxrYlLSh0qtvbDkKkqp">/files/XAxrYlLSh0qtvbDkKkqp</a></td><td><a href="/pages/VTWdCc7guKu1x0azAizi">/pages/VTWdCc7guKu1x0azAizi</a></td></tr><tr><td>Processing and energy use</td><td><a href="/files/xqDoBuMbX7fcBqJ8AanC">/files/xqDoBuMbX7fcBqJ8AanC</a></td><td><a href="/pages/BTxxPIM3a4Nai1Wkwu2Y">/pages/BTxxPIM3a4Nai1Wkwu2Y</a></td></tr><tr><td>Infrastructure and machinery</td><td><a href="/files/gE6Zo8o6awA0p9LnSTnF">/files/gE6Zo8o6awA0p9LnSTnF</a></td><td><a href="/pages/IwqpSqlee22qTIPti3Sl">/pages/IwqpSqlee22qTIPti3Sl</a></td></tr><tr><td>Energy co-products</td><td><a href="/files/CxuE4U5JkYE63biLhW6k">/files/CxuE4U5JkYE63biLhW6k</a></td><td><a href="/pages/5o87C1B9WEcsBRQuyYwi">/pages/5o87C1B9WEcsBRQuyYwi</a></td></tr></tbody></table>


# Rainbow Standard Rules

| **Document name** | Rainbow Standard Rules |
| ----------------- | ---------------------- |
| **Document type** | Standard document      |
| **Version**       | 7.2                    |
| **Release date**  | July 2nd, 2026         |
| **Status**        | In use                 |

## **Purpose of this document**

This document outlines the objectives of the Rainbow Standard and sets the general requirement for Project Developers for registering and operating Rainbow projects and issuing Rainbow Carbon Credits (RCC).

It should be used together with the latest versions of the [Rainbow Procedures Manual](/rainbow-standard-documents/procedures-manual), [Methodologies](/rainbow-standard-documents/methodologies), and all other documentation found on this site.

In all Rainbow documentation the following terms are to be interpreted as:

* **Shall** and **must**: a requirement
* **Should**: a recommendation
* **May**: an option, permissible
* **Is** and **will**: in the context of Rainbow, standard operational procedures

{% content-ref url="/pages/D1bECpowUAiJorSGzbQY" %}
[Glossary](/glossary)
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# Overview of Rainbow

## Standard scope

Rainbow supports projects globally that **remove or avoid greenhouse gas (GHG) emissions**. The Standard issues both removal and avoidance carbon credits.

To be certified by Rainbow and to issue credits, all projects must be eligible under a Rainbow methodology. Each Rainbow methodology defines the applicable technologies and sets out the high-level eligibility criteria that projects must meet. All currently available methodologies are detailed in the [Methodologies ](/rainbow-standard-documents/methodologies)section.

Compliance with a methodology is determined on a per-project basis. **Every project seeking certification under the Rainbow Standard shall be evaluated individually** and independently audited against the Standard’s [Principles and requirements](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements), and those of the relevant methodology. All projects must be certified with a [Rainbow Methodology](/rainbow-standard-documents/methodologies).

Project activities must avoid locking in harmful technologies and must align with the host country’s national climate goals and net-zero commitments.

All Rainbow Carbon Credits are issued ex post, after the verification process.

Two types of RCCs are issued by Rainbow: **removal RCCs** and **avoidance RCCs**. Both types are measured by calculating the difference in GHG emissions and removals of the project scenario compared to the baseline scenario, following the approach outlined in ISO 14064-2:2019. See details in the [GHG Quantification](/rainbow-standard-documents/rainbow-standard-rules/ghg-quantification) section.

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><p><strong>Removal Rainbow Carbon Credits</strong> come from projects that physically remove carbon (present in short-lifetime biomass or in the atmosphere) and convert it into a long-term chemical or biological stable compound (i.e. high resistance to degradation process when placed in the environment).</p><p>Removal RCCs represent one tonne of carbon dioxide equivalent captured and stored: 1 removal RCC = 1 <a data-footnote-ref href="#user-content-fn-1">t CO2eq</a>.</p></td></tr><tr><td><strong>Avoidance Rainbow Carbon Credits</strong> represent avoided GHGs that would have been emitted without the project’s intervention. They substitute products or services with lower-emitting alternatives.<br><br>Avoidance RCCs represent one avoided tonne of carbon dioxide equivalent: 1 avoidance RCC = 1 <a data-footnote-ref href="#user-content-fn-1">t CO2eq</a>.</td></tr></tbody></table>

## Organization <a href="#id-1fob9te" id="id-1fob9te"></a>

### Presentation of Rainbow <a href="#id-1fob9te" id="id-1fob9te"></a>

Rainbow is the registered trademark of the carbon crediting standard and platform operated by the French company Riverse SAS (SIREN: 908 082 332), headquartered at 28 Avenue des Pépinières, 94260 Fresnes, France. Throughout this documentation, “Rainbow” refers to the programs, platforms, and operations developed and managed by Riverse SAS under this trademark.

As a mission-driven company (“société à mission”), Rainbow is committed to creating measurable environmental and social impact through its activities, conducted with professionalism and in the collective interest. This commitment is formalized in accordance with Articles L. 210-10 and 1835 of the French Commercial Code, which define the legal framework for companies integrating a social or environmental mission into their corporate purpose.

Rainbow’s mission is to:

* Quantify, verify, and guarantee the quality of avoided or removed CO₂ emissions through robust methodologies and processes aligned with international best practices;
* Maximize the financial benefit delivered to project developers by ensuring a fair distribution of value from carbon credit sales;
* Build a diverse and inclusive team, fostering equality of opportunity and representation to enable a fair, respectful, and innovative work environment.

This mission underpins all aspects of Rainbow’s certification, governance, and platform operations.

### Standard and tech platform <a href="#jd4z557gorzj" id="jd4z557gorzj"></a>

Rainbow operates two interlinked components:

* **Rainbow Standard**: A carbon crediting program focused on engineered carbon avoidance and removal projects. The Standard sets transparent, science-based requirements to ensure the environmental integrity of each Rainbow Carbon Credit (RCC).
* **Rainbow Technology Platform**: The infrastructure that supports the implementation of the Standard, consisting of:
  * Rainbow Registry: A public ledger that ensures traceability and transparency of Rainbow Carbon Credits from issuance to retirement, preventing double counting and aligning with integrity standards.
  * Certification Platform: A digital interface that streamlines the certification process by supporting project developers and validation bodies with tools for impact assessment, documentation, and audit facilitation.

Both components are managed by the Rainbow Executive Team and supported by Rainbow’s internal teams.

Overview of the Rainbow organization:

<figure><img src="/files/2FP1fS1AgrwwdCsQKMoD" alt=""><figcaption></figcaption></figure>

### Governance and teams <a href="#id-3znysh7" id="id-3znysh7"></a>

Rainbow’s governance structure ensures transparency, accountability, and independence in the development and operation of the Standard.

<table><thead><tr><th width="213">Entity</th><th>Role</th></tr></thead><tbody><tr><td><strong>Governing Board</strong></td><td>The board of directors of Rainbow, responsible for fiduciary oversight and strategic direction. It ensures the organization’s long-term sustainability.</td></tr><tr><td><strong>Standard Advisory Board (SAB)</strong></td><td>An independent body in charge of validating or vetoing updates to the Standard Rules, Methodologies, and Procedures. It ensures alignment with Rainbow’s mission and scientific integrity.</td></tr><tr><td><strong>Expert Community</strong></td><td>A consultative body composed of independent sectoral experts. It provides technical input and guidance on methodological, standard-level, or project-related matters.</td></tr></tbody></table>

Rainbow’s work is executed by cross-functional teams with clear responsibilities:

<table><thead><tr><th width="218">Team</th><th>Function</th></tr></thead><tbody><tr><td><strong>Executive Team</strong></td><td>Manages Rainbow’s day-to-day operations and strategic execution.</td></tr><tr><td><strong>Secretariat</strong></td><td>Compiles and synthesizes feedback and updates on standard documents, and conveys these to the Standard Advisory Board for deliberation and approval.</td></tr><tr><td><strong>Science Team</strong></td><td>Develops Rainbow methodologies, GHG quantification models, and contributes to the continuous alignment of the Standard with scientific and integrity criteria.</td></tr><tr><td><strong>Certification Operations Team</strong></td><td>Manages project interactions, supports validation and verification processes, and conducts technical reviews of project documentation.</td></tr><tr><td><strong>Product &#x26; Engineering Team</strong></td><td>Develops and maintains the Rainbow Registry and Certification Platform, ensuring secure, user-friendly, and interoperable systems.</td></tr><tr><td><strong>Partnerships Team</strong></td><td>Manages ecosystem relations, stakeholder engagement, and external collaboration efforts.</td></tr></tbody></table>

See the [Governance Framework](/other/governance-and-integrity/governance-framework) section for more details.

### Conflict of interest and grievance mechanisms <a href="#qpxbawghsp32" id="qpxbawghsp32"></a>

All participants in the Rainbow ecosystem are required to adhere to Rainbow’s[ Conflict of Interest Policy](/other/governance-and-integrity/conflict-of-interest-policy), which outlines how actual or potential conflicts are identified, managed, and resolved.

Key participants subject to this policy include:

* Members of the Governing Board
* Members of the Standard Advisory Board and Expert Community
* Rainbow team members involved in standard setting, methodology development, certification operations, or registry functions
* Accredited Validation and Verification Bodies (VVBs)
* Project Developers and other contractors involved in certification procedures or registry operations

Rainbow’s [Complaints and Appeals Policy](/other/governance-and-integrity/complaints-and-appeals-policy) provides a formal mechanism for all stakeholders to raise issues, submit appeals, or report misconduct.

### Rainbow Registry <a href="#x8ancywlv64z" id="x8ancywlv64z"></a>

The Rainbow Registry, accessible at [registry.rainbowstandard.io](https://registry.rainbowstandard.io), is a public platform that provides full transparency over the lifecycle of Rainbow Carbon Credits, including:

* Project information, validation/verification reports, and impact assessments
* Issuance, transfer, and retirement data for all RCCs
* Unique serial numbers encoding key information (e.g., project ID, credit type, vintage, geography)
* Current status of each unit (issued, verified, retired, or canceled)

The registry adheres to stringent information security and transparency standards to ensure credibility, traceability, and integrity.

More details about the registry content are provided in the [Registry](/rainbow-standard-documents/procedures-manual/registry-requirements) section of the Procedures Manual.

[^1]: *Carbon dioxide equivalent (CO*$$\_2$$*eq): A measure that normalizes all types of GHG emissions to a common unit. To calculate the CO2eq for a given activity, measures are made using the global warming potential (GWP) at 100 years, which are provided in the IPCC AR6 from 2021. The GWP of a gas represents the relative effect it has on global warming, compared to CO2. For example, the GWP of methane (CH4) over a 100-year time horizon is 27-30, because its contribution to global warming is 27-30 times as strong as CO2.*


# Project certification

An overview of the project certification process and project status are provided below. See the [Project Certification](/rainbow-standard-documents/procedures-manual/project-certification-procedure) section in the Procedures Manual for more details.

## Certification steps

<table data-full-width="true"><thead><tr><th width="180">Certification step</th><th>Description</th></tr></thead><tbody><tr><td>Application</td><td><ul><li>Project Developer (PD) submits a Project Application (PA), which is reviewed by the Rainbow team.</li><li>Clarifications may be requested, and a refusal report is issued if the application is rejected. Approved applications proceed to registration.</li></ul></td></tr><tr><td>Registration</td><td><ul><li>PD signs Rainbow Service Agreement, agreeing to the Terms &#x26; Conditions, and completes administrative setup, including Know Your Customer (KYC) requirements.</li><li>Any Registration Partners are formally documented.</li><li>Rainbow performs Double-registration check.</li><li>Project is added on the Rainbow Registry.</li><li>PD submits data and proof to the Certification Platform.</li></ul></td></tr><tr><td>Pre-Validation</td><td><ul><li><p>Project Design Document (PDD) is generated, outlining project operations, GHG quantification, additionality, and Monitoring Plan.</p><ul><li>If the project is not yet operational, the certification process stops here. Only a draft PDD is generated, and made available on the project's registry page. The draft PDD is updated and finalized once the project starts operations.</li></ul></li><li>Certification team reviews the PDD, possibly involving domain experts, and approves it before third-party validation.</li></ul></td></tr><tr><td>Validation</td><td><ul><li>VVB conducts a validation audit to confirm project adherence to Rainbow Standard Rules and chosen methodology, involving the PD and Certification team as needed.</li><li>In parallel, a public comment period is open for 30 days on the Rainbow Registry.</li></ul></td></tr><tr><td>Monitoring and Verification</td><td><ul><li>Key parameters are monitored regularly to track project impact and eligibility.</li><li>PD submits monitored parameters per the Monitoring Plan; prepares a Monitoring Report which subject to the verification audit by the VVB annually (or as per schedule) to verify GHG quantification and RCC issuance.</li></ul></td></tr><tr><td>Compliance and Updates</td><td><ul><li>Projects may have to stay compliant with Rainbow Standard and methodology revisions, depending on the methodology.</li><li>All projects must report major operational changes and updates in the Monitoring Report.</li><li>VVB audits any revisions or changes, ensuring alignment with updated methodologies and standards.</li></ul></td></tr><tr><td>Crediting Period Renewal</td><td><ul><li>After the end of the crediting period, the project may be renewed by undergoing a full revalidation, including a new PDD, validation audit, and stakeholder consultation to continue issuing credits.</li></ul></td></tr></tbody></table>

## Project status on the registry

<table><thead><tr><th width="139">Status</th><th>Definition</th></tr></thead><tbody><tr><td><strong>Pending</strong></td><td><ul><li>The Project Developer has completed the <a href="https://rainbowstandard.io/get-started">Project Application</a> and the project is created in the registry back office.</li><li>The Rainbow team waits for the Project Developer's submission of more complete data to perform the Project Eligibility Assessment.</li><li>Project does not exist on the registry.</li></ul></td></tr><tr><td><strong>Listed</strong></td><td><ul><li>The Rainbow team has completed the Project Eligibility Assessment and approves the project.</li><li>The Project Developer has signed up for registration by signing the <a href="/pages/4zblKwZkVRLgfMUUUhCz">General Terms of Arc</a>, and is submitting full information to comply with Rainbow Standard and methodology requirements.</li><li>A draft PDD may be under preparation, with the aim of gathering 80% of responses and proof.</li><li>The project is now listed on the registry.</li></ul></td></tr><tr><td><strong>Registered</strong></td><td><ul><li>Draft PDD is reviewed by the Rainbow team and and is accessible on the registry.</li><li>A Draft PDD may include but is not limited to the project's estimated RCCs, co-benefits, photos, project description and location.</li></ul></td></tr><tr><td><strong>Public comment period</strong></td><td><ul><li>Third-party validation audit by the VVB is in progress.</li><li>The public comment period facilitated by Rainbow is available from the project's registry page. It shall remain open for at least 30 days.</li></ul></td></tr><tr><td><strong>Validated</strong></td><td><ul><li>The audit statement from the VVB has been shared with Rainbow, checked and uploaded to the registry.</li><li>The project's validation date is displayed on the registry (also referred to as "registration date").</li><li>The PDD is finalized and uploaded.</li><li>Project is eligible to issue credits.</li><li>If the project is already operating, it may undergo validation and verification at the same time, and pass directly to "Credited" status below.</li></ul></td></tr><tr><td><strong>Credited</strong></td><td><ul><li>Same as "Validated", and has completed at least one round of Monitoring and verification.</li><li>A Monitoring Report has been submitted by the Project Developer and been audited by a VVB.</li><li>The project must be operating.</li><li>RCCs are issued and made available on the registry.</li></ul></td></tr><tr><td><strong>Completed</strong></td><td><ul><li>The project has reached the end of its lifetime, is not renewed, and is no longer issuing new RCCs.</li><li>The project remains visible on the registry.</li></ul></td></tr><tr><td><strong>Withdrawn</strong></td><td><ul><li>The project stops certification before reaching "Validated" status.</li><li>Project Developer decides to no longer list the project on the Rainbow registry, the project is no longer visible.</li></ul></td></tr><tr><td><strong>De-registered</strong></td><td><ul><li>The project was validated (reached "Validated" status), and may or may not have been credited, but is no longer active.</li><li>The Project Developer requested deregistration, or the project was automatically deregistered after failing to undergo monitoring and verification within the specified timeframe.</li><li>The project is still visible on the Rainbow registry.</li></ul></td></tr><tr><td><strong>Rejected</strong></td><td><ul><li>Rainbow or the VVB decides to not certify the project, prior to validation (reaching "Validated" status).</li><li>The project is not visible on the Rainbow registry.</li></ul></td></tr><tr><td><strong>Suspended</strong></td><td><ul><li>A major non-conformity has been identified or the Project Developer was found responsible for an erroneous issuance</li><li>The project is still visible on the Rainbow registry.</li></ul></td></tr></tbody></table>


# Project and baseline scope

## Project scope

Project developers must define the scope of the project, i.e. the mitigation activities that are under consideration for RCC issuance. The scope specifies the **geographic, temporal (i.e. project start date), site, and operation limits** of the project. Only activities that are [additional](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#additionality) shall be considered in the project scope.

The **project start date** is when the mitigation activity within the project scope first begins. This date shall fall within three years of the [**project’s registration date**](#user-content-fn-1)[^1], unless the project was previously registered under a different standard/program. See the [Project timeline](/rainbow-standard-documents/procedures-manual/project-certification-procedure#timeline) section of the Procedures Manual for more details.&#x20;

The **crediting period** is the duration of project mitigation activities that are eligible for credit issuance under the Rainbow Standard. The maximum duration of the crediting period shall be defined by the methodology, and shall be&#x20;

* short enough to allow for a progressive increase in ambition over time, and
* appropriate to the type of mitigation activity, based on, e.g., the rate of technological change, lifetime of equipment used in the baseline scenario, or changes in the regulatory environment.

Upon reaching the maximum duration, a project's crediting period may be renewed, according to the [Crediting Period Renewal](/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal) procedure.

* If the project is already registered with Rainbow as of the project start date, the crediting period start date shall start when the mitigation activities begin.
* If the project is already underway upon registration with Rainbow, the crediting period may start up to 18 months prior to its registration date with Rainbow.

## Baseline scope

{% hint style="info" %}
The baseline scenario is the set of business-as-usual (BAU) activities and their resulting GHG emissions that would have occurred in the absence of the project mitigation activity. For the purpose of issuing carbon credits, baselines should conservatively be set to below-BAU emissions. The baseline scenario is used in project crediting to:

* **determine the project scope** (i.e. the project includes only activities that are additional to the baseline), and
* **quantify the baseline GHG emissions and removals**, to compare to the project emissions and removal, to quantify the number of credits to issue.
  {% endhint %}

### General baseline setting requirements

Baselines shall be set according to the following principles.

* **Realistic**: The baseline shall include the likely, appropriate, technically-plausible scenario and/or product that is substituted by the project mitigation activity.
  * For projects that manufacture a product, and claim RCCs from their product's substitution of a baseline product, Project Developers shall prove that their product has **similar performance metrics to the baseline product and delivers equivalent functions**. Project Developers shall identify and quantify performance metrics to compare between the baseline and the project scenario.
* **Defensible:** The method for setting the baseline shall be backed up by verifiable, reputable proof. Where specific proof is not available, and assumptions are made, these shall be transparently ds
* **Conservative:** The baseline shall be set in a conservative way that does not lead to overestimating project benefits and overissuing RCCs. In cases of uncertainty, the modeling approach, assumptions, and data sources for the baseline scenario should adopt conservative estimates.
* **Transparent**: The baseline, the method for setting baselines, and/or their underlying assumptions shall be transparently described, with proof and justification, in the methodology and PDD. The choice of the baseline scenario is approved by the Rainbow team, and audited by the third-party VVB in the validation audit and the ongoing verification audits.
* **Consistent:** The quantification approach for the baseline scenario shall be comparable to the project scenario. Methodologies shall establish baseline scenarios, or baselining setting methodologies, that ensure consistent results across similar circumstances.

### Approach to setting the baseline

Methodologies shall provide specific instructions for setting baselines, including defining whether an activity-specific or a standardized baseline shall be used.

* A **standardized baseline** may be defined in a methodology if the BAU conditions are highly certain and unchanging between project contexts.
* If this is not possible due to lacking data or heterogeneous conditions, an **activity-specific baseline** based on the operator’s individual performance shall be used.
* Methodologies may outline a **mixed approach** based on the:
  * geography of the project: standardized baselines may be defined for only specific geographies, and activity-specific baselines used elsewhere
  * component of the baseline: e.g. the emission factor of a product in the baseline may be standardized at the methodology level, but the amount of the product substituted by the project is activity-specific.

Where a standardized baseline cannot be identified, an activity-specific baseline may be set according to:

* **Best available technology (BAT)**: the practice or technology that results in the lowest baseline emissions or highest baseline removals and is also a reasonable substitute, meaning it is economically and technically feasible, and geographically available.
* **Historical or current market conditions**: if the project mitigation activity replaces specific, known products or practices, that were used before the project implementation and could continue to be used, the baseline may be set as the specific replaced product or practice.

The selected baseline scenario shall be highly **representative of the standard performance of comparable practices and processes** in similar social, economic, environmental, technological and regulatory circumstances. It shall take into account the geographical context, including local environmental and market conditions. After identifying the representative baseline scenario, conservative choices shall be made to **adjust this baseline downward and result in below-BAU baseline emissions**.

The **degree of conservativeness in this choice shall be based on the level of the overall uncertainty**, taking into account the choice of assumptions, models, parameters, data sources, measurements methods and other factors (e.g., assuming a better-performing baseline in case of higher uncertainties).

The choice of a baseline shall **account for any regulatory conditions** that support a given baseline technology or scenario. Any government policies and legal requirements that lower baseline emissions shall be explicitly considered and accounted for in the establishment of the baseline scenario (e.g. feed-in tariffs for renewable energy, minimum product efficiency standards, carbon taxes...). If a technology or practice is required by regulations, and these regulations are enforced, then this shall be reflected in the baseline (see also the [Additionality](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#additionality) section). This ensures that the project is only credited for emission avoidance and removals that are additional to what would have occurred anyway.

The choice of a baseline scenario shall address any **rebound effects**. Any direct, quantifiable rebound effects shall be explicitly included in the GHG quantification.

If the project activity is multifunctional, the baseline scenario shall cover all functions of the project, and different approaches to baseline setting may be used for the different project activities.

When the average market solution is represented by a market mix of solutions, the market mix shall include the portion of the project mitigation activity that is already used in the market.

### Updating the baseline

Standardized baselines shall be updated in the methodology at a minimum every 5 years. Activity-specific baselines shall be updated for a given project at a minimum frequency of each crediting period renewal.

The chosen baseline for a project may be revised more frequently due to changing baseline conditions, such as regulatory or market changes.

A project's updated baseline shall be audited by the VVB upon the next verification.

[^1]: the date the Project Developer signs the Service Agreement, and the project is created on the registry


# Principles & requirements

All projects must meet the Principles & requirements described below. Their compliance with the following requirements shall be audited by a VVB and checked by the Rainbow team. Detailed instructions and examples are presented in [Methodologies](/rainbow-standard-documents/methodologies).

Project Developers that seek to issue credits eligible as emissions units for the Carbon Offsetting and Reduction Scheme for International Aviation ([CORSIA](https://www.icao.int/CORSIA)) or [Article 6.2](https://unfccc.int/process-and-meetings/the-paris-agreement/article6) of the [Paris Agreement](#user-content-fn-1)[^1] must also comply with Rainbow's [CORSIA and Article 6](/rainbow-standard-documents/procedures-manual/corsia-and-article-6)procedures.

Project Developers that seek to issue credits that comply with the EU [Carbon Removals and Carbon Farming (CRCF) Regulation](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202403012) (EU/2024/3012) must also comply with Rainbow's [CRCF Requirements](/rainbow-standard-documents/procedures-manual/crcf-requirements).

***

## Additionality

{% hint style="info" %}
The Rainbow Standard certifies projects that would not have occurred without revenue from carbon finance. This principle ensures that **carbon financing spurs additional climate action**, rather than subsidizing actions that would have happened anyway.
{% endhint %}

All projects shall prove their additionality by meeting the requirements of **at least three additionality tests:**&#x20;

1. regulatory surplus analysis,&#x20;
2. common practice analysis, and&#x20;
3. either investment or barrier analysis.

Project Developers shall fill in the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template) to demonstrate their additionality, using project-specific justifications and verifiable evidence. Methodologies may provide further instructions or requirements for demonstrating additionality.

{% hint style="info" %}
Note that RCCs are only issued for GHG reductions and/or removals that are additional to the baseline environmental conditions. This is sometimes referred to as **environmental or carbon additionality**. This is addressed in the [baseline scope](/rainbow-standard-documents/rainbow-standard-rules/project-and-baseline-scope#baseline-scope) requirements.
{% endhint %}

### Regulatory surplus analysis

Mitigation activities must go **beyond what is required by regulations**. Project Developers shall prove the following:

* There is no enforced law, regulation, statute, legal ruling or other regulatory framework that makes the implementation of the project or specific mitigation activity mandatory.
* If there is an enforced regulation related to the project, the project results in greater GHG emission avoidance/removals than what is required by regulations. In this case, only the project activities that surpass the mandated amount are eligible for RCCs.
* If regulations promote or subsidize technologies, set targets for increased adoption of a technology, or otherwise support the technology, the resulting lower baseline scenario emissions shall be explicitly considered and accounted for in the establishment of the [baseline scenario](/rainbow-standard-documents/rainbow-standard-rules/project-and-baseline-scope#baseline-scope).

Project Developers shall describe the current and upcoming regulatory environment related to their mitigation activity in the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template).

Upcoming regulations include those that are confirmed and set to go into effect within 5 years.

### Common practice analysis

Mitigation activities shall not already be common practice. Project Developers shall demonstrate that the mitigation activity is not common practice using the **Market prevalence rate** or **Small number of peers** approaches detailed below.

Methodologies may specify the required method, indicator, or further conditions for the common practice analysis. In the absence of methodology specific requirements, Project Developers may use any of the methods below, provided it is relevant for their application and conservatively applied.

All common practice analyses shall:&#x20;

* Use the most recent available data.
* Define a geographic scope that is relevant and conservative.
* Document all assumptions and data sources transparently.

#### Market prevalence rate

Calculate the portion of the current or potential market that the project activity and other actors carrying out the same activity have collectively reached. Two variants are available:

* **Total market prevalence rate**: the share of the current total market for the same function, service, or output that is met by the mitigation activity.
* **Target market prevalence rate**: the share of the realistic potential market for the mitigation activity that the activity already makes up.

Steps:

1. **Define the mitigation activity**, its main function or output, and the geographic scope of the analysis.
2. **Define the denominator**:
   * For total market prevalence: the current total market for activities serving the same function or producing the same output, at a comparable level of service.
   * For target market prevalence: the realistic addressable market for the mitigation activity, taking into account technical, economic, geographic, regulatory, and behavioral constraints on uptake.
3. **Define the numerator** using the same units and scope as the denominator: the current deployment of the mitigation activity, including uptake of the same activity type by other actors in the geographic area. Document the criteria used to identify the same activity type (e.g. technology, feedstock, end use).
4. **Calculate the prevalence rate** as numerator divided by denominator.

Rules common to both variants:

* The indicator may be a count (sites, facilities, companies, units sold) or a capacity, output, or performance metric.
* The analysis may consider current cumulative stock or recent uptake over a defined period (e.g. uptake over the last three years).
* Exclude from both numerator and denominator any activities already registered for carbon credit issuance under Rainbow or another carbon standard.
* A **total market prevalence rate below 20% demonstrates that the activity is not common practice**. Methodologies may set lower rates.&#x20;

{% hint style="info" %}
**Examples: total market prevalence rate**

Denominator (current total market for the same function or output):

* Electronic device refurbishing: total devices of the relevant category sold annually in the area.
* Biochar production: total annual biomass residues managed by any means in the area (tonnes biomass).
* Enhanced rock weathering: total annual farmland area receiving any soil amendment (hectares).

Numerator (mitigation activity and other actors doing the same):

* Electronic device refurbishing: refurbished devices of the relevant category sold annually.
* Biochar production: biomass residues converted to biochar via pyrolysis annually (tonnes biomass).
* Enhanced rock weathering: farmland area receiving silicate rock dust application annually (hectares).
  {% endhint %}

{% hint style="info" %}
**Examples: target market prevalence rate**

Denominator (realistic addressable market for the activity):

* Biobased construction: new-build and major-retrofit floor area where bio-based insulation is technically and economically substitutable for conventional insulation
* Biochar production: annual biomass residues technically and economically available for pyrolysis, given feedstock logistics and end-use demand (tonnes biomass).
* Enhanced rock weathering: farmland area whose soil chemistry, crop types, and farm economics make ERW feasible (hectares).

Numerator (current deployment of the activity):

* Biobased construction: Actual m<sup>2</sup> of bio-based insulation installed annually in the defined addressable market.
* Biochar production: actual annual biochar production today (tonnes biomass converted).
* Enhanced rock weathering: farmland area under ERW today (hectares).
  {% endhint %}

#### Small number of peers

Where the mitigation activity is early in deployment and total or target market data are unreliable or unavailable, common practice may be assessed by counting comparable peer activities in the geographic area. **If 3 or fewer comparable peer activities are identified, the mitigation activity is considered not common practice**.

A comparable peer activity is one that:

* Is located in the geographic area of the analysis
* Produces the same output or delivers the same function as the mitigation activity
* Began commercial operation before the Project start date.

The definition of "the same" output and function used to identify peers shall be conservative, and broad enough that the assessment reflects the genuine prevalence of the activity type, not a narrow technical subset. Project Developers shall document and justify the level of specificity used. Distinctions that may be considered material include but are not limited to:

* Energy source or fuel used
* Feedstock characteristics
* Market and policy conditions at the time of the investment decision (e.g. subsidies, regulatory frameworks, technology access)
* Level of investment cost per unit of capacity or output.

### Investment analysis

Project Developers using investment analysis shall prove that **revenue from carbon finance is necessary to make the project investment financially viable**.

Project Developers shall prove that revenue from carbon finance is necessary for investments to **launch or expand the project**. For investments in expansion, only the additional avoided or removed carbon enabled by the expansion shall be eligible for Rainbow Carbon Credits.

Investment analysis shall be done using either:

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><p><strong>Benchmark analysis:</strong> Compute a financial indicator for the project against a benchmark hurdle rate, with and without carbon finance. Demonstrate that:</p><ul><li>the mitigation activity would not meet the required financial benchmark without carbon credit revenues, and</li><li>carbon finance can raise the economic performance at or above the required financial benchmark, and</li><li>economic performance of the mitigation activity increases decisively through carbon finance.</li></ul><p>Choose a financial benchmark that is consistent with the weighted average cost of capital (or the cost of equity, as applicable) that is commonly applicable to the country, sector and type of mitigation activity.</p></td></tr><tr><td><p><strong>Comparison analysis:</strong> Compute a financial indicator for the project and for each alternative scenario. Demonstrate that: </p><ul><li>the mitigation activity would not be the economically most attractive scenario in absence of carbon credits, and </li><li>competitiveness with alternative scenarios increases decisively through carbon finance.</li></ul><p>Ensure the alternative scenarios considered are mutually exclusive and provide the same type of products or service levels as the mitigation activity, where applicable</p></td></tr></tbody></table>

Project Developers shall conduct one of the above analyses and provide the accompanying spreadsheet and calculations, meeting the following requirements:

* Include all of the project's funding sources, including government subsidies.
* Provide project costs and revenue with actual financial results as much as possible, plus well documented, reasonable and conservative assumptions where necessary.
* Provide the fraction of total project expected revenue from carbon finance (for informational purposes only).
* Perform a sensitivity analysis, by increasing and decreasing the value of key input data points by 20%, and recalculating the financial indicator. Confirm that the original conclusion holds across all scenarios, and the project remains additional under each tested realistic condition.
* Document and explain the assumptions and conclusions underpinning the analysis.
* Demonstrate that the assumptions, data and conclusions in the investment analysis or business plan are consistent with information presented to the company’s decision-making management and investors/lenders.
* Use parameters and assumptions that are internally consistent with one another (e.g., cash flows  expressed in either real or nominal terms consistently), and perform calculations that are consistent with the indicator used (e.g., project IRR or equity IRR)
* For retrofit or expansion projects, prove that revenue from the existing operations would not have been sufficient to finance the project.

Methodologies may provide further requirements on which financial indicators shall be used. If Project Developers use either the project’s **Internal Rate of Return (IRR) or Net Present Value (NPV), with and without carbon finance** as the basis for investment analysis, the calculations shall meet the following requirements:

* Calculations shall reflect the period of expected operation of the project activity, or shall be a period of at least ten years, and not the crediting period.
* Fair value of project activity assets at the end of the assessment period should be included as a cash inflow.
* Depreciation and other non-cash items should be added back to net profits for calculating financial indicators.
* Cost of financing expenditures should not be included in calculations.
* In equity-based calculations, only the portion of investment costs financed by equity shall be considered as the net cash outflow.
* Appropriate benchmarks (for IRR) or discount rates (for NPV) shall be selected and justified based on the type of calculation performed.
* Market return values shall be selected and justified for the calculation of equity cost.

### Barrier analysis

Project Developers using barrier analysis shall prove that **barriers prevent the mitigation activity from continuing or expanding**, and that revenue from carbon finance is necessary to allow projects to overcome these barriers. Barriers shall be categorized as either:

* **Financial** (e.g. lack of access to loans or other forms of financing)
* **Institutional** (e.g. the investor not being the beneficiary of cost savings associated with the investment)
* **Information** (e.g. households not aware of life-cycle costs of efficient appliances)

Project Developers shall identify, describe and quantify the barrier, with verifiable proof. Proof may include independent studies, publicly available surveys, relevant market data, or data from national or international statistics. Project Developers shall demonstrate that **revenue from carbon finance is decisive in overcoming this barrier**, including justification that:

* the magnitude of revenue from carbon finance is similar to the amount of funding needed to overcome the barrier, and
* the project could not have provided the funding itself, providing financial results and considering all project funding sources, and
* all proof are interpreted and applied conservatively,&#x20;
* in case of uncertainty in the level of the identified barrier, the proof and indicators shall be interpreted to assure that it is very unlikely that the effect of the barrier is overestimated.&#x20;

Project Developers shall demonstrate that at least one alternative to the project activity does not face significant barriers, including the barriers faced by the project.

Note that for **overcoming barriers to expansion**, only the additional avoided or removed carbon enabled by the expansion shall be eligible for Rainbow Carbon Credits.

***

## GHG quantification

GHG avoidance and removals shall be rigorously and conservatively quantified. Further details are provided in the [dedicated section](/rainbow-standard-documents/rainbow-standard-rules/ghg-quantification).

***

## Durability

{% hint style="info" %}
Durability requirements ensure that GHG avoidance and/or removals persist through the entire duration of the commitment period.
{% endhint %}

Methodologies shall establish all of the following:

* durability for removals, in years
* requirements for proving that a project's mitigation activity will meet or surpass the durability threshold
* minimum buffer pool contributions
* reversal risk assessment requirements, detailed below

Project Developers shall prove that their GHG emission avoidance or removals meet the durability threshold established in the methodology. All projects issuing removal RCCs are subject to the [Reversal risk assessment](#reversal-risk-assessment) requirements outlined below.

To prove durability, Project Developers shall meet the following requirements, listed here and detailed below:

* **Risk assessment**: evaluate the technology-specific risks of carbon sequestration reversal
* **Mitigate:** intervene in the project design or processes to reduce risk of reversal; establish buffer pool contribution or reversal insurance
* **Monitor:** include remaining, unmitigated reversal risks in the project's Monitoring Plan
* **Compensate:** follow detailed procedure to report any reversals and replace with equivalent removal RCCs

### Reversal risk assessment

{% hint style="info" %}
Carbon removals are not permanent if the carbon is re-emitted (i.e. the removal is reversed). A **GHG reversal** occurs when previously sequestered carbon is re-released into the atmosphere, resulting in a partial or complete loss of stored carbon of at least 1 tCO<sub>2</sub>eq. Reversals can result from natural disturbances or project mismanagement, and be [avoidable ](#user-content-fn-2)[^2]or unavoidable[^3].
{% endhint %}

The following types of projects/reversals can be considered:

{% tabs %}
{% tab title="Technological removals" %}
Technological, non-nature based removals based on chemically bound carbon are **not likely to have material reversal risks**, upon meeting the durability requirements set out in the methodology to issue credits. Such removals are covered by several Rainbow methodologies, and may include but are not limited to:

* BiCRS: Biomass carbon removal and storage (e.g., biochar)
* BioCCS and DACCS (biogenic carbon or direct air carbon capture and storage)
* Carbon storage in long-lived products
* Accelerated mineralization
* Enhanced rock weathering

Such project activities shall follow the methodology- and project-level requirements below.
{% endtab %}

{% tab title="Nature based removals and avoidance" %}
This includes activities such as:

* conservation and avoided conversion (e.g., grassland/rangeland management, avoided deforestation)
* agriculture soil carbon sequestration
* forestry sequestration (improved forest management, afforestation/reforestation, agroforestry)
* wetland and marine ecosystem restoration/management (including seagrasses, saltmarshes, mangroves, peatlands)

Such activity types are **not currently covered by Rainbow**. If Rainbow develops methodologies for these project types, Rainbow will also develop relevant requirements and procedures for assessment of GHG reversal risk, contribution to buffer pool and any other relevant requirements and procedures.
{% endtab %}

{% tab title="Avoidance" %}
Durability and reversal risks are not evaluated for avoidance methodologies currently offered by Rainbow, because they are considered to have little to no material reversal risks (e.g. [Battery second life](/methodologies/battery-second-life), [Biogas from anaerobic digestion](/methodologies/biogas-from-anaerobic-digestion)...).
{% endtab %}
{% endtabs %}

By default, at least 2% of all verified removal RCCs shall be transferred to the [buffer pool](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits#buffer-pool) upon issuance. Methodologies may define higher default minimum buffer pool contributions.

#### Methodology-level reversal risk assessment

Methodologies shall assess the risk of reversals for the technology type. Where material risk is identified, they shall establish **project design requirements that mitigate reversal risk**, which may render the reversal risk negligible or lowered.

If material reversal risks remain, which cannot be mitigated by project design requirements, methodologies shall establish:

* procedures to **assess GHG reversal risks at the project level**, including the methodology reversal risk assessment template
* requirements for projects to **mitigate and compensate** for reversal risks, such as increased minimum contributions to the [buffer pool](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits#buffer-pool) and/or reversal risk insurance.

#### Project-level reversal risk assessment

All projects eligible for removal RCCs under methodologies that have identified **outstanding material reversal risks must assess reversal risks** during the validation step. An assessment procedure and a minimum list of reversal risks to assess shall be provided in each methodology, tailored to the specific technology. Further details on completing the assessment are in the [Reversal risk assessment instructions](#reversal-risk-assessment-instructions) section below.

Where a material risk of reversal is identified in the project reversal risk assessment step, Project Developers shall address those risks by creating a **risk mitigation** plan. The risk mitigation plan shall account for both the technology type and the project design, and outline how the project will **prevent, monitor, report and compensate** identified reversal risks.

<details>

<summary><strong>Reversal risk assessment instructions</strong></summary>

Risks are identified in **Risk Assessment Templates**, which are provided in each methodology and tailored to the given project type. These templates guide Project Developers in evaluating the likelihood and severity of each risk type. Project Developers must assess the likelihood and severity scores of each risk for their specific project at validation.

The **Reversal Risk Assessment** template covers carbon reversal risks, and responds to the Durability criteria. This is evaluated to identify and mitigate potential reversal risks. Reversal risks may include social, economic, natural, and delivery risks.

Each identified material risk (defined as issues with a risk score of moderate or higher) is subject to creation of a risk mitigation plan, developed by the Project Developer, that details the long-term strategies and investments for **preventing, monitoring, reporting and compensating** carbon removal reversal and/or environmental and social damages.

Note that some risks shall be monitored and reported regardless of the risk score. This are defined at the methodology level, and include technology-specific risks that are particularly sensitive, likely, or variable, and/or subject to project design requirements.

</details>

Any remaining reversal risks that could not be fully prevented and deemed negligible by risk mitigation shall be **monitored regularly** and added to the project's Monitoring Plan. Methodologies shall define whether reversal monitoring requirements are set at the methodology level, and/or whether they shall be assessed at the project level. Reversal monitoring may continue after the project's crediting period ends, until a negligible risk of reversal has been proven, using models or other scientifically-backed methods.

If a reversal is detected during monitoring, the credit **cancelation and compensation** procedure described in the [Rainbow Carbon Credits](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits#cancelation) section of the Procedures Manual shall be applied.

Projects shall follow the applicable methodology's requirements regarding minimum contributions to the buffer pool and/or reversal risk insurance.

***

## Double counting

{% hint style="info" %}
Double counting includes double issuance, double use and double claiming, defined as follows:

* **Double issuance**:
  * On multiple registries: simultaneously issuing carbon credits for the same mitigation activity, in the same crediting period, under the Rainbow Standard and a different standard.
  * Along the value chain: issuing multiple carbon credits for the same mitigation activity by multiple actors along the supply chain. RCCs are issued to projects that are fundamental in the value chain, and are fully allocated to the project.
* **Double use**: retiring a credit more than once.
* **Double claiming**: both issuing RCCs and claiming the environmental benefit of the mitigation activity under other environmental schemes.
  {% endhint %}

Rainbow Carbon Credits shall be used, issued and claimed only once. Double counting is prevented under the Rainbow Standard via the requirements listed in sections below.

Project Developers shall outline the risks of double counting for their mitigation activity, and the VVB shall verify the risks and accordingly conduct cross checks across relevant registries and platforms.&#x20;

Any instances of double counting shall result in the project being suspended and undergoing a review by Rainbow, which may result in deregsitration and/or cancelation of credits.

### Double issuance

Project Developers shall not issue carbon credits for their mitigation activity for the same monitoring period, under a different project at another crediting program or Rainbow.

If a project is registered with Rainbow to issue RCCs, and also registered (or seeking registration) with another crediting program, the Project Developer shall disclose this with Rainbow, including the following details:

* Complete name of the project
* Date of the registration of the project
* Link to the publicly available registry of the crediting program
* Vintage and serial number of the credits issued with the crediting program
* The geographic and operational boundaries of the project scope registered under each program.&#x20;

Project Developers shall ensure that specified upstream and downstream actors in the supply chain have not and will not issue carbon credits for their role in the mitigation activity. Specific requirements are outlined in methodologies.

Double issuance is prevented by the signing of the [Rainbow MRV & Registry Terms & Conditions](/other/terms-and-contracts/terms-and-conditions-for-project-developers-mrv-+-registry), where all Project Developers agree to follow the Double Counting requirements outlined in the present document.

Rainbow shall perform a [double-registration check](/rainbow-standard-documents/procedures-manual/project-certification-procedure#double-registration-check) before registering any project, to ensure they are not already registered for the same mitigation activity under another crediting standard.

If a project transfers from another crediting program to the Rainbow registry, the monitoring period shall not overlap. The Project Developer shall provide follow the [deregistration](/rainbow-standard-documents/procedures-manual/project-certification-procedure#deregistration) procedure and provide the **deregistration certificate** from the other carbon-crediting program, stating from which date the project's activity is no longer credited under the other carbon-crediting program, and the end date of the last monitoring period.

### Double use

Double use is prevented by the Rainbow Registry, where each project is automatically assigned a unique identification number from issuance to retirement, with project ID, location, and Project Developer name and contact information.

An immutable certificate is generated upon retirement, and all retirement transactions are transparently and publicly available on the registry (see example [here](https://registry.rainbowstandard.io/ledger/transactions/6c891548-31c7-4215-ad52-85ce98036429)). This ensures that all RCC retirements can be uniquely identified and traced back to the project and credit batch. See the Rainbow Carbon Credits [retirement](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits#retirements) section for more details.

### Double claiming

RCCs shall not be claimed by both the entity retiring the carbon credit for the purpose of making a GHG emission offsetting claim, and

* nationally determined contributions (NDCs),
* Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA),
* national climate policies and emissions trading schemes, or
* other GHG-related environmental credits.

See the [Procedures Manual](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits#authorised-uses) for the detailed authorized uses of retired credits.

Project Developers shall prove that credit issuance for their mitigation activity is compatible with a transition to net zero by reference to the net zero objectives of the host country. This includes but is not limited to proving that credit issuance for the given [authorized credit use](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits#authorised-uses) is allowed by the project's host country.

For double claiming between entities retiring carbon credits, and the end-users of products that have been issued carbon credits, guidance from reporting schemes, GHG Protocol, and other accounting mechanisms shall be followed.

Double claiming with NDCs shall be prevented by signed agreements with host countries and confirmation of corresponding adjustments. Such agreements will be made publicly available with the project documentation, and updated as needed.

Double claiming with national climate policies and emissions trading schemes shall be prevented by proof that the mitigation activity is outside the scope of such policies and schemes. If this is not the case, Project Developers must obtain proof of an accounting adjustment or cancellation in the emissions trading scheme.

Double claiming with other GHG-related environmental credit frameworks is not allowed. This is prevented by the signing of the [General Terms of Arc Platform (Certification Platform)](/other/terms-and-contracts/terms-and-conditions-for-project-developers-mrv-+-registry), where all Project Developers agree to follow the requirements outlined in the present document.

For double claiming between entities retiring carbon credits, and the end-users of products that have been issued carbon credits, guidance from reporting schemes, GHG Protocol, and other accounting mechanisms shall be followed.

For purposes of voluntary climate pledges and reporting (e.g. GHG protocol), Project Developers must inform upstream and downstream supply chain entities of claimed project/intervention/insetting emission reductions, report them to Rainbow, document any transfer of emission reduction units, and seek guidance in cases of conflicting claims from reporting bodies like the GHG Protocol.

***

## Environmental and Social Safeguards

{% hint style="info" %}
Climate action should not come at the expense of environmental and social wellbeing, and should do no net harm.
{% endhint %}

Environmental and social safeguards are managed through the following, detailed in sections below:

* **Environmental and social risk assessment**: Project Developers shall evaluate the risk of environmental and social impacts during the validation step using the Environmental and Social Damage evaluation section of Risk Assessment Templates. Identified risks shall be minimized and addressed.
* **Stakeholder consultation**: Project Developers shall conduct a comprehensive and documented stakeholder consultation to provide insights into unintended outcomes, and foster collaboration with local impacted communities.
* **Free prior and informed consent procedure**: for applicable project types, indigenous people/local communities (IPLCs) shall be explicitly consulted, ensuring free, prior and informed consent (FPIC), as part of the stakeholder consultation.
* **Benefit sharing**: projects involving IPLCs shall set up, and demonstrate the execution of, a benefit sharing scheme with IPLCs.

Project activities shall comply with all applicable local, state, national, and international regulations. Project Developers shall provide any relevant documentation (such as permits, licenses, or regulatory applications) obtained at the start of the project, or on an ongoing basis, to demonstrate this compliance. Depending on the methodology used, **additional evidence may be required** to confirm adherence to regulations specific to the project’s technology type.

### Environmental and social risk assessment

Project Developers shall assess material **risks of negative environmental and social impacts** or adverse outcomes that could potentially occur across the entire project scope (e.g., onsite, upstream, and downstream). The minimum list of safeguard principles and their general requirements listed in Table 1 below shall be evaluated for all projects, alongside any technology-specific requirements outlined in an applicable methodology. Risk assessment includes the following steps:

1. Any material negative environmental and/or social impacts or adverse outcomes shall be **clearly documented in the PDD**.
2. Project Developers shall take measures to **minimize and address these impacts** in the project design, and document these mitigation measures in the PDD.
3. Identified impacts and mitigation measures shall also be **included in the Monitoring Plan**, to ensure they are continuously tracked, addressed, and minimized throughout the project lifetime.
4. Monitoring results shall **inform project adaptation strategies** to enhance environmental and social performance over time.

Project Developers shall complete the methodology’s Risk Assessment Template for their project type, evaluating the likelihood and severity of all potential negative impacts or adverse outcomes that could result in violations of safeguard principles or misalignment with their associated requirements. Available risk assessment templates can be found in each methodology and grouped in [this page](/rainbow-standard-documents/procedural-templates/environmental-and-social-risk-assessment-templates).

<details>

<summary><strong>Environmental and social risk assessment</strong></summary>

Risks are identified in **Risk Assessment Templates**, which are provided in each methodology and tailored to the given project type. These templates guide Project Developers in evaluating the likelihood and severity of each risk type at project validation. Project Developers must assess the likelihood and severity scores of each risk for their specific project.

The **Environmental and Social Risk Assessment** template covers risk of environmental and social damages, and responds to the Environmental and Social Do No Harm criteria. This is evaluated to transparently identify environmental and social risks, and determine which risks shall be monitored on an ongoing basis.

Each identified material risk (defined as issues with a risk score of moderate or higher) is subject to creation of a risk mitigation plan, developed by the Project Developer, that details the long-term strategies and investments for **preventing, monitoring, reporting and compensating** carbon removal reversal and/or environmental and social damages.

Note that some risks shall be monitored and reported regardless of the risk score. This are defined at the methodology level, and include technology-specific risks that are particularly sensitive, likely, or variable, and/or subject to project design requirements.

</details>

*Table 1 The minimum list of safeguard principles and their associated requirements, to be evaluated for all projects.*

<table data-full-width="true"><thead><tr><th width="215.930419921875">Safeguard Principle</th><th>Associated Requirements</th></tr></thead><tbody><tr><td>Labor rights and working conditions</td><td><ul><li>provide safe and healthy working conditions for employees</li><li>provide fair treatment of all employees, avoiding discrimination and ensuring equal opportunities</li><li>prohibit the use of forced labor, child labor, or trafficked persons, and protects contracted workers employed by third parties.</li></ul></td></tr><tr><td>Resource efficiency and pollution prevention</td><td><ul><li>minimize pollutant emissions to air</li><li>minimize pollutant discharges to water, noise and vibration</li><li>minimize generation of waste and release of hazardous materials, chemical pesticides and fertilizers</li></ul></td></tr><tr><td>Land acquisition and involuntary resettlement</td><td><ul><li>minimize forced physical and/or economic displacement</li></ul></td></tr><tr><td>Biodiversity conservation and sustainable management of living natural resources</td><td><ul><li>avoid and/or minimizes negative impacts on terrestrial and marine biodiversity and ecosystems</li><li>protect the habitats of rare, threatened, and endangered species, including areas needed for habitat connectivity</li><li>do not convert natural forests, grasslands, wetlands, or high conservation value habitats</li><li>minimize soil degradation and soil erosion</li><li>minimize water consumption and stress in the project</li></ul></td></tr><tr><td>Indigenous Peoples (IPs), Local Communities (LCs), and cultural heritage</td><td><ul><li>recognize, respect and promote the protection of the rights of IPs &#x26; LCs in line with applicable international human rights law, and the <a href="https://www.un.org/development/desa/indigenouspeoples/wp-content/uploads/sites/19/2018/11/UNDRIP_E_web.pdf">UN Declaration on the Rights of Indigenous Peoples</a> and ILO Convention 169 on Indigenous and Tribal Peoples</li><li>identify the rights-holders possibly affected by the mitigation activity (including customary rights of local rights holders);</li><li>when relevant, apply the FPIC principles through the stakeholder consultation process, described below.</li><li>do not force eviction or any physical or economic displacement of IPs &#x26; LCs, including through access restrictions to lands, territories, or resources, unless agreed upon with IPs &#x26; LCs during the FPIC process</li><li>preserve and protect cultural heritage consistent with IPs &#x26; LCs protocols/rules/plans on the management of cultural heritage or UNESCO Cultural Heritage conventions</li></ul></td></tr><tr><td>Respect for human rights, stakeholder engagement</td><td><ul><li>avoid discrimination and respect human rights</li><li>abide by the <a href="https://www.ohchr.org/en/what-are-human-rights/international-bill-human-rights">International Bill of Human Rights</a> and universal instruments ratified by the host country</li><li>take into account and responds to local stakeholders’ views</li></ul></td></tr><tr><td>Gender equality</td><td><ul><li>provide for equal opportunities in the context of gender</li><li>protect against and appropriately responds to violence against women and girls</li><li>provide equal pay for equal work</li></ul></td></tr></tbody></table>

### Stakeholder consultation

Project Developers shall engage with **all relevant local stakeholders** who may be directly or indirectly affected by the project’s design, development, implementation, or operations. The goal is to inform stakeholders of project details, gather feedback, ensure their views are considered, and establish a pathway for communication or grievances throughout the project lifetime.

Project Developers shall thoroughly identify and document all relevant stakeholders. Types of relevant stakeholders vary by project, and may include but are not limited to:

* Local, regional, or national government bodies
* Community members and groups
* Neighboring industrial or commercial sites
* NGOs, CBOs, and other social organizations
* Landowners or land users impacted by the project
* Indigenous peoples (IPLC, if involved, [Free, Prior, and Informed Consent](#free-prior-and-informed-consent) FPIC must be followed)

The stakeholder consultation process shall include a **communication letter sent to all relevant stakeholders and at least one meeting with stakeholders**.

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><p>The <strong>communication letter</strong> may follow the <a href="/pages/PmuSKoit5UvCnkZX4KDM">Rainbow template</a>, shall be sent at least 14 days before the meeting, and shall contain at least the following information:</p><ul><li>A summary of the project and mitigation activity</li><li>Project location and expected start date</li><li>Key anticipated impacts (positive and negative)</li><li>Meeting invitation</li><li>Project Developer contact information and grievance mechanism.</li></ul><p>Language, cultural context, and accessibility must be considered. Where relevant, Project Developers are encouraged to use other appropriate methods of communicating with stakeholders, such as letters, calls, posters, announcements, or local media.</p></td></tr><tr><td><p>The <strong>meeting</strong> must be hosted in a format that is appropriate and accessible to stakeholders. During the meeting:</p><ul><li>Project details and expected carbon revenue must be presented</li><li>A forum must be provided for feedback, concerns, and suggestions</li><li>All comments must be addressed, and responses recorded</li><li>Meeting minutes must document attendance, shared information, feedback, and responses</li><li>The project’s grievance mechanism must be explained</li><li>It is strongly recommended to provide a meeting recording and/or transcript</li></ul><p>Following the meeting, Project Developers shall evaluate stakeholder feedback and incorporate changes into the project design where appropriate. All feedback, responses and resulting project changes must be documented in a separate report made publicly available with other project documentation.</p></td></tr></tbody></table>

Additionally, a 30-day [public comment period](/rainbow-standard-documents/procedures-manual/project-certification-procedure#public-comment-period) shall be open on the Rainbow Registry for every project during validation, where stakeholders can review project details and provide feedback. This feedback is gathered by the Rainbow team and shared with the Project Developer, who shall evaluate all stakeholder feedback, incorporate changes into the project design where appropriate, and document all feedback and resulting changes in the publicly available project documentation. If no feedback is received, this must be clearly stated in the public documentation available on the Rainbow Registry.

If a stakeholder consultation has already been conducted (to obtain a permit for instance), Project Developers may submit the existing stakeholder consultation in lieu of conducting a new one. In this case, Project Developers shall submit **proof that the previous stakeholder consultation met the requirements herein**, including a list of stakeholders, proof of meetings, results, outcomes, and proof that contact information was shared for a grievance mechanism.

The stakeholders identified and all outcomes of stakeholder consultation shall be included in the PDD.

{% hint style="info" %}
All interested parties and stakeholders are encouraged to continuously provide any feedback or raise concerns about projects certified under the Rainbow Standard. They can do so by email at <hello@rainbowstandard.io>, or [via this form](https://rainbowstandard.io/general-inquiries).
{% endhint %}

### **Free prior and informed consent**

Project activities that use or share land, resources, and/or knowledge with [indigenous people](#user-content-fn-4)[^4]/[local communities](#user-content-fn-5)[^5] (IPLCs) shall comply with the following free, prior and informed consent (FPIC) principles. These principles shall be incorporated into the stakeholder consultation procedure in an explicit and separate FPIC section.

* **Free**: IPLCs are free to decide/consent selling/share of their land, resources and traditional knowledge. IPLCs are not forced to make a decision or give consent through coercion, intimidation or other means, regardless of the decision to give consent.
* **Prior:** Any consent that is sought from IPLCs is sufficiently ahead of time in relation to project start date. This time allows IPLCs to discuss and decide within their own community-oriented processes.
* **Informed:** IPLCs are provided with all relevant information about the project. This includes but is not limited to potential sharing of resources, traditional knowledge, expectations from IPLCs, and any potential environmental and social risks of the project.
* **Consent:** IPLCs consent to the project activity or reject it, a decision made through their community consultative process. The consent given is not of an individual but “collective”, i.e., given by the community. The decision may be communicated via the leaders or representatives of the IPLCs.

### Benefit sharing

Where projects include IPLCs, the project shall have a benefit sharing mechanism with the IPLCs. Benefits of the project shall be shared equitably with the IPLCs. Benefits from the project include but are not limited to services and products produced by the projects, and revenues from sales of carbon credits.

Where the project includes sharing of resources with the IPLCs (such as produce from traditional or community forests) or use of traditional knowledge of the IPLCs, the IPLCs shall be provided with appropriate compensation and recognition.

The benefit sharing procedure shall be documented in the PDD upon validation, and updated in the monitoring report at every verification audit.

***

## Co-benefits

{% hint style="info" %}
Projects should have a positive systemic impact by providing environmental and social benefits along with their climate benefits. The [United Nations Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global%20Indicator%20Framework%20after%202022%20refinement_Eng.pdf) (UN SDGs) are used as a framework to measure co-benefits. Co-benefit claims made by projects are real and audited.
{% endhint %}

Projects should support at least two **quantifiable and verifiable** environmental or social co-benefits, aligned with the UN SDG framework. If a Project Developer claims co-benefits, these must:

* be in addition to climate benefits already accounted for in the issuance of RCCs,
* be positive environmental or social impacts that are substantial and additional, and
* if applicable, include any SGD indicators that are required by the host country.

Claimed **co-benefits shall be quantified and audited** by a VVB using one of the following methods:

* the project’s GHG quantification results, calculated using the Rainbow MRV platform and the corresponding methodology quantification model,
* primary data collection from the project (e.g. value displayed on an invoice),
* an LCA of the project or similar technology, or
* other reputable scientific documents, calculated by the Project Developer in a separate file and shared with the VVB and the Rainbow team.

Project Developers shall provide information in the PDD on any standardized tools and methods that were used to assess the co-benefits.

Claimed **co-benefits shall be monitored** by the Project Developer. They shall be:

* included in the project’s [Monitoring Plan](#monitoring),
* updated with supporting evidence at each credit verification, and
* audited by a third-party VVB.

***

## Leakage

{% hint style="info" %}
Carbon leakage refers to the displacement of emitting activities from the project scope to areas outside the project scope, resulting in an indirect transfer of GHG emissions rather than the absolute avoidance/removal of emissions.
{% endhint %}

Projects shall minimize leakage, where carbon-emitting activities are geographically displaced or relocated to areas outside the project boundaries as a direct result of the project's implementation.

Project Developers shall perform a **robust leakage assessment**, **mitigate any identified leakage, and justify any steps taken** to do so. Any material sources of leakage identified shall be quantified or conservatively estimated and **deducted in the project GHG quantification**. Material sources of leakage shall be monitored and added to the project's Monitoring Plan.

Project Developers shall follow any further methodology-specific instructions to conduct their project's leakage assessment, and document all of the above-mentioned steps to manage leakage risks in publicly available project documentation.

For activities that **physically replace or decommission baseline equipment**, methodologies shall outline requirements to quantify any leakage emissions from disposal and continued use of baseline equipment outside the project boundary (unless under the [GHG quantification cutoff](/rainbow-standard-documents/rainbow-standard-rules/ghg-quantification)). Methodologies may require such baseline equipment to be destroyed, decommissioned, or otherwise phased out.

Projects are ineligible if their quantified leakage impacts exceed:

* 20% of total induced emissions for avoidance credit calculation or
* 20% of gross removals for removals credit calculation.

{% hint style="info" %}
**Upstream and downstream emissions** can be considered a form of leakage, and are already accounted for in the Rainbow GHG quantification requirements. The comprehensive life cycle assessment approach considers upstream and downstream emissions as part of the project scope. Therefore, these emissions are included by default in the project’s GHG reduction quantification.
{% endhint %}

{% hint style="info" %}
Only **net-negative leakage impacts shall be counted** towards the project's GHG quantification (i.e. those that result in higher climate change impact, and fewer RCCs issued). Any net-positive leakage impacts may be treated as co-benefits.
{% endhint %}

***

## Traceability

{% hint style="info" %}
Project information must be easily traceable and publicly documented. This ensures transparency, accountability and rigor at Rainbow, and contributes to a more robust VCM.
{% endhint %}

### Site registration

All **sites where the project operates shall be registered** during the certification process. This includes all factories, facilities, or operations under direct control of the Project Developer, whose activities are involved in RCC verification and issuance. Site registration procedures are detailed in the [Rainbow Procedures Manual](/rainbow-standard-documents/procedures-manual/project-certification-procedure#registration).

Upstream and downstream actors in the supply chain are not counted as project sites.

To register sites, Project Developers shall fill in the Rainbow [Site registration template](/rainbow-standard-documents/procedural-templates/site-registration-template), and shall include the site’s:

* purpose
* relationship to the project
* street address or, if not available, GPS coordinates
* reference person
* contact information
* host country

### No scheme hopping

Project Developers shall disclose if they or their [legal predecessor](#user-content-fn-6)[^6] are **currently certified under another standard or registry**, which would render the project ineligible under the Rainbow Standard.

Project Developers shall disclose if they have **applied for certification under another standard or registry in the last 5 years**. If so, they shall inform Rainbow:

* if they were **validated and issued credits**, they shall provide auditing reports for the last 2 verification audits under the other standard/registry, including any decision to suspend or withdraw certification, and shall provide proof of deregistration from the other standard/registry.
* if they were **rejected for validation as a result of the validation audit** under another standard or registry within the past 3 years, Project Developers shall provide a valid reason unrelated to project integrity issues (e.g. the methodology was discontinued by the other standard). Otherwise, the project is ineligible under the Rainbow Standard.
* if they were **validated but withdrew before the first verification audit** within the past 3 years, Project Developers shall provide a valid reason unrelated to project integrity issues (e.g. the methodology was discontinued by the other standard). Otherwise, the project is ineligible under the Rainbow Standard.

***

## Delivery

{% hint style="info" %}
Delivery requirements ensure that project mitigation activity occurs as expected. For credit issuance and verification, the project mitigation activity must be ex-post.

These requirements ensure the project is real, it operates with the scale and procedures described by the Project Developer, and transparently assesses and reports delivery risk.
{% endhint %}

### Feasibility

Project Developers shall prove that the project is feasible, likely to occur as expected in a continuous manner, and poses little delivery risk. Project Developers shall assess their project's feasibility by transparently discussing and proving:

* their [technology readiness level](#user-content-fn-7)[^7] (TRL)
* acquisition and sourcing of key inputs (e.g. feedstock, machinery)
* demonstrate internal expertise to carry out project activities and monitoring.

### Site audit

Projects shall undergo a site audit according to the procedure outlined in the [Procedures Manual](/rainbow-standard-documents/procedures-manual/project-certification-procedure#site-audit). The purpose of this site audit is to confirm that:

* The project exists and is functional
* The scale of the project is in line with the description
* Key processes operate as described in the project PDD.

### Monitoring

Project Developers shall **monitor and** **report ongoing key parameters** about their activities to demonstrate that:

* the ex-post mitigation activity has occurred,
* the GHG quantification and credits issued are accurate and real,
* any mitigation measures established in the Environmental and social risk assessment are implemented,
* any measures established in the Reversal risk assessment are in place,
* any claimed co-benefits are quantified and verifiable,
* the project's ongoing compliance with the Rainbow Standard Rules and the relevant methodology.

First, at validation, Project Developers shall submit a **Monitoring Plan** to Rainbow and the VVB, outlining the parameters to monitor and procedures for monitoring them. Then, at the end of every monitoring period, when undergoing verification for credit issuance, Project Developers shall submit a **Monitoring Report** to Rainbow and the VVB that demonstrates the execution of the Monitoring Plan and provides the monitored parameters and information.

#### Monitoring Plan

The Monitoring Plan is created during the project validation stage. It shall be created by the Project Developer, adhering to the minimum requirements for a Monitoring Plan in the given methodology and outlined below. It shall be approved by the Rainbow team, and audited by a VVB during the validation audit.

Upon submission at validation, Monitoring Plans shall be as complete as possible. If it is not possible to fully complete parts of the Monitoring Plan at validation, incomplete Monitoring Plans may be submitted with proper justification of why they cannot be finalized at that time, clearly identifying any non-final aspects, and plans for how they will be addressed later. The Monitoring Plan shall be completed and finalized by the end of the first Monitoring Period.&#x20;

A project's **Monitoring Plan may be revised during the crediting period** if the Project Developer proposes a modification. Any such change must be approved by the Rainbow team and audited by a VVB to ensure continued compliance with the methodology and the Rainbow Standard Rules.

<details>

<summary>Minimum requirements for the Monitoring Plan</summary>

These key parameters, which must be regularly tracked and reported, shall be **defined in each project's Monitoring Plan** in the PDD. Each methodology defines the minimum requirements for a Monitoring Plan, and individual projects may have include additional parameters to monitor.

#### **Parameters to include in the Monitoring plan:**

Monitoring Plans shall include parameters that are:

* material to GHG quantification,
* critical for determining project eligibility, including but not limited to environmental and social risks and leakage,
* critical to confirm the mitigation measures established in the Environmental and social risk assessment are in place,
* critical to confirm the measures established in the Reversal risk assessment are in place,
* quantify the claimed co-benefits.

These may include but are not limited to quantitative values, categorical data, qualitative criteria, descriptive parameters, or justification of procedures.

#### **Information to include per parameter:**

Monitoring Plans shall include the following information for each monitored parameter:

* a description of the parameter to be monitored
* monitoring frequency
* emission sources and sinks
* data storage and management plan, including the format, location and duration of data keeping records
* Primary data
  * description of measurement methods/procedures, and their level of accuracy and calibration procedures
  * quality assessment or quality control procedures
  * laboratory name and relevant accreditations for any measurement conducted by external laboratories
  * responsible party for collecting and archiving data, including how they are assigned/selected, and how their competence to monitor the parameter is assessed
  * plan in case of unexpected interruption or errors in monitoring, ensuring conservative treatment of data and an appropriate deduction of emission reductions
* Secondary data
  * data source and, where applicable, value and frequency of update

</details>

#### Monitoring Report

Parameters in the Monitoring Plan shall be regularly monitored by the designated responsible party, and **submitted in the Monitoring Report** for each monitoring period, accompanied by verifiable proof. These parameters and their proof are [verified](/rainbow-standard-documents/procedures-manual/project-certification-procedure#verification-audit) by third-party VVBs for every issuance of RCCs.

[^1]: Paris Agreement to the United Nations Framework Convention on Climate Change, Dec. 12, 2015. <https://unfccc.int/files/essential\\_background/convention/application/pdf/english\\_paris\\_agreement.pdf​>

[^2]: Reversal that

    * results from actions or omissions within the project’s control,
    * could have been prevented with reasonable foresight and risk mitigation
    * typically a result of failure to maintain equipment, follow protocol, or update systems; human error or negligence; or foreseeable and mitigable natural disturbances.

[^3]: Reversals that

    * are caused by events beyond reasonable control or prediction,
    * where mitigation was not feasible or would have imposed unreasonable burden,
    * resulted from natural disasters (e.g. wildfire, earthquake, extreme weather); pest or disease outbreaks; or policy or regulatory change beyond project control

[^4]: Indigenous peoples are defined in the [Glossary](/glossary#general) as people that self-identify as Indigenous and are recognized by others as Indigenous, with historical continuity with pre-colonial societies; distinct languages, customs, and institutions; a strong connection to ancestral lands or territories; and are often governed by customary laws or traditional authorities.

[^5]: Local communities are defined in the [Glossary](/glossary#general) as non-Indigenous people with a long-standing connection to a particular rural or semi-rural geographic area; reliance on local natural resources for livelihood; social cohesion or shared cultural traits, though not necessarily Indigenous; living in geographic proximity to a part of the project area, including but not limited to sourcing, production, and/or end use locations.

[^6]: for example, as a result of:

    * A merger or acquisition
    * A company split or spin-off
    * Re-registration or change of legal form
    * Bankruptcy or restructuring
    * Change of ownership (sale of the company or its assets)
    * Rebranding or name change
    * Succession
    * Transfer of a project or business unit (e.g., selling a division to another company)
    * Reorganization
    * Dissolution and continuation under a new entity (the old company is closed, but its activities continue under a new one)
    * Change in controlling interest (new majority shareholders take over)
    * Legal or regulatory replacement

[^7]: Technology Readiness Levels (TRLs) are a method for understanding the maturity of a technology. TRLs allow engineers to have a consistent reference for understanding technology evolution, regardless of their technical background.


# GHG quantification

## General principles and requirements

RCCs shall be calculated for each credit issuance by subtracting the GHG emissions and removals of the project scenario from the emissions and removals of a [baseline scenario](/rainbow-standard-documents/rainbow-standard-rules/project-and-baseline-scope#baseline-scope), representing the product or practices that would have occurred without the implementation of the project. Quantification of GHG emissions for the baseline and project scenarios shall follow [ISO 14064-2:2019](#user-content-fn-1)[^1].

One RCC is issued per one tonne of CO$$\_2$$ equivalent avoided or removed by the project, compared to the baseline.

Project quantification of emissions and removals shall follow the instructions outlined in the relevant methodology. These quantifications shall adhere to the following principles:

* **Science-based:** Use sound scientific methods, backed up by reputable sources.
* **Complete:** Use a life-cycle approach, and a wide enough scope to encompass all GHG sources, sinks and reservoirs that are materially affected by the mitigation activity.
* **Transparent:** Reproducible using the information provided in the project documentation and the methodologies. All necessary data and calculations shall be made publicly available to ensure transparency and allow for independent verification.
* **Accurate:** Based on project-specific data as much as possible where relevant. The number of RCCs issued shall be as close as possible to the actual number of GHGs avoided/removed.
* **Conservative:** Ensure that RCC issuance is not [likely ](#user-content-fn-2)[^2]overestimated, and when faced with uncertainty, choose approaches that systematically underestimate GHG avoidance/removals.

Upon project validation, Project Developers shall provide an estimate of total GHG avoidance and/or removals for the entire crediting period.

All data and results shall be reported in [SI units](#user-content-fn-3)[^3] or units officially accepted for use with the SI.

## Project system boundary

{% hint style="info" %}
The project system boundary defines which GHG emissions and removals to include and exclude in a project scenario, for the purpose of GHG quantification.
{% endhint %}

The project system boundary shall include:

* all processes under direct control of the project,
* the key upstream and downstream processes,
* indirect processes, such as activity shifting, identified in the [leakage](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#leakage) assessment, and
* other processes that differ between the project and baseline, as a result of the project mitigation activity.

Due to the comparative measurement approach, processes that are **identical in the project and baseline scenario may be excluded**, since they will not affect the comparative results.

Processes to consider shall include but are not limited to raw material extraction, delivery of supplies, processing, manufacturing, distribution, use, retail, distribution, disposal of replaced and end-of-life baseline equipment, and waste treatment.

Methodologies may define the minimum processes to include in the project system boundary, and additional processes may be included where relevant for a given project. The project system boundary shall be transparently described in the project documentation and accompanying methodology.

#### Materiality assessment

Processes with individually small contributions, each below 1% of total impacts, may be accounted for using a conservative default rather than a site-specific value, provided the cumulative excluded processes do not exceed:

* 2% of total induced emissions (for avoidance credit calculations), or
* 2% of gross removals (for removal credit calculations).

Where processes are excluded, a conservative proxy emission term equal to the applicable 2% threshold value, or smaller maximum estimated value, shall be substituted in the calculation.

Project Developers must transparently document all excluded processes in the PDD, including an upper and lower/worst and best case estimate of their contribution, and demonstrate that exclusion is conservative (i.e. the upper or lower bound used is the one that makes the strongest case for remaining below the 2% threshold). If any major project operations or design changes occur, and are flagged by the Project Developer or the VVB at a verification audit, the materiality assessment shall be updated to reflect the project changes.&#x20;

Methodologies may provide more specific instructions for materiality assessment.

## Baseline system boundary

{% hint style="info" %}
The baseline system boundary defines the GHG emissions and removals against which a project’s emission avoidance or removal is compared to determine the number of credits to issue.
{% endhint %}

The baseline system boundary shall represent the processes and activities defined in the [Baseline scope](/rainbow-standard-documents/rainbow-standard-rules/project-and-baseline-scope#baseline-scope). Baselines shall be realistic, defensible, and conservative baseline estimations of emissions.

The baseline system boundary shall include the set of processes that are **functionally equivalent to all products and services delivered in the project scenario**.

The baseline system boundary shall be transparently described in the project documentation and accompanying methodology. Further details for defining the baseline are included in the [Baseline scope](/rainbow-standard-documents/rainbow-standard-rules/project-and-baseline-scope#baseline-scope) section.

## Removal and avoidance equations

#### Removal equation

The following equation shall be used for quantifying net project carbon removals and issuing removal RCCs.

$$\textbf{(Eq.1)}\ Net\ Removal = R\_{baseline}-R\_{project}-E\_{project}$$

where,

* $$Net\ Removal$$ represents the net removals from the project during the verification period, in tonnes of CO$$\_2$$eq. Its sign is positive.
* $$R\_{baseline}$$ represents any baseline GHG removals from the capture module(s), representing permanent storage that would have occurred in the absence of the project, in tonnes of CO$$\_2$$eq. Its sign is negative.
* $$R\_{project}$$ represents the project's gross GHG removals from the storage module(s) used by the project, in tonnes of CO$$\_2$$eq. Its sign is negative.
* $$E\_{project}$$ represents the project's total induced GHG emissions across the life cycle of the project's removal activities, in tonnes of CO$$\_2$$eq. Its sign is positive.

Methodologies shall provide further details on quantifying gross removals and project induced emissions.

#### Avoidance equation

The following equation shall be used for quantifying net project carbon avoidance and issuing avoidance RCCs.

$$\textbf{(Eq.2)}\ E\_{avoided} = E\_{baseline} - E\_{project}$$

where,

* $$E\_{avoided}$$ represents the avoided GHG emissions from the project scenario, in tonnes of CO$$\_2$$eq. Its sign is positive.
* $$E\_{baseline}$$ represents the GHG emissions from the baseline scenario during the verification period, in tonnes of CO$$\_2$$eq. Its sign is positive.
* $$E\_{project}$$ represents the project's total induced GHG emissions across the life cycle of the project's avoidance activities, in tonnes of CO$$\_2$$eq. Its sign is positive.

## Input data

GHG quantification shall be based on **verifiable primary data from project operations** as much as possible. Project's primary data must be based on ongoing representative measurements, or recent conditions.

All **secondary/background data** (for example, emission factors, rates of recycling, composition of national electricity grid) shall be derived from traceable, transparent, unbiased, and reputable sources.

All **assumptions and estimates** shall be conservative, transparently presented and justified, in the methodology and/or in the project documentation

For geographic accuracy and consistency across projects, national-level background data should be prioritized. Local (region, state, city-scale) or global sources may be used if justified.

Methodologies shall define the project-specific input data needed, and any information that is set at the methodology level, such as common assumptions or background data.

## Uncertainty assessment

{% hint style="info" %}
Uncertainty is inherent in any measurement and calculation. The purpose of uncertainty assessment is to:

* identify areas where more effort is needed to improve accuracy,
* identify areas where conservative approaches are needed, and
* improve transparency.
  {% endhint %}

All GHG quantifications and credit issuances shall include an **uncertainty assessment**, that:

* evaluates the uncertainty of key elements of the GHG quantification,
* manages uncertainties in a conservative manner, and
* reports the uncertainties in publicly available documentation.

An uncertainty assessment must be conducted and documented **at the methodology level** for all aspects of GHG quantification set there. The findings from this assessment are then applied **at the project level**, where project-specific GHG quantification also undergoes an uncertainty assessment.

The **overall project GHG quantification uncertainty** is determined by qualitatively combining both the methodology-level and project-specific uncertainties for each identified source of uncertainty.

#### Evaluating uncertainty

The following GHG quantification elements shall be included in uncertainty assessments:

* assumptions
* selection of the baseline scenario
* measurements
* equations and models
* estimates or secondary data used

#### Managing uncertainty

The **degree of uncertainty shall inform the degree of conservativeness to take.** Elements with higher uncertainty shall adopt a more conservative approach. The significance and sensitivity shall also be accounted for, where more significant and sensitive elements should be treated more conservatively.

Uncertainty shall be addressed by taking a conservative approach in at least one of the following ways:

* **Quantitative approach**: where possible, a statistical approach (e.g. confidence intervals and standard deviations) should be used to quantify uncertainty, and to select conservative values.
* **Qualitative approach:** where a quantitative approach is not possible, a qualitative approach based on informed judgement may be used to assess uncertainty and make a conservative choice.
* **Discount factor**: after applying quantitative and qualitative approaches to manage uncertainty, any untreated sources of uncertainty shall be managed by applying a discount factor to the final GHG quantification. This represents a percent of credits that will not be issued in order to avoid overestimating GHG avoidance and/or removals.

#### Discount factor

Methodologies shall establish a **minimum discount factor** for all projects certified under them. This factor shall reflect all unmanaged sources of uncertainty, their impact on quantification, and any conservative measures already applied to mitigate uncertainty. Complemented by a project-specific uncertainty assessment, a higher factor may be applied for any given project.

Discount factors shall be determined by **qualitatively scoring the uncertainty of each source as none, low, medium, high or very high**, after accounting for conservative approaches. The [IPCC framework ](#user-content-fn-4)[^4]for outcome probability should be used for assessing the uncertainty of each element, as presented in the "Assigning uncertainty level" column of the table below.

By combining these individual uncertainty scores at both the project and methodology levels, an **overall project uncertainty score** is determined. This score can then be translated into a discount factor using the following criteria:

<table><thead><tr><th width="188.3333740234375">Degree of uncertainty</th><th width="343">Assigning uncertainty level (IPCC)</th><th>Project discount factor</th></tr></thead><tbody><tr><td>None</td><td>>99% of being accurate, it is virtually certain</td><td>—</td></tr><tr><td>Low</td><td>90-99% chance of the quantification element being accurate</td><td>3%</td></tr><tr><td>Medium</td><td>66-90% chance of being accurate</td><td>6%</td></tr><tr><td>High</td><td>50-66% chance of being accurate, more likely than not</td><td>9% or higher</td></tr><tr><td>Very high</td><td>&#x3C;50% chance of being accurate</td><td>15%, ineligible</td></tr></tbody></table>

If the overall project uncertainty score is rated "Very high", and/or the project requires a >15% uncertainty discount factor, then the **uncertainty is considered too high and the project is not eligible**.

{% hint style="info" %}
For example, if an assumption is evaluated as 95% certain to occur, the corresponding GHG quantification element is rated as low uncertainty. If most other GHG quantification elements—assessed at both the project and methodology levels—are also rated as low uncertainty, the overall project uncertainty is classified as low, and a 3% discount factor is applied.
{% endhint %}

## Global Warming Potentials <a href="#global-warming-potentials" id="global-warming-potentials"></a>

GHG emissions shall be calculated by default using the following IPCC Global Warming Potential values for a 100 year horizon (GWP100) according to [IPCC 2021 AR6, Chapter 7](#user-content-fn-5)[^5]. The GWPs for the main greenhouse gasses are summarized below, and the full list of GWPs can be found in the [IPCC AR6 Chapter 7 Supplementary Material, Table 7.SM.7](#user-content-fn-6)[^6].

Alternative GWP100 values from other IPCC versions may be used by projects in order to comply with Host Country's NDC and relevant schemes or accreditations (e.g. [CRCF](/rainbow-standard-documents/procedures-manual/crcf-requirements), CORSIA, Article 6.2).

The source of GWP100 values shall be reported in the PDD.

<table><thead><tr><th width="381">Species</th><th>Global warming potential 100-year</th></tr></thead><tbody><tr><td>CO<sub>2</sub></td><td>1</td></tr><tr><td>CH<sub>4</sub>​ fossil</td><td>29.8</td></tr><tr><td>CH<sub>4</sub> biogenic</td><td>27</td></tr><tr><td>N<sub>2</sub>​O</td><td>273</td></tr><tr><td>HFC-32</td><td>771</td></tr><tr><td>HFC-134a</td><td>1526</td></tr><tr><td>CFC-11</td><td>6226</td></tr><tr><td>PFC-14</td><td>7380</td></tr></tbody></table>

[^1]: ISO 14064-2:2019. Greenhouse gases — Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements.

[^2]: this can be interpreted as a 66-100% chance, according to the [IPCC](https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-1/#h3-9-siblings).

    IPCC, 2021: *Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change* \[Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, Chapter 1: Framing, Context, and Methods, pp. 147–286, doi:[10.1017/9781009157896.003](https://doi.org/10.1017/9781009157896.003).

[^3]: International System of Units

[^4]: Box 1.1, Figure 1 in IPCC, 2021: Chapter 1. In: *Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change \[Chen, D., M. Rojas, B.H. Samset, K. Cobb, A. Diongue Niang, P. Edwards, S. Emori, S.H. Faria, E. Hawkins, P. Hope, P. Huybrechts, M. Meinshausen, S.K. Mustafa, G.-K. Plattner, and A.-M. Tréguier, 2021: Framing, Context, and Methods. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change \[Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfield, O. Yelekçi, R. Yu, and B. Zhou (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 147–286, doi:* [*10.1017/9781009157896.003* ](https://dx.doi.org/10.1017/9781009157896.003)*.]*

[^5]: Intergovernmental Panel on Climate Change 2021. Chapter 7: The Earth’s Energy Budget, Climate Feedbacks, and Climate Sensitivity. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, doi:10.1017/9781009157896.009. [URL](https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter07.pdf)

[^6]: Intergovernmental Panel on Climate Change 2021.The Earth’s Energy Budget, Climate Feedbacks, and Climate Sensitivity Supplementary Material. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. [URL](https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter07_SM.pdf)


# Version history

Version history and changes to the Rainbow Standard Rules

:point\_right: See [Archived Rainbow Standard Documents](/other/archived-methodologies/archived-rainbow-standard-documents) for full versions of previous documents

<details>

<summary>Change log for Rainbow Standard Rules V7.2</summary>

**May 2026**

**Additionality:**

* Add Common Practice analysis requirement
* Investment analysis:&#x20;
  * require assumptions and conclusions to be documented, investment analysis to be consistent with information presented to decision makers, and financial indicators used to be internally consistent
  * create investment comparison analysis option, explicitly differentiate from  benchmark analysis
  * limit financial indicators allowed to IRR or NPV
* Barrier analysis:&#x20;
  * redefine financial and institutional barrier scope
  * remove technological barrier option
  * add information barrier option

**Crediting period duration:** add instructions on how methodologies must set appropriate crediting period durations

**Monitoring plan:** must include for each monitored parameter, plan for conservatively treating and/or deducting credits related to unexpected interruptions in monitoring

**Double counting:**

* specify no double issuance within Rainbow Standard
* consequences for double counting
* require VVB to conduct cross checks across other platforms
* add Rainbow double registration cross check requirements
* add requirement to prove compatibility with a transition to net zero by reference to the net zero objectives of the host country

**Materiality assessment:** in GHG quantification, require processes with small impacts to be substituted by default emission deduction rather than excluded from calculations.

**No scheme hopping:** only applies to projects rejected within the last 3 years. Disclosure period of 5 years remains.

</details>

<details>

<summary>Change log for Rainbow Standard Rules V7.1</summary>

**March 2026**

**Additionality**

* Investment: move IRR calculation instructions from additionality template to Standard Rules
* Regulatory: define "upcoming regulations"

Specify downward adjustment required for baseline setting

Co-benefit reporting must include, if applicable, include any SGD indicators that are required by the host country.

Specific standard-level requirement to assess, mitigate, deduct and monitor leakage.

</details>

<details>

<summary>Change log for Rainbow Standard Rules V7</summary>

**Replace V6.2 with V7, linked with Procedures Manual V3.0 release**

**Public Consultation: November 2025**

* **General**
  * Eligibility criteria replaced with Principles and requirements
  * Remove Minimum impact requirement
* **Environmental and social safeguards**
  * Specify all projects must prove compliance with local and national regulations
  * Strengthened stakeholder consultation procedure, including a required meeting and thorough documentation
  * New IPLC and FPIC requirements
  * Risk assessment: any material risk identified must have a risk mitigation plan
  * Expanded list of risks to assess
* **No scheme hopping**
  * New requirements for Project Developers to disclose if they have applied for certification under another standard or registry in the last 5 years
* **Durability**
  * Renamed from Permanence section
  * Move risk of reversal assessment to methodology-level, if no material risks identified, no project requirements. If material risks are identified, projects follow risk assessment procedure.
  * Defined avoidable vs unavoidable reversals
  * No standard-level minimum durability threshold, methodologies define minimum permanence
  * Minimum contribution to buffer pool changed to 2%, higher minimums may be determined in methodologies
* **Co-benefits**
  * Require quantification approach to be detailed and publicly disclosed
  * All co-benefits must be monitored
  * Removed minimum and maximum limit of 2-4 co-benefits
* **Delivery**
  * New section, addresses the removed Real eligibility criteria requirements
  * Removed TRL eligibility criteria requirements, replaced with Feasibility
  * Added requirements for minimum content of Monitoring plan
* **GHG quantification**
  * Added cumulative limit for exclusion cutoff threshold
  * Strengthened Uncertainty assessment requirements, and approaches to making conservative choices when faced with uncertainty
  * Maximum uncertainty level/discount factor of >15%
  * Allow for GWP100 from other IPCC versions, if required for compliance with regulatory schemes
* **Monitoring plan**
  * Specify information to be provided with each monitored parameter
* **Baseline**
  * Moved out of GHG quantification and into new section, Project and baseline scope
  * Replace Guidance on Avoided Emissions by the World Business Council for Sustainable Development (WBCSD) with other best-practice guidelines for baselines (from ICVCM, CORISA, CRCF)
  * Specify baseline must account for government policies and legal requirements that lower GHGs
  * Remove substitution and targets alignment, reference these principles in Baseline section

**Post-Public Consultation: January 2026**

* Remove all mention of carbon “reduction”, in relation to avoidance, for clarity
* Update high-level carbon removal quantification equtions and sign conventions

</details>

<details>

<summary>Change log for Rainbow Standard Rules V6.2</summary>

Replace V6.1 with V6.2 October 2024

* Replace DPD and Detailed Project Description with PDD and Project Design document
* Revised Additionality Template with new requirements:
  * Sensitivity analysis
  * For barrier analysis, demonstrate alternative activities does not face same barrier
* Revise ESDNH criteria, minimum risks to consider for all projects

</details>

<details>

<summary>Change log for Rainbow Standard Rules V6.1</summary>

Replace V6.0 with V6.1 August 2024

* New appendix with IT Security requirements
* Terminology changes, reflected in the Glossary (notably discount factor and buffer pool)

</details>

<details>

<summary>Change log for Rainbow Standard Rules V6</summary>

{% embed url="<https://drive.google.com/file/u/0/d/1wp7SnmEO9TlUZ5KyA80mD8Ir7d9_sE-o/view>" %}

</details>

<details>

<summary>Change log for Rainbow Standard Rules V5.2</summary>

{% embed url="<https://drive.google.com/file/d/1jzrqLC-siL0Pc-HYPBJAzrT4fF-S5xpD/view>" %}

</details>


# Rainbow Procedures Manual

| **Document name** | Rainbow Procedures Manual |
| ----------------- | ------------------------- |
| **Document type** | Standard document         |
| **Version**       | 3.2                       |
| **Release date**  | July 2nd, 2026            |
| **Status**        | In use                    |

## Purpose of this document

This manual describes the rules and procedures for registering and operating Rainbow projects and issuing Rainbow Carbon Credits (RCCs). It should be used together with the latest versions of the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules), [Methodologies](/rainbow-standard-documents/methodologies), and all other documentation found on this site.

In all Rainbow documentation the following terms are to be interpreted as:

* **Shall** and **must**: a requirement
* **Should**: a recommendation
* **May**: an option, permissible
* **Is** and **will**: in the context of Rainbow, standard operational procedures

{% content-ref url="/pages/D1bECpowUAiJorSGzbQY" %}
[Glossary](/glossary)
{% endcontent-ref %}


# Governance and oversight

Rainbow is the registered trademark of the carbon crediting standard and platform operated by the French company Riverse SAS (SIREN: 908 082 332), headquartered at 28 Avenue des Pépinières, 94260 Fresnes, France. Throughout this documentation, “Rainbow” refers to the programs, platforms, and operations developed and managed by Riverse SAS under this trademark.

See the [Governance and integrity](/other/governance-and-integrity) section for more Rainbow policies related to governance.

## Conflict of interest

All individuals or entities involved in Rainbow’s certification or governance activities shall sign and adhere to the Rainbow [Conflict of Interest Policy](/other/governance-and-integrity/conflict-of-interest-policy) (COI Policy). The COI policy outlines the procedures to identify, declare, and manage potential or actual conflicts of interest across the Rainbow ecosystem.

The following stakeholders are explicitly bound by the Conflict of Interest Policy, and are detailed in sections below:

* Members of the Standard Advisory Board
* Members of the Expert Community
* Members of the Governing Board
* Members of the Executive Team
* Validation and Verification Bodies (VVBs)
* Members of the Secretariat
* Members of the Science, Certification, Product & Tech, and Partnerships teams
* Other contractors involved in any Rainbow certification or registry procedure.

## Main stakeholders

### Standard Advisory Board

The **Standard Advisory Board (SAB)** is an independent governing body overseeing the Rainbow Standard. It is responsible for ensuring that Rainbow’s activities remain aligned with the organization’s foundational mission. Its responsibilities include:

* Endorsing or rejecting proposed changes to the Rainbow Standard Rules, Procedures Manual, and Registry Procedures
* Providing strategic guidance to ensure alignment with international integrity frameworks
* Advising the Executive Team on regulatory trends and stakeholder expectations

Only SAB members can vote in SAB decisions. A simple majority is required, with the Chair casting the deciding vote in case of a tie. The SAB is self-renewing and composed of independent experts. Appointments are made by the Executive Team and approved by sitting members. SAB members are not involved in certification audit decisions.

Further details are available in the [Terms of Reference – Standard Advisory Board](/other/governance-and-integrity/terms-of-reference-standard-advisory-board).

### Expert Community

The **Expert Community** is a standing pool of sectoral experts that supports the scientific integrity of the Rainbow Standard. Experts are engaged on an ad hoc basis and may be convened into dedicated working groups to:

* Review methodologies and revisions
* Support project-specific technical evaluations
* Conduct applied research relevant to Rainbow sectors

Members of the Expert Community are appointed by the Rainbow Science Team. While the Community holds no decision-making authority, its technical input is foundational to scientific and technical decision making at Rainbow.&#x20;

Further details are available in the [Terms of Reference – Expert Community](/other/governance-and-integrity/terms-of-reference-expert-community)<mark style="color:purple;">.</mark>

### Governing Board

The Governing Board is Rainbow’s fiduciary body, established under the bylaws of Riverse SAS. It is responsible for ensuring Rainbow’s financial sustainability, operational continuity, compliance with internal policies, and alignment with its mission as a *société à mission*.

The Governing Board shall:

* Provide oversight of Rainbow’s financials, risk exposure, and continuity planning
* Review and monitor internal integrity policies and processes, including but not limited to the [COI policy](/other/governance-and-integrity/conflict-of-interest-policy)
* Offer strategic guidance and evaluate organizational performance against mission objectives

Board members, appointed by Rainbow shareholders, include at least one independent member. Meetings are held at least quarterly. Members adhere to Rainbow’s Conflict of Interest Policy and may be supported by external advisors when needed. Governing Board members are not  involved in certification audit decisions.

Further details are available in the [Terms of Reference — Governing Board](/other/governance-and-integrity/terms-of-reference-governing-board).

### Executive Team

The Executive Team leads Rainbow’s day-to-day operations and long-term strategic execution. Their responsibilities include:

* Overseeing the operations and implementation of the Standard
* Making decisions by majority vote within the team
* Appointing members to the SAB
* Ensuring financial sustainability and legal compliance

The Executive Team is appointed collectively by the shareholders of Riverse SAS in accordance with the statutes.

### Validation and verification bodies

Validation and verification bodies (VVBs) conduct audits on project activities, assessing their conformity with the Rainbow Standard Rules, the procedures outlined in the present document, and the applicable methodology.

Further details on VVB accreditation and responsibilities are outlined in the [VVB requirements](/rainbow-standard-documents/procedures-manual/vvb-requirements) section.

### Secretariat

The **Secretariat** coordinates governance processes and cross-team communication. Its main tasks include:

* Preparing and consolidating proposed changes to Rainbow Standard documentation
* Facilitating information flow between teams and the SAB
* Organizing public consultations and managing stakeholder feedback
* Organizing the Rainbow [Annual Report](#rainbow-annual-report)
* Oversight of VVBs including managing accreditation applications, performance reviews and sanctions.

### Science Team

The **Science Team** oversees the environmental and scientific rigor of Rainbow’s methodologies. Key responsibilities include:

* Developing and revising methodologies
* Monitoring scientific developments and references
* Coordinating with the Expert Community
* Providing training and guidance to VVBs and the Certification Team

### Certification team

The **Certification Team** ensures transparent and accurate project assessments. Its responsibilities include:

* Supporting Project Developers throughout certification
* Reviewing Project Documentation and VVB audit reports
* Providing feedback on VVB performance and compliance
* Managing the Rainbow Registry, including credit issuance and retirement

### Product & Tech Team

The **Product & Tech Team** develops and maintains the digital platform that supports the Rainbow Standard’s implementation. This includes:

* The Rainbow Registry, which ensures the traceability, issuance, and retirement of Rainbow Carbon Credits.
* The Certification Platform, used by Project Developers and VVBs to manage certification workflows.
* APIs and data pipelines to enable interoperability and transparency.

### Partnerships Team

The **Partnerships Team** supports Rainbow’s growth and credibility by managing stakeholder relationships and advancing market engagement. The team’s work includes:

* Developing and maintaining relationships with carbon credit resellers and project developers.
* Representing Rainbow at events.
* Communicating around Rainbow’s methodologies, programs, and mission.

## Rainbow Annual Report

The Rainbow Secretariat shall publish an **Annual Report about the operation of the Rainbow Standard**, by April 30th each year, covering activities from the previous calendar year. The required minimum contents of the report are listed below.

This report shall be made publicly available on the Rainbow website, with previous reports archived on the documentation hub.

<details>

<summary>Minimum requirements for the Rainbow Annual Report</summary>

The Annual Report shall contain the following minimum information:

**General operations**

* Rainbow's revenue, expenses, and net assets over the past year
* An overview of Rainbow's mission, major programs and activities, and governance
* A summary of the number and type of certified projects per methodology
* A summary of the amount, type and status of RCCs on the registry, the end-use purpose and users of the retired RCCs
* Evidence of public information on Rainbow's website of:&#x20;
  * contact information, email and mailing addresses
  * latest version of governance rules and procedures
  * certification and credit fee structure
  * links to the Rainbow Registry and Complaints and Appeals procedure

**Internal monitoring and oversight**

* List of **major and critical** [**non-conformities**](/rainbow-standard-documents/procedures-manual/project-certification-procedure#non-conformities) by Project Developers and VVBs, detailing the projects and monitoring periods concerned, the nature of the non-conformity and the outcome
* The number and description of cases where fraud has been identified including an action plan for how to solve any complaint raised or non-conformity identified
* Overview of **trainings, technical workshops, resources, or initiatives Rainbow provided to VVBs,** to improve the overall certification process; improve the qualification and independence of VVBs; and facilitate the exchange of experience, knowledge and best practices.
* Overview of the **stakeholder involvement in decision-making** and Rainbow's response to their contributions
* Summary of **complaints received and any remedial measures** or changes to the governance system necessary as part of the internal monitoring
* Criteria and process for the **approval of VVBs**.
* Results of VVB Oversight spot checks
* Evaluation of the suitability of the internal monitoring system to prevent fraudulent activities

</details>

## Documentation management system

Rainbow shall manage key governance, oversight, and certification documents in a transparent, accessible and durable manner.

**General program documents**, manuals, requirements, and policies shall be made publicly available on this documentation hub, available at [docs.rainbowstandard.io](https://docs.rainbowstandard.io/).

**Certification documents** and records are stored in the Rainbow Certification Platform and on the registry. Their accessibility is described in the [Project documentation](/rainbow-standard-documents/procedures-manual/registry-requirements#project-documentation) page.

The **Rainbow Annual Report** describes Rainbow's operations including but not limited to non-conformities by Project Developers and VVBs, trainings, and complaints. This report shall be made publicly available on this documentation hub in the [Administrative Oversight Record](/other/administrative-oversight)section. More details are in the [Rainbow Annual Report](#rainbow-annual-report) section.

* The Rainbow Annual Report summarizes any **VVB non-conformities and sanctions**. Additionality, VVB sanction reports will be made publicly available at the time of sanctioning, according to the [VVB Sanctions](/rainbow-standard-documents/procedures-manual/vvb-requirements#vvb-sanctions) requirements.
* The Rainbow Annual Report summarizes any **complaints** received from any stakeholder and remedial measures taken. The original complaints received shall be kept confidential and saved by the Rainbow team in a confidential repository, following the [Complaints and Appeals Policy](/other/governance-and-integrity/complaints-and-appeals-policy).

All documents listed above shall be kept for at least 5 years after the end of the monitoring period.


# Standard and methodologies

## Revising Rainbow Standard Documentation

The Rainbow Standard Rules and the Procedures Manual undergo regular revision to ensure they reflect up-to-date science and best practice in the voluntary carbon market. The revision of the documents shall follow the procedure outlined below.

### Major revisions

Major revisions are tracked through the first integer after the standard document name (e.g. Rainbow Standard Rules V1 → V2). Major revisions include three phases: Feedback Collection, Draft Preparation, and Approval.

#### Feedback Collection Phase

**Open external feedback**: Any interested party can provide feedback on the Rainbow Standard Rules and methodologies at any time. The latest versions of all documentation are published on Rainbow’s website, enabling continuous input—not just during public consultations.

{% hint style="info" %}
All interested parties, irrespective of their background or involvement, are encouraged to continuously provide their feedback on the current Rainbow Standard Documentation. They can do so by email at <hello@rainbowstandard.io>, or [via this form](https://rainbowstandard.io/general-inquiries).
{% endhint %}

**Internal planned revisions:** Rainbow continuously reviews and updates its Standard documents to reflect new knowledge, market developments, evolving regulations and accreditation requirements. The Rainbow Science team actively monitors all referenced standards and tools (e.g. IPCC, ISO …) to ensure alignment with best practices.

**Compilation of feedback**: The Secretariat compiles external feedback and internally-identified planned revisions into a Standard Revision Proposal.

#### Draft Preparation Phase

**Evaluation of Revision Proposal:** The Secretariat analyzes the suggested changes in the Standard Revision Proposal, and evaluates the changes deemed necessary to the Rainbow Standard Documentation based on the feedback received. Responses to any external feedback, including a decision on whether to incorporate the feedback or not, will be made publicly available with the [public consultation](/rainbow-standard-documents/public-consultations) feedback responses.

**Revision draft:** The Secretariat and the Rainbow Science team make the revisions in a draft update to the Standard Documentation.

**Submission to SAB and deliberation**: The draft update is presented to the SAB for their critical evaluation, highlighting key updates plus providing the full revised text. The SAB provides feedback.

**Public Consultation:** The Secretariat organizes a public consultation of the proposed revisions (see [Public consultation](/rainbow-standard-documents/public-consultations) section).

#### Approval Phase

**Integration of Public Feedback:** the Secretariat integrates feedback from the public consultation into the draft update to the Standard Documentation.

**SAB Review and Approval:** The draft update to the Standard Documentation is submitted to the SAB for final approval. The SAB ensures that feedback from the public consultation phase, as well as their own comments, has been appropriately incorporated or that adequate justification is provided for any feedback not adopted.

**Implementation**: The Science team implements the approved revisions into the Rainbow Standard Documentation and any affiliated documents. All changes are documented in the [Version History](/rainbow-standard-documents/rainbow-standard-rules/version-history), [previous versions are archived](/other/archived-methodologies/archived-rainbow-standard-documents), and changes to certification are implemented.

### Minor revisions

Minor revisions may be made by the Rainbow Science Team when they are deemed necessary. Minor revisions are tracked through the second integer after the standard document name (e.g. Rainbow Standard Rules V1.1 → V1.2). Revisions are considered minor if they do not result in widespread material changes affecting the eligibility of projects, such as:

* Updating references to external documents, tools, or standards
* Adjusting procedural and operational steps to improve clarity or efficiency
* Adding or updating examples or case studies to aid understanding
* Simplifying documentation language to improve accessibility
* Formalizing processes that are already implemented in practice
* Making other non-critical changes to requirements.

All changes are documented in the [Version History](/rainbow-standard-documents/rainbow-standard-rules/version-history), and [previous versions are archived](/other/archived-methodologies/archived-rainbow-standard-documents).

## Creating new Rainbow Standard Documentation

The creation of new Rainbow Standard Documentation follows the Draft Preparation and Approval phases described in the [#revising-rainbow-standard-documentation](#revising-rainbow-standard-documentation "mention") section, with the following differences:

* All Rainbow Standard Documentation is initially drafted internally by the Rainbow Science team.
* Procedures are tailored to Rainbow’s operations, but shall draw inspiration and guidance from established standards such as ISO 9001 and ISO 31000, ensuring global compliance and recognition.
* Instead of a Revision Proposal as described in the Draft Preparation section, a Creation Proposal is submitted to the Standard Advisory Board for validation.
* A public consultation is conducted for the creation of any new Rainbow Standard Documentation.

## Creating a new methodology

### Submission

Any interested party may submit a request for a new methodology at any time. The requests are summarized by the Secretariat into a Methodology Creation Proposal (template [here](/rainbow-standard-documents/procedural-templates/methodology-creation-proposal-template)).

The Methodology Creation Proposal is reviewed first by the Rainbow Science Team, and if approved then it is reviewed by the SAB for final approval.

The reviews consider factors such as:

* Maturity of the technology
* Number of existing projects
* Scientific consensus of substantial carbon avoidance/removal potential
* Feasibility of MRV
* Feasibility of meeting other [Principles and requirements](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements) from the Rainbow Standard Rules

If the proposal is validated by the SAB, a **Methodology Creation Mandate** is granted to the Secretariat and the Rainbow Science Team. This mandate assigns the designated teams to research, develop, and finalize the methodology. The [current Methodology Creation Mandates ](#methodologies-white-list)are presented below.

If the proposal is rejected by the SAB, it then decides whether to earmark it for reworking or, based on the gravity of the concerns, abandon it altogether.

### Development

The Secretariat gathers a **technical working group** composed of at least 3 individuals, including members of the Expert Community and at least one independent external expert (i.e. an individual with relevant technical expertise who is not affiliated with Rainbow, its funders, or eligible projects, and who has declared no conflict of interest). The technical working group collaborates with the Rainbow Science Team to develop the methodology.

Members of the technical working group shall be selected based on

* **expertise** related to e.g. the scientific foundations, sustainability issues, LCA/GHG quantification, policy, or operations of the methodology's subject.
* **representation from diverse stakeholders** from e.g. researchers/academics, project developers, independent experts, or NGOs.

Members of technical working groups are subject to the relevant provisions of the [Terms of Reference - Expert Community](/other/governance-and-integrity/terms-of-reference-expert-community), including but not limited to rules on independence, conflict of interest, confidentiality, and conduct.

To research and develop the methodology, the Rainbow Science team gathers and consults the technical working group on a regular basis. Final decisions rest with the Rainbow Science team.

The minimum requirements for a Rainbow methodology include the following:

<details>

<summary>Minimum requirements for a methodology</summary>

**Scope/general**

* Eligible technologies and activities, description of the practices and processes covered
* Scope/delineation of a project (e.g. number of sites can be included in one project)
* Geographic locations covered, if not global
* Minimum requirements for a monitoring plan
* Maximum duration of the crediting period
* Maximum duration of the monitoring period/frequency of credit issuance
* Glossary with definitions of technical terms
* Requirements for project compliance with methodology revisions
* Requirements for site audits to be on-site or remote

**Baseline scenario**

* Justification of the pre-defined/standardized baseline scenario, or guidance for defining an activity-specific baseline scenario
* Frequency of updating the baseline scenario

**Principles and requirements**

* Any standardized calculations for co-benefits
* Durability (for removal RCCs)
  * durability threshold, in years
  * technology/methodology level reversal risk assessment
  * post-crediting monitoring requirements for reversals
  * liability and compensation requirements
  * minimum buffer pool contribution (if higher than the Standard default of 2%)
* Technology/methodology-specific leakage assessment and if applicable, further requirements
* Reversal and ESDNH Risk assessment template

**GHG quantification**

* Assumptions
* Secondary data sources
* Description of processes, GHG sinks, and GHG sources to include in the project and baseline scenario
* Uncertainty assessment and minimum discount factor
* Approaches to account for uncertainties in a conservative matter
* All equations and rules needed to calculate, where relevant in the applicable methodology:
  * project and baseline induced emissions
  * project and baseline removals,
  * LULUCF soil emissions,
  * agricultural soil emissions, and
  * total GHGs avoided and/or removed

</details>

### Review and acceptance

Once the initial methodology draft is complete, the Secretariat launches a public consultation for a minimum of 30 days, following the [Public consultation](#public-consultation) procedures outlined below.

The Secretariat and the Rainbow Science team then assess all feedback, deciding and justifying whether to incorporate each feedback into the final methodology draft. This draft is validated by the SAB, which verifies that input from the Expert Community, other experts, and the public consultation has been fully integrated.

<details>

<summary>Current Methodology Creation Mandates</summary>

The following Methodology Creation Mandates have already been approved by the SAB as of November 2025, and may be created by Rainbow at any time:

* Low carbon cement
* BiCRS carbon storage modules on geologic storage, and biomass sinking
* BiCRS carbon capture modules on biogenic CO$$\_2$$
* Distributed biochar production
* Ocean alkalinity enhancement
* Reuse of building materials
* Textile second life
* Direct Air Capture

</details>

## Revising a methodology

Methodologies are revised regularly based on external feedback and internally planned updates. The Rainbow Science team manages two types of revisions:

* **Major updates** involve substantive changes and undergo a rigorous vetting process, following the [Rainbow Standard Documentation Major revision procedure](#major-revisions) and the **technical working group** requirements described the [Creating a new methodology](#creating-a-new-methodology) section, including a public consultation. These updates are indicated by changes to the first number after the methodology name (e.g. BiCRS methodology V1 → V2). Major updates include:
  * Changes to eligible project types, technologies, or geographies
  * Revisions to Principles & requirements that could disqualify previously validated projects (compliance procedures apply as outlined in the [Versioning and project compliance](/rainbow-standard-documents/procedures-manual/project-certification-procedure#versioning-and-project-compliance) section
  * Adjustments to quantification methodologies, such as scope reviews or database updates, that result in at least a 20% average change in avoided or removed emissions
  * Any changes deemed as major by the SAB
* **Minor updates and clarifications** are published regularly and remain open for continuous public feedback on the [Rainbow website](/rainbow-standard-documents/public-consultations). These updates are tracked by changes to the second number after the methodology name (e.g. BiCRS methodology V1.1 → V1.2).

All methodologies shall be reviewed and undergo public consultation **at least every three years**.

Project requirements for updating and complying with methodology revisions during the crediting period are detailed in the [Versioning and project compliance](/rainbow-standard-documents/procedures-manual/project-certification-procedure#versioning-and-project-compliance) section.

Modules follow the same creation and revision requirements as methodologies.

## Discontinuing a methodology

A methodology may be discontinued if:

* shifts in scientific consensus indicate it no longer aligns with best practices
* it fails to achieve measurable carbon avoidance/removal
* it is no longer additional
* it consistently overestimates credits and cannot be revised to ensure conservativeness
* projects under that methodology consistently fail to meet the [Principles and requirements](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements) outlined in the Rainbow Standard Rules

Methodologies are evaluated against these criteria **at least once every three years** during the mandatory major revision process, though they can also be reviewed and discontinued at any time if necessary.

Projects already validated under a discontinued methodology may continue using it until their next verification. After that, they must transition to a new methodology or become ineligible for new RCCs. Previously issued RCCs remain valid and tradable.

## Public consultation

#### **Criteria for Public Consultation**

Public consultations are mandatory for:

* major revisions of the Rainbow Standard Documents
* major revisions of a methodology and module and
* creation of new methodologies and modules.

For minor revisions, the Rainbow Science team shall decide whether to launch a public consultation, based on the complexity and the impact of the changes on projects.

#### **Publishing the Call for Consultation**

The Secretariat initiates the public consultation through a Call for Consultation. This call is widely broadcasted through relevant channels to ensure maximum outreach, inviting Project Developers; carbon credit resellers, brokers, and marketplaces; net-zero engaged corporates; VVBs; climate and environmental scientists; and the general public to provide their insights and feedback on the topic. The **minimum duration of the consultation is 30 days.**

Rainbow shall provide an accessible mode of comment submission, through e.g. a dedicated platform or form. Stakeholders may also provide feedback via email, during a webinar, or in one-on-one meetings with the Rainbow Science team.

For the creation of new methodologies, the Secretariat should organize a webinar to explain the rationale of the methodology and an overview of its requirements.

#### **Compilation and integration of feedback**

After the public consultation period, the Secretariat compiles all feedback, suggestions, and perspectives collected. The Rainbow Science team assesses and responds to each feedback, deciding and justifying whether to incorporate the feedback or not.

This collective feedback and the Rainbow Science team responses are summarized and published on the Rainbow Documentation Hub under the [Closed public consultations ](/rainbow-standard-documents/public-consultations)section.

The Rainbow Science team integrates relevant feedback into the methodology or Rainbow Standard Documents draft, finalizing the process and publishing the document for use.


# Project certification

The steps for project certification, including validation and verification, under the Rainbow Standard are summarized in the table and detailed in corresponding sections below.

## Summary

<table data-full-width="true"><thead><tr><th width="180">Certification step</th><th>Description</th></tr></thead><tbody><tr><td>Application</td><td><ul><li>Project Developer (PD) submits a Project Application (PA), which is reviewed by the Rainbow team.</li><li>Clarifications may be requested, and a refusal report is issued if the application is rejected. Approved applications proceed to registration.</li></ul></td></tr><tr><td>Registration</td><td><ul><li>PD signs Rainbow Service Agreement, agreeing to the Terms &#x26; Conditions, and completes administrative setup, including Know Your Customer (KYC) requirements.</li><li>Any Registration Partners are formally documented.</li><li>Rainbow performs Double-registration check.</li><li>Project is added on the Rainbow Registry.</li><li>PD submits data and proof to the Certification Platform.</li></ul></td></tr><tr><td>Pre-Validation</td><td><ul><li><p>Project Design Document (PDD) is generated, outlining project operations, GHG quantification, additionality, and Monitoring Plan.</p><ul><li>If the project is not yet operational, the certification process stops here. Only a draft PDD is generated, and made available on the project's registry page. The draft PDD is updated and finalized once the project starts operations.</li></ul></li><li>Certification team reviews the PDD, possibly involving domain experts, and approves it before third-party validation.</li></ul></td></tr><tr><td>Validation</td><td><ul><li>VVB conducts a validation audit to confirm project adherence to Rainbow Standard Rules and chosen methodology, involving the PD and Certification team as needed.</li><li>In parallel, a public comment period is open for 30 days on the Rainbow Registry.</li></ul></td></tr><tr><td>Monitoring and Verification</td><td><ul><li>Key parameters are monitored regularly to track project impact and eligibility.</li><li>PD submits monitored parameters per the Monitoring Plan; prepares a Monitoring Report which subject to the verification audit by the VVB annually (or as per schedule) to verify GHG quantification and RCC issuance.</li></ul></td></tr><tr><td>Compliance and Updates</td><td><ul><li>Projects may have to stay compliant with Rainbow Standard and methodology revisions, depending on the methodology.</li><li>All projects must report major operational changes and updates in the Monitoring Report.</li><li>VVB audits any revisions or changes, ensuring alignment with updated methodologies and standards.</li></ul></td></tr><tr><td>Crediting Period Renewal</td><td><ul><li>After the end of the crediting period, the project may be renewed by undergoing a full revalidation, including a new PDD, validation audit, and stakeholder consultation to continue issuing credits.</li></ul></td></tr></tbody></table>

## Project timeline

* **Project start date**: when the mitigation activity within the project scope first begins. This date shall fall within three years of the project’s validation date, unless the project was previously registered under a different standard/program.
* **Project registration date**: the date the Project Developer signs the Service Agreement, and the project is created on the registry.
* **Project validation date**: the date after which the project is eligible to issue RCCs. This is the date the project has completed a validation audit by a VVB, has completed project validation review by the Rainbow team, and the PDD is made available on the registry.
* **Monitoring period**: the duration of project activities covered by a single monitoring report, and eligible for credit issuance. The default monitoring period duration is one year, but may be shorter at the Project Developer's request for more frequent credit issuance. The first monitoring period may begin up to 18 months before the registration date, and subsequent monitoring periods shall be no longer than 24 months long.
* **Crediting period**: the duration of project mitigation activities that are eligible for credit issuance. The maximum duration of the crediting period shall be defined by the methodology. If the project is already underway upon registration with Rainbow, the crediting period and the first monitoring period may start up to 18 months prior to its registration date with Rainbow.

## Application

The Project Developer shall submit a [Project Application](https://rainbowstandard.io/get-started) (PA) to start the certification process. This step is free of charge for Project Developers.

Once received, the PA shall be reviewed by the Rainbow team. If clarification or additional details are needed, questions shall be sent to the Project Developer. Applications are assessed according to their compliance with the Eligible technologies section of each methodology.

For rejected applications, a refusal report explaining the decision shall be provided to the Project Developer. Approved PAs proceed to project registration.

## Registration

To continue the certification process, the Project Developer shall sign the Rainbow Service Agreement and accepts the [General Terms of Arc Platform (Certification Platform)](/other/terms-and-contracts/terms-and-conditions-for-project-developers-mrv-+-registry).

Upon this signature, the **Rainbow team adds the project on the registry**.

To activate a Rainbow Registry Account Holder account, the Project Developer must complete the following steps:

* Use the connection link received via email
* Complete all administrative information required in the Admin page
* Follow the [Know Your Customer (KYC) policy ](/other/governance-and-integrity/kyc-policy)to ensure the Project Developer is registered properly

Once the account is activated, the Rainbow team gives the Project Developer access to the Certification Platform and dMRV platform to submit all elements required for the Project Design Document (PDD), including data and proof files.

{% hint style="warning" %}
If the Project Developer chooses a partner to register projects under the Rainbow Standard, they must sign a Letter of Delegation (template provided [here](/rainbow-standard-documents/procedural-templates/letter-of-delegation-for-registration-partner)).

This document must name the **Registration Partner** and define their authority and responsibilities, formally authorizing them to represent the Project Developer in all registration, documentation, and project management activities under the Rainbow Standard.
{% endhint %}

### Double-registration check

Prior to adding the project to the registry, the Rainbow team shall verify that the activity is not already registered under another registry. The Rainbow team shall search across registries operating in relevant pathways using the Project Developer's legal name and the project's site location.

If no matching registration is found, the Rainbow team proceeds with registration. The search procedure, scope, and findings are documented in the project's PDD.

If a matching registration is found, the Rainbow team shall contact the Project Developer to request clarification. If the Project Developer cannot demonstrate that the registered activity and the proposed Rainbow project have fully non-overlapping scopes with no double-counted GHG claims, the application shall be refused.

## Pre-validation

### PDD creation

The data, responses, and their proof submitted by the Project Developer are used to generate the PDD through the Rainbow Certification platform. The PDD serves as the final validation document used for audit. Minimum requirements for a PDD are listed below.

<details>

<summary>Minimum requirements for the PDD</summary>

PDDs shall contain, at a minimum, the following information:

**General and scope description**

* Non-technical description of the project operations, technology, infrastructure, scope, location, Project Developer, and other relevant actors
* Legal ownership and contact information of the Project Developer
* If using a registration partner or a group of Project Developers, a description of if and how advisory services are provided to Project Developers
* Technical description of the technology and project operations
* Specific location of the project, including [georeferenced boundaries](#user-content-fn-1)[^1] and/or GPS coordinates of the mitigation activity
* Compliance with any accreditations beyond Rainbow certification (e.g. CRCF, ICVCM..)
* Start date of the project, and start and end dates of the crediting period
* [Monitoring Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#monitoring) with parameters to be monitored
* Site registration
* Procedure and findings of [double-registration check](/rainbow-standard-documents/procedures-manual/project-certification-procedure#double-registration-check)

**Eligibility, principles and requirements**

* Justification that the project meets all [Principles and requirements](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements) described in the Rainbow Standard Rules, and the chosen methodology
* Stakeholders identified and outcomes of the stakeholder consultation
* Assessment of environmental and social risks, and demonstration of sustainability
* Project specific buffer pool contribution (if issuing removal RCCs)

**GHG quantification**

* Source for GWP100 values (IPCC AR6 or other IPCC version)
* Information on how the methodology was applied for the purpose of
  * determining the baseline,
  * demonstrating additionality and
  * quantifying GHG emission reductions or removals, including but not limited to assumptions, data sources, and emission sources/sinks, that are not already defined at the methodology level
* Project-specific uncertainty assessment and discount factor
* Future projections throughout the crediting period including:
  * Operational, production, delivery information
  * Expected total **gross** GHG emissions, carbon removals, and avoidance
  * Expected total **net** GHG emissions, carbon removals, and avoidance (after applying the discount factor and buffer pool contribution)

The PDD shall require any other information required for the VVB to validate the project as compliant with the Rainbow Standard Rules and the applicable methodology.

PDDs shall be made publicly available on the Rainbow Registry upon completing [Validation](#validation). See the [Registry and documentation](/rainbow-standard-documents/procedures-manual/registry-requirements#project-documentation) section for further instructions on publicly available documentation.

</details>

### PDD review

The Rainbow team evaluates the PDD and any supporting documents to ensure they respect Rainbow’s general and methodology GHG quantification steps and eligibility requirements.

The Rainbow team may require clarifications and additional information about the project via the Certification Platform.

For projects unlike any previously validated by Rainbow, or in cases of uncertainty, the Rainbow team may recommend a full or partial **review of the PDD by a domain expert** from the [Expert Community](/rainbow-standard-documents/procedures-manual/governance-and-oversight#expert-community). This review incurs fees based on the expert’s rates, charged to the Project Developer.

After the PDD undergoes expert review (if needed) and is approved by the Rainbow team, the project proceeds to third-party validation with the VVB.

## Validation

{% hint style="info" %}
Validation is **always the first audit** for a project. Validation only occurs once at the beginning of each crediting period.

A project may undergo:

* **validation only**, if they are in the early stages of operation, have activities that can be assessed in the site audit, but may not want to issue credits yet. In this case, no RCCs are issued as an outcome of the audit, or
* **validation and verification simultaneously**, if it is operational and ready to issue ex-post RCCs.
  {% endhint %}

### Validation audit

All projects shall undergo a **validation audit with an accredited third-party VVB** to become eligible for issuing RCCs.

Once the Rainbow team completes the PDD review, and approves of the PDD, the Rainbow team puts together the **Validation audit package**, containing the elements listed below, available to the third-party VVB on the Certification Platform.

The VVB shall follow the [VVB requirements](/rainbow-standard-documents/procedures-manual/vvb-requirements#validation-and-verification-process), to define the **audit team, scope and plan**.

<details>

<summary>Validation audit package</summary>

The audit package **shall contain the following elements**:

* PDD
* Risk assessment (Environmental and Social Risk Assessment, Reversal Risk Evaluation)
* Additionality template
* Baseline setting
* Monitoring Plan
* GHG quantification spreadsheets (extracts from Rainbow Certification Platform)
* Stakeholder consultation procedure and outcome
* Site registration
* All relevant supporting documents and sources

</details>

<details>

<summary>Audit procedure</summary>

The Validation and Verification audits shall be conducted by VVB in accordance **ISO 14064-3 and ISO 14065**, and in compliance with the requirements of EN ISO/IEC 17021-1 in conjunction with EN ISO/IEC 19011 (or equivalent standards).

Validation and verification audits shall cover at least the following elements:

* identification of the activity undertaken by the Project Developer which is relevant for the methodology
* identification of the **relevant methodology and Rainbow Standard Rules requirements** of the project and the Project Developer's organization, and check its effective implementation;
* analysis of the risks which could lead to a material misstatement, based on the auditor’s professional knowledge and the information submitted by the Project Developer. The analysis of risks shall take into consideration the overall risk profile of the activity, depending on the level of risk of the operator. The audit intensity or scope, or both, shall be adapted to the level of overall risk items.
* an audit plan which corresponds to the risk analysis and the scope and complexity of the Project Developer’s activity, and which defines the sampling methods to be used with respect to that operator’s activity;
* implementation of the audit plan by gathering evidence in accordance with the defined sampling methods, plus all relevant additional evidence, upon which the auditor’s conclusion will be based;
* a request by the auditor to the Project Developer to provide any missing elements of audit trails, an explanation of variations, or the revision of claims or quantification, before reaching a final audit conclusion;
* identification of any unresolved non-conformities, concerns, discrepancies, and material misstatements, of the project's information and evidence assessed against the relevant methodology and Rainbow Standard Rules requirements;
* Internal Review by an auditor who is not the Audit Leader, in the same VVB organization, to perform a final QA/QC review (Quality Assurance/Quality Control), attesting to accuracy of data and of the Audit Leader's findings.

A **Conflict of Interest (COI) form** shall be submitted to Rainbow’s Certification team for the audit team for each validation and verification audit.

</details>

The VVB's approach and findings are documented in the [Audit Report](/rainbow-standard-documents/procedures-manual/vvb-requirements#audit-report), shared with the Project Developer and the Rainbow team, and made publicly available on the Rainbow Registry.

Any concerns, discrepancies and/or non-conformities identified in the audit shall be handled according to the requirements in the [Non-conformities](#non-conformities) section.

### Site audit

A **site audit** is a required component of the [Validation audit](#project-validation-audit). The goal of the site audit is to confirm that:

* The project exists and is functional
* The scale of the project is in line with the description
* Key processes operate as described in the project PDD

The VVB shall specify in the [Audit Plan](/rainbow-standard-documents/procedures-manual/vvb-requirements#audit-plan) which specific components to be checked during the site audit.

The methodology shall define whether the site audit must be based on an **on-site visit or a remote audit**. Remote site audits shall ensure confidence in the VVB audit process by enabling direct observations via electronic means:

* **Video evidence** is required for remote site audits. The videos should allow the VVB to confirm that each component is true, and will typically consist of a tour of the site with commentary.
* Formats may include **video calls with the auditors or pre-recorded videos**.

The findings and comments of the site audit shall be documented in the Audit Report.

Any concerns, discrepancies and/or non-conformities identified in the audit shall be handled according to the requirements in the [Non-conformities](#non-conformities) section.

If a project **already conducted a site audit** (e.g. for registration with a different standard), the past site audit may be submitted to meet this requirement, as long as it meets the requirements described herein and in the applicable methodology. The VVB shall evaluate whether the past site audit is adequate by assessing whether:

* the past site audit and findings meet the goals listed above,
* remote vs. in-person requirements are met, and
* the site audit process, findings, and non-conformity resolution steps are sufficiently and transparently documented.

### Public comment period

Projects shall undergo a public comment period on the Rainbow Registry for at least 30 days, in parallel with or before the validation audit. The public comment period complements the project [stakeholder consultation](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#stakeholder-consultation), and provides an open-access space where stakeholders can check the project details, provide feedback and raise concerns.

Any feedback received is gathered by the Rainbow team and shared with the Project Developer, who shall evaluate all stakeholder feedback, incorporate changes into the project design where appropriate, and document all feedback and resulting changes in the publicly available project documentation.

If no feedback is received on the registry, this must be clearly stated in the public documentation available on the Rainbow Registry.

{% hint style="info" %}
All interested parties and stakeholders are encouraged to continuously provide any feedback or raise concerns about projects certified under the Rainbow Standard. They can do so by email at <hello@rainbowstandard.io>, or [via this form](https://rainbowstandard.io/general-inquiries).
{% endhint %}

### Project validation review

Once approved by the VVB, the PDD is sent back to the Rainbow Team to review the VVB’s remarks, and evaluate feedback from the registry public comment period.

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><p>The Rainbow Certification Team ensures <strong>that the VVB has followed the</strong> <a href="/pages/UFYVGUgzCEQVXiNMjvUg"><strong>VVB requirements</strong></a> and thoroughly audited the following elements:</p><ul><li>Project Design Document (PDD)</li><li>Risk assessment (i.e. Environmental and Social Evaluation, Reversal Risk Evaluation)</li><li>Additionality template</li><li>Baseline setting</li><li>Monitoring Plan</li><li>GHG quantification spreadsheets (extracts from Rainbow Certification Platform)</li><li>Stakeholder consultation materials</li></ul></td></tr><tr><td><p>The Rainbow Certification Team <strong>directly reviews</strong> the following content:</p><ul><li>the VVB’s remarks and the Project Developer's responses</li><li>the PDD, with clarifications asked by the VVB included in the Appendix</li><li>feedback from the <a href="#public-comment-period">public comment period</a></li><li>the VVB's <a href="/pages/UFYVGUgzCEQVXiNMjvUg#audit-report">Audit Report</a></li></ul></td></tr></tbody></table>

After all concerns are addressed, **the project is validated**. The PDD is made publicly available on the Rainbow Registry.

The date this occurs is recorded as the **project's validation date** in the registry. From this point onward, the project becomes eligible to issue credits for the duration of the crediting period.

The project may undergo a [verification audit](#verification) simultaneously, which results in RCC issuance.

If the VVB or the Rainbow team identifies non-conformities, the requirements from the [Non-conformities ](#non-conformities)section applies.

## Monitoring and verification

### Monitoring

{% hint style="info" %}
Project Developers monitor ongoing processes and report key parameters during each monitoring period to issue RCCs.
{% endhint %}

Project Developers shall adhere to the [Monitoring Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#monitoring), which is established and audited during the validation stage. The Monitoring Plan specifies the key parameters to track to:

* quantify GHG avoidance/removals and
* demonstrate compliance with the [Principles and requirements](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements) in the Rainbow Standard Rules and the applicable methodology.

<details>

<summary>Minimum requirements for the Monitoring Plan</summary>

These key parameters, which must be regularly tracked and reported, shall be **defined in each project's Monitoring Plan** in the PDD. Each methodology defines the minimum requirements for a Monitoring Plan, and individual projects may have include additional parameters to monitor.

#### **Parameters to include in the Monitoring plan:**

Monitoring Plans shall include parameters that are:

* material to GHG quantification,
* critical for determining project eligibility, including but not limited to environmental and social risks and leakage,
* critical to confirm the mitigation measures established in the Environmental and social risk assessment are in place,
* critical to confirm the measures established in the Reversal risk assessment are in place,
* quantify the claimed co-benefits.

These may include but are not limited to quantitative values, categorical data, qualitative criteria, descriptive parameters, or justification of procedures.

#### **Information to include per parameter:**

Monitoring Plans shall include the following information for each monitored parameter:

* a description of the parameter to be monitored
* monitoring frequency
* emission sources and sinks
* data storage and management plan, including the format, location and duration of data keeping records
* Primary data
  * description of measurement methods/procedures, and their level of accuracy and calibration procedures
  * quality assessment or quality control procedures
  * laboratory name and relevant accreditations for any measurement conducted by external laboratories
  * responsible party for collecting and archiving data, including how they are assigned/selected, and how their competence to monitor the parameter is assessed
  * plan in case of unexpected interruption or errors in monitoring, ensuring conservative treatment of data and an appropriate deduction of emission reductions
* Secondary data
  * data source and, where applicable, value and frequency of update

</details>

Project Developers shall submit a **Monitoring Report** **at least once per 24 months**. Failure to do so shall result in the project being [deregistered](#deregistration). The default monitoring period duration is **one year,** but may be shorter according to the requirements of the relevant Methodology, or at the Project Developer's request. Monitoring Reports are made publicly available on the Rainbow Registry, according to the requirements for [Project documents publicly available on the registry](/rainbow-standard-documents/procedures-manual/registry-requirements#project-documents-publicly-available-on-the-registry).

The Monitoring Report shall document for the monitoring period:

* any project scope change;
* any process change;
* all of the parameters laid out in the Monitoring Plan;
* if applicable, the updated responses to modified requirements from a methodology or Rainbow Standard update (see [Versioning and project compliance](#versioning-and-project-compliance)).

Major changes to the project scope or processes may additionally result in the revision of the PDD, at the request of the Project Developer. All past PDD versions shall remain publicly on the Rainbow Registry with their dates, version numbers, and version history. Any modification shall be&#x20;

* justified by the Project Developer,&#x20;
* subject to re-calculation of the project's expected GHG removals and induced emissions,&#x20;
* assessed for compliance with all Principles & requirements, and
* undergo an audit by the VVB as part of the Verification audit.

### Verification audit

{% hint style="info" %}
Verification occurs after a project is validated, and has provided a Monitoring Report.

The first verification may happen alongside validation or separately. Subsequent verifications (e.g., in years 2, 3, etc.) occur independently, as validation is conducted only once at the start of the crediting period.
{% endhint %}

Projects shall undergo a **verification audit with an accredited VVB** for each RCC issuance.

The verification audit may occur at the **same time as the** [**validation audit**](#validation-audit)**.**

Once the Rainbow team completes the Monitoring Report review, and approves it, the Rainbow team puts together the **Verification audit package**, containing the elements listed below, available to the third-party VVB on the Certification Platform.

VVBs shall follow [VVB requirements](/rainbow-standard-documents/procedures-manual/vvb-requirements#validation-and-verification-process) to define the audit team, scope and plan, in compliance with the Rainbow Standard Rules, the specified methodology and project's Monitoring Plan.

<details>

<summary>Verification audit package</summary>

The audit package **shall contain the following elements** :

* Monitoring Plan
* Monitoring Report
* GHG quantification spreadsheets (extracts from Rainbow Certification Platform)
* Any relevant supporting documents and sources

</details>

<details>

<summary>Audit procedure</summary>

The Validation and Verification audits shall be conducted by VVB in accordance **ISO 14064-3 and ISO 14065**, and in compliance with the requirements of EN ISO/IEC 17021-1 in conjunction with EN ISO/IEC 19011 (or equivalent standards).

Validation and verification audits shall cover at least the following elements:

* identification of the activity undertaken by the Project Developer which is relevant for the methodology
* identification of the **relevant methodology and Rainbow Standard Rules requirements** of the project and the Project Developer's organization, and check its effective implementation;
* analysis of the risks which could lead to a material misstatement, based on the auditor’s professional knowledge and the information submitted by the Project Developer. The analysis of risks shall take into consideration the overall risk profile of the activity, depending on the level of risk of the operator. The audit intensity or scope, or both, shall be adapted to the level of overall risk items.
* an audit plan which corresponds to the risk analysis and the scope and complexity of the Project Developer’s activity, and which defines the sampling methods to be used with respect to that operator’s activity;
* implementation of the audit plan by gathering evidence in accordance with the defined sampling methods, plus all relevant additional evidence, upon which the auditor’s conclusion will be based;
* a request by the auditor to the Project Developer to provide any missing elements of audit trails, an explanation of variations, or the revision of claims or quantification, before reaching a final audit conclusion;
* identification of any unresolved non-conformities, concerns, discrepancies, and material misstatements, of the project's information and evidence assessed against the relevant methodology and Rainbow Standard Rules requirements;
* Internal Review by an auditor who is not the Audit Leader, in the same VVB organization, to perform a final QA/QC review (Quality Assurance/Quality Control), attesting to accuracy of data and of the Audit Leader's findings.

A **Conflict of Interest (COI) form** shall be submitted to Rainbow’s Certification team for the audit team for each validation and verification audit.

</details>

Once the Monitoring Report is audited and approved, the VVB shall deliver a verification [Audit Report](/rainbow-standard-documents/procedures-manual/vvb-requirements#audit-report) for each verification, and for CRCF[^2] compliant projects, the [Certificate of Compliance](/rainbow-standard-documents/procedures-manual/vvb-requirements#certificate-of-compliance).

Any concerns, discrepancies and/or non-conformities identified in the audit shall be handled according to the requirements in the [Non-conformities](#non-conformities) section.

### Verification review and issuance

The Rainbow Certification Team **directly reviews** the following content:

* the VVB’s remarks and the Project Developer's responses
* the verification Audit Report
* the Monitoring Report
* for CRCF[^2] compliant projects, the [Certificate of Compliance](/rainbow-standard-documents/procedures-manual/vvb-requirements#certificate-of-compliance).

If all concerns are resolved, the **verified amount of RCCs are issued with the corresponding attributes (durability, vintage, mechanism)**. The Monitoring Report and Audit Report are made publicly available on the Rainbow Registry.

Any concerns, discrepancies and/or non-conformities identified in the audit shall be handled according to the requirements in the [Non-conformities](#non-conformities) section.

## Versioning and project compliance

Each project validation, verification, and credit issuance is conducted under a specific version of the Rainbow Standard Rules and the applicable methodology. These versions are tracked and reported in the registry. When the methodology used during project validation is updated, the following applies:

* Methodologies must specify whether projects are required to adopt the latest version for subsequent verifications of RCCs.
* Project Developers are strongly encouraged to update their projects to comply with the latest requirements whenever possible.

Methodologies may:

* Require all projects to **comply with the latest version**, unless a grace period has been explicitly granted for the project by Rainbow; or
* Allow projects to **continue under the previous version** used for their initial validation.

To demonstrate compliance with updated versions, the Project Developer **must show adherence to new requirements in the next Monitoring Report**. The VVB shall audit all changes summarized in the Monitoring Report to ensure compliance with any updates in the selected methodology or Rainbow Standard Rules during the subsequent [Verification audit](#verification-audit).

If a methodology update renders a project ineligible, the project cannot issue new credits at the next verification. Credits already issued remain valid on the registry.

A grace period applies before any new version of a Rainbow Standard document or methodology becomes mandatory. Projects **already undergoing a validation or verification audit are exempt and may continue using the previous version** for that audit event only.

## Non-conformities

The types of non-conformities by Project Developers that may emerge as a result of a validation or verification audit, and their remediation measures, are detailed in the table below.

Credits shall not be issued until all non-conformities are resolved and approved by the VVB. Failure to resolve or remediate minor non-conformities shall result in **no credit issuance for the concerned monitoring period**.

Other instances of non-conformity not listed here shall be raised by a VVB and classified by the Rainbow team as critical, major, or minor, and handled accordingly.

<table data-full-width="false"><thead><tr><th width="142">Non-conformity</th><th width="244">Description</th><th width="355">Remediation/sanctions</th></tr></thead><tbody><tr><td>Critical</td><td><ul><li>Grave and irreconcilable violation of Rainbow Principles and requirements, as outlined in the <a href="/pages/4uybo1rKTeqN3arLDfI4">Rainbow Standard Rules</a></li><li>Deliberate misstatement or misrepresentation of the project and/or mitigation activity</li><li>Falsification of data used for GHG quantification</li></ul></td><td><p><strong>Validation audit</strong>:</p><ul><li>the project shall not be validated</li><li>may reapply for validation <strong>12 months</strong> after final decision of non-conformity</li></ul><p><strong>Verification audit</strong>:</p><ul><li>credits shall not be issued</li><li>a new certificate of compliance shall not be issued, and the existing certificate of compliance is withdrawn (<em>for</em> <a data-footnote-ref href="#user-content-fn-2"><em>CRCF</em></a> <em>projects only</em>)</li><li>the project shall be <strong>immediately deregistered</strong> from the Rainbow Registry</li><li><p>previously-issued credits that are</p><ul><li>unaffected by the non-conformity <strong>may remain on the registry</strong></li><li>affected by the non-conformity <strong>shall be cancelled</strong> according to the <a href="/pages/PFnP2GjoQlU2GAENGCg3#canceling-credits-due-to-erroneous-issuance">cancelation procedure</a></li></ul></li></ul></td></tr><tr><td>Major</td><td><ul><li>Repeated problems with data used for GHG quantification, e.g. incorrect documentation identified in >10% of the claims included in the representative sample</li><li>Project Developers failing to declare their participation in other certification schemes simultaneously with Rainbow</li><li>Repeated failure to provide relevant information to the VVB</li></ul></td><td><p><strong>Validation audit</strong>:</p><ul><li>the project shall not be validated</li><li>may reapply for validation <strong>6 months</strong> after final decision of non-conformity</li></ul><p><strong>Verification audit:</strong></p><ul><li>credits shall not be issued</li><li>the project shall be <strong>immediately suspended</strong> from the Rainbow Registry</li><li>The project's existing certificate of compliance shall be suspended and a new one will not be issued. Credits associated with that certificate shall not be sold until the remediation action is taken and the suspension is lifted (<em>for</em> <a data-footnote-ref href="#user-content-fn-2"><em>CRCF</em></a> <em>projects only</em>)</li><li><p>Project Developers shall implement the <strong>identified remediation action/s within 90 days</strong> of notification of suspension.</p><ul><li>Failure to do so shall result in the project being <strong>deregistered</strong> from the Rainbow Registry</li><li>Failure to do so shall result in the existing certificate of compliance being withdrawn (<em>for</em> <a data-footnote-ref href="#user-content-fn-2"><em>CRCF</em></a> <em>projects only</em>)</li><li>Upon resolving or remediating the non-conformities within 90 days, the project is re-registered and is eligible to issue credits in subsequent monitoring periods.</li></ul></li></ul></td></tr><tr><td>Minor</td><td><ul><li>Isolated problems with data used for GHG quantification</li><li>Isolated provision of insufficient or irrelevant proof</li><li>Violation of Rainbow requirements or procedures that have a limited impact</li></ul></td><td><p><strong>Validation audit:</strong></p><ul><li>VVBs shall communicate minor non-conformities to Rainbow and the Project Developer</li><li><p>Project Developers shall implement the <strong>identified remediation action/s within 90 days</strong> of notification of non-conformity.</p><ul><li>Failure to do so shall result in the termination of the project validation. The project may reapply for validation <strong>3 months</strong> after final decision of non-conformity.</li><li>Upon resolving or remediating the non-conformities within <strong>3 months</strong>, the project may be immediately validated.</li></ul></li></ul><p><strong>Verification audit:</strong></p><ul><li>Credits shall not be issued until all non-conformities are resolved and approved by the VVB</li><li>Failure to resolve or remediate minor non-conformities within 90 days shall result in <strong>no credit issuance for the concerned monitoring period</strong>.</li><li>Validated projects may issue credits in subsequent monitoring periods.</li></ul></td></tr></tbody></table>

## Crediting Period Renewal

The **maximum duration of the crediting period shall be defined by the methodology**. For the defined number of years after the start of the crediting period, the validation and Monitoring Plan are valid, and verification may be performed by following the Monitoring Plan requirements.

Upon reaching the end of the crediting period, **the crediting period must be renewed** for the project to remain registered with Rainbow, and to continue issuing credits.

Upon renewal of the crediting period, projects must comply with the most recent version of the applicable methodology and the Rainbow Standard Rules, and undergo a **new validation assessment** by performing the following steps, including all elements described in the [Project validation](#validation) section:

* Preparation of a new PDD, with updated responses to all principles and requirements, updated GHG quantification, and an updated selection of a baseline scenario
* Validation audit
* Site audit
* Stakeholder consultation
* Project validation review

Upon renewing a crediting period, a new crediting period start and end date shall be defined for the project.

## Deregistration

Project Developers may deregister a project from Rainbow by notifying the Secretariat (at <climate@rainbowstandard.io>). Deregistration is activated within a calendar month of the receipt of this information.

Rainbow shall send a certificate of deregistration to the Project Developer, stating from which date the project's activity is deregistered and the end date of the last monitoring period. The crediting period duration shall be modified on the registry, so that the end of the crediting period matches the end date of the last monitoring period. The Project Developer is responsible for completing any audits still due and to pay any fees still due.

The Project Developer shall choose how to manage any credits that were issued but not transferred, sold, or retired on the Rainbow registry. They may choose between:

* keeping those credits available on the Rainbow registry, or
* canceling those credits on the Rainbow registry, e.g. to convert and re-issue them by the other GHG program on its registry.

Projects shall be automatically deregistered if they do not conduct [monitoring and verification ](#monitoring-and-verification)according to the minimum specified frequency (every 1 or 2 years, depending on the methodology).

Once a project is deregistered, it must undergo a new validation assessment and audit in order to become registered and issue credits again.

Deregistered projects remain on the Rainbow registry for at least 5 years after deregistration, including all associated project documentation and auditing reports.&#x20;

## Project status on the registry

Project status is related to the different steps in the certification process, and is outlined in the table below.

See the [RCC Status on the registry](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits#rcc-status) section for corresponding information on credit status.

<table><thead><tr><th width="139">Status</th><th>Definition</th></tr></thead><tbody><tr><td><strong>Pending</strong></td><td><ul><li>The Project Developer has completed the <a href="https://rainbowstandard.io/get-started">Project Application</a> and the project is created in the registry back office.</li><li>The Rainbow team waits for the Project Developer's submission of more complete data to perform the Project Eligibility Assessment.</li><li>Project does not exist on the registry.</li></ul></td></tr><tr><td><strong>Listed</strong></td><td><ul><li>The Rainbow team has completed the Project Eligibility Assessment and approves the project.</li><li>The Project Developer has signed up for registration by signing the <a href="/pages/4zblKwZkVRLgfMUUUhCz">General Terms of Arc</a>, and is submitting full information to comply with Rainbow Standard and methodology requirements.</li><li>A draft PDD may be under preparation, with the aim of gathering 80% of responses and proof.</li><li>The project is now listed on the registry.</li></ul></td></tr><tr><td><strong>Registered</strong></td><td><ul><li>Draft PDD is reviewed by the Rainbow team and and is accessible on the registry.</li><li>A Draft PDD may include but is not limited to the project's estimated RCCs, co-benefits, photos, project description and location.</li></ul></td></tr><tr><td><strong>Public comment period</strong></td><td><ul><li>Third-party validation audit by the VVB is in progress.</li><li>The public comment period facilitated by Rainbow is available from the project's registry page. It shall remain open for at least 30 days.</li></ul></td></tr><tr><td><strong>Validated</strong></td><td><ul><li>The audit statement from the VVB has been shared with Rainbow, checked and uploaded to the registry.</li><li>The project's validation date is displayed on the registry (also referred to as "registration date").</li><li>The PDD is finalized and uploaded.</li><li>Project is eligible to issue credits.</li><li>If the project is already operating, it may undergo validation and verification at the same time, and pass directly to "Credited" status below.</li></ul></td></tr><tr><td><strong>Credited</strong></td><td><ul><li>Same as "Validated", and has completed at least one round of Monitoring and verification.</li><li>A Monitoring Report has been submitted by the Project Developer and been audited by a VVB.</li><li>The project must be operating.</li><li>RCCs are issued and made available on the registry.</li></ul></td></tr><tr><td><strong>Completed</strong></td><td><ul><li>The project has reached the end of its lifetime, is not renewed, and is no longer issuing new RCCs.</li><li>The project remains visible on the registry.</li></ul></td></tr><tr><td><strong>Withdrawn</strong></td><td><ul><li>The project stops certification before reaching "Validated" status.</li><li>Project Developer decides to no longer list the project on the Rainbow registry, the project is no longer visible.</li></ul></td></tr><tr><td><strong>De-registered</strong></td><td><ul><li>The project was validated (reached "Validated" status), and may or may not have been credited, but is no longer active.</li><li>The Project Developer requested deregistration, or the project was automatically deregistered after failing to undergo monitoring and verification within the specified timeframe.</li><li>The project is still visible on the Rainbow registry.</li></ul></td></tr><tr><td><strong>Rejected</strong></td><td><ul><li>Rainbow or the VVB decides to not certify the project, prior to validation (reaching "Validated" status).</li><li>The project is not visible on the Rainbow registry.</li></ul></td></tr><tr><td><strong>Suspended</strong></td><td><ul><li>A major non-conformity has been identified or the Project Developer was found responsible for an erroneous issuance</li><li>The project is still visible on the Rainbow registry.</li></ul></td></tr></tbody></table>

[^1]: including, if applicable, codes from the national integrated administration and control system (IACS) and land parcel identification system (LPIS) pursuant Regulation (EU) 2021/2116

[^2]: *Projects seeking eligibility under the European Union* [*Carbon Removals and Carbon Farming (CRCF) Regulation*](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202403012) *(EU/2024/3012)*


# Registry requirements

## User roles and access control

### **Roles & Permissions**

The Rainbow Registry has the following four distinct user roles, which are built into the technical specifics of the registry and cannot be bypassed.

<table><thead><tr><th width="214">Role types</th><th>Description</th></tr></thead><tbody><tr><td><strong>Registry administrator</strong></td><td>The registry administrator has the highest level of permissions, including the management of RCCs, projects, and users. This role is held by the Secretariat.</td></tr><tr><td><strong>Certification lead</strong></td><td>The Certification lead is a member of the Rainbow Certification team is responsible for creating and managing projects within the registry. They issue and cancel RCCs. They upload project-related files and update project statuses.</td></tr><tr><td><strong>Account holder administrator</strong></td><td>Account Holder Administrators are designated by the Account Holder during the account setup process and are created by Rainbow. They have the authority to manage Users within their account and oversee RCCs, including transfers and retirements.</td></tr><tr><td><strong>Account holder user</strong></td><td>can access the registry, and manage RCCs (transfers, retirements) when appropriate</td></tr></tbody></table>

### **Account holder types**

**Account holder organizations** on the Rainbow Registry are limited to one of the following **account holder types**:

<table><thead><tr><th width="166">Account holder type</th><th width="223.181640625">Description</th><th>Allowed actions</th></tr></thead><tbody><tr><td><strong>General Account (Buyer)</strong></td><td>Organizations interested in purchasing Rainbow Carbon Credits for offsetting or sustainability reporting.</td><td><ul><li>View and purchase Rainbow Carbon Credits</li><li>Access transaction history</li><li>Not allowed to issue or list projects</li></ul></td></tr><tr><td><strong>General Account (Trader)</strong></td><td>Organizations authorized to engage in the buying and selling of carbon credits (including brokers and agents).</td><td><ul><li>Buy, hold, transfer, and sell carbon credits on behalf of themselves or a Project Developer</li><li>Must have valid and current authorization from the Project Developer</li><li>Not allowed to issue or list projects</li></ul></td></tr><tr><td><strong>Project Developer</strong></td><td>Organizations responsible for developing carbon credit-generating projects following Rainbow methodologies.</td><td><ul><li>List and manage project activities</li><li>Submit documentation for issuance of Rainbow Carbon Credits</li><li>View credit status, issuance, and retirements</li><li>Retire, transfer and sell carbon credits from managed projects.</li></ul></td></tr><tr><td><strong>Validation/Verification Body (VVB)</strong></td><td>Independent third-party entities accredited to validate and verify project performance.</td><td><ul><li>View and validate documentations</li></ul></td></tr></tbody></table>

Individual/natural person accounts are not permitted under any of the categories.

### **Account creation**

#### Account Holder

Account holders shall accept the [Terms of Use of the Rainbow Registry](/other/terms-and-contracts/terms-and-conditions-for-registry-users) and go through [KYC](/other/governance-and-integrity/kyc-policy) and [AML](/other/governance-and-integrity/anti-money-laundering-aml-policy) assessment.

To open an account, the organization must submit all required documentation and identification information to Rainbow, including:

* Account holder type
* Legal entity name
* Organization registration number
* Organization phone number
* Registration address (postal code, city, address)
* Country
* Industry/Sector
* Website
* VAT number (if relevant)

Requests shall be sent through the website [here](https://rainbowstandard.io/get-started) or via email at <hello@rainbowstandard.io>.

Following document verification, and confirmation that the organization is an eligible Account Holder type, Rainbow will submit KYC and AML assessment materials to the organization.

Once the KYC and AML procedures are successfully completed, Rainbow will activate the account. Rainbow reserves the right to refuse account creation at its sole discretion.

#### User account

Once the Account Holder account is approved, **user accounts within that organization** may be created. The organization is responsible for:

* Creating and managing user access within its organization account
* Ensuring that each user operates under the appropriate role
* Promptly revoking access when a user no longer represents the organization

Each User must act on behalf of their organization and may not use the registry for personal or investment purposes.

### **User responsibilities**

All users must:

* Use their credentials securely and not share them
* Comply with Rainbow Standard Rules, Procedures Manual and applicable laws
* Avoid misuse of the platform (e.g., fraudulent activity, promoting unrelated services, system interference)

Rainbow conducts periodic reviews of access rights and user activity. Rainbow may **suspend or terminate access** in cases of non-compliance, fraud, revoked authorization, or any activity that brings the platform into disrepute. Account Holders are expected to:

* Review and update their user lists regularly
* Notify Rainbow of any changes in user roles or legal authorizations

## Project documentation

The Rainbow Registry is the central platform for publishing project information, ensuring transparency, traceability, and accessibility. All projects must provide a **minimum set of publicly available information** on their registry page. This information may appear **directly on the registry page**, or within **documentation linked from it**, as detailed in below sections.

Exceptions apply if disclosure is restricted by confidentiality, proprietary rights, privacy laws, or data protection regulations.

Project documentation and relevant data shall be preserved for more than three years beyond the end date of the monitoring period.

### Information on the registry

The following information shall be available **directly on the Rainbow registry** for each project:

* the name and type of the project
* name and contact details of the Project Developer
* the applicable methodology and version number
* the location of the activity, including the geographically explicit location of the activity boundaries, respecting 1:5000 mapping scale requirements
* the duration of the monitoring period and crediting period, including the start date and end date
* compliance with any accreditation or regulatory schemes such as CRCF, ICVCM, CORSIA...
* quantified co-benefits
* type of credit (e.g. removal vs avoidance)
* durability in years (if applicable)
* certification status, including certificates of compliance and validation and verification audit reports
* GHG quantification results (i.e. without application of the buffer pool and discount factor)
* quantity and status of RCCs (e.g. issued, retired, expired, cancelled or allocated to a buffer)
* end-use of the certified units, and the entity that uses the certified units.

### Project documents publicly available on the registry

The following information must be publicly accessible in linked project documents available on the registry:

* Demonstration of **project compliance with the Rainbow Standard Rules and the applicable methodology**. This includes, at a minimum:
  * Additionality template
  * ESS risk assessment template
  * Stakeholder consultation process and outcome
* Sufficient detail on the quantification of issued RCCs to allow **independent replication of calculations** at validation and for all subsequent verification events/credit issuances, including but not limited to quantification spreadsheet exports displaying:
  * calculation formulas
  * default values/secondary data
  * assumptions, and
  * project input data/primary measurements.
* The **Audit Reports** of every project validation and verification audit
* The **Project Design Document** (PDD) and any subsequent **Monitoring Reports**, with the following minimum content:

<details>

<summary>Minimum requirements for the PDD</summary>

PDDs shall contain, at a minimum, the following information:

**General and scope description**

* Non-technical description of the project operations, technology, infrastructure, scope, location, Project Developer, and other relevant actors
* Legal ownership and contact information of the Project Developer
* If using a registration partner or a group of Project Developers, a description of if and how advisory services are provided to Project Developers
* Technical description of the technology and project operations
* Specific location of the project, including [georeferenced boundaries](#user-content-fn-1)[^1] and/or GPS coordinates of the mitigation activity
* Compliance with any accreditations beyond Rainbow certification (e.g. CRCF, ICVCM..)
* Start date of the project, and start and end dates of the crediting period
* [Monitoring Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#monitoring) with parameters to be monitored
* Site registration
* Procedure and findings of [double-registration check](/rainbow-standard-documents/procedures-manual/project-certification-procedure#double-registration-check)

**Eligibility, principles and requirements**

* Justification that the project meets all [Principles and requirements](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements) described in the Rainbow Standard Rules, and the chosen methodology
* Stakeholders identified and outcomes of the stakeholder consultation
* Assessment of environmental and social risks, and demonstration of sustainability
* Project specific buffer pool contribution (if issuing removal RCCs)

**GHG quantification**

* Source for GWP100 values (IPCC AR6 or other IPCC version)
* Information on how the methodology was applied for the purpose of
  * determining the baseline,
  * demonstrating additionality and
  * quantifying GHG emission reductions or removals, including but not limited to assumptions, data sources, and emission sources/sinks, that are not already defined at the methodology level
* Project-specific uncertainty assessment and discount factor
* Future projections throughout the crediting period including:
  * Operational, production, delivery information
  * Expected total **gross** GHG emissions, carbon removals, and avoidance
  * Expected total **net** GHG emissions, carbon removals, and avoidance (after applying the discount factor and buffer pool contribution)

The PDD shall require any other information required for the VVB to validate the project as compliant with the Rainbow Standard Rules and the applicable methodology.

PDDs shall be made publicly available on the Rainbow Registry upon completing [Validation](#validation). See the [Registry and documentation](/rainbow-standard-documents/procedures-manual/registry-requirements#project-documentation) section for further instructions on publicly available documentation.

</details>

Commercially sensitive information may be redacted from publicly available documentation, where it can be proven that disclosure of such information is harmful. Such redaction shall be approved by the Rainbow team, and the information shall always be provided to the VVB.

### Procedure for requesting non-public information

A thorough description of the project’s design, implementation, and assessment findings must always be publicly disclosed. However, the primary proof supporting these assessments (such as raw monitoring data, internal reports, or proprietary models) may contain commercially sensitive or confidential information. These documents are not required to be made publicly available, but must be **listed in the PDD and/or Monitoring Reports as proof**, and made available to the VVB and the Rainbow team.

Stakeholders may request access to non-public documents by contacting either the Rainbow team at <climate@rainbowstandard.io> or the Project Developer via the contact details listed on the project page.

If the request is made to the Rainbow team, they must forward it to the Project Developer within 5 working days. Access must be granted if the information can be shared without:

* violating licensing agreements,
* disclosing commercially sensitive information,
* violating privacy and data protection restrictions, or
* where it cannot be proven that disclosure of such information is harmful.

The Project Developer must respond to the requester within 10 working days, either by granting access or providing a justification for non-disclosure.

## Registry IT security

### Security standards

The following security measures are the minimum requirements for the Rainbow Registry:

* Data transfers shall always use industry-standard encryption technology (SSL/TLS/HTTPS).
* Application authentication shall be enabled and verified by a third-party provider that meets industry best practice, is internationally recognized, and is ISO27001 certified.
* Backend service and database hosting shall be enabled by a third-party provider that enables encryption.
* Administrative tools shall be provided 2FA for admin authentication and sign-in.

### Security audit

The Rainbow Secretariat shall verify **at least twice per calendar year** that the IT security requirements are met, and summarize the findings in a report made publicly available on the Rainbow documentation hub. The following elements shall be verified:

* Verify compliance with the above requirements
* Verify security vulnerability status and upgrade all JavaScript dependencies with npm.
* Review Authentication provider access
* Review Cloud provider IAM accounts and access
* Rotate database passwords, API keys (internal and external)
* Review Database connection allowlist
* Review repository history for leaked secrets
* Verify application authorization rules

Past IT security Audit Reports can be found in the [Administrative Oversight Record](/other/administrative-oversight#miscellaneous) section.

### Incident procedures

#### Incident definition

A technological incident is defined as:

* Theft or loss of data
* Transfer of data to those unauthorized to receive it
* Attempts to gain unauthorized access to Rainbow data or systems
* Unintended disruption of the availability of Rainbow systems
* Other significant events or bugs that compromise Rainbow's position as a trusted actor in the VCM ecosystem

#### Reporting incidents

* The general public is encouraged to report suspected incidents or vulnerabilities to <support@rainbowstandard.io>
* Employees shall report incidents to the internal Rainbow oncall engineer, <support@rainbowstandard.io>, or to their manager

#### Incident response

1. Within one working day (24 hours) of being informed of a suspected incident, the oncall engineer shall confirm reception of the incident report and begin an investigation to verify and assess the scope of the issue.
2. If the engineering oncall finds that the issue qualifies as an incident, they shall set up a dedicated channel to coordinate a response, including members of relevant teams as dictated by the nature of the problem.
   1. The response team shall then work to contain, eliminate and then recover from the problem as their highest-priority task.
   2. The response team shall communicate information about the incident to all relevant parties affected by the incident, including but not limited to clients, certifying bodies, employees, during and after recovery.
   3. The response team shall hold a post-mortem meeting to deeply understand the underlying causes of the incident and plan proportional follow-up tasks to prevent similar failures from happening in the future. Findings from the post-mortem shall be shared internally or externally as appropriate.

[^1]: including, if applicable, codes from the national integrated administration and control system (IACS) and land parcel identification system (LPIS) pursuant Regulation (EU) 2021/2116


# Rainbow Carbon Credits

## Credit attributes

### Credit blocks

A **credit block** refers to a group of Rainbow Carbon Credits (RCCs) that share the same key characteristics. Each credit block contains only RCCs from the same:

* project,
* mechanism (e.g., avoidance or removal),
* vintage year (year of verified carbon impact), and
* verification event.

On the Rainbow Registry, each transaction can only involve credits from **a single credit block**. For example, if credits belong to different credit blocks (e.g., different vintage years or mechanisms), they must be transacted in separate operations.

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><p>A <strong>project</strong> is uniquely described on the registry by:</p><ul><li>Project registry ID</li><li>Project name</li><li>Name of the Project Developer</li><li>Location</li><li>Host country</li><li>Type of mechanism (avoidance and/or removal)</li><li>Crediting period</li><li>Validation body</li><li>Most recent version of the Rainbow Standard Rules and methodology used</li><li><a href="/pages/LqYMOAq4owP6jpiFyN5K#project-status-on-the-registry">Project status</a></li><li>Labels where relevant</li></ul></td></tr><tr><td><p><strong>Each RCC</strong> credit block is uniquely described on the registry by:</p><ul><li>Credit serial number range</li><li>Number of credits in the block</li><li>Project registry ID</li><li>Vintage year (year of verified activity in verification)</li><li>Type of mechanism (avoidance or removal)</li><li>Methodology ID and version number</li><li>Rainbow Standard Rules version number</li><li>Host country (inherited from Project)</li><li>Durability (in years, for removal RCCs only)</li><li><a href="#rcc-status">Credit status</a></li><li>Labels where relevant (e.g. CORSIA, Article 6, CCP…)</li></ul></td></tr></tbody></table>

Labels are supplementary information and do not change the inherent status of a verified avoidance or removal RCC. Labels may cover, for example:

* **Compliance with trading schemes:** e.g. CORSIA eligible, pending CORSIA-eligibility, Article 6/PACM eligible, CRCF-compliant
* **Accredited:** e.g. ICROA accredited, ICVCM accredited

### Credit serial numbers

Each RCC has its own unique **credit serial number** on the Rainbow Registry. Credit serial numbers are generated using a consistent naming convention with the following components:

* **Registry identifier:** `RIV` **or** `RBW`
* **Country code** (e.g. `FR`, `DE`)
* **Project ID** (internal registry identifier)
* **Mechanism** abbreviated as:
  * `AVD` for avoidance
  * `RMV` for removal
* **Vintage year** (e.g. `2023`)
* **Last 5 characters** of the issuance transaction UUID
* **Credit number** within the issuance transaction (e.g. `1` or `248`)

Credit blocks are identified by a unique **credit serial number range**, including the serial number and the range of credit numbers of the credits contained within that block.

{% hint style="info" %}
For example, a credit block may have the following credit serial number range:

<pre><code><strong>RIV-FR-P123-AVD-2025-3f9a1-1:100
</strong></code></pre>

This serial number indicates a credit block from project `P123` in France, with avoidance credits from 2025, issued under a transaction ending in `3f9a1`, and covering credits numbered from 1 to 100.&#x20;

This credit block contains a credit with the following credit serial number, representing credit number 3 within the credit block:

<pre><code><strong>RIV-FR-P123-AVD-2025-3f9a1-3
</strong></code></pre>

{% endhint %}

### RCC status

The Rainbow Registry identifies and tracks the following:

* **RCC status** according to the definitions outlined below
* **RCC ownership/holding,** from issuance to cancelation or retirement.

Rainbow Carbon Credits (RCCs) shall have an assigned status on the Rainbow Registry, including one of the following:

<table><thead><tr><th width="133">Status</th><th>Definition</th></tr></thead><tbody><tr><td>Available</td><td>RCCs issued ex-post at the end of the reporting period, following submission of a Monitoring Report and <a href="/pages/LqYMOAq4owP6jpiFyN5K#monitoring-and-verification">verification audit</a> by a third-party VVB. Available to be transferred and retired.</td></tr><tr><td>Retired</td><td>Once retired, an RCC and its climate benefit are locked, with its designated purpose for the beneficiary. They are no longer transferable, ensuring exclusivity and preventing any further use or transfer.</td></tr><tr><td>Canceled</td><td>RCCs that were Available but were found to be invalid (e.g., issued in error, or reversed in the case of removal RCCs. See the <a href="#cancelation">Cancelation</a> procedure).</td></tr><tr><td>Buffer</td><td>Verified removal RCCs issued to the Project Developer account and immediately and automatically transferred to the Rainbow Buffer Pool to cover potential reversal events.</td></tr></tbody></table>

All **events** (issuance, transfer, retirement, cancelation) shall be recorded on the registry, including the following details:

* **Transaction ID:** unique identification of the transaction
* **Completed at**: date of the event
* **From**: organization initial owner of the units
* **To**: new organization owner of the units
* **Credit serial numbers**
* **Amount of credits**

All events are made public and shall allow for tracking history of ownership of the units.

## Discount factor

A fraction of a project’s quantified RCCs may be eliminated using the uncertainty discount factor to mitigate carbon credit overestimation. These verified avoided/removed emissions are **never issued as RCCs and will not appear on the registry**.

A discount factor shall be applied when **material uncertainty is identified** in the project's GHG quantification. This may be related to, for example, the project’s measured data, assumptions, or the selection of the baseline scenario.

When material uncertainty is detected:

* Steps shall be taken to reduce uncertainty wherever possible.
* Conservative choices must be adopted.
* If uncertainty remains, a discount factor is applied.

Detailed requirements are provided in the [Uncertainty Assessment](/rainbow-standard-documents/rainbow-standard-rules/ghg-quantification#uncertainty-assessment) section of the Rainbow Standard Rules.

The discount factor may vary from 0% to a maximum of 15% of estimated RCCs. If a project requires a discount factor higher than 15%, the uncertainty is deemed too high and the project is not eligible. The specific discount factor value is determined for each project, considering both **project-specific uncertainty** and the **minimum required discount factor** defined in the applicable methodology.

## Buffer pool

All projects that issue removal RCCs are required to allocate **at least 2% of their verified removal RCCs to the Rainbow Buffer Pool**. Methodologies may determine a higher minimum buffer pool contribution for projects under them, and/or further instructions for how to determine a project-specific buffer pool contribution amount.

This pool acts as an **insurance mechanism against the risk of reversal** of sequestered carbon before the agreed upon commitment period. RCCs shall be canceled from the buffer pool if there is a reversal event (see details in the [Cancelation](#cancelation) section). This may occur due to, for example, natural disaster (fires, drought, pests) or project mismanagement. These RCCs cannot be retired by buyers. The buffer pool is shared across all projects.

The detailed content of Rainbow Buffer Pool is publicly available on the Rainbow Registry.

## Issuance

The issuance of RCCs is operated by the Rainbow Certification team once the project's [monitoring & verification](/rainbow-standard-documents/procedures-manual/project-certification-procedure#monitoring-and-verification) is conducted, and all Audit Reports are available.

A member of the Rainbow Certification team initiates the issuance, and their name is registered and tracked in the Registry. The issuance details are reviewed by a second Rainbow Certification team member who verifies the accuracy, completeness, and compliance of the issuance with Rainbow’s procedures. The second team member must explicitly approve the issuance in the system. Only upon approval are the RCCs officially issued in the registry.

Upon issuance of **removal RCCs**, a portion of credits are automatically and immediately transferred from Project accounts to the shared [Rainbow Buffer Pool](#buffer-pool) account. The number of RCCs, when calculated as a percentage of the buffer pool contribution, is always rounded up to the nearest whole credit.

All issuance events shall be recorded on the Rainbow registry with at least the following details:

* **Verified by**: Accredited VVB that conducted the audit
* **Monitoring period**: period covered by the issuance
* **Audit Report**: audit report produced by the VVB

The initial owner of all RCCs shall be the Project Developer.

## Transfers

Registry users may transfer RCCs between two Account Holders.

Transfer of RCCs are subject to the following rules:

* Users can only transfer RCCs that they own; and
* Users can only transfer RCCs to Buyers who have an active registry account.

All transfer events shall be recorded on the Rainbow registry with the former owner of the units and the recipient.

The Rainbow registry shall ensure that transactions are secure, with a double validation system, requiring both sender and recipient to acknowledge and validate the transfer.

Rainbow does not allow any transfer of RCCs outside of the Rainbow registry.

## Cancelation <a href="#cancelation" id="cancelation"></a>

RCCs shall be canceled in the event of a reversal or erroneous over-issuance evaluated at least 1 tCO$$\_2$$eq avoided or removed. The cancelation of RCCs is operated by the Rainbow team once a **Cancelation Notice** is submitted and is validated by the Rainbow Secretariat. The Cancelation Notice shall include:

* The project and Project Developer name
* Type of credits concerned (vintage, durability, any accreditations/labels)
* Reason for the cancelation (reversal or erroneous issuance)
* Date, description and type (avoidable or unavoidable) of reversal (if applicable)
* Date the Cancelation Notice is sent to Rainbow
* Number of credits to be canceled, with quantification and proof

After investigation by the Rainbow team, and the execution of the applicable compensation, a **Cancelation Report** is generated, confirming or updating the information of the Cancelation Notice and stating the party responsible for the compensation.

The Cancelation Report is submitted to an accredited VVB and shall follow the Monitoring audit procedures.

A member of the Rainbow Certification team initiates the cancelation, and their name is registered and tracked in the Registry. The cancelation details are reviewed by a second Rainbow Certification team member who verifies the completeness and compliance of the cancelation with Rainbow’s procedures. The second team member must explicitly approve the cancelation in the system. Only upon approval are the RCCs officially canceled in the registry.

### Canceling removal credits due to reversals

When a GHG reversal is identified, Rainbow shall **cancel credits from the buffer pool to compensate for the reversal**. A GHG reversal is defined as any event that re-emits at least 1 tCO$$\_2$$eq of the carbon removed by the project mitigation activity, before the monitoring period ends.

The Project Developer must submit a Cancelation Notice to notify Rainbow within 30 calendar days of becoming aware of the reversal event. Rainbow shall then **cancel an equivalent amount of RCCs from the buffer pool**, matching the tCO₂eq estimated to have been released in the reversal event. The canceled RCCs must correspond to the same type as the reversed removal RCCs, including durability and labels.

Reversals are classified as avoidable or unavoidable. The **replacement of canceled credits in the buffer** **pool** shall be managed according to the procedure in Table 1, depending on the type of reversal.

*Table 1 The different types of reversals are defined. In case of any reversal, credits from the Buffer Pool of the same type are canceled to compensate the reversal. The Buffer Pool replacement requirements column outlines the requirements for Project Developers to replace those canceled Buffer Pool credits, depending on the reversal type.*

<table><thead><tr><th width="151">Type of reversal</th><th width="293.552734375">Definition</th><th>Buffer Pool replacement requirements</th></tr></thead><tbody><tr><td>Avoidable</td><td><p>Reversal that</p><ul><li>results from actions or omissions within the project’s control,</li><li>could have been prevented with reasonable foresight and risk mitigation</li><li>typically a result of failure to maintain equipment, follow protocol, or update systems; human error or negligence; or foreseeable and mitigable natural disturbances.</li></ul></td><td><p>The Project Developer shall fully compensate the canceled Buffer Pool credits with credits of the same type,</p><p>The Project Developer shall do this by either:</p><ul><li>transferring already issued credits from their project/s to the buffer pool immediately;</li><li>transferring all credits issued in future monitoring periods from their project/s to the buffer pool, or</li><li>purchasing credits of the same type, and transferring them to the buffer pool.</li></ul></td></tr><tr><td>Unavoidable</td><td><p>Reversals that</p><ul><li>are caused by events beyond reasonable control or prediction,</li><li>where mitigation was not feasible or would have imposed unreasonable burden,</li><li>resulted from natural disasters (e.g. wildfire, earthquake, extreme weather); pest or disease outbreaks; or policy or regulatory change beyond project control</li></ul></td><td>The Project Developer is not liable for replacing the buffer pool credits.</td></tr></tbody></table>

Classification of a reversal as avoidable or unavoidable will be decided by Rainbow, following inputs from the Project Developer and an accredited VVB.

A **Cancelation Report** will be generated and attached to the cancelation event in the Registry, that includes the Cancelation Notice provided by the Project Developer, plus a detailed description of the outcome and steps taken to fully compensate the reversal.

### Cancelation and insufficient buffer pool size

If the buffer pool holds an **insufficient balance of RCCs to fully compensate a project's avoidable reversal event**, all subsequent removal RCCs of the same type issued by the Project Developer shall be transferred to the buffer pool and immediately canceled until the full amount of the reversal has been compensated. This requirement applies whether such RCCs originate from the same project or from other projects operated by the same Project Developer.

If the project is not expected to generate sufficient RCCs to fully compensate for the reversal during the remaining crediting period (for example, if the project is nearing the end of its crediting period and will not seek renewal), the Project Developer shall procure RCCs of the same type from other projects and transfer them to the buffer pool, where they shall be immediately canceled to offset the reversal.

If the Project Developer ceases operations, Rainbow shall assess and address the situation on a case-by-case basis.

If the buffer pool holds an **insufficient balance of RCCs to fully compensate a project's unavoidable reversal event**, Rainbow shall ensure the buffer pool is fully compensated with credits of the same type.

### **Canceling credits due to erroneous issuance**

Verified RCCs may be deemed erroneously issued due to, for example, use of wrong input data, or inaccurate proof. While the comprehensive audit process renders this highly unlikely, a procedure has been prepared.

Erroneous issuance may be signaled by the Project Developer, the VVB, the Rainbow team, or any stakeholder, by submitting a Cancelation Notice. They can do so by email at <hello@rainbowstandard.io>, or [via this form](https://rainbowstandard.io/general-inquiries). The Rainbow team shall investigate the incident, determine the number of excess credits issued, and take the following remediating action:

* **Credits not yet transferred**: an amount of credits corresponding to the number of excess credits issued for the given project's credit block shall be frozen during the investigation, and canceled once the Cancelation Report is issued.
* **Credits already transferred or retired:**
  * Rainbow shall notify the Account Holder, and cancel the corresponding credits once the Cancelation Report is issued.
  * All subsequent RCCs of the same type issued by the Project Developer shall be transferred to the Account Holder, until the full amount of the cancelation has been compensated. This requirement applies whether such RCCs originate from the same project or from other projects operated by the same Project Developer.
  * If the project is not expected to generate sufficient RCCs to fully compensate for the cancelation during the remaining crediting period (for example, if the project is nearing the end of its crediting period and will not seek renewal), the Project Developer shall procure RCCs of the same type from other projects and transfer them to the Account Holder.

Rainbow shall suspend the project and this Project Developer from further verification, and outline remediation actions for the Project Developer to compensate the erroneous issuance and, if applicable, comply going forward. The Project Developer shall implement the **identified remediation action/s within 90 days** of notification of suspension.

* Failure to do so shall result in the project being **deregistered** from the Rainbow Registry
* Upon resolving or remediating the non-conformities within 90 days, the project is re-registered and is eligible to issue credits in subsequent monitoring periods.

A **Cancelation Report** will be generated and attached to the cancelation event in the Registry, that includes the Cancelation Notice provided by the Project Developer, plus a detailed description of the outcome and steps taken to fully remediate the erroneous issuance.

## Retirements

Retirement marks the final ownership and event for an RCC. By retiring an RCC, the associated climate benefit is locked into a specific accounting purpose, preventing any future use whether by the original owner, the designated beneficiary, or any other party. This guarantees the unit’s exclusivity in its intended claim.

The beneficiary of a retirement is the organization on behalf of whom the RCC was retired, and must be **publicly identified** **on the Rainbow registry**. Beneficiaries can be the current holder, or an organization that is specified by the owner of the unit during the Retirement procedure.

Users may request retirements of the RCC owned by their organization, by following the process on the Rainbow registry.

All retirement events shall be recorded with the following additional information:

* **Retired by**: legal name of the last known owner of the RCCs
* **On behalf of**: identification of the beneficiary of the the RCCs
* **Country**: country of incorporation of the beneficiary of the RCCs
* **Reason**: purpose for which the credits were retired;

The **retirement certificate**, generated automatically on the Rainbow registry, serves as proof of the retirement event, relating to one or more units. Retirement certificates may be downloaded from the registry public page, and shall contain all event details and additional retirement details.

Once RCCs are retired, any event type linked to them shall be prohibited.

### Authorized uses

Rainbow Carbon Credits (RCCs) under the Rainbow Standard may be used for the following authorized purposes:

* **Article 6:** Contribution to the Nationally Determined Contribution (NDC) target of the country buying the RCCs, through the use of Internationally Transferred Mitigation Outcomes (ITMOs).
* **CORSIA:** Fulfillment of aircraft operators' obligations for compliance with the **Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA)**, operated by the International Civil Aviation Organization (ICAO) (approved methodologies only).
* **French Airline Decree:** Fulfillment of aircraft operators' obligations under **Article L229-55 / R229-102** of the French R229-102-1 decree (approved methodologies only).
* Retirement of RCCs within the voluntary carbon market, to make **contribution or offsetting claims**.

Voluntary contributions and offsetting claims represent action taken without any government mandate.

* These actions do not require approval or a corresponding adjustment (CA), unless specified by the host country.
* If no approval or CA is required, the GHG avoidance or removals achieved by the project are considered to count toward the host country’s Nationally Determined Contribution (NDC).


# VVB Requirements

## VVB accreditation

All Validation and Verification Bodies (VVBs) must undergo **accreditation by Rainbow** in order to audit projects for validation and verification under the Rainbow Standard Rules and Rainbow methodologies.

### General requirements

VVBs shall have a valid accreditation from either:

* ISO 14065 or EN ISO 14065
* ISO 17029 or EN ISO/IEC 17029, with a scope of application related to GHG emissions

VVBs must be accredited by an Accreditation Body that is part of the IAF MLA/MRA framework.

The VVB company shall prove that they employ auditors with more than 5 years of auditing experience, including at least 2 years in environmental/sustainability auditing (refer to [Structure and qualification of VVB audit teams](#structure-and-competency-of-vvb-audit-teams) section).

VVBs shall adhere to the Rainbow [Conflict of Interest Policy](/other/governance-and-integrity/conflict-of-interest-policy) and confirm their independence from the market and carbon credit transactions. VVBs shall submit a [declaration of conflict of interest form](https://i2fdkskubbk.typeform.com/to/kOgHVIiX) at each validation or verification audit they perform. VVBs appointed by Rainbow may not hold membership, ownership, or voting rights in the Rainbow Standard.

VVBs shall demonstrate that they employ auditors with knowledge of and experience on the sector it seeks accreditation for by providing CVs of the lead auditors, and proof that those auditors have worked on at least 2 projects within the sector within the 2 previous years.

Upon initial accreditation review, and on a yearly basis in the annual [Activity Report](#vvb-oversight-1), the VVB shall:

* Prove that the company is financially sound
* Disclose to Rainbow any negative media coverage
* Disclose any legal/juridical proceedings

### Sectors for accreditation

The VVB must demonstrate its knowledge of and experience related to a specific sector on which it can conduct the VVB tasks. Relevant sectors include but are not limited to:

* Circular/industrial solutions
* Bioenergy & biomass processing
* Construction sector
* Geochemistry: Enhanced Rock Weathering, Mineralization, Ocean Alkalinity Enhancement
* Land based mitigation activity: forest, soil carbon or carbon farming

### Accreditation process

To initiate the accreditation application, the VVB submits the [VVB application form](https://i2fdkskubbk.typeform.com/to/cZaO2iez) to Rainbow. Upon receipt of the application, the Rainbow Secretariat reviews the information provided and rejects or approves the application.

* Rejection: Rainbow rejects applications where it determines that the applicant does not possess the required competencies, specified in the section above.
* Approval: Rainbow approves the application and sends the documents listed below to be signed.

If approved, the VVB shall:

* submit a signed copy of the Rainbow [Conflict of Interest Policy](/other/governance-and-integrity/conflict-of-interest-policy), and
* submit a signed copy of the present Procedures Manual section on VVBs, and
* attend a training session for VVBs on the Rainbow Standard, relevant methodologies, and the Certification Platform, organized by the Rainbow Secretariat and the Certification team.

Upon satisfactorily completing these steps, the Rainbow Secretariat delivers an accreditation to the VVB, allowing them to audit projects seeking validation and/or verification under the Rainbow program.

The VVB organization is added as an approved VVB, and is publicly disclosed on Rainbow’s website.

## VVB Oversight

### VVB rotation

A single VVB shall conduct **validation/verification audits for a specific project for a maximum of three sequential years**. Upon reaching this limit, the Project Developer shall engage a different VVB for subsequent verifications. The Project Developer is granted a transition period of six months to engage a new VVB for the subsequent verification.

Project Developers shall maintain comprehensive records of all verifications, including the VVBs involved, to demonstrate compliance with this rule.

The Rainbow certification platform coordinates and tracks VVB audits, flagging and preventing VVBs from surpassing the sequential audit limit for a single project.

### VVB training

All [Audit Leaders](#user-content-fn-1)[^1] must attend a training on the Rainbow Standard and the relevant methodology before conducting any audits. Additionally, Audit Leaders shall undergo a training any time there is a major Standard or methodology release. Training shall also be triggered by regulatory updates, significant audit findings, and other events affecting audit competence. The courses shall include an examination to demonstrate the participants’ compliance with the training requirements in the technical area or areas in which they are active.

Rainbow shall record the presence of all individual auditors and their affiliated VVB at training events. This shall be reported in the VVB annual Activity Report, and assessed in the VVB's performance review.

### VVB oversight

Rainbow shall oversee VVB performance annually, resulting in [sanctions](#vvb-sanctions) (detailed below) or approved continued use of the VVB for the Rainbow standard.

To facilitate this review, VVBs shall submit an **annual Activity Report** to Rainbow that details its activities (including number of validation and verification audits), challenges, trainings undertaken, and areas of improvement relating to its work with the Rainbow certification process.

Project Developers are asked to **provide feedback on the VVB's performance** after each validation and verification process, as part of the [Rainbow satisfaction survey.](https://i2fdkskubbk.typeform.com/to/Q79TnJ9y)

The performance review uses this feedback from Project Developers, Rainbow's feedback on audit activities, and the Activity Report to evaluate each VVB for compliance with the VVB requirements herein. Rainbow will report significant and/or repeated VVB performance concerns to the relevant VVB which may result in [sanctions](#vvb-sanctions).

If Rainbow receives a request from the competent authorities, the VVB shall cooperate with the authorities, including granting access to the premises or provide the information needed by the authorities.

Rainbow shall conduct **spot checks** to ensure VVB compliance with the present VVB requirements. These spot checks shall cover a risk-based sample of projects, and assess VVB documentation (including audit plans, audit trail, collected evidence and conflict of interest disclosures), and project documentation.

### VVB sanctions

VVBs may be sanctioned and suspended at any time, upon annual review or upon a single project audit, at the discretion of the Rainbow Standard Secretariat, due to:

* **non-conformities** with the VVB requirements presented in this section, or
* **other red flags** such as fraud, negligence, COIs, loss of team members with required technical competence, or revoked accreditations listed in the [General requirement](#general-requirements) section.

Depending on the gravity of the breach, and the corrective measures taken the VVB, the Secretariat shall determine the duration of the VVB suspension. VVBs may be reinstated upon taking corrective measures, clarifying and proving compliance, or where no resolution is available, may reapply as a Rainbow accredited VVB two years after suspension.

Rainbow shall report to the relevant accreditation body (e.g. IAF, COFRAC, ANAB, etc) the identified breach.

VVBs that are no longer entitled to conduct auditing under Rainbow shall be listed for at least 24 months on Rainbow’s website after the last audit with an indication to that effect.

The Secretariat shall publish a publicly-available summary of the reason for sanctions, the potentially affected projects and audits, any corrective measures to these audits, corrective measures and/or clarification from the VVB to regain accreditation, and final status and next steps.

## Validation and Verification process

{% hint style="info" %}
All Projects must undergo an initial [Validation](/rainbow-standard-documents/procedures-manual/project-certification-procedure#validation) audit, carried out by an accredited VVB, to assess conformity with the Rainbow Standard, and with the applied methodology. Once a project has been Validated, the Project Developer follows the Monitoring Plan, submits the parameters in the Monitoring Report, which undergoes a [Verification](/rainbow-standard-documents/procedures-manual/project-certification-procedure#monitoring-and-verification) audit in order to to issue RCCs.
{% endhint %}

To conduct the **Validation Audit**, the Project Developer and VVB team shall follow the procedures outlined in the [Project validation](/rainbow-standard-documents/procedures-manual/project-certification-procedure#validation) section of the Rainbow Procedures Manual.

To conduct the **Verification Audit**, the Project Developer and VVB team shall follow the procedures outlined in the [Monitoring and verification](/rainbow-standard-documents/procedures-manual/project-certification-procedure#monitoring-and-verification) section of the Rainbow Procedures Manual.

The level of assurance for Validation and Verification Audits must be **reasonable**. VVBs are responsible for ensuring the audits they conduct meet this level of assurance.

The methodology shall define whether the [site audit](/rainbow-standard-documents/procedures-manual/project-certification-procedure#site-audit) must be based on an **on-site visit or a remote audit**. The VVB may, based on an independent risk assessment:

* mandate an on-site visit for the site audit where a remote audit would otherwise be acceptable, and/or
* require an on-site visit for subsequent verification audits, even when site audits would otherwise not be necessary.

The Validation and Verification audits shall be conducted by VVB in accordance **ISO 14064-3 and ISO 14065**, and in compliance with the requirements of EN ISO/IEC 17021-1 in conjunction with EN ISO/IEC 19011 (or equivalent standards).

Validation and verification audits shall cover at least the following elements:

* identification of the activity undertaken by the Project Developer which is relevant for the methodology
* identification of the **relevant methodology and Rainbow Standard Rules requirements** of the project and the Project Developer's organization, and check its effective implementation;
* analysis of the risks which could lead to a material misstatement, based on the auditor’s professional knowledge and the information submitted by the Project Developer. The analysis of risks shall take into consideration the overall risk profile of the activity, depending on the level of risk of the operator. The audit intensity or scope, or both, shall be adapted to the level of overall risk items.
* an audit plan which corresponds to the risk analysis and the scope and complexity of the Project Developer’s activity, and which defines the sampling methods to be used with respect to that operator’s activity;
* implementation of the audit plan by gathering evidence in accordance with the defined sampling methods, plus all relevant additional evidence, upon which the auditor’s conclusion will be based;
* a request by the auditor to the Project Developer to provide any missing elements of audit trails, an explanation of variations, or the revision of claims or quantification, before reaching a final audit conclusion;
* identification of any unresolved non-conformities, concerns, discrepancies, and material misstatements, of the project's information and evidence assessed against the relevant methodology and Rainbow Standard Rules requirements;
* Internal Review by an auditor who is not the Audit Leader, in the same VVB organization, to perform a final QA/QC review (Quality Assurance/Quality Control), attesting to accuracy of data and of the Audit Leader's findings.

A **Conflict of Interest (COI) form** shall be submitted to Rainbow’s Certification team for the audit team for each validation and verification audit.

### Audit teams

The VVB shall select and appoint the **audit team** in accordance with EN ISO/IEC 17021-1 in conjunction with EN ISO/IEC 19011, taking into account the competence needed to achieve the objectives of the audit.

The VVB must employ a minimum of two auditors for each audit: **one Audit Leader** and one **internal reviewer**. The audit team may also include additional auditors, local experts, content experts, and/or translators. The Audit Leader is the main contact person for project verification.

The auditors chosen by the VVB to audit a specific project shall meet the following requirements:

* be **independent** of the activity being audited;
* be **free from conflict of interest**, for instance not being involved simultaneously

  in consultancy and audit with the same Project Developer over the past three years

  previous to the audit;
* have the **knowledge, experience and skills necessary** for conducting the audit

  related to the Rainbow Standard and applicable methodology’s scope, including:

  * The Rainbow Standard Rules, methodologies, and relevant procedures, as well as specific expertise in the project type/activity;
  * The GHG emission avoidance/removal accounting methodology(ies) applied by the project, including activity data and emissions factors;
  * Data sampling techniques, including risk weighting and statistical significance calculation;
  * Project baselines, removals, and sequestration;
  * Concepts such as additionality, leakage and permanence;
  * Risk assessment techniques;
  * Data monitoring, auditing, and assurance;
  * Desk-based reviews of documents, data, and records;
  * Validation and verification techniques, to assess accuracy and appropriateness of gathered evidence; and
  * Preparation of validation and verification reports.

The site audit team must demonstrate knowledge and expertise in:

* Country-specific knowledge and language skills;
* Interviewing, listening, and observing; and
* Sensitivity towards socio-economic matters and environmental and social safeguards.

### Materiality Threshold

The threshold for Materiality in audits, considering the totality of all omissions, errors and mis-statements, is 5% for all projects. To accept a Verification Audit Report, any discrepancy between the GHG avoidance/removals estimated by the Project Developer and by the VVB for a given Monitoring Period shall be less than the Materiality threshold.

Qualitative materiality issues may also be identified and documented, and flagged as project non-conformities where necessary, such as:

* control issues that erode the auditor’s confidence in the reported data;
* poorly managed documented information;
* difficulty in locating requested information;
* noncompliance with regulations indirectly related to GHG emissions, removals or storage.

### Audit plan

Prior to a Validation/Verification audit, the VVB must prepare a **Validation/Verification Audit plan** that details the activities and schedules related to the audit. The plan may be revised as necessary during the process. The plan must be communicated with the Project Developer and must include, at minimum:

* the audit scope and objectives;
* identification of the Audit team and their roles;
* client/responsible party contact;
* schedule of activities;
* level of assurance (at least reasonable level of assurance required);
* verification criteria;
* materiality; and
* schedule for any site visits.

### Audit Report

The VVB shall produce an Audit Report that documents the activities, results, findings, and conclusion of each Validation and Verification audit. The Audit Report shall reflect the findings and work of all members of the audit team (i.e. Audit Lead, internal reviewers, and if applicable, local experts, content experts, and/or translators). The Audit Report must be made publicly available on the registry for each Validation and Verification audit, and contain at least the following content.

<details>

<summary>Minimum requirements for Audit Reports</summary>

**Summary of the Audit Report**

**Project Developer information:**

* Contact information (name and address);
* Geographical locations of the activity, including longitude and latitude coordinates;
* Scope of the certification and relevant certification methodology applied;
* Reference number of the PDD and Monitoring Plan.
* a statement that the Project Developer is responsible for the fair presentation of the PDD in accordance with the criteria;

**Project information:**

* Expected (for validation audit), verified (for verification audit) total amounts of carbon removals, and of associated greenhouse gas emissions resulting from the project;
* Expected (for validation audit), verified (for verification audit) amount of RCCs with the relevant vintage and durability resulting from the project;
* Sustainability co-benefits associated with the project.

**VVB information**

* Contact information (name and address) and logo;
* Composition of the audit team;
* National accreditation body and scope and date of accreditation, or national recognition authority and scope and date of recognition.
* a statement that the Auditor is responsible for expressing an opinion on the PDD based on the Validation/Verification;
* the Auditor’s location;

**Information on the audit process**

* Date/s of the audit;
* Audit itinerary and duration (split by duration spent on-site and remotely – where relevant);
* Standard Rules version and Methodology version used for the audit;
* Sites audited;
* Audit method (risk assessment and sampling basis, stakeholder consultation);
* a description of the evidence-gathering procedures used to assess the PDD;
* Certification of other voluntary schemes or standards;
* reference to the Monitoring Plan and verification scope;
* GHG data type.

**Information on audit results**

* Place and date of issuance of the audit report;
* The following outcomes of the audit:
  * confirmation of compliance to a **reasonable Level of Assurance** with Regulation (EU) 2024/3012 and applicable certification methodology;
  * list of [non-conformities](/rainbow-standard-documents/procedures-manual/project-certification-procedure#non-conformities) identified with applicable timeline for their remediation.
* the Lead Auditor’s signature.

</details>

### Certificate of compliance

For projects that seek to comply with the EU [Carbon Removals and Carbon Farming (CRCF) Regulation](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202403012) (EU/2024/3012), a **certificate of compliance** shall be issued by the VVB for each successful verification audit, along with the Audit Report.

See the [CRCF Requirements](/rainbow-standard-documents/procedures-manual/crcf-requirements) section for more details.&#x20;

[^1]: Defined in the [Audit teams](#audit-teams) section below:

    *The VVB must employ a minimum of two auditors for each audit: **one Audit Leader** and one **internal reviewer**. The audit team may also include additional auditors, local experts, content experts, and/or translators. The Audit Leader is the main contact person for project verification.*


# CORSIA and Article 6

The present section describes eligibility requirements and procedures for Project Developers that seek to issue credits that are eligible as:

* emissions units for the Carbon Offsetting and Reduction Scheme for International Aviation ([CORSIA](https://www.icao.int/CORSIA)) and/or
* Internationally Transferred Mitigation Outcomes (ITMOs) for trading and use towards the Nationally Determined Contribution (NDC) target of the country buying the RCCs, through the use of [Article 6.2](https://unfccc.int/process-and-meetings/the-paris-agreement/article6) of the [Paris Agreement](#user-content-fn-1)[^1] under the The United Nations Framework Convention on Climate Change (UNFCCC).

{% hint style="info" %}
For clarity, these cases shall be referred to as **issuing CORSIA credits and issuing Article 6 credits**.
{% endhint %}

Project Developers seeking to issue credits that are not CORSIA or Article 6 eligible do not need to meet the following requirements.

## CORSIA eligibility procedure

Project Developers seeking eligibility for CORSIA Phase 1 shall comply with the following:

* Projects shall have their first crediting period start on or post January 1, 2016
* RCCs are issued for vintages 2021 and beyond
* RCCs have been authorized by the host country, following the [Host Country authorization ](#host-country-authorization)procedure outlined below.
* Projects **must be under a Rainbow methodology that has been approved by the CORSIA TAB** for issuing CORSIA Eligible Emissions Units
* Projects must report their sustainable development contributions or co-benefits, following the [co-benefit ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#co-benefits)reporting requirements outlined in the Rainbow Standard Rules
* Projects must follow all other ICAO requirements.

Rainbow shall act as the final guarantor for CORSIA-eligible emissions units in cases where other safeguards, such as mechanisms outlined in [Buffer Pool](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits#buffer-pool) or insurance policies, are insufficient to fully compensate for any reversal of issued CORSIA-eligible emissions units.

Project Developers seeking to issue [CORSIA credits](#user-content-fn-2)[^2] shall:

* ensure that CORSIA-eligible emissions units are **not claimed both by airline operators for CORSIA compliance, and by Host Countries** for the fulfillment of their Nationally Determined Contributions (NDCs).
* monitor Host Country reporting and submit accurate, timely information on **corresponding adjustments** to Rainbow.

The specific procedures to meet the above requirements are outlined in the sections below.

{% stepper %}
{% step %}
**Request**

To have credits labeled as CORSIA-eligible, Project Developers must submit a formal request to Rainbow, specifying the relevant vintage year of the GHG avoidance and/or removal. This **may be submitted after credits are already issued**.

Following receipt of the request, the concerned credits will be labeled in the registry as “Pending CORSIA-eligibility”.
{% endstep %}

{% step %}
**Letter of Authorization**

To ensure that credits are not counted toward both a Host Country’s NDCs and CORSIA compliance, Project Developers shall obtain **explicit authorization** from the Host Country, in the form of a Letter of Authorization (LoA). This shall be issued by an **authorized representative of the Host Country’s national focal point**, and completed using the [UNFCCC template](#user-content-fn-3)[^3] or country's own template or Rainbow’s [template Letter of Authorization for CORSIA](/rainbow-standard-documents/procedural-templates/letter-of-authorization-for-corsia).

The LoA must follow all requirements outlined in the detailed [LoA section](#letter-of-authorisation) below.
{% endstep %}

{% step %}
**Reconciliation mechanism**

Project Developers shall comply with the [#procedure-for-updates-to-host-country-authorization](#procedure-for-updates-to-host-country-authorization "mention") and the [#corsia-double-claiming-reconciliation-procedures](#corsia-double-claiming-reconciliation-procedures "mention").

In addition, Project Developers shall establish a reconciliation mechanism to resolve any disputes between them and the host country concerning the **revocation of a Corresponding Adjustment** (CA). This mechanism shall ensure that all parties have a clear, transparent and mutually agreed-upon process for addressing and resolving disagreements.
{% endstep %}

{% step %}
**Insurance**

Project Developers shall secure double-claiming insurance coverage from a provider [approved by Rainbow](#user-content-fn-4)[^4]. **The insurance policy must ensure that, in the event of double claiming:**

* The insurer replaces an equivalent volume of the affected units authorized with CORSIA-eligible units; or
* The insurer provides financial compensation sufficient to procure an equivalent volume of eligible units, such as CORSIA-eligible RCCs or other recognized units.
  {% endstep %}

{% step %}
**CORSIA approval**

The Letter of Authorization, reconciliation mechanism, and insurance policy shall be evaluated by the Rainbow to assess completeness and compliance with the present requirements.

Once Rainbow has reviewed the requirements and approved, and the Letter of Approval (LoA) is publicly made available on the Rainbow Registry, the units shall be labeled as CORSIA-eligible.
{% endstep %}

{% step %}
**Registry management**

In addition to the standard-level requirements for managing [Rainbow Carbon Credits](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits) on the registry, CORSIA-Eligible Units shall include:

* **Public Documentation:** The Letter of Authorization will be made publicly available alongside other project documentation on the Rainbow Registry.
* **Public Record:** The status of authorized use and Corresponding Adjustments will be recorded and made publicly available through the Rainbow Registry.
* **Retirement Transparency:** Retirement records will clearly specify the airline operator for which the carbon credits were canceled, as well as the date of retirement.
  {% endstep %}

{% step %}
**Ongoing monitoring of Corresponding Adjustments**

Following the first transfer or retirement of eligible credits, Rainbow will [monitor the annual Host Country’s submissions](#review-of-host-country-adjustments) to the **Article 6 database in the Agreed Electronic Format**, biennial transparency reports, and any relevant listings or reporting required by future CMA decisions. This monitoring ensures evidence of the appropriate Corresponding Adjustment against the Host Country’s NDCs.

Additionally, Project Developers are responsble for continuous monitoring and reporting any updates to Host Country authorization.

Any cases of double claiming will be managed following the [#corsia-double-claiming-reconciliation-procedures](#corsia-double-claiming-reconciliation-procedures "mention").
{% endstep %}
{% endstepper %}

## Article 6 eligibility procedure

Project Developers seeking to issue [Article 6 credits](#user-content-fn-5)[^5] must comply with following requirements.

{% stepper %}
{% step %}
**Request**

To have credits labeled as Article 6 eligible, Project Developers must submit a formal request to Rainbow, specifying the relevant vintage year of the GHG avoidance and/or removal. This **may be submitted after credits are already issued**.

Following receipt of the request, the concerned credits will be labeled in the registry as “pending CORSIA-eligibility”.
{% endstep %}

{% step %}
**Letter of Authorization**

Project Developers shall obtain **explicit authorization** from the Host Country, in the form of a Letter of Authorization (LoA). This shall be issued by an **authorized representative of the Host Country’s national focal point**, and completed using the [UNFCCC template](#user-content-fn-3)[^3] or country's own template or Rainbow’s [template Letter of Authorization for CORSIA](/rainbow-standard-documents/procedural-templates/letter-of-authorization-for-corsia).

The LoA must follow all requirements outlined in the detailed [LoA section](#letter-of-authorisation) below.
{% endstep %}

{% step %}
**Reconciliation mechanism**

Project Developers shall comply with the [#procedure-for-updates-to-host-country-authorization](#procedure-for-updates-to-host-country-authorization "mention").

In addition, Project Developers shall establish a reconciliation mechanism to resolve any disputes between them and the host country concerning the **revocation of a Corresponding Adjustment** (CA). This mechanism shall ensure that all parties have a clear, transparent, and mutually agreed-upon process for addressing and resolving disagreements.
{% endstep %}

{% step %}
**Insurance**

Project Developers may secure double-claiming insurance coverage from a provider [approved by Rainbow](#user-content-fn-4)[^4].

If a Project Developer obtains such an insurance policy, they must report this in their Project Design Document (PDD).
{% endstep %}

{% step %}
**Article 6 approval**

The Letter of Authorization, reconciliation mechanism, and any insurance policy used shall be evaluated by the Rainbow Certification Team to assess completeness and compliance with the present requirements.
{% endstep %}

{% step %}
**Registry management**

In addition to the standard-level requirements for managing [Rainbow Carbon Credits](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits) on the registry, Article 6-Eligible Units shall include:

* **Public Documentation:** The Letter of Authorization will be made publicly available alongside other project documentation on the Rainbow Registry.
* **Public Record:** The status of authorized use and Corresponding Adjustments will be recorded and made publicly available through the Rainbow Registry.
* **Retirement Transparency:** Retirement records will clearly specify the country for which the carbon credits were canceled, as well as the date of retirement.
  {% endstep %}

{% step %}
**Ongoing monitoring of Corresponding Adjustments**

Following the first transfer or retirement of eligible credits, Rainbow will [monitor the annual Host Country’s submissions](#review-of-host-country-adjustments) to the **Article 6 database in the Agreed Electronic Format**, biennial transparency reports, and any relevant listings or reporting required by future CMA decisions. This monitoring ensures evidence of the appropriate Corresponding Adjustment against the Host Country’s NDCs.

Additionally, Project Developers are responsble for continuous monitoring and reporting any updates to Host Country authorization.

Any cases of double claiming will be managed following the [#article-6-double-claiming-reconciliation-procedures](#article-6-double-claiming-reconciliation-procedures "mention").
{% endstep %}
{% endstepper %}

## Host Country authorization

### Letter of Authorization

Project Developers shall obtain a Host Country Attestation in the form of a Letter of Authorization (LoA) completed by an authorized representative of the relevant national authority of the Host Country.

Project Developers shall use the LoA template provided by their Host Country. If one is not provided by the Host Country, Project Developers shall use the applicable Rainbow template:

* [Template Letter of Authorization for CORSIA eligibility](/rainbow-standard-documents/procedural-templates/letter-of-authorization-for-corsia),
* [Template Letter of Authorization for Article 6 eligibility](/rainbow-standard-documents/procedural-templates/letter-of-authorization-article-6).

The letter of Authorization shall meet the following general requirements, and include all information listed below in the [#information-to-include-in-the-loa](#information-to-include-in-the-loa "mention")section:

* Be issued by the relevant government authority (such as designated national authority or UNFCCC focal point), and their include contact details such as email address and/or phone number and/or physical address of the office.
* Explicitly authorize the use of RCCs for the purpose of CORSIA or Article 6. This shall reflected in the LoA as “CORSIA” or “International Mitigation Purposes” or “Other International Mitigation Purposes”.
* Explicitly confirm that a Corresponding Adjustment will be made.
* Include information on the project, including at least the complete project name on the Rainbow registry and Rainbow reference number.
* Specify the amount of RCCs authorized, which may cover all credits issued during the project's crediting period, a defined portion of credits, or credits from a specific monitoring period.
* Include the established reconciliation mechanism set up by the Project Developer.

If the project’s credits are generated in more than one country, each country involved must issue its own Letter of Authorization.

<details>

<summary>Information to include in the LoA</summary>

The Letter of Authorization must include the following information:

* The official name of the Host Country and the name and title of its authorized representative.
* The date the authorization is issued.
* The name, details, and project code of the project covered by the authorization.
* The sector, activity type, and crediting period for which the authorization applies (or vintage).
* Explicit confirmation that the host country authorizes the use of the specified credits for CORSIA or Article 6.
* Any limits on the number of credits permitted for CORSIA (e.g. CORSIA compliance period) or Article 6 use and any applicable time restrictions.
* A formal declaration that the host country will not count the mitigation outcome toward its Nationally Determined Contribution (NDC).
* A definition of “first transfer,” specifying when a Corresponding Adjustment will be applied, this may be at the time of authorization, issuance, or use/cancellation of the mitigation outcome.
* A statement confirming that a Corresponding Adjustment will be made in accordance with the Paris Agreement to account for the use under CORSIA or Article 6.
* A commitment to demonstrate that Corresponding Adjustments have been completed and reported in the country’s biennial transparency reports, as required by the Annex to decision 18/CMA.1 and consistent with decisions in 2/CMA.3, as well as any relevant future decisions by the CMA.
* An assurance that the host country will transparently report on granted authorizations and the use of carbon dioxide avoidance/removals for CORSIA or Article 6 in its biennial transparency reports under Article 13 of the Paris Agreement or in subsequent reports as required by future CMA decisions.

</details>

Rainbow shall make publicly available all LoAs that have been approved on the Rainbow Registry.

Rainbow shall support the Project Developer in identifying the designated national point of contact responsible for the authorization and oversight of the attestation process.

Project Developers shall ensure the project adheres to all host country regulations and guidance regarding the voluntary use of carbon credits that are also accounted for in a country’s NDC.

### Corresponding Adjustments

{% hint style="info" %}
A Corresponding Adjustment is an accounting entry made by a Host Country to its national greenhouse gas inventory, ensuring that GHG avoidance and removals are not counted toward both the host country’s Nationally Determined Contribution (NDC) and the acquiring country’s or entity’s climate targets.
{% endhint %}

Project Developers shall follow the steps outlined in the [Letter of Authorization](#letter-of-authorization-2) section to obtain written confirmation from the host country that the **carbon credits will receive a corresponding adjustment**.

### Procedure for updates to Host Country authorization

**Project Developers must inform Rainbow of any changes they become aware of to the Host Country authorization.** This may result in:

* **Increase in Authorized Credits:** If a change results in an increased number of authorized credits, the Project Developer must submit a formal request and provide a revised LoA that covers the concerned RCCs. The LoA shall be evaluated for compliance by the Rainbow Certification team, and if all requirements are met, the credits shall be labeled as CORSIA-eligible or Article 6-eligible on the registry.
* **Reduction or Revocation of Authorization:** If a Letter of Authorization reduces the number of CORSIA-eligible or Article 6-eligible credits, or is revoked entirely, Rainbow will review the affected credits and work with the host country to resolve any discrepancies. If the issue remains unresolved after **three months**, Rainbow will take the following steps:
  * **Untransacted or Developer-Held Credits:** The CORSIA-eligible or Article 6-eligible designation will be removed.
  * **Transacted but Unretired Credits:** The CORSIA-eligible or Article 6-eligible designation will be removed with the agreement of the credit holder. If no agreement is reached, the credits will be treated as double claimed, and compensation must be provided in accordance with Rainbow’s [#double-claiming-reconciliation-procedures](#double-claiming-reconciliation-procedures "mention").
  * **Retired Credits:** The [#double-claiming-reconciliation-procedures](#double-claiming-reconciliation-procedures "mention") must be followed.

If Rainbow identifies **changes in a host country authorization**, through ongoing reporting, reconciliation processes, or direct notifications from the host country or Project Developer, it will promptly notify all relevant stakeholders, including the Project Developer, credit holders, the Host Country, UNFCCC, and ICAO.

## Double claiming reconciliation procedures

Despite the present requirements, **double claiming may occur due to, for example, reduction or revocation of the LoA or CA, or failure of the Host Country to carry out the CA** as planned. The following sections outline fallback procedures for handling cases where double claiming occurs, violating the [#host-country-authorization](#host-country-authorization "mention")requirements.

### CORSIA double claiming reconciliation procedures

For RCCs to be labeled as CORSIA-eligible, Project Developers must establish a reconciliation mechanism for any double claims of their CORSIA-eligible emissions units between airline operators and Host Countries.

Any double-claimed units that have not received a CA **must be compensated with an equivalent volume of eligible units**, following the project's established a reconciliation mechanism.

The reconciliation mechanism must include an **insurance policy guaranteeing that any double-claimed units will be replaced** with an equivalent volume of CORSIA-eligible credits for the same compliance cycle. The guarantee shall commit to one of the following:

* Replace the units directly, or
* Provide full financial compensation for Rainbow to procure replacement units.

Insurance must be provided by Rainbow-approved insurance providers, which must be highly reputable, regulated, and hold a Very Strong rating from recognized agencies (e.g., Fitch’s, Standard & Poor’s).

In the event of double-claiming, the following steps must be taken:

1. **Notification:** Rainbow will notify the Project Developer within **48 hours** of confirming a double-claiming event.
2. **Compensation:** Upon notification, the Project Developer shall deploy the defined compensation mechanism.
3. **Revoke CORSIA eligibility:** Rainbow shall revoke the CORSIA-eligible label for the affected credits until the double-claimed event is investigated and resolved. The project should re-obtain eligibility under CORSIA following [CORSIA eligibility procedure](#corsia-eligibility-procedure).

**Project Developers are responsible for continuously monitoring Host Country reporting** and submitting accurate, timely information to Rainbow. Rainbow will verify submissions from Project Developers, and conduct independent annual checks of Host Country GHG reporting and completed CAs.

If, three months after the expected declaration and execution of the CA, the Host Country has not provided evidence of the required CA, Rainbow will oversee the carrying out of the compensation for any double-claimed units using the established reconciliation mechanism.

### Article 6 double claiming reconciliation procedures

Any double-claimed units that have not received a CA must be compensated with an equivalent volume of eligible units. This includes specifically:

* **Revocation of a CA:** The CA is not applied as previously agreed with the Project Developer, or if reliable evidence of the CA is not provided within one year from the date the host country was expected to report it to the UNFCCC.
* **Non-Use of Authorization:** The host country is unable to apply CAs in the same calendar year in which the net GHG removal occurred.

In the event of double-claiming, the following steps must be taken:

1. **Notification:** Rainbow will notify the Project Developer within **48 hours** of confirming a double-claiming event.
2. **Remedy:** Upon notification, the Project Developer shall:
   * Sign a **new Letter of Authorization (LoA)** with the host country, ensuring that any subsequent units issued will not be double claimed.
   * Develop and implement a **compensation plan**
3. **Revoke CORSIA eligibility:** Rainbow shall revoke the Article 6-eligible label for the affected credits until the double-claimed event is investigated and resolved. The project should re-obtain eligibility under Article 6 following [Article 6 eligibility procedure](#article-6-eligibility-procedure).
4. **Gap in supply:** If the Project Developer has signed a new LoA but cannot supply the required units due to a shortage of eligible units, Rainbow may grant a three-year grace period to replace the double-claimed units. During this period, the project may regain its eligibility for Article 6 and issue units with the corresponding tag. If, after three years, the Project Developer has not supplied the required units, the project’s eligibility for Article 6 will be permanently revoke&#x64;**.**

## Reporting

### Review of Host Country Adjustments

**Rainbow will review each Host Country’s biennial transparency report under Article 13 of the Paris Agreement** to verify that required Corresponding Adjustments have been applied.

* If the Host Country has applied the CA, Rainbow will identify the affected credits (e.g., by unique batch identifiers) and publish evidence of the Adjustment on the Rainbow Registry.
* If the Host Country has not applied the CA this will also be documented and published with the credits. Rainbow will continue monitoring for any future claims, according to the timeframe committed in the LoA. If after the end of the timeframe CA hasn't been applied, then reconciliation procedures for [CORSIA](#corsia-double-claiming-reconciliation-procedures) or [Article 6 ](#article-6-double-claiming-reconciliation-procedures)apply.

The monitoring of the national emissions reports shall ensure consistency with the provided LoA with the specified information in the LoA, including notably the relevant accounting (in accordance with Section IV of Annex I to Decision 2/CMA.3 and expected timing of the CAs.

### Notification of relevant bodies

**Rainbow will notify relevant Host Countries, and ICAO, and other pertinent bodies on an annual basis** regarding all issuances and retirements that may impact claims under Nationally Determined Contributions (NDCs) or ICAO guidelines.

**Rainbow will publish every year a CORSIA Annual Oversight Report** including detailed information on CORSIA-eligible emissions units, covering:

* Quantity and serial numbers of credits authorized by Host Countries for CORSIA, broken down by country, vintage, and calendar year.
* Quantity of CORSIA-eligible credits retired by airline operators for each CORSIA compliance period.
* Corresponding Adjustments confirmed for Rainbow-authorized credits.
* Quantity of CORSIA-eligible credits that are active, retired, or canceled, including their serial numbers.
* Quantity of CORSIA-eligible credits identified as double-claimed and subsequently compensated by Rainbow, including both quantity and serial numbers.

**Rainbow will publish an Article 6 Annual Oversight Report** including detailed information on Article 6-eligible emissions units, covering:

* Quantity and serial numbers of Internationally Transferred Mitigation Outcomes (ITMOs) authorized by Host Countries, broken down by country, vintage, and calendar year.
* Quantity of Article 6-eligible credits transferred or retired for international mitigation purposes, including the receiving entities or compliance periods.
* Corresponding Adjustments confirmed for Rainbow-authorized Article 6 credits.
* Quantity of Article 6-eligible credits that are active, transferred, retired, or canceled, including their serial numbers.
* Quantity of Article 6-eligible credits identified as double-claimed and subsequently compensated by Rainbow, including both quantity and serial numbers.

The reports must be publicly shared on the Rainbow's [Administrative Oversight Record](/other/administrative-oversight) and submitted to UNFCCC Focal Points linked with the authorization of RCCs and relevant organisations (e.g., ICAO) within six months following the close of the calendar year.

[^1]: Paris Agreement to the United Nations Framework Convention on Climate Change, Dec. 12, 2015. <https://unfccc.int/files/essential\\_background/convention/application/pdf/english\\_paris\\_agreement.pdf​>

[^2]: emissions units for the Carbon Offsetting and Reduction Scheme for International Aviation ([CORSIA](https://www.icao.int/CORSIA))

[^3]: Available here: <https://unfccc.int/documents/646071>

[^4]: the list of approved insurers can be requested from Rainbow’s Secretariat

[^5]: Internationally Transferred Mitigation Outcomes (ITMOs) for trading and use towards the Nationally Determined Contribution (NDC) target of the country buying the RCCs, through the use of [Article 6.2](https://unfccc.int/process-and-meetings/the-paris-agreement/article6) of the [Paris Agreement](#user-content-fn-1)[^1] under the The United Nations Framework Convention on Climate Change (UNFCCC).


# CRCF Requirements

The present section describes additional eligibility requirements and procedures for Project Developers that seek to issue credits that comply with the EU [Carbon Removals and Carbon Farming (CRCF) Regulation](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202403012) (EU/2024/3012).

All other requirements in the Rainbow Standard Documents not mentioned here apply.&#x20;

{% hint style="info" %}
For clarity, these cases shall be referred to as **CRCF compliant credits**.
{% endhint %}

Project Developers seeking to issue credits that are not CRCF compliant do not need to meet the following requirements.

## CRCF and non-CRCF crediting tracks

Applicable Rainbow methodologies set out crediting requirements for two tracks:

* Non-CRCF RCCs, under the base, default VCM track.
* CRCF-compliant RCCs, under tracks with additional requirements.

CRCF compliance is assessed at each monitoring period, verification audit, and credit issuance, and is indicated at the credit-block level using [credit block labels](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits#credit-blocks). A project may therefore issue CRCF-compliant RCCs in one monitoring period and non-CRCF RCCs in another monitoring period under the same methodology. This is treated as a single project applying a single methodology and does not pose a double counting or double registration risk.

## Inter-scheme information exchange

Rainbow's Double counting and No scheme hopping requirements are intended to render all project information publicly available for other standards to conduct due diligence with publicly available and easily accessible information.

In addition to these publications, Rainbow will, upon request by another CRCF-recognized certification scheme, provide any other relevant certification history (including validation outcomes, non-conformity decisions, suspensions and withdrawals) for any Project Developer that has applied to or been certified by Rainbow, for the purpose of complying with their equivalent Double counting and No scheme hopping requirements.&#x20;

Rainbow will similarly request such information from other CRCF-recognized schemes when an operator discloses prior participation, and this information is not already made publicly available.

## Monitoring frequency

Project Developers shall submit a **Monitoring Report** **at least once per 12 months**. See the Rainbow [Monitoring](/rainbow-standard-documents/procedures-manual/project-certification-procedure#monitoring) requirements for further requirements.&#x20;

## Site audits

Projects shall undergo an **in-person validation site audit**. Remote site audits are not allowed. See the Rainbow [Site audit](/rainbow-standard-documents/procedures-manual/project-certification-procedure#site-audit) requirements for further requirements.&#x20;

## VVB accreditation

In addition to meeting the Rainbow VVB requirements, VVBs must demonstrate accreditation to operate under this standard through one of the following two pathways:

<table><thead><tr><th width="174.90911865234375">Pathway</th><th>Requirements</th></tr></thead><tbody><tr><td><strong>Pathway 1: Recognition by a National Competent Authority</strong></td><td><p>VVBs may be recognized by a national competent authority as being competent to cover the scope of Regulation (EU) 2024/3012 or the specific scope of this certification scheme.</p><p>VVBs operating under this pathway are <strong>not subject</strong> to the specific ISO standards set out in Pathway 2 below. They remain subject to the general eligibility requirements set out in the Rainbow <a href="/pages/UFYVGUgzCEQVXiNMjvUg">VVB requirements</a>.</p></td></tr><tr><td><strong>Pathway 2: Accreditation by a National Accreditation Body</strong></td><td><p>VVBs may be accredited by a national accreditation body operating in accordance with Regulation (EC) No 765/2008 (e.g. COFRAC in France, UKAS in the UK, DAkkS in Germany).</p><p>The accreditation shall cover the specific scope of certification under Regulation (EU) 2024/3012 (the CRCF). When assessing a VVB's qualifications, the national accreditation body shall take into account any prior accreditation obtained under:</p><ul><li>Commission Implementing Regulation (EU) 2022/996 (carbon farming), or</li><li>Commission Implementing Regulation (EU) 2018/2067 (permanent carbon removals and carbon storage in products)</li></ul><p>VVBs accredited under this pathway shall demonstrate compliance with the following ISO standards:</p><ul><li>EN ISO/IEC 17065 — Requirements for bodies certifying products, processes and services. This is the baseline accreditation standard that all VVBs under this pathway must meet.</li><li>EN ISO/IEC 17029 and EN ISO 14065 — Additionally required where the VVB conducts verification activities, whether using internal resources or other resources under its direct control.</li></ul></td></tr></tbody></table>

Upon satisfactorily completing the steps outlined in the Rainbow general [VVB requirements](/rainbow-standard-documents/procedures-manual/vvb-requirements), and demonstrating compliance with one of the pathways listed above, the Rainbow Secretariat delivers a CRCF accreditation to the VVB, allowing them to audit CRCF projects.

The VVB organization is labeled as a **CRCF approved VVB** under the Rainbow Standard, and is publicly disclosed on Rainbow’s website.

VVB organizations auditing CRCF projects shall&#x20;

* be headquartered in the European Union (EU) or European Economic Area (EEA), and
* cooperate with and provide information to the Commission and the national competent authorities of the Member States if requested.

## Certificates of compliance

A **certificate of compliance** shall be issued by the VVB for each successful verification audit, along with the Audit Report. This serves as a conformity statement, certifying that the carbon removal activities comply with the regulation.

The Rainbow Certification team reviews the certificate of compliance as part of the [Project Verification Review](/rainbow-standard-documents/procedures-manual/project-certification-procedure#verification-review-and-issuance), and shall make the certificate publicly available on the Rainbow Registry. For [deregistered](/rainbow-standard-documents/procedures-manual/project-certification-procedure#deregistration) projects, certificates of compliance shall remain on the registry for at least 5 years after the date of deregistration.&#x20;

Certificates of compliance shall contain at least the following information.

<details>

<summary>Minimum requirements for a certificate of compliance (for <a data-footnote-ref href="#user-content-fn-1">CRCF </a>projects only)</summary>

**Project information:**

* Name of the project and Unique registry ID;
* Description of the project mitigation activity;
* Type of RCCs issued (removal and/or avoidance);
* Name and contact details of the Project Developer;
* Location of the activity, including the geographically explicit location of the activity boundaries;
* Duration of the crediting period, including the start date and end date.

**Certification information**

* Name, address and logo of the third-party VVB;
* Unique number or code of the certificate of compliance;
* Place, date of issuance and validity period of the certificate of compliance;
* Duration of the monitoring period of the activity;
* Reference to the applicable methodology.

**Claim**

* Breakdown of the GHG quantification results including:
  * the net permanent or temporary carbon removal, or net soil emission reduction
  * baseline carbon removals or soil emissions
  * total gross project carbon removals or soil emissions
  * total project's induced GHG emissions
  * all of the above points broken down by gases, sources, carbon sinks and stocks;
* Quantity and serial numbers of issued RCCs;
* Quantification of uncertainties in the quantification of carbon removals and induced emissions, and the resulting discount factor applied;
* Buffer pool contribution;
* Other type of liability mechanism, the liable natural or legal person;
* Reference to any other international or national certification, including the unique number or code of the certificate of compliance.

**Sustainability**

* Amount of biomass used and proof of its compliance with the requirements;
* Any sustainability co-benefits claimed.

</details>

Upon [deregistration](/rainbow-standard-documents/procedures-manual/project-certification-procedure#deregistration), a project's certificate of compliance shall be&#x20;

* terminated and designated a **terminated certificate** if it has been voluntarily canceled, or&#x20;
* withdrawn and designated a **withdrawn certificate** if it is canceled by Rainbow or the VVB, for example as the result of a critical or unresolved major nonconformity.

Certificates of compliance expire once they have reached the end of their defined validity period, and are then designated **expired certificates.**

## Reporting requirements

In addition to the minimum requirements for project documentation, outlined in the Project certification section of the Procedures Manual, the following points shall be reported:&#x20;

PDD

* list of specific emission sources and sinks that are relevant to the project mitigation activity and included in the project scenario of the GHG quantification, according to the GHG sources and sinks outlined in the applicable CRCF methodology (Sections 2.1.1 and 2.2.1 of the [Delegated Regulation (EU) 2026/285](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202600285) on permanent carbon removals). All sources and sinks shall be listed, regardless of if they are already listed in the methodology.
* GHG quantification future projections shall be included in the PDD and broken down by gases, sources, carbon sinks and stocks.

Monitoring plan:

* For any primary measurements, quality assurance and calibration descriptions shall cover all elements in the standard for quality assurance from Article 60 of [Implementing Regulation (EU) 2018/2066](https://eur-lex.europa.eu/eli/reg_impl/2018/2066/oj).
* Description of the data storage system and plan, ensuring that all project raw data will be maintained and accessible for a minimum of 10 years. This shall cover at least all elements listed in Annex IX of the [Implementing Regulation (EU) 2018/2066](https://eur-lex.europa.eu/eli/reg_impl/2018/2066/oj).

Monitoring report:&#x20;

* All monitored parameters shall be measured, calculated and reported in the Monitoring Report. Furthermore, the Monitoring Report shall include all parameters defined in the applicable CRCF methodology (Section 1.3.3 of the [Delegated Regulation (EU) 2026/285](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202600285) on permanent carbon removals)
* GHG quantification results from the given monitoring period shall be reported in the Monitoring Report and broken down by gases, sources, carbon sinks and stocks. All sources and sinks shall be listed, regardless of if they are already listed in the methodology or the PDD.
* All assumptions, secondary data sources, project activity data and measurements and calculation factors, regardless of if they are already listed in the methodology or the PDD.
* The quantity and details of any carbon farming sequestration credits purchased for voluntary compensation as part of the project, according to Section 4.3.3 of the [Delegated Regulation (EU) 2026/285](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202600285) on permanent carbon removals.
* Any sources of public funding, including ongoing funding that was already reported, and new sources of funding.

## Credit retirement

Beneficiaries of retired CRCF-compliant RCCs shall be unambiguously identified by providing all information in the [RCC retirement](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits#retirements) section of the Procedures Manual, plus a unique identifier, such as company registration number or tax identification number.

## Materiality assessment

Materiality assessment as described in the Project Scope section of the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/ghg-quantification#materiality-assessment) may only be applied to&#x20;

1. any individual material input and
2. the sum of all infrastructure emissions, and
3. any emissions not explicitly required by the CRCF [Delegated Regulation (EU) 2026/285](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202600285)

All other elements of the quantification shall be fully accounted for.

## Global Warming Potential

GHG emissions shall be calculated using the following IPCC Global Warming Potential values for a 100 year horizon (GWP100) according to [IPCC 2013 AR5, Chapter 8](#user-content-fn-2)[^2]. The GWPs for the greenhouse gasses from Table 8.7 are summarized below for informational purposes only.

<table><thead><tr><th width="381">Species</th><th>Global warming potential 100-year</th></tr></thead><tbody><tr><td>CO<sub>2</sub></td><td>1</td></tr><tr><td>CH<sub>4</sub></td><td>28</td></tr><tr><td>N<sub>2</sub>​O</td><td>265</td></tr><tr><td>HFC-134a</td><td>1300</td></tr><tr><td>CFC-11</td><td>4660</td></tr></tbody></table>

[^1]: Projects seeking eligibility under the European Union [Carbon Removals and Carbon Farming (CRCF) Regulation](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202403012) (EU/2024/3012)

[^2]: Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: Anthropogenic and Natural Radiative Forcing. In: *Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change* \[Stocker, T.F. et al. (eds.)]. Cambridge University Press. [URL](https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf)


# Appendix

## Minimum requirements for documentation

<details>

<summary>Minimum requirements for the PDD</summary>

PDDs shall contain, at a minimum, the following information:

**General and scope description**

* Non-technical description of the project operations, technology, infrastructure, scope, location, Project Developer, and other relevant actors
* Legal ownership and contact information of the Project Developer
* If using a registration partner or a group of Project Developers, a description of if and how advisory services are provided to Project Developers
* Technical description of the technology and project operations
* Specific location of the project, including [georeferenced boundaries](#user-content-fn-1)[^1] and/or GPS coordinates of the mitigation activity
* Compliance with any accreditations beyond Rainbow certification (e.g. CRCF, ICVCM..)
* Start date of the project, and start and end dates of the crediting period
* [Monitoring Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#monitoring) with parameters to be monitored
* Site registration
* Procedure and findings of [double-registration check](/rainbow-standard-documents/procedures-manual/project-certification-procedure#double-registration-check)

**Eligibility, principles and requirements**

* Justification that the project meets all [Principles and requirements](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements) described in the Rainbow Standard Rules, and the chosen methodology
* Stakeholders identified and outcomes of the stakeholder consultation
* Assessment of environmental and social risks, and demonstration of sustainability
* Project specific buffer pool contribution (if issuing removal RCCs)

**GHG quantification**

* Source for GWP100 values (IPCC AR6 or other IPCC version)
* Information on how the methodology was applied for the purpose of
  * determining the baseline,
  * demonstrating additionality and
  * quantifying GHG emission reductions or removals, including but not limited to assumptions, data sources, and emission sources/sinks, that are not already defined at the methodology level
* Project-specific uncertainty assessment and discount factor
* Future projections throughout the crediting period including:
  * Operational, production, delivery information
  * Expected total **gross** GHG emissions, carbon removals, and avoidance
  * Expected total **net** GHG emissions, carbon removals, and avoidance (after applying the discount factor and buffer pool contribution)

The PDD shall require any other information required for the VVB to validate the project as compliant with the Rainbow Standard Rules and the applicable methodology.

PDDs shall be made publicly available on the Rainbow Registry upon completing [Validation](#validation). See the [Registry and documentation](/rainbow-standard-documents/procedures-manual/registry-requirements#project-documentation) section for further instructions on publicly available documentation.

</details>

<details>

<summary>Minimum requirements for a methodology</summary>

**Scope/general**

* Eligible technologies and activities, description of the practices and processes covered
* Scope/delineation of a project (e.g. number of sites can be included in one project)
* Geographic locations covered, if not global
* Minimum requirements for a monitoring plan
* Maximum duration of the crediting period
* Maximum duration of the monitoring period/frequency of credit issuance
* Glossary with definitions of technical terms
* Requirements for project compliance with methodology revisions
* Requirements for site audits to be on-site or remote

**Baseline scenario**

* Justification of the pre-defined/standardized baseline scenario, or guidance for defining an activity-specific baseline scenario
* Frequency of updating the baseline scenario

**Principles and requirements**

* Any standardized calculations for co-benefits
* Durability (for removal RCCs)
  * durability threshold, in years
  * technology/methodology level reversal risk assessment
  * post-crediting monitoring requirements for reversals
  * liability and compensation requirements
  * minimum buffer pool contribution (if higher than the Standard default of 2%)
* Technology/methodology-specific leakage assessment and if applicable, further requirements
* Reversal and ESDNH Risk assessment template

**GHG quantification**

* Assumptions
* Secondary data sources
* Description of processes, GHG sinks, and GHG sources to include in the project and baseline scenario
* Uncertainty assessment and minimum discount factor
* Approaches to account for uncertainties in a conservative matter
* All equations and rules needed to calculate, where relevant in the applicable methodology:
  * project and baseline induced emissions
  * project and baseline removals,
  * LULUCF soil emissions,
  * agricultural soil emissions, and
  * total GHGs avoided and/or removed

</details>

<details>

<summary>Minimum requirements for the Rainbow Annual Report</summary>

The Annual Report shall contain the following minimum information:

**General operations**

* Rainbow's revenue, expenses, and net assets over the past year
* An overview of Rainbow's mission, major programs and activities, and governance
* A summary of the number and type of certified projects per methodology
* A summary of the amount, type and status of RCCs on the registry, the end-use purpose and users of the retired RCCs
* Evidence of public information on Rainbow's website of:&#x20;
  * contact information, email and mailing addresses
  * latest version of governance rules and procedures
  * certification and credit fee structure
  * links to the Rainbow Registry and Complaints and Appeals procedure

**Internal monitoring and oversight**

* List of **major and critical** [**non-conformities**](/rainbow-standard-documents/procedures-manual/project-certification-procedure#non-conformities) by Project Developers and VVBs, detailing the projects and monitoring periods concerned, the nature of the non-conformity and the outcome
* The number and description of cases where fraud has been identified including an action plan for how to solve any complaint raised or non-conformity identified
* Overview of **trainings, technical workshops, resources, or initiatives Rainbow provided to VVBs,** to improve the overall certification process; improve the qualification and independence of VVBs; and facilitate the exchange of experience, knowledge and best practices.
* Overview of the **stakeholder involvement in decision-making** and Rainbow's response to their contributions
* Summary of **complaints received and any remedial measures** or changes to the governance system necessary as part of the internal monitoring
* Criteria and process for the **approval of VVBs**.
* Results of VVB Oversight spot checks
* Evaluation of the suitability of the internal monitoring system to prevent fraudulent activities

</details>

<details>

<summary>Minimum requirements for Audit Reports</summary>

**Summary of the Audit Report**

**Project Developer information:**

* Contact information (name and address);
* Geographical locations of the activity, including longitude and latitude coordinates;
* Scope of the certification and relevant certification methodology applied;
* Reference number of the PDD and Monitoring Plan.
* a statement that the Project Developer is responsible for the fair presentation of the PDD in accordance with the criteria;

**Project information:**

* Expected (for validation audit), verified (for verification audit) total amounts of carbon removals, and of associated greenhouse gas emissions resulting from the project;
* Expected (for validation audit), verified (for verification audit) amount of RCCs with the relevant vintage and durability resulting from the project;
* Sustainability co-benefits associated with the project.

**VVB information**

* Contact information (name and address) and logo;
* Composition of the audit team;
* National accreditation body and scope and date of accreditation, or national recognition authority and scope and date of recognition.
* a statement that the Auditor is responsible for expressing an opinion on the PDD based on the Validation/Verification;
* the Auditor’s location;

**Information on the audit process**

* Date/s of the audit;
* Audit itinerary and duration (split by duration spent on-site and remotely – where relevant);
* Standard Rules version and Methodology version used for the audit;
* Sites audited;
* Audit method (risk assessment and sampling basis, stakeholder consultation);
* a description of the evidence-gathering procedures used to assess the PDD;
* Certification of other voluntary schemes or standards;
* reference to the Monitoring Plan and verification scope;
* GHG data type.

**Information on audit results**

* Place and date of issuance of the audit report;
* The following outcomes of the audit:
  * confirmation of compliance to a **reasonable Level of Assurance** with Regulation (EU) 2024/3012 and applicable certification methodology;
  * list of [non-conformities](/rainbow-standard-documents/procedures-manual/project-certification-procedure#non-conformities) identified with applicable timeline for their remediation.
* the Lead Auditor’s signature.

</details>

<details>

<summary>Minimum requirements for a certificate of compliance (for <a data-footnote-ref href="#user-content-fn-2">CRCF </a>projects only)</summary>

**Project information:**

* Name of the project and Unique registry ID;
* Description of the project mitigation activity;
* Type of RCCs issued (removal and/or avoidance);
* Name and contact details of the Project Developer;
* Location of the activity, including the geographically explicit location of the activity boundaries;
* Duration of the crediting period, including the start date and end date.

**Certification information**

* Name, address and logo of the third-party VVB;
* Unique number or code of the certificate of compliance;
* Place, date of issuance and validity period of the certificate of compliance;
* Duration of the monitoring period of the activity;
* Reference to the applicable methodology.

**Claim**

* Breakdown of the GHG quantification results including:
  * the net permanent or temporary carbon removal, or net soil emission reduction
  * baseline carbon removals or soil emissions
  * total gross project carbon removals or soil emissions
  * total project's induced GHG emissions
  * all of the above points broken down by gases, sources, carbon sinks and stocks;
* Quantity and serial numbers of issued RCCs;
* Quantification of uncertainties in the quantification of carbon removals and induced emissions, and the resulting discount factor applied;
* Buffer pool contribution;
* Other type of liability mechanism, the liable natural or legal person;
* Reference to any other international or national certification, including the unique number or code of the certificate of compliance.

**Sustainability**

* Amount of biomass used and proof of its compliance with the requirements;
* Any sustainability co-benefits claimed.

</details>

<details>

<summary>Minimum requirements for the Monitoring Plan</summary>

These key parameters, which must be regularly tracked and reported, shall be **defined in each project's Monitoring Plan** in the PDD. Each methodology defines the minimum requirements for a Monitoring Plan, and individual projects may have include additional parameters to monitor.

#### **Parameters to include in the Monitoring plan:**

Monitoring Plans shall include parameters that are:

* material to GHG quantification,
* critical for determining project eligibility, including but not limited to environmental and social risks and leakage,
* critical to confirm the mitigation measures established in the Environmental and social risk assessment are in place,
* critical to confirm the measures established in the Reversal risk assessment are in place,
* quantify the claimed co-benefits.

These may include but are not limited to quantitative values, categorical data, qualitative criteria, descriptive parameters, or justification of procedures.

#### **Information to include per parameter:**

Monitoring Plans shall include the following information for each monitored parameter:

* a description of the parameter to be monitored
* monitoring frequency
* emission sources and sinks
* data storage and management plan, including the format, location and duration of data keeping records
* Primary data
  * description of measurement methods/procedures, and their level of accuracy and calibration procedures
  * quality assessment or quality control procedures
  * laboratory name and relevant accreditations for any measurement conducted by external laboratories
  * responsible party for collecting and archiving data, including how they are assigned/selected, and how their competence to monitor the parameter is assessed
  * plan in case of unexpected interruption or errors in monitoring, ensuring conservative treatment of data and an appropriate deduction of emission reductions
* Secondary data
  * data source and, where applicable, value and frequency of update

</details>

[^1]: including, if applicable, codes from the national integrated administration and control system (IACS) and land parcel identification system (LPIS) pursuant Regulation (EU) 2021/2116

[^2]: Projects seeking eligibility under the European Union [Carbon Removals and Carbon Farming (CRCF) Regulation](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202403012) (EU/2024/3012)


# Version history

Version history and changes to the Rainbow Procedures Manual

:point\_right: See [Archived Rainbow Standard Documents](/other/archived-methodologies/archived-rainbow-standard-documents) for full versions of previous documents

<details>

<summary>Change log for Procedures Manual V3.2</summary>

* Create CRCF requirements section for projects that comply with the EU [Carbon Removals and Carbon Farming (CRCF) Regulation](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202403012) (EU/2024/3012).
* Project timeline: project start date must fall within three years of the project’s validation date, not registration date
* Suspension for major non-compliance: specify this includes suspending the sale of credits associated with the suspended certificate of compliance
* Add Rainbow double-registration cross check procedure
* Create procedure for updating a project's PDD
* Revise VVB training requirements, triggers for training, and add examination

</details>

<details>

<summary>Change log for Procedures Manual V3.1</summary>

**Replace V3.0 with V3.1 March 2026, linked with Standard Rules V7.1 update**

**Double Counting**

* removed the separate Double Counting Policy, moved content on double claiming, CORSIA and Article 6 to the dedicated page on [CORSIA and Article 6](/rainbow-standard-documents/procedures-manual/corsia-and-article-6)

**Creation of CORSIA and Article 6 eligibility procedures**, with detailed

* Double claiming reconciliation procedures
* Reporting requirements

Specify **authorized uses of Rainbow Carbon Credits**

</details>

<details>

<summary>Change log for Procedures Manual V3.0</summary>

**Replace V2.2 with V3.0 November 2025, linked with Standard Rules V7 release**

**Public Consultation: November 2025**

* **General**
  * Update and rename [Teams and stakeholders](/rainbow-standard-documents/procedures-manual/governance-and-oversight) section with current governance structure
  * Remove Provisional Credits, continuous issuance, and ex-ante validation
  * Update Credit Status types and definitions to align with new procedures
  * New requirements for creation of Rainbow Annual Report, with specific content
* **Project certification**
  * Methodologies define the crediting period duration
  * Methodologies define whether projects must update and comply with revised versions of methodologies
  * Non-conformities procedure for enforcement, consequences, and remediation procedures for project non-conformities
* **Project documentation**
  * Define project documentation that must be made publicly available
  * Create procedure for requesting non-publicly accessible project information
* **New "Registry" section**
  * Outlines organization and user types, user requirements
  * New IT Security standards, audit, and incident procedure
  * Revise credit pool block definition
* **Minimum requirements for various documents**
  * PDDs, methodologies, monitoring plans, audit reports, compliance certificates
* **Cancelation and compensation**
  * Procedure for compensation if there are insufficient buffer pool credits
  * Define avoidable and unavoidable reversals, and corresponding buffer pool replacement liability
* **VVBs**
  * Non-conformities for projects
  * Move Requirements for Validation and Verification Bodies (VVBs) file into VVB section of Procedures Manual
  * New VVB oversight requirements on training, rotation/sequential audits, qualifications/accreditation, trainings, and sanctions
  * Updated VVB performance review procedure
  * Detailed requirements for Audit Plan and Audit Report

**Post-Public Consultation: January 2026**

* **VVBs**
  * VVB must be ETS approved to audit [CRCF ](#user-content-fn-1)[^1]projects
  * Created procedures for issuing Certificate of compliance, for [CRCF ](#user-content-fn-1)[^1]projects
  * Specify that if a VVB is accredited using ISO 17029 or EN ISO/IEC 17029, they must have scope of application related to GHG emissions
  * Revise VVB eligibility to be based on employed individual auditor expertise and years of experience, not based on the VVB organization
* **Other**
  * Rename Technical Advisory Committee (TAC) to Expert Community, and appointments now made by the Science Team
  * Added requirement for a second check by a Certification Team member in RCC issuance and cancelation procedure, to reflect current practice
  * Strengthened KYC procedures requiring certificate of incorporation/registration
  * Specified possibility for Project Developers to use past site audits, if they are equivalent to and meet the current requirements
  * Specified that when projects deregister, the crediting period is shortened to reflect the date when they are no longer eligible to issue credits
  * Created documentation management system requirements

</details>

<details>

<summary>Change log for Procedures Manual V2.2</summary>

Replace V2.1 with V2.2 October 2024, linked with Standard Rules V6.2 release

* Replace PDD and Project Design Document with PDD and Project Design document
* New ABC policy
* Replace some instances of Verification Report with Monitoring Report, harmonized
* Create procedures for
  * Erroneous issuance cancelation
  * Discontinuing a methodology
  * Renewing crediting periods
* Introduce continuous issuance procedure and eligibility criteria
* Publish current Methodology Creation Mandates
* Minimum requirements for PDDs
* Clarify Project status throughout certification procedure

</details>

<details>

<summary>Change log for Procedures Manual V2.1</summary>

Replace V2.0 with V2.1 May 2024

Terminology changes, reflected in the Glossary (notably discount factor and buffer pool). Clearer performance criteria for VVBs, including timeliness, accuracy, and communication metrics. Clarifications regarding compliance with updates to Rainbow Standards or methodologies.

</details>

<details>

<summary>Change log for Procedures Manual V2.0</summary>

Replace V1.0 with V2.0 February 2024

More detailed/new procedures related to site registration, VVB protocols, site audits (remote and in-person), methodology creation/revision, RCC management section on provision pools, over/under achievement and reversal/cancelation

</details>

[^1]: Projects seeking eligibility under the European Union [Carbon Removals and Carbon Farming (CRCF) Regulation](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=OJ:L_202403012) (EU/2024/3012)


# Methodologies

The available methodologies and modules for use under the Rainbow Standard are listed below, with links to the respective methodology document.

## Rainbow Methodologies

Each methodology gives specific requirements and quantification methods per project types.

<table data-card-size="large" data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="image">Cover image</th></tr></thead><tbody><tr><td>Biogas from anaerobic digestion</td><td></td><td></td><td><a href="/pages/obRdXsWwQ3QKd33cPfRG">/pages/obRdXsWwQ3QKd33cPfRG</a></td><td><a href="/files/q6E23xtpYegumN0r1WTp">/files/q6E23xtpYegumN0r1WTp</a></td></tr><tr><td>Biomass carbon removal and storage (BiCRS)</td><td></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo">/pages/Jy6o8q5Q31d2U0OK7Yuo</a></td><td><a href="/files/4B3R2CjT9hA3bBYbzz1a">/files/4B3R2CjT9hA3bBYbzz1a</a></td></tr><tr><td>Refurbishing of electronic devices</td><td></td><td></td><td><a href="/pages/rqZzogSgVlIRAB55Oki1">/pages/rqZzogSgVlIRAB55Oki1</a></td><td><a href="/files/ZAxqYlP50vM4pzsvknrg">/files/ZAxqYlP50vM4pzsvknrg</a></td></tr><tr><td>Biobased construction materials</td><td></td><td></td><td><a href="/pages/RqfJGxwJIa5eql8owuF4">/pages/RqfJGxwJIa5eql8owuF4</a></td><td><a href="/files/f5cKAncYBa43GiMMU7HB">/files/f5cKAncYBa43GiMMU7HB</a></td></tr><tr><td>Battery second life</td><td></td><td></td><td><a href="/pages/h2OzRlsij4Sb7h6ufm2X">/pages/h2OzRlsij4Sb7h6ufm2X</a></td><td><a href="/files/eoFyTVMVVZVZgcowt7cX">/files/eoFyTVMVVZVZgcowt7cX</a></td></tr><tr><td>Mineralization of alkaline materials (ex situ)</td><td></td><td></td><td><a href="/pages/dWUzpkT7ZGzmw6bBk7m4">/pages/dWUzpkT7ZGzmw6bBk7m4</a></td><td><a href="/files/msi0QQdy9fGE46fIQeou">/files/msi0QQdy9fGE46fIQeou</a></td></tr><tr><td>Enhanced rock weathering</td><td></td><td></td><td><a href="/pages/IzD2vrA9ezW0AapQTp1l">/pages/IzD2vrA9ezW0AapQTp1l</a></td><td><a href="/files/UF1GBglM39hR3jIMKvUW">/files/UF1GBglM39hR3jIMKvUW</a></td></tr></tbody></table>

## Rainbow modules

General Rainbow modules cover parts of project life cycles that are repeated across many technology types and methodologies. They contain basic eligibility requirements and GHG quantification approaches, and are combined with Rainbow methodologies when needed.

<table data-card-size="large" data-view="cards"><thead><tr><th></th><th data-hidden data-card-cover data-type="image">Cover image</th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td>Transportation</td><td><a href="/files/XAxrYlLSh0qtvbDkKkqp">/files/XAxrYlLSh0qtvbDkKkqp</a></td><td><a href="/pages/VTWdCc7guKu1x0azAizi">/pages/VTWdCc7guKu1x0azAizi</a></td></tr><tr><td>Processing and energy use</td><td><a href="/files/xqDoBuMbX7fcBqJ8AanC">/files/xqDoBuMbX7fcBqJ8AanC</a></td><td><a href="/pages/BTxxPIM3a4Nai1Wkwu2Y">/pages/BTxxPIM3a4Nai1Wkwu2Y</a></td></tr><tr><td>Infrastructure and machinery</td><td><a href="/files/gE6Zo8o6awA0p9LnSTnF">/files/gE6Zo8o6awA0p9LnSTnF</a></td><td><a href="/pages/IwqpSqlee22qTIPti3Sl">/pages/IwqpSqlee22qTIPti3Sl</a></td></tr><tr><td>Energy co-products</td><td><a href="/files/CxuE4U5JkYE63biLhW6k">/files/CxuE4U5JkYE63biLhW6k</a></td><td><a href="/pages/5o87C1B9WEcsBRQuyYwi">/pages/5o87C1B9WEcsBRQuyYwi</a></td></tr></tbody></table>


# Procedural templates

This section includes all procedural templates used in the Rainbow process.


# Project Design Document template

This document summarizes all key elements of a project, allowing Rainbow and the general public to have a complete understanding of its actions and expected results.

:point\_right: Download the template [here](https://docs.google.com/document/d/1uxxsnO3zkgVvsL42l79erLBKpfeCk2V6Yg2vh_yJ6Ss/edit?usp=sharing)

{% hint style="info" %}
The data, responses, and their proof submitted by the Project Developer are used to generate the PDD through the Rainbow Certification platform. See the [PDD creation](/rainbow-standard-documents/procedures-manual/project-certification-procedure#pdd-creation) section of the Procedures Manual for more information.
{% endhint %}

{% hint style="info" %}
Templates are for reference only. In case of any conflict, the requirements of the Standard or methodologies take precedence.
{% endhint %}

{% embed url="<https://docs.google.com/document/d/1uxxsnO3zkgVvsL42l79erLBKpfeCk2V6Yg2vh_yJ6Ss/edit?usp=sharing>" %}


# Additionality evaluation template

The purpose of this document is to provide extra information on how to evaluate additionality of projects, according to the Rainbow Standard.

This is already described in the Rainbow Standard Rules and methodology documents, but this document provides detailed templates to guide project developers through their additionality proof.

Additionality shall be evaluated for each project, and there are no automatically additional project types or positive lists.

{% hint style="info" %}
Templates are for reference only. In case of any conflict, the requirements of the Standard or methodologies take precedence.
{% endhint %}

:point\_right: Download the template [here](https://docs.google.com/document/d/1lnE0rQo7EGQ1Bgdk4fF-zbKK3hILAl8m6LlQ_3ccrKw/edit?usp=drive_link)

{% embed url="<https://docs.google.com/document/d/1AtEavAbXOq_asr9idVe666SOtAk3NUfG/edit?usp=sharing&ouid=101176204343908482369&rtpof=true&sd=true>" %}


# Site registration template

This template shall be used to register all operating sites. All sites where the project operates shall be registered. This includes all factories, facilities, or operations under direct control of the project developer, whose activities are issued carbon credits.

{% hint style="info" %}
Templates are for reference only. In case of any conflict, the requirements of the Standard or methodologies take precedence.
{% endhint %}

Find the Template [here](https://docs.google.com/document/d/1l4IcYvFoB8lsWBeIehvHDwlS-RnCaU01LXk1oHGsEJ0/edit?usp=sharing).

{% embed url="<https://docs.google.com/document/d/1l4IcYvFoB8lsWBeIehvHDwlS-RnCaU01LXk1oHGsEJ0/edit?usp=sharing>" %}


# Stakeholder consultation letter

Projects are requested to send this letter to local communities and stakeholders. This letter should articulate the project's intent to issue RCC as a means to finance its operations and monetize its mitigation activities.

{% hint style="info" %}
Templates are for reference only. In case of any conflict, the requirements of the Standard or methodologies take precedence.
{% endhint %}

:point\_right: Download the template [here](https://docs.google.com/document/d/1X9oZIOufWGSn9LmPZv82jLqGoNlAah1ZerkHqMAdoNo/edit?usp=drive_link).

{% embed url="<https://docs.google.com/document/d/1X9oZIOufWGSn9LmPZv82jLqGoNlAah1ZerkHqMAdoNo/edit?usp=drive_link>" %}


# Environmental and social risk assessment templates

Below are the Environmental and Social Risk Assessment templates for each Rainbow methodology. These templates help Project Developers assess the likelihood and severity of risks, as well as the potential failure to maintain safeguards.

{% hint style="info" %}
Templates are for reference only. In case of any conflict, the requirements of the Standard or methodologies take precedence.
{% endhint %}

<table data-view="cards"><thead><tr><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td>Mineralization of alkaline materials (ex-situ)</td><td><a href="/pages/R9RmeDqWwKc8gL90xhPK">/pages/R9RmeDqWwKc8gL90xhPK</a></td></tr><tr><td>Enhanced rock weathering</td><td><a href="/pages/ND0z4r9cBLAei29RHo83">/pages/ND0z4r9cBLAei29RHo83</a></td></tr><tr><td>Biobased construction materials</td><td><a href="/pages/9QL0seuVseT7h1KpkmRT">/pages/9QL0seuVseT7h1KpkmRT</a></td></tr><tr><td>BiCRS: Biochar application to soils</td><td><a href="/pages/Om2iC8BSJ1GdkHA5oMoA#risk-assessment-template">/pages/Om2iC8BSJ1GdkHA5oMoA#risk-assessment-template</a></td></tr><tr><td>BiCRS: Biomass feedstock</td><td><a href="/pages/V0dXfN5yPUaU1ws1h7sV#risk-assessment-template">/pages/V0dXfN5yPUaU1ws1h7sV#risk-assessment-template</a></td></tr><tr><td>BiCRS: Marine sub-sediment burial</td><td><a href="/pages/GxlSYzJC7Dkt7JmbJ2y2#risk-evaluation-template">/pages/GxlSYzJC7Dkt7JmbJ2y2#risk-evaluation-template</a></td></tr><tr><td>Refurbishing of electronics devices</td><td><a href="/pages/3o5w7slzA8KYqfkoj4VT">/pages/3o5w7slzA8KYqfkoj4VT</a></td></tr><tr><td>Biogas from anaerobic digestion</td><td><a href="/pages/IA7D8rG4ulcO5Tukokpe">/pages/IA7D8rG4ulcO5Tukokpe</a></td></tr><tr><td>Battery second life</td><td><a href="/pages/TH1m4sYXSNWZ4steTYv7">/pages/TH1m4sYXSNWZ4steTYv7</a></td></tr><tr><td>BioCCS</td><td><a href="/pages/CmCcl8zcn4IUqpAnxkk2">/pages/CmCcl8zcn4IUqpAnxkk2</a></td></tr></tbody></table>


# Monitoring report template

This document reports all activities carried out by the Project Developer during the year and its respective achievements. It serves as a channel to track the Project’s progress and communicate it to the general public.

{% hint style="info" %}
Templates are for reference only. In case of any conflict, the requirements of the Standard or methodologies take precedence.
{% endhint %}

You can download the template [here](https://docs.google.com/document/d/1BX0pLAbo4oMO-Bkb9RSDvpu6OLQtnLuRXzrCyHgAUAI/edit?usp=sharing).

{% embed url="<https://docs.google.com/document/d/1BX0pLAbo4oMO-Bkb9RSDvpu6OLQtnLuRXzrCyHgAUAI/edit?usp=sharing>" %}


# Methodology creation proposal template

Any stakeholder may submit a request for a new methodology at any time. The requests are summarized and grouped into sectors by the Secretariat, in the creation of a Methodology Creation Proposal.

:point\_right: Download the template [here](https://docs.google.com/document/d/1YBg-qZ4SJuIcDSUXGGeFcu7aTYmEbCSCsVSiQ1cSv1g/edit?usp=drive_link)

{% hint style="info" %}
Templates are for reference only. In case of any conflict, the requirements of the Standard or methodologies take precedence.
{% endhint %}

{% embed url="<https://docs.google.com/document/d/1YBg-qZ4SJuIcDSUXGGeFcu7aTYmEbCSCsVSiQ1cSv1g/edit?usp=drive_link>" %}


# Letter of Authorization for CORSIA

As required in the Rainbow Double counting policy, Project Developers seeking to obtain the CORSIA eligibility on Rainbow Carbon Credits must provide an official Letter of Authorisation from the Host Country.

:point\_right: Download the template [here](https://docs.google.com/document/d/1S8CQchqWLr7scckxJM5_VlEAQpkISomROklqjLaVoDs/edit?usp=sharing).

{% embed url="<https://docs.google.com/document/d/1S8CQchqWLr7scckxJM5_VlEAQpkISomROklqjLaVoDs/edit?usp=sharing>" %}


# Letter of Authorization Article 6

As required in the Rainbow Double counting policy, Project Developers seeking to obtain the Article 6 eligibility on Rainbow Carbon Credits must provide an official Letter of Authorisation from the Host Country.

:point\_right: Download the template [here](https://docs.google.com/document/d/1Bxvq6W2jfzDWGyZDxRYnRNBFmvPRPgUQKsJ4HYzqtbw/edit?usp=sharing).

{% embed url="<https://docs.google.com/document/d/1Bxvq6W2jfzDWGyZDxRYnRNBFmvPRPgUQKsJ4HYzqtbw/edit?usp=sharing>" %}


# Letter of delegation for registration partner

This letter template shall be used by Project Developers willing to use the services of a third party firm to conduct part or all of the validation and/or verification process.

:point\_right: Download the template [here](https://docs.google.com/document/d/1JyB5uyziSes_pVRZ6nNX0qbrrHoKnXy0uoTGbmi2OKU/edit?usp=drive_link)

{% hint style="info" %}
Templates are for reference only. In case of any conflict, the requirements of the Standard or methodologies take precedence.
{% endhint %}

{% embed url="<https://docs.google.com/document/d/1JyB5uyziSes_pVRZ6nNX0qbrrHoKnXy0uoTGbmi2OKU/edit?usp=drive_link>" %}


# Public consultations

Explore the results of our public consultations, including feedback summaries and responses that drive improvements in our standards and methodologies.

## Open public consultations

Public consultations are open for a minimum of 30 days. All relevant details can be accessed here with the results of these consultations.

<table data-view="cards"><thead><tr><th></th><th data-hidden data-card-cover data-type="image">Cover image</th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><p>The Rainbow <strong>Biobased Construction Materials methodology V3.0</strong> is open for public consultation, from July 6th to August 6th. <br>🔎 Provide your feedback <a href="https://tally.so/r/yPkDl8">here</a>!</p><p>👉 Read the methodology <a href="https://docs.rainbowstandard.io/~/changes/226/methodologies/biobased-construction-materials">here</a>!</p></td><td></td><td></td></tr></tbody></table>

Would you like to be notified of future consultations? Please [**contact us.**](https://rainbowstandard.io/general-inquiries)

## Closed public consultations

<table><thead><tr><th width="201">Document</th><th width="163">Start date</th><th width="153">Closing date</th><th>Useful links</th></tr></thead><tbody><tr><td>Biogenic carbon capture and storage</td><td>April 21st, 2026</td><td>May 28th, 2026</td><td><a href="https://drive.google.com/file/d/1Uy53Q-dyhDK89nSfeWG6FGriQC27F_0y/view?usp=sharing">Responses to comments</a></td></tr><tr><td>Distributed open and closed kiln biochar</td><td>Feb 6th, 2026</td><td>March 17th, 2026</td><td><a href="https://drive.google.com/file/d/1_tDoXXZ7HXW5cdUGWCQqglgE8R0sk59z/view?usp=drive_link">Responses to comments</a></td></tr><tr><td>Rainbow Standard Rules V7.0 and Procedures Manual V3.0</td><td>November 25th 2025</td><td>December 28th 2025</td><td><a href="https://docs.google.com/spreadsheets/d/1gRDKokI60uxEt2r9t7ZmQ7g9k01gleDdJRY3RTIPKxY/edit?usp=sharing">Responses to comments</a></td></tr><tr><td>Enhanced rock weathering V1.0</td><td>April 3 2025</td><td>May 5, 2025</td><td><a href="https://drive.google.com/file/d/1o3QMayulqBfXPNkWdc1CpQPQC5ItBgtH/view?usp=drive_link">Responses to comments</a></td></tr><tr><td>Mineralization of alkaline materials ex situ V1.0</td><td>June 20, 2025</td><td>July 23, 2025</td><td><a href="https://drive.google.com/file/d/1NamE0k-p2MAQYlellw4tceakcuYj2oz5/view?usp=sharing">Responses to comments</a></td></tr><tr><td>BiCRS: Marine sub-sediment burial v1.0</td><td>February 7, 2025</td><td>March 10, 2025</td><td><a href="https://docs.google.com/spreadsheets/d/1R0NklcRAmwKM9DfnYlk_XH9p6Uw8_BF3P4NcWxmjoK4/edit?usp=sharing">Responses to comments</a></td></tr><tr><td>Battery second life v1.0</td><td>December 4, 2024</td><td>January 6, 2025</td><td><a href="https://docs.google.com/spreadsheets/d/1Syy6FHN7ZrBdA6oYQHoaeItXEO0tX5XbB10NClNizJo/edit?usp=sharing">Responses to comments</a></td></tr><tr><td>Biomass Carbon Removal Storage v1.0</td><td>September 12, 2024</td><td>October 12, 2024</td><td><a href="https://docs.google.com/spreadsheets/d/1nfeViGu0Xx1mTsp2iOTZuTt7oy4z9pavkCWtF0NezRE/edit?gid=1359453849#gid=1359453849">Responses to comments</a></td></tr><tr><td>Biogas from anaerobic digestion v3.0</td><td>May 27, 2024</td><td>June 28, 2024</td><td><a href="https://docs.google.com/spreadsheets/d/1u_HjJ2B2D2Q454txweboWYNDbMKSoeacp4L6qvuDmR0/edit?usp=sharing">Responses to comments</a></td></tr><tr><td>Electronic device refurbishing v2.0</td><td>April 23, 2024</td><td>May 24, 2024</td><td><a href="https://docs.google.com/spreadsheets/d/1bzjf5aFUqHtjDIQqEoqS4KGjuAaHkn0U_l5zVl-rW5k/edit?usp=sharing">Responses to comments</a></td></tr><tr><td>Riverse Standard Rules v6</td><td>March 12, 2024</td><td>April 12, 2024</td><td><a href="https://docs.google.com/spreadsheets/d/1jdicooEKzfVWYHj2NtKYKgMJ5lSeX7hwxEQnCKmpnWI/edit?usp=sharing">Responses to comments</a></td></tr><tr><td>Biobased Construction Materials Methodology v2.0</td><td>January 24, 2024</td><td>March 1, 2024</td><td><a href="https://www.youtube.com/watch?v=s0IpqxGA2kA&#x26;ab_channel=Riverse">Watch the webinar<br></a><br><br><a href="https://docs.google.com/spreadsheets/d/1FFCd-9A2dNL7fVAAInW8nkdfnUoLSZyzIWmlmZMfbV8/edit#gid=1272317981">Responses to comments</a></td></tr><tr><td>Riverse Standard Rules for European Greentechs v5</td><td>February 1, 2023</td><td>March 8, 2023</td><td><a href="https://www.youtube.com/watch?v=tc8qOJ3kNpc">Watch the webinar</a><br><br><a href="https://docs.google.com/spreadsheets/d/1Y7y-evrxHlfLXle6C0RNDffvzLbtEPBWPDLnZonnoTo/edit?usp=sharing">Responses to comments</a></td></tr></tbody></table>

Access all archived versions of Rainbow Standard Documents and methodologies here :point\_down:

{% content-ref url="/pages/0K4eTnY0WFz1e6nBBC4l" %}
[Archived documents](/other/archived-methodologies)
{% endcontent-ref %}


# Industrial biochar


# Eligibility and scope

### Eligible technologies \[biomass]

Eligible biomasses are those that:

* could not have been used as main material products,
* were not grown for the purpose of CDR[^1] or bioenergy production.

For simplification, all feedstocks that meet the above requirements will be referred to hereafter as waste. Biomass feedstocks are categorized accordingly:

<table><thead><tr><th width="202">Biomass type</th><th width="315">Description</th><th>Source</th></tr></thead><tbody><tr><td>Forest waste from secondary forest</td><td>Natural but not primary old-growth forest, may still be managed for timber</td><td>Default if no other forest type can be proven</td></tr><tr><td>Forest waste from managed forest</td><td>Managed mixed-use forests that may include agroforestry, plantations or rotational logging</td><td>Must provide proof</td></tr><tr><td>Necessary tree removal from any forest</td><td>Damaged trees, or trees removed for planned forest management such as preventing disease spread or fires</td><td>Must provide proof</td></tr><tr><td>Agricultural residues with value</td><td>Residues left on soil or reapplied to soils for nutrient recycling (e.g. mulching, composting, spreading fast-decaying cellulose-based residues with decay within 5 years)</td><td>Default if prior use could not be determined</td></tr><tr><td>Agricultural residues with no value</td><td>Plowed into soil, burnt in the field, no substantial return of nutrients to soil</td><td>Must provide proof</td></tr><tr><td>Other waste or residue</td><td>To be evaluated on a case by case basis according to criteria outlined in the present document</td><td>Must provide proof</td></tr></tbody></table>

### Eligible technologies \[biochar]

Industrial biochar projects must meet all of the following requirements:

<table data-view="cards"><thead><tr><th></th><th></th><th></th></tr></thead><tbody><tr><td><strong>Feedstock</strong></td><td><ul><li>Use waste and residual biomass as feedstock, according to the <a href="/pages/V0dXfN5yPUaU1ws1h7sV">Biomass feedstock</a> module.</li></ul></td><td></td></tr><tr><td></td><td><strong>Processing</strong></td><td><ul><li>Heat biomass to at least <strong>350°C</strong> during production.</li><li>Capture or cleanly burn pyrolysis gasses, as outlined in the <a href="/pages/BTxxPIM3a4Nai1Wkwu2Y#environmental-and-social-do-no-harm">Processing and Energy Use</a> module</li><li>Report methane emissions from pyrolysis, using the <a href="/pages/BTxxPIM3a4Nai1Wkwu2Y#environmental-and-social-do-no-harm">Processing and Energy Use</a> module</li></ul></td></tr><tr><td></td><td><strong>Biochar Quality and Use</strong></td><td><ul><li>Produce high-quality biochar with a molar <span class="math">H/C_{\text{org}}</span> below <strong>0.7</strong>.</li><li>Apply biochar to agricultural, forest, or urban soils, ensuring permanent sequestration of its organic carbon content.</li></ul></td></tr></tbody></table>

Projects may be designed to prioritize bio-oil or bioenergy production, where biochar is the co-product. Such projects may still be eligible for removal Rainbow Carbon Credits under this module, if they meet all criteria outlined herein.

This module allows for issuance of **removal RCCs on the basis of biochar end use/delivery**, i.e. application to soils and permanent storage, not on the basis of biochar production.

**Eligible end uses of biochar** include application directly to soils or incorporation into soil-related products, such as soil additives, horticultural substrates, potting soils, fertilizer mixes, or compost.

This module also allows for issuance of **avoidance RCCs on the basis of avoided horticultural products** from the use of biochar (with strict proof of replacement, see the [Baseline Scope](#baseline-scope) section).

The Project Developer and entity eligible for receiving carbon finance may be either:

* the operator of the biochar production site, or
* land owners or managers who purchase biochar and apply it to their soil.

Pyrolysis and gasification equipment manufacturers are not eligible Project Developers.

### Certification requirements

**Crediting period duration:** the maximum duration of the crediting period for projects certified under this methodology is 5 years. Upon reaching the maximum duration, a project's crediting period may be renewed, according to the [Crediting Period Renewal](https://docs.rainbowstandard.io/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal) procedure.

**Monitoring period duration:** The default monitoring period duration is one year, but may be shorter at the Project Developer's request. Project Developers shall submit a Monitoring Report at least once per 24 months. Failure to do so shall result in the project being [deregistered](https://docs.rainbowstandard.io/rainbow-standard-documents/procedures-manual/project-certification-procedure).

**Site audits:** validation site audits for projects under this methodology may be performed **either remotely or in-person**, depending on the project size. Projects that issue more than 5,000 RCCs per year must undergo an in-person site audit. Projects that issue less than 5,000 RCCs per year may choose between an in-person or remote audit. The Rainbow team may require an in-person site audit for any project, regardless of the size.

**Versioning and project compliance:** When this methodology is revised, projects are required to comply with the latest version for subsequent verifications of RCCs.

### Project scope

One project is defined as:

* the operation of one or more pyrolysis units, across one or more sites,
* within a single country,
* using similar types of pyrolysis units,
* using the same carbon removal measurement approach and durability claims, and
* operated at sites that are under the oversight or data access of a single Project Developer, regardless of whether the developer directly owns or manages each site.

The project scope is cradle-to-grave and includes all processes that result from biochar production and application. This includes but is not limited to the following: all removals from biochar production, and all induced emissions related to biomass sourcing, leakage, upstream and downstream transport, embodied emissions from infrastructure and machinery, and onsite process emissions from biomass and biochar processing and energy use.

Any processes that would have occurred regardless of the biochar production and application activities may be excluded from the project scope.

### Baseline scope \[biomass] <a href="#project-scope" id="project-scope"></a>

The baseline shall include **any permanent carbon removal that would have occurred in the absence of the project**. For biomass use, this includes permanent carbon storage from the alternate fate of the biomass feedstock used for pyrolysis.

Project Developers shall justify the alternate fate of business-as-usual biomass feedstock use.

* If biomass would have been left on agricultural fields, or otherwise applied to soil to decompose, a default **0.5% of the carbon in the biomass feedstock** is assumed to be permanently stored.
* For any other alternate fate of biomass, it is assumed that no carbon is permanently stored, and no baseline is considered for this module.

It shall be assumed by default that no biomass feedstock would have been used for dedicated carbon removal projects in the absence of the project (i.e. there is no share of the project activity in the baseline scenario).

More conservative baseline scenarios may be applied on a case-by-base basis. They must be representative and transparently justified.

See the [GHG quantification ](#id-4l7lx2ihb6hj-2)section for more details on how baseline removals are calculated.

### Baseline scope \[biochar]

Several baselines may be applied depending on the type of credit issued:

**Removal RCCs from biochar carbon removal**:

* the baseline shall include any permanent carbon removal that would have occurred in the absence of the project.
* This includes but is not limited to permanent carbon storage from the alternate fate of the biomass feedstock used for pyrolysis.
* It shall be assumed by default that no biomass feedstock would have been used to produce biochar in the absence of the project (i.e. there is no share of the project activity in the baseline scenario).

**Avoidance RCCs from energy co-products**:

* the baseline shall include the equivalent amount of energy produced and exported by the project.
* The type of energy selected for the baseline shall be representative of the energy produced by the project, and shall be specific and conservative.
* All life cycle emissions from the baseline energy source shall be accounted for, including but not limited to raw material extraction, processing, upgrading, distribution, and if relevant, combustion.

**Avoidance RCCs from horticultural products**:

* the baseline shall include the equivalent amount of horticultural products (e.g. peat, fertilizer...) produced and sold by the project.
* The specific amount and type of avoided products must be **provided by the Project Developer with project-specific documentation**. It must show that the user of the biochar **actually uses less of the horticultural product than they did previously**, as a result of their use of biochar. This must be proven using, for example, operations tracking or invoices from the biochar user. In other words, it is not sufficient to prove that biochar could *technically* substitute products, because there is high uncertainty in which products biochar would *actually* substitute.
* All emissions from the baseline horticultural product life cycle that differ from the biochar life cycle shall be accounted for, including but not limited to raw material extraction and processing. If processes are equivalent between the biochar and horticultural product, such as transport delivery or packaging, they may be excluded from both the project and baseline scope for the purpose of quantifying avoidance RCCs from horticultural products.
* By default, it shall be **assumed that biochar application to soils does not replace any measurable, verifiable product**.

The baseline scenario **structure** remains valid for the entire crediting period but may be significantly revised earlier if:

* The Project Developer notifies Rainbow of a substantial change in project operations or baseline conditions, and/or
* The methodology is revised, affecting the baseline scenario.

The **specific values** within the baseline scenario will be updated during each crediting period, using project data to accurately reflect the equivalent of the project’s operations.

## Production batches <a href="#id-2xck12gc2auz" id="id-2xck12gc2auz"></a>

A production batch is the **biochar produced under the same conditions regarding production temperature and feedstock mix**. It is assumed that all biochar from the same production batch has similar characteristics (i.e. $$H/C\_{\text{org}}$$, moisture content…).

Specifically, the definition of a production batch follows the [European Biochar Certificate Guidelines](#user-content-fn-2)[^2] definition, where pyrolysis temperature and biomass feedstock composition must not change by more than 20%.

Measurements and reporting are performed at the **production batch level**. Verification and credit issuance may be done per production batch, or annually on the cumulative production batches from that year.

{% hint style="info" %}
For example, if the declared pyrolysis temperature is 600 °C, temporary fluctuations between 480 °C and 720 °C are acceptable.

If a mixture of 50% tree clippings and 50% nut shells is pyrolyzed, the proportions can vary between 40% and 60% (±10% of the original 50%)
{% endhint %}

A production batch has a **maximum validity of 365 days**, after which biochar shall be considered part of a different production batch even if conditions are unchanged. In other words, the production batch ID number resets and a new production batch is created, and new monitoring requirements applied, after 365 days, regardless of if feedstock or pyrolysis conditions change or not.

[^1]: Carbon dioxide removal

[^2]: *EBC (2012-2023) 'European Biochar Certificate - Guidelines for a Sustainable Production of Biochar.' Carbon Standards International (CSI), Frick, Switzerland. (<http://european-biochar.org>). Version 10.3 from 5th Apr 2022.*


# Principles & requirements

### Additionality

To demonstrate additionality, Project Developers shall perform **regulatory surplus analysis, plus either investment or barrier analysis**, using the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template).

{% tabs %}
{% tab title="Regulatory surplus analysis" %}
**Regulatory surplus analysis** shall demonstrate that there are no regulations that require or mandate project activities (for removal and avoidance activities). It is acceptable if regulations promote or set targets for these activities, because the resulting increase in activities shall be accounted for in the [baseline scenario](#id-8422amp7fe3k-1).

At the European Union level, projects automatically pass the regulatory surplus analysis, which has been conducted by the Rainbow Science Team. Project Developers are only required to provide a country-level regulatory surplus analysis.
{% endtab %}

{% tab title="Investment analysis" %}
**Investment analysis** may be used to prove that revenue from carbon finance is necessary to make the project investment a financially viable and interesting option. The investment may cover:

* The creation and launching of new sites
* Expansion of capacity of existing activities
* Expansion by installing new processes

Business plans shall be provided as initial proof for investment analysis. During verification, audited financial statements shall be used to demonstrate that the initial estimates from the business plan were reasonable, and that carbon finance was used as initially described for the expected investment.

For launching brand new sites, additionality can be simply demonstrated if the business plan shows that carbon finance is expected to make up at least 80% of the company’s revenue, as detailed in the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template).

Note that for investments in expansion, **only the additional carbon reductions enabled by the expansion shall be eligible for Rainbow Carbon Credits.**
{% endtab %}

{% tab title="Barrier analysis" %}
**Barrier analysis** may be used to prove that the project faces financial, institutional, or technological barriers to ongoing operations that can only be overcome using carbon finance. Examples include but are not limited to:

* Financial barrier: financial analysis demonstrating that the project is not financially viable, evidenced by net cash being lower than the working capital requirements, or proof that the project is not meeting the projected financial targets in the business plans and loan documents, and that carbon finance would make it financially viable.
* Institutional barrier: description of new regulation that the project must make costly changes to comply with, financial analysis showing that the project cannot fund the changes on their own, and carbon finance is necessary to make it viable.

For any type of barrier analysis, **audited financial statements must be provided** as proof. These documents should either demonstrate the financial status to prove financial barriers, or show that the project could not independently fund solutions to overcome institutional or technological barriers.
{% endtab %}
{% endtabs %}

### Durability <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

#### Durability threshold

All projects certified under this methodology shall prove **durable carbon removals for at least 100 years**. Project Developers may claim an extended durability threshold of 1000 years if they choose the 1000-year pathway for [GHG quantification](#ghg-quantification) and measurements.

#### Reversal risk assessment

The major carbon reversal risks from biochar application to soil are:

1. **Insufficient biochar stability**, where biochar carbon is not sufficiently carbonized and is decomposed by microbes and soil organisms, resulting in re-emission of CO<sub>2</sub>.
2. **Failure to durably incorporate into soils**, where biochar does not end up in a durable storage matrix (e.g. soil or soil-like material) and is instead burned or destroyed, intentionally or unintentionally (e.g. as fuel, in storage fires, or via waste incineration).

This methodology establishes the following mandatory project design requirements to mitigate these risks, detailed in the following sections:

* measuring the durable carbon fraction
* verification of biochar end use

Upon meeting these requirements for each verification and credit issuance, the risk of reversal is considered **negligible** for biochar application to soils. There are no further project requirements to assess reversal risks or conduct post-crediting monitoring for reversals.

All projects certified under this methodology shall contribute the default minimum 2% of their verified removal RCCs to the Rainbow Buffer Pool, as defined in the Rainbow Standard Rules.

#### Risk mitigation: Measuring permanent carbon fraction <a href="#kmzukpswu89" id="kmzukpswu89"></a>

Not all biomass carbon that is converted to biochar is expected to remain durably stored. The durability of biochar carbon depends on the its physicochemical stability, which is influenced by factors such as carbonization temperature and biomass feedstock.

Project Developers shall measure one of the following well-known [proxy indicators](#user-content-fn-1)[^1] of biochar durability for each production batch. These indicators serve both as **eligibility thresholds**, and as inputs to **quantify the permanent fraction of carbon** ($$F\_{perm}$$) expected to remain durably stored beyond the applicable durability threshold.

The fraction of permanently stored carbon shall be quantified using the models and equations specified in the [GHG quantification](#ghg-quantification) section. Only this fraction shall be issued as removal RCCs.

<table><thead><tr><th width="136">Pathway</th><th width="213">Indicator</th><th>Threshold requirement</th></tr></thead><tbody><tr><td>100-year pathway</td><td>Hydrogen-to-organic-carbon atomic ratio (<span class="math">H/C_{\text{org}}</span>)</td><td><span class="math">H/C_{\text{org}}</span> must be less than 0.7</td></tr><tr><td>1000-year pathway</td><td>Random reflectance distribution</td><td><ul><li>The fraction of the biochar residual organic carbon that has a random reflectance of 2% or higher can be considered <a data-footnote-ref href="#user-content-fn-2">inertinite</a>, which is an extremely stable, permanent storage of mineral-like organic carbon.</li><li>Must also have <span class="math">H/C_{\text{org}}</span> less than 0.7</li></ul></td></tr></tbody></table>

The distinction between the 100-year and 1,000-year durability pathways provides supplementary qualitative information and does not affect the inherent attributes of the removal RCC.

These indicators are **suitable proof that a substantial fraction** of the carbon present in biochar is permanently stable. The **specific amount** of permanently stored carbon is determined using the models and equations detailed in the [GHG quantification](#ghg-quantification) section.

These durability indicators shall be monitored for each production batch according to the Rainbow [Sampling Requirements](#sampling-and-measurements).

Issuing removal RCCs only for the verified, highly stable fraction of biochar carbon mitigates the risk of biological decomposition and re-emission after soil application.

#### Risk mitigation: Proof of biochar end use <a href="#id-5a8ye61po9ri" id="id-5a8ye61po9ri"></a>

Project Developers shall prove that all biochar has been used in the intended durable storage application (e.g. incorporated into soils, added to fertilizer mixes…). This shall be done in **Biochar Application Verification Reports** that contain all of the following:

* Tracking records of the purchase and/or delivery of the biochar to its end use point of use, specifying the date, amount of biochar and Production Batch ID.
* GPS coordinates of all end use points with according amounts of biochar, if known to the Project Developer.
* Company name and individual contact information for each buyer/user of biochar, for traceability and random checking by VVBs.
* Photo diary of biochar application, including photos of for example the biochar being delivered, tags/labels with information, road signs during delivery, process of biochar spreading.

Issuing removal RCCs only after verified incorporation into a permanent storage matrix mitigates the risk that biochar is burned, destroyed or otherwise re-emitted.

### No double counting \[BiCRS] <a href="#n1iy4xaxuthk" id="n1iy4xaxuthk"></a>

Project Developers shall sign the [Rainbow MRV & Registry Terms & Conditions](/other/terms-and-contracts/terms-and-conditions-for-project-developers-mrv-+-registry), committing to follow the requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules), including not double using or double issuing carbon credits.

BiCRS projects have a risk of double issuance of credits if the user of the removal solution and/or operator of the storage site also seeks credit issuance. Project Developers shall:

* Identify all direct downstream users/buyers/actors in their supply chain, providing the company/organization name, name of an individual contact person at the company/organization, and their contact information (email address at minimum).
* Provide proof that measures have been taken to avoid double issuance with those actors, such as through signed agreements, packaging/marketing material stating carbon credits have already been issued, and/or sales contract clauses.

If the Project Developer proves that the removal solution stays within the project scope all the way through storage, and it is never sold or transferred, then the requirements above may be disregarded.

### No double counting \[Biochar] <a href="#id-8f3i2uvmiuhl" id="id-8f3i2uvmiuhl"></a>

See the [BiCRS methodology No double counting](/methodologies/biomass-carbon-removal-and-storage-bicrs#n1iy4xaxuthk) section for general requirements on this topic. Since both **biochar producers and users** are eligible for removal RCCs under this methodology, additional details are provided here.

If **both the biochar producer and the farmer intend to issue carbon credits**, they must agree on how to divide the annual biochar production for credit issuance. The credited biochar amount must be tracked and reported separately, governed by agreements outlining which party receives credits.

{% hint style="info" %}
For example, they might decide that the farmer will issue credits for the biochar produced from January through April (Production Batch #1), while the producer will issue credits for biochar produced from May through December (Production Batch #2).
{% endhint %}

Since both **biochar producers and users** are eligible for removal RCCs under this methodology, additional details are provided here.

If **only one party seeks to issue carbon credits**, this must be proven through signed agreements, minimizing the risk of double counting.

{% hint style="info" %}
For example, if only the biochar producer seeks to issue carbon credits, they must obtain a signed agreement from the farmer whose land biochar will be spread on, stating that the farmer will not also try to issue carbon credits for their use of biochar.
{% endhint %}

If **both the biochar producer and the farmer intend to issue carbon credits**, they must agree on how to divide the annual biochar production for credit issuance. The credited biochar amount must be tracked and reported separately, governed by agreements outlining which party receives credits.

{% hint style="info" %}
For example, they might decide that the farmer will issue credits for the biochar produced from January through April (Production Batch #1), while the producer will issue credits for biochar produced from May through December (Production Batch #2).
{% endhint %}

### Co-benefits <a href="#id-8f3i2uvmiuhl" id="id-8f3i2uvmiuhl"></a>

Projects should support at least two **quantifiable and verifiable** environmental or social co-benefits, aligned with the [UN Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDGs) framework. Any co-benefits claimed by the Project Developer shall be **quantified, monitored, and audited** for each verification and credit issuance.

Common co-benefits under this methodology are detailed in the table below. Project Developers may suggest and prove other co-benefits not mentioned here.

SDG 13 on Climate Action by default is not considered a co-benefit here, since it is implicitly accounted for in the issuance of carbon credits. If the project delivers climate benefits that are not accounted for in the GHG reduction quantifications, then they may be considered as co-benefits.

*Table 1 Common co-benefits that projects under this methodology may provide are detailed, including types of proof that can be used to justify each co-benefit.*

<table><thead><tr><th width="200">UN SDG</th><th width="345">Example</th><th>Proof</th></tr></thead><tbody><tr><td><strong>SDG 2.4:</strong> Ensure sustainable food production systems, increase productivity, help maintain resilient ecosystems, improve land and soil quality.</td><td>Biochar application to agricultural soils can <a data-footnote-ref href="#user-content-fn-3">increase crop yields,</a> therefore reducing the amount of land, pesticides, fertilizer, and other environmentally impactful resources needed to grow food</td><td>Proof of biochar use in agriculture as opposed to other applications: contract, invoices, receipts of sale of biochar to farmers.</td></tr><tr><td><strong>SDG 12.2:</strong> Achieve the sustainable management and efficient use of natural resources</td><td>The project’s <a data-footnote-ref href="#user-content-fn-4">circularity </a>will be measured by the <a data-footnote-ref href="#user-content-fn-5">Material Circularity Indicator (MCI)</a>, according to the Ellen MacArthur Foundation's methodology. The indicator is expected to be 100% circularity for all biochar projects, since they use biomass feedstock and do not landfill or incinerate their product.</td><td>Type of feedstocks used, verification of end use of biochar</td></tr></tbody></table>

### Environmental and social safeguards \[biomass] <a href="#id-82n4j72vjt9v" id="id-82n4j72vjt9v"></a>

Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.**

Projects must follow all national, local and European (if located in Europe) environmental regulations, including but not limited to those related to biomass harvesting and forest management.

In addition to completing the [Biomass feedstock risk assessment](#esdnh-risk-assessment) described below, Project Developers must prove the following elements.

{% tabs %}
{% tab title="Waste status" %}
Project Developers shall provide proof that the **biomass feedstock is classified as waste**. This can be done via any one of the following three methods:

* **Price**: if Project Developers did not pay for the biomass, or if they were paid to handle it, the biomass can be considered waste. Acceptable proof includes invoices, receipts, or contracts.
* **Contextual analysis**: Project Developers may submit an analysis supported by reputable sources that the biomass 1) could not be used as main material products, and 2) was not grown for the purpose of CDR[^6].
* **Positive list of wastes**: if the biomass is included in the following list, it can be considered waste. Acceptable proof includes invoices, receipts, contracts, or photographic evidence and is required for validation:
  * sawmill residues
  * sawdust
  * shavings
  * bark
  * forestry tops and branches
  * wildfire management residues
  * straw
  * husks
  * corn cobs
  * wood from horticulture (trimmings or whole plants)
  * nut shells
  * bagasse
  * sugar beet pulp
    {% endtab %}

{% tab title="Alternative use" %}
Project Developers shall evaluate the most likely alternative use/s of the biomass in order to assess environmental risks, leakage risks, and to calculate replacement emissions (if applicable). The assessment shall be transparent and conservative.

The alternative use shall address questions such as:

* was the biomass used for a product or service, that now needs to be replaced?
* was the biomass going to store carbon anyway (in the biomass itself and/or in the soil)?

Proof shall be provided and may include signed statements from the biomass provider, historical records from the biomass provider, regional statistics or reputable reporting.

A short list of likely alternative uses may be provided for descriptive purposes, but for the purpose of further analysis, one single alternative use shall be proposed.
{% endtab %}

{% tab title="Forestry certification" %}
Biomass feedstock originating from forests shall provide at least one of the following forestry sustainability certificates (or similar, with a sufficient justification):

* FSC (Forest Stewardship Council)⁠
* PEFC (Program for the Endorsement of Forest Certification)⁠
* RSB (Roundtable on Sustainable Biomaterials)⁠
* SFI (Sustainable Forestry Initiative)⁠
* SBP (Sustainable Biomass Program)⁠

These certifications are used to prove:

* Legal and transparent chain of custody
* Proper forest regeneration
* Safeguarding biodiversity and soil health
* Historically stable or increasing forest carbon stocks
* Sound socio-environmental practices in forestry operations⁠
  {% endtab %}
  {% endtabs %}

#### Environmental and social risk assessment <a href="#esdnh-risk-assessment" id="esdnh-risk-assessment"></a>

Project Developers shall fill in the [Biomass feedstock risk assessment](#risk-assessment-template) template, to evaluate the identified environmental and social risks of projects. The identified risks include:

* Disruption of soil health when collecting and exporting organic matter
* Presence of heavy metals, toxins or other chemical pollutants in the biomass⁠
* Spread of diseases or invasive species
* Cultivation of feedstock
* Deforestation from use of forestry products as feedstock
* Distant transport of feedstock inputs (>100 km)

### Environmental and social safeguards \[biochar] <a href="#id-82n4j72vjt9v" id="id-82n4j72vjt9v"></a>

Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.**

Projects must follow all national, local, and European (if located in Europe) environmental regulations, including but not limited to those related to pyrolysis, gasification, waste feedstock management, and biochar spreading on soils.

**Feedstock sustainability risks** shall be taken from the [Biomass feedstock module](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock).

Biochar applied to soils must be below the pollutant concentration thresholds outlined in Table 2, defined by the [World Biochar Certificate Guidelines](#user-content-fn-7)[^7] (for WBC-Agro). This shall be measured for each production batch.

*Table 2 The thresholds for pollutant concentrations allowed in biochar, as detailed in the* [*World Biochar Certificate Guidelines*](#user-content-fn-7)[^7]*.*

<table><thead><tr><th width="353.44439697265625">Substance</th><th>Limit amount (g/tonne dry matter)</th></tr></thead><tbody><tr><td>Pb</td><td>300</td></tr><tr><td>Cd</td><td>5</td></tr><tr><td>Cu</td><td>200</td></tr><tr><td>Ni</td><td>100</td></tr><tr><td>Hg</td><td>2</td></tr><tr><td>Zn</td><td>1000</td></tr><tr><td>Cr</td><td>200</td></tr><tr><td>As</td><td>20</td></tr><tr><td>8 EFSA PAH</td><td>1</td></tr></tbody></table>

{% hint style="info" %}
*Disclaimer: The European Biochar Certificate (EBC) and the World Biochar Certificate (WBC) are independent certification programs designed to ensure the quality of biochar products. These certifications are administered and trademarked by Carbon Standards International (CSI) and are distinct from the Rainbow certification and the issuance of carbon credits.*

*The threshold values provided here are based on the voluntary guidelines of the World Biochar Certificate (WBC), reproduced with permission. While these values have been adopted by the Rainbow standard as pollutant thresholds, they are only indicative. Meeting these thresholds for Rainbow certification does not imply eligibility for or any association with the EBC or WBC programs. Project Developers certified under the Rainbow standard shall not make claims or use any trademarked materials from CSI, unless explicitly allowed by CSI.*

*Voluntary certification under the WBC and EBC schemes is overseen by CSI and includes additional requirements beyond pollutant thresholds.*
{% endhint %}

#### Environmental and social risk assessment

Project Developers shall fill in the [Rainbow Biochar application to soils risk assessment](#risk-assessment-template), to evaluate the identified environmental and social risks of projects. The identified risks include:

* Heavy metal or other pollutants in biochar applied to agricultural soils
* Health risks from exposure to harmful gasses and particles

Project Developers shall fill in the[ General BiCRS risk assessment](#risk-evaluation-template), in addition to all module-specific risk assessments, to evaluate the identified environmental and social risks of projects.

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

### Leakage <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

Biomass feedstock sourcing must not contribute to activity shifting leakage.

The requirement that biomass feedstock must be classified as waste prevents activity shifting leakage. Consequently, the evidence provided in the [Environmental and social safeguards](#id-82n4j72vjt9v) section shall also be applied here to verify that the feedstock is waste.

Several other types of leakage risks are already covered by other components of this module:

* Displacement of soil carbon storage: a small amount of soil carbon storage is assumed and modeled in the Baseline Scenario where relevant, effectively deducted from the project's carbon storage.
* Upstream and downstream emissions: considered in the life-cycle based GHG quantifications in companion modules.

### Monitoring \[biomass] <a href="#snhouoxhyrzi" id="snhouoxhyrzi"></a>

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information **for each monitoring period**:

* Mass, type and source of all biomass feedstocks collected by the project.
* Sustainable forestry certification (if applicable)

### Monitoring \[biochar]

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information **for each Production Batch**:

* Description of the pyrolysis conditions (temperature and residence time) and any variability in the process
* Amount of biochar produced, in tonnes of fresh biochar
* Moisture content of biochar
* Organic carbon content
* $$H/C\_{\text{org}}$$ (only for [Approach 1: Modeling 100-year removals with H/C org](#unteq8ror26g))
* Random reflectance ( $$R\_o$$) mean and distribution, and residual carbon content (only for [Approach 2: Estimating 1000-year removals using random reflectance](#id-2rhx2av7of74))
* [Environmental and social safeguards: biochar pollutant measurements](#id-82n4j72vjt9v-1)
* [Biochar Application Verification Reports](#id-5a8ye61po9ri), with names and GPS coordinates of spreading locations, among other information
* [Sampling records](#sampling-records)

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information **for each reporting period**:

* Number of Production Batches
* Total amount of biochar produced per year, in tonnes of fresh biochar
* Co-benefits

Monitoring Plans shall include the following information for each monitored parameter:

* monitoring frequency
* emission sources and sinks
* data source
* measurement methods/procedures, and their accuracy and calibration
* quality assessment or quality control procedures
* responsible party for collecting and archiving data

[^1]: - Rodrigues, L., Budai, A., Elsgaard, L., Hardy, B., Keel, S.G., Mondini, C., Plaza, C., Leifeld, J., 2023. The importance of biochar quality and pyrolysis yield for soil carbon sequestration in practice. European Journal of Soil Science 74, e13396. [https://doi.org/10.1111/ejss.1339](https://doi.org/10.1111/ejss.13396)
    - Rudra, A., Petersen, H.I., Sanei, H., 2024. Molecular characterization of biochar and the relation to carbon permanence. International Journal of Coal Geology 291, 104565. <https://doi.org/10.1016/j.coal.2024.104565>
    - Wang, J., Xiong, Z., Kuzyakov, Y., 2016. Biochar stability in soil: meta-analysis of decomposition and priming effects. GCB Bioenergy 8, 512–523. <https://doi.org/10.1111/gcbb.12266>
    - Sanei, H., Rudra, A., Przyswitt, Z.M.M., Kousted, S., Sindlev, M.B., Zheng, X., Nielsen, S.B., Petersen, H.I., 2024. Assessing biochar’s permanence: An inertinite benchmark. International Journal of Coal Geology 281, 104409. <https://doi.org/10.1016/j.coal.2023.104409>

[^2]: Inertinite is a type of maceral. Macerals are the organic compounds in materials like coal and shale, and are extremely permanent. They are analogous to mineral carbon in rocks.

[^3]: * Schmidt, H.-P., Kammann, C., Hagemann, N., Leifeld, J., Bucheli, T.D., Sánchez Monedero, M.A., Cayuela, M.L., 2021. Biochar in agriculture – A systematic review of 26 global meta-analyses. GCB Bioenergy 13, 1708–1730.[ https://doi.org/10.1111/gcbb.12889](https://doi.org/10.1111/gcbb.12889)
    * Joseph, S., Cowie, A.L., Van Zwieten, L., Bolan, N., Budai, A., Buss, W., Cayuela, M.L., Graber, E.R., Ippolito, J.A., Kuzyakov, Y., Luo, Y., Ok, Y.S., Palansooriya, K.N., Shepherd, J., Stephens, S., Weng, Z. (Han), Lehmann, J., 2021. How biochar works, and when it doesn’t: A review of mechanisms controlling soil and plant responses to biochar. GCB Bioenergy 13, 1731–1764.[ https://doi.org/10.1111/gcbb.12885](https://doi.org/10.1111/gcbb.12885)

[^4]: Goddin, J., Marshall, K., Pereira, A., Tuppen, C., Herrmann, S., Jones, S., Krieger, T., Lenges, C., Coleman, B., Pierce, C., Iliefski-Janols, S., Veenendaal, R., Stoltz, P., Ford, L., Goodman, T., Vetere, M., Mistry, M., Graichen, F., Natarajan, A., Sullens, W., 2019. Circularity Indicators: An Approach to Measuring Circularity, Methodology. <https://doi.org/10.13140/RG.2.2.29213.84962>

[^5]: Ellen Macarthur Foundation, ANSYS Granta, 2019. An approach to measuring circularity. Published in 2015, adapted in 2019. [URL](https://emf.thirdlight.com/link/3jtevhlkbukz-9of4s4/@/preview/1?o)

[^6]: Carbon dioxide removal

[^7]: WBC (2023): World Biochar Certificate – Guidelines for a Sustainable Production of Biochar and its Certification.' Carbon Standards International, Frick, Switzerland, (<http://www.european-biochar.org>), version 1.1 from 20th December 2024. [URL](https://www.carbon-standards.com/en/standards/service-514~production-of-biochar.html).


# GHG quantification

### GHG quantification \[BiCRS]

General GHG quantification rules can be found in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules).

Calculations of GHG emissions for the baseline and project scenarios shall follow a robust, recognized method and good practice guidance. The overall methodological approach is a comparative life cycle assessment (LCA) at the project-scale, based on [ISO 14064-2:2019](#user-content-fn-1)[^1].

BiCRS projects may be eligible for **removal and avoidance Rainbow Carbon Credits**. Removal and avoidance RCCs are calculated and issued according to two completely separate accounting mechanisms, described below. This conservative approach results in double counting the project's induced emissions, and avoids the need for allocation of emissions/removals.

GHG quantifications shall be completed either for each batch (batches are defined in the relevant [carbon storage modules](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage)), or for each calendar year. Carbon storage module documents may provide specific requirements.

### Functional unit \[BiCRS] <a href="#id-8422amp7fe3k" id="id-8422amp7fe3k"></a>

The functional unit shall be **1 tonne of carbon storage solution** (e.g. 1 tonne of biochar spread on soils, 1 tonne of biomass buried...).

The GHG quantification instructions from all other BiCRS modules used by the project must be used in conjunction with the present module in order to obtain full life-cycle GHG quantifications.

The system boundary of this quantification section starts at the arrival of biochar at the site of permanent incorporation/application (i.e. field for spreading, mixing into potting soil...) and ends at the biochar end of life, after accounting for decay and re-emission in its end use application.

The system boundary of this quantification section starts at the arrival of biochar at the site of permanent incorporation/application (i.e. field for spreading, mixing into potting soil...) and ends at the biochar end of life, after accounting for decay and re-emission in its end use application.

**Quantification shall be done at a minimum for each biochar production batch**, and may be done more frequently for continuous issuance.

GHG emissions covered in this module include:

* Permanent carbon storage modeling
* Production of avoided baseline scenario materials

### Data sources \[biomass] <a href="#kpxsamb8logm" id="kpxsamb8logm"></a>

The **required data from all projects using biomass feedstocks** are presented in Table 2.

*Table 2 Summary of primary data needed from projects and their source for initial project certification and validation. Asterisks (\*) indicate which data are required to be updated annually during verification (see Monitoring Plan section).*

<table><thead><tr><th width="237">Parameter</th><th width="174">Unit</th><th>Source</th></tr></thead><tbody><tr><td>Amount of biomass used*</td><td>Tonnes of fresh matter</td><td>Primary: Internal tracking documents, invoices, contracts</td></tr><tr><td>Carbon content of biomass</td><td>% w/w, fraction, kg/tonne</td><td>Primary or secondary: Laboratory chemical analyses, <a data-footnote-ref href="#user-content-fn-2">scientific publications</a> or local/national agriculture government agencies</td></tr></tbody></table>

### Data sources \[biochar] <a href="#kpxsamb8logm" id="kpxsamb8logm"></a>

The required **primary data** for GHG reduction calculations from projects are presented in Table 2. These data shall be provided for each production batch and made publicly available.

*Table 2 Summary of primary data needed from projects and their source for initial project certification and validation. All primary data sources listed here are required to be monitored and updated during verification (see Monitoring Plan section).*

{% tabs %}
{% tab title="Option 1: 100-year removals with H/C" %}

| Parameter                                                              | Unit                   | Source                                                                     |
| ---------------------------------------------------------------------- | ---------------------- | -------------------------------------------------------------------------- |
| Amount of biochar produced\*                                           | Tonnes of fresh matter | Internal tracking documents, invoices, contracts                           |
| Biochar $$H/C\_{\text{org}}$$\*                                        | Ratio                  | Laboratory chemical analyses                                               |
| Organic carbon content                                                 | Percent                | Laboratory chemical analyses                                               |
| Biochar moisture content ($$M\_{\text{%}}$$) \*                        | Percent                | Laboratory chemical analyses                                               |
| [GPS coordinates ](#user-content-fn-3)[^3]of biochar spreading sites\* | coordinates            | Internal tracking documents, invoices, mapping software (e.g. Google Maps) |
| Amount and type of avoided horticultural product (optional)            | kg, tonnes, m3         | Operations tracking and invoices from the product user                     |
| {% endtab %}                                                           |                        |                                                                            |

{% tab title="Option 2: 1000-year removals random reflectance" %}

<table><thead><tr><th width="302">Parameter</th><th width="154">Unit</th><th>Source</th></tr></thead><tbody><tr><td>Amount of biochar produced*</td><td>Tonnes of fresh matter</td><td>Internal tracking documents, invoices, contracts</td></tr><tr><td>Organic carbon content</td><td>Percent</td><td>Laboratory chemical analyses</td></tr><tr><td>Average random reflectance <span class="math">R_o</span></td><td>Percent</td><td>Laboratory chemical analyses</td></tr><tr><td>Fraction of <span class="math">R_o</span> distribution measurements above 2%</td><td>Fraction</td><td>Laboratory chemical analyses</td></tr><tr><td>Residual organic carbon (<span class="math">C_{org,\ \%residual}</span>)</td><td>Fraction</td><td>Laboratory analyses</td></tr><tr><td>Biochar moisture content (<span class="math">M_{\text{%}}</span>)*</td><td>percent</td><td>Laboratory chemical analyses</td></tr><tr><td>Amount and type of avoided horticultural product (optional)</td><td>kg, tonne, m3</td><td>Operations tracking and invoices from the product user</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

The [ecoinvent database](#user-content-fn-4)[^4] version 3.12 (hereafter referred to as ecoinvent) shall be the main source of emission factors unless otherwise specified. Ecoinvent is preferred because it is traceable, reliable, and well-recognized. The ecoinvent processes selected are detailed in [Appendix 1](#appendix).

No other secondary data sources are used in this module.

### Co-product allocation

The rules outlined at the methodology-level in the [BiCRS methodology document](/methodologies/biomass-carbon-removal-and-storage-bicrs) shall be applied for allocating GHG emissions between co-products.

### Assumptions \[biomass] <a href="#id-4l7lx2ihb6hj" id="id-4l7lx2ihb6hj"></a>

Major assumptions in this module include:

* The permanent carbon sequestration rate in the [baseline scenario](#id-4l7lx2ihb6hj-2) is 0.5%.

### Assumptions \[biochar]

1. By default, biochar application to soils does not replace any product.
2. The fraction of biochar with an $$R\_o$$ below 2% does not contribute to any permanent carbon storage. This fraction, classified as semi-inertinite rather than inertinite, likely plays a role in long-term carbon storage. However, due to limited research on its quantification, it is conservatively excluded from this analysis.
3. All biochar from the same production batch has the same characteristics (e.g. $$M\_{\text{%}}$$, $$H/C\_{\text{org}}$$, $$R\_o$$).

### Baseline Scenario \[biomass] <a href="#id-4l7lx2ihb6hj" id="id-4l7lx2ihb6hj"></a>

{% hint style="warning" %}
This section is only required if the feedstock's alternative use was to be **left on the soil or reapplied to soils for nutrient recycling**. Specifically this includes but is not limited to:

* mulching
* composting
* spreading fast-decaying cellulose-based residues (e.g. decay within 5 years)
  {% endhint %}

The Baseline Scenario shall include permanent carbon storage that would have occurred anyway in the absence of the project.

Although most biomass carbon would be released before the CDR project's permanence horizon, a small fraction is stabilized permanently as soil carbon. This portion is accounted for in the Baseline Scenario and deducted from the project's carbon removal capacity.

The uncertainty around biomass carbon being 1) naturally incorporated into the soil and 2) converted to a stable carbon form is high, influenced by factors such as climate, soil type, soil health, and land use, making it hard to estimate for individual projects. Thus, it is assumed that **0.5% of the carbon in the biomass feedstock** left on the soil, or reapplied to soil, will be permanently stored in soils.

<details>

<summary>Calculations- Baseline scenario</summary>

$$\textbf{(Eq.1)}\ {R}*{baseline}= A*{feedstock}\* C \* S\*-1$$

Where,

* $${R}\_{baseline}$$ represents the permanent carbon removal in the baseline scenario in the monitoring period, in t CO$$\_2$$eq. This value shall be applied to Equation 1 from the general [BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals) to calculate total project removals.
* $$A\_{feedstock}$$ represents the amount of biomass feedstock used in the monitoring period, in tonnes of dry matter.
* $$C$$ represents the concentration of carbon in the biomass feedstock, in tonnes of carbon per tonne of dry matter.
* $$S$$ represents the permanent sequestration rate of carbon applied to soils, which is 0.5%, as described in the [Assumptions ](#id-4l7lx2ihb6hj)section.
* It is multiplied by -1 to obtain a negative sign. Removals are reported as a negative value in the [BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals).

</details>

### Baseline scenario \[biochar] <a href="#ly65klblzpa9" id="ly65klblzpa9"></a>

The baseline scenario for the purpose of Removal vs Avoidance RCCs issuance is detailed below.

{% tabs %}
{% tab title="Removal RCCs" %}
For removal RCCs, there is no baseline from this module because it is assumed that there is no significant share of the project activity already occurring in business-as-usual. Therefore, the baseline for removal credits is zero and is omitted from calculations.

According to the Rainbow Procedures Manual, this assumption shall be re-assessed at a [minimum every 3 years](broken://pages/B6RuQQtXkQShQGfpsbEN#revising-a-methodology) during the mandatory methodology revision process, and any changes to this assumption would be [applied to existing projects](/rainbow-standard-documents/procedures-manual/project-certification-procedure#compliance-and-project-updates).

Note that baseline scenario carbon sequestration may be included for the project from the [biomass feedstock module](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock#ghg-quantification).
{% endtab %}

{% tab title="Avoidance RCCs" %}
By default, it shall be **assumed that biochar application to soils does not replace any measurable, verifiable product**.

If Project Developers can prove that their biochar product replaces a **specific and known amount of a specific product**, then the product may be considered as replaced and avoided.

Examples of ecoinvent processes for these products are presented in [Appendix 1](#appendix).

Note that avoidance from energy co-products is covered in a[ separate module](/modules/energy-co-products).

The equations for calculating avoidance are presented in the [BiCRS methodology ](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals)document and shall be applied here.
{% endtab %}
{% endtabs %}

### Project Scenario \[biomass] <a href="#id-4l7lx2ihb6hj" id="id-4l7lx2ihb6hj"></a>

Because the only biomass types allowed are waste, they are assigned no environmental impacts from their production/cultivation stage. Impacts from following stages, such as harvest, transport, and processing, shall be accounted for in the [Processing and energy use](/modules/processing-and-energy-use) module.

### Project scenario \[BiCRS] <a href="#letyqrgxkbuh" id="letyqrgxkbuh"></a>

Modules include specific instructions on calculating GHG emissions and removals for the relevant processes.

Each project must use **at least one module from the following categories**: carbon capture, transformation and carbon storage.

<details>

<summary><strong>Calculations:</strong> Removals</summary>

$$\textbf{(Eq.1)}\ Net\ Removal = R\_{baseline}-R\_{project}-E\_{project}$$

where,

* $$Net\ Removal$$ represents the net removals from the project during the verification period, in tonnes of CO$$\_2$$eq. Its sign is positive.
* $$R\_{baseline}$$ represents any baseline GHG removals from the capture module(s), representing permanent storage that would have occurred in the absence of the project, in tonnes of CO$$\_2$$eq. Its sign is negative.
* $$R\_{project}$$ represents the project's gross GHG removals from the storage module(s) used by the project, in tonnes of CO$$\_2$$eq. Its sign is negative.
* $$E\_{project}$$ represents the project's total induced GHG emissions across the project life cycle, in tonnes of CO$$\_2$$eq. Its sign is positive.

$$\textbf{(Eq.2)}\ E\_{project} = {E}*{project,\ biomass} + {E}*{project,\ Transformation}+ {E}\_{project,\ Storage}$$

where,

* $$E\_{project}$$ was described in Eq. 1.
* $$E\_{project,\ biomass}$$ represents the project's GHG emissions from the capture module(s) used by the project.
* $$E\_{project,\ Transformation}$$ represents the project's GHG emissions from the transformation module(s) used by the project.
* $${E}\_{project,\ Storage}$$ represents the project's GHG emissions from the storage module(s) used by the project.

</details>

<details>

<summary><strong>Calculations - Avoidance</strong></summary>

$$\textbf{(Eq.3)}\ E\_{project} = \Sigma{E}*{P,\ Capture} + \Sigma{E}*{P,\ Transformation} + \Sigma{E}\_{P,\ Storage}$$

where,

* $$E\_{project}$$ represents the induced GHG emissions from the project during the verification period, in tonnes of CO$$\_2$$eq. It does not account for any carbon removals in the storage modules.
* $$E\_{P,\ Capture}$$, $$E\_{P,\ Transformation}$$ and $${E}\_{P, Storage}$$ were described in Equation 1.

$$\textbf{(Eq.4)}\ E\_{baseline} = \Sigma{E}*{B,\ Capture} + \Sigma{E}*{B,\ Transformation} + \Sigma{E}\_{B,\ Storage}$$

where,

* $$E\_{baseline}$$ represents the GHG emissions from the baseline scenario during the verification period, in tonnes of CO$$\_2$$eq.
* $$E\_{B,\ Capture}$$, $$E\_{B,\ Transformation}$$ and $${E}\_{B, Storage}$$ represent GHG emissions from any baseline scenario created in the respective modules.

$$\textbf{(Eq.5)}\ E\_{avoided} = E\_{baseline} - E\_{project}$$

where,

* $$E\_{avoided}$$ represents the avoided GHG emissions from the project scenario, in tonnes of CO$$\_2$$eq.
* $$E\_{baseline}$$ was calculated in Equation 5.
* $$E\_{project}$$ was calculated in Equation 3.

</details>

### Project scenario \[biochar] <a href="#i4figd8ytjua" id="i4figd8ytjua"></a>

Project Developers must choose between one of two approaches to quantify the total carbon removals from their biochar product, as described in the [Durability section](#lc9eewbyvlyk). A single approach must be used consistently throughout each monitoring period, though a different approach may be chosen for subsequent monitoring periods.

1. [Modeling 100-year removals using bulk measurements of $$H/C\_{\text{org}}$$](#unteq8ror26g), or
2. [Estimating 1000-year removals using random reflectance measurements as proxies for inertinite](#id-2rhx2av7of74).

#### Approach 1: Modeling 100-year removals with $$H/C\_{\text{org}}$$ <a href="#unteq8ror26g" id="unteq8ror26g"></a>

This approach is based on research from [Woolf et al., 2021](#user-content-fn-5)[^5], and the [IPCC modeling method](#user-content-fn-6)[^6]. It is rooted in soil ecology and soil biochemistry disciplines. The **permanent fraction** of biochar carbon remaining after 100 years ( $$F\_{\text{perm 100}}$$) is modeled according to the local average annual soil temperature.

Soil temperature shall be obtained for the location of each biochar spreading/end use event, using the GPS coordinates provided in the [Verification of end use report](#id-5a8ye61po9ri) and the global soil temperature dataset from [Lembrechts et al., 2021](#user-content-fn-7)[^7]. The Rainbow Certification Team can provide soil temperature values for Project Developers based on the provided GPS coordinates.

For verification, Project Developers shall provide primary project data in the form of laboratory measurements for $$H/C\_{\text{org}}$$ and $$M\_{\text{%}}$$ following the [Sampling requirements](#sampling-requirements).

*Table 3 Soil temperature ranges are categorized and their corresponding c and m regression coefficients are presented, which are used in Eq. 1 below to calculate* $$F\_{perm}$$. Values are taken from [Woolf et al., 2021](#user-content-fn-5)[^5].

| Soil temperature (°C) | c    | m    |
| --------------------- | ---- | ---- |
| <7.49                 | 1.13 | 0.46 |
| 7.5-12.49             | 1.10 | 0.59 |
| 12.5-17.49            | 1.04 | 0.64 |
| 17.5-22.49            | 1.01 | 0.65 |
| >22.5                 | 0.98 | 0.66 |

<details>

<summary><strong>Calculations: 100-year removal credits with</strong> <span class="math">H/C_{org}</span></summary>

$$\textbf{(Eq.1)}\ F\_{perm\ 100} = c - m\*H/C\_{org}$$

where,

* $$F\_{perm\ 100}$$ represents the fraction of biochar carbon remaining after 100 years
* $$c$$ and $$m$$ represent regression coefficients, taken from [Woolf et al., 2021](#user-content-fn-5)[^5], and summarized in Table 3 for the corresponding project's soil temperature.
* $$H/C\_{org}$$ represents the ratio of molar hydrogen to organic carbon in biochar, measured by laboratory analysis for each project.

$$\textbf{(Eq.2)}\ R\_{project,\ 100}= F\_{perm\ 100}\*{C\_{org}*A}\_{biochar}*(1 - M\_{%})*C\ to\ {CO}\_{2}*-1$$

where,

* $$R\_{project,\ 100}$$ represents the total carbon removals from biochar during the verification period, in tonnes of CO$$\_2$$eq. This value shall be applied to Equation 1 from the [General BiCRS methodology ](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals)document to calculate total project removals.
* $$F\_{perm\ 100}$$ is calculated in Equation 1
* $$C\_{org}$$ represents the concentration of organic carbon in biochar, on a weight basis.
* $$A\_{biochar}$$ represents the amount of biochar delivered during the verification period, in tonnes of fresh biochar.
* $$M\_{%}$$ represents the moisture content of biochar, on a weight basis (%w/w), so $$1-M\_{%}$$converts to dry mass of biochar
* $$C\ to\ {CO}\_{2}$$ is 44/12 = 3.67, and represents the molar masses of CO$$\_2$$ and C respectively, and is used to convert tonnes C to tonnes of CO$$\_2$$eq.
* It is multiplied by -1 to obtain a negative sign. Removals are reported as a negative value in the [BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals).

</details>

#### Approach 2: Estimating 1000-year removals based on inertinite fraction <a href="#id-2rhx2av7of74" id="id-2rhx2av7of74"></a>

This approach is based on the research from [Sanei et al., 2024](#user-content-fn-8)[^8], and is rooted in the organic petrology and geochemistry disciplines. This approach is built upon research showing that fractions of inertinite in biochar samples are:

* [inert and permanent](#user-content-fn-9)[^9] and will not re-release their carbon for at least 1000 years.
* represented by the fraction of residual (i.e. not reactive, not labile) organic carbon in the sample with a Random Reflectance ($$R\_o$$) of [2% or higher](#user-content-fn-8)[^8].

For verification, Project Developers shall provide primary project data in the form of laboratory measurements for $$R\_o$$ distribution, [labile organic carbon content](#user-content-fn-10)[^10], and moisture content for each production batch, following the [Sampling requirements](#sampling-and-measurements).

To determine the inertinite fraction of the biochar's organic carbon, first the labile carbon fraction is measured and subtracted from total organic carbon content, and only the residual organic carbon content is considered.

Next, random reflectance measurements are used to determine the fraction of residual organic carbon that is classified as inertinite:

* The fraction of the distribution with an $$R\_o$$ **above 2%** represents the fraction of the biochar carbon that is stored permanently for 1000 years.
* The fraction of the distribution with an $$R\_o$$ **below 2%** represents the fraction of biochar carbon that is not permanently stored, and for which no removal RCCs are issued.
* $$R\_o$$ distribution shall be based on at least 500 measurements, yielding a frequency distribution diagram similar to the examples in Figure 1a and 1b.

![Figure 1a An example of a random reflectance frequency distribution diagram, with an analysis described below.](/files/RvDwkJem5UkBnsnCmFSv)

{% hint style="info" %}
Example 1: This biochar sample has heterogenous quality and a wide distribution of $$R\_o$$ measurements. The biochar sample has:

* labile organic carbon content of 5%,
* residual organic carbon content of 95%,
* mean $$R\_o$$ of 2.12, and
* 72% of the $$R\_o$$ measurements are above the 2% inertinite threshold.

Therefore, this biochar sample has an $$F\_{\text{perm\ 1000}}$$ of $$0.72 \times 0.95=0.684$$ , so 68.4% of the organic carbon in the sample will be converted to CO$$\_2$$eq and considered as 1000-year carbon removals. The remaining 31.6% of carbon is assumed to decompose within the 1000-year permanence horizon, and is not considered for any removal RCCs.
{% endhint %}

![Figure 1b An example of a random reflectance frequency distribution diagram, with an analysis described below.](/files/zys8iUA26XGiah6RpKoc)

{% hint style="info" %}
Example 2: This biochar sample has rather homogenous quality and a narrow distribution of $$R\_o$$ measurements. The biochar sample has:

* labile organic carbon content of 1%
* residual organic carbon content of 99%
* mean $$R\_o$$ of 2.32, and
* 95% of the $$R\_o$$ measurements are above the 2% inertinite threshold.

Therefore, this biochar sample has an $$F\_{\text{perm\ 1000}}$$ of $$0.99\*0.95=0.94$$, so 94% of the organic carbon in the sample will be converted to CO$$\_2$$eq and considered as 1000-year carbon removals. The remaining 6% of carbon is assumed to decompose within the 1000-year permanence horizon, and is not considered for any removal RCCs.
{% endhint %}

<details>

<summary><strong>Calculations: 1000-year removal credits with random reflectance</strong></summary>

$$\textbf{(Eq.3)}\ F\_{perm\ 1000} = {Sample\ fraction}*{> 2%\ Ro} \times C*{org,\ f\ residual}$$

where,

* $$F\_{perm\ 1000}$$ represents the fraction of biochar carbon remaining after 1000 years.
* $${Sample\ fraction}\_{> 2%\ Ro}$$ represents the fraction of the distribution sample that has a random reflectance ($$R\_O$$) of 2% or higher.
* $$C\_{org,\ f\ residual}$$ represents the fraction of the biochar organic carbon that is residual carbon, as opposed to reactive/labile organic carbon. It may be measured and reported directly, or obtained by subtracting measured *reactive* carbon from 100.

$$\textbf{(Eq.4)}\ R\_{project,\ 1000}=F\_{perm\ 1000}*{C\_{org}*A}\_{biochar}*{(1 - M}*{%})\*C\ to\ {CO}*{2}*-1$$

where,

* $$R\_{project,\ 1000}$$ represents the total carbon removals from biochar during the verification period, in tonnes of CO$$\_2$$eq. This value shall be applied to Equation 1 from the [General BiCRS methodology ](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals)document to calculate overall project removals.
* $$F\_{perm\ 1000}$$ is calculated in Equation 3
* $$C\_{org}$$, $$A\_{biochar}$$, $$M\_{%}$$, and $$C\ to\ {CO}\_{2}$$ are described in Equation 1.
* It is multiplied by -1 to obtain a negative sign. Removals are reported as a negative value in the [BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals).

</details>

Rainbow is actively monitoring ongoing research and seeking expert advice on the potential development of a third approach that uses $$H/C\_{\text{org}}$$ measurements as proxies for inertinite content. For example, if the $$H/C\_{\text{org}}$$ value is less than 0.2, it could be interpreted as indicating that 95% of the biochar is inertinite. While this simplification has been suggested by experts and holds promise, it is currently considered insufficiently rigorous due to a lack of supporting evidence and clear guidance.

#### Future Approach 3: Using H/C as a proxy for inertinite

Rainbow is actively monitoring ongoing research and seeking expert advice on the potential development of a third approach that uses $$H/C\_{org}$$ measurements as proxies for inertinite content. For example, if the $$H/C\_{org}$$ value is less than 0.2, it could be interpreted as indicating that 95% of the biochar is inertinite. While this simplification has been suggested by experts and holds promise, it is currently considered insufficiently rigorous due to a lack of supporting evidence and clear guidance.

### Uncertainty assessment \[biochar] <a href="#dk35zb8m2b1p" id="dk35zb8m2b1p"></a>

An uncertainty assessment is presented below for all aspects of GHG quantification set **at the methodology level**. The findings from this assessment are then applied **at the project level**, where project-specific GHG quantification also undergoes an uncertainty assessment.

The **overall project GHG quantification uncertainty** is determined by qualitatively combining both the methodology-level and project-specific uncertainties for each identified source of uncertainty.

The three assumptions presented in the [Assumptions ](#assumptions)section have moderate uncertainty, but the most conservative approach is taken in the quantifications.

The baseline scenario selection (if applicable) has low uncertainty, because the specific circumstances, amount and type of baseline horticultural material avoided must be proven by the Project Developer.

The equations and models have moderate uncertainty. The model for 100-year permanence from [Woolf et al., 2021](#user-content-fn-5)[^5] has moderate uncertainty because it is a model fitted to experimental data, which always introduces variability. The equations for 1000-year permanence from [Sanei et al., 2024](#user-content-fn-8)[^8] have low uncertainty because they are basic conversion equations.

The uncertainty at the methodology level is estimated to be low. This translates to an **expected discount factor of at least 3%** for projects under this methodology.

### Uncertainty assessment \[biomass]

See general instructions for uncertainty assessment in the [Rainbow Standard Rules.](/rainbow-standard-documents/rainbow-standard-rules/ghg-quantification#uncertainty-assessment) The outcome of the assessment shall be used to determine the percent of RCCs to eliminate with the [**discount factor**](#user-content-fn-11)[^11].

For projects that include baseline permanent carbon storage, the assumption that 0.5% of carbon is permanently sequestered is has high uncertainty, but the total net project removals is not sensitive to this assumption. Therefore, this translates to an **expected discount factor of at least 3%** for projects that include baseline permanent carbon storage.

[^1]: ISO 14064-2:2019. Greenhouse gases — Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements.

[^2]: * Fu, B., Chen, L., Huang, H., Qu, P., Wei, Z., 2021. Impacts of crop residues on soil health: a review. Environmental Pollutants and Bioavailability 33, 164–173. [URL](https://doi.org/10.1080/26395940.2021.1948354)
    * Torma, S., Vilček, J., Lošák, T., Kužel, S., Martensson, A., 2018. Residual plant nutrients in crop residues – an important resource. Acta Agriculturae Scandinavica, Section B — Soil & Plant Science 68, 358–366. [URL](https://doi.org/10.1080/09064710.2017.1406134)
    * Wang, X., Yang, Z., Liu, X., Huang, G., Xiao, W., Han, L., 2020. The composition characteristics of different crop straw types and their multivariate analysis and comparison. Waste Management 110, 87–97. [URL](https://doi.org/10.1016/j.wasman.2020.05.018)

[^3]: The coordinates are used by Rainbow Certification Team to obtain the average soil temperature (°C) where the biochar is spread.

[^4]: Wernet, G., Bauer, C., Steubing, B., Reinhard, J., Moreno-Ruiz, E., Weidema, B., 2016. The ecoinvent database version 3 (part I): overview and methodology. Int J Life Cycle Assess 21, 1218–1230. <https://doi.org/10.1007/s11367-016-1087-8>

[^5]: Woolf, D., Lehmann, J., Ogle, S., Kishimoto-Mo, A.W., McConkey, B., Baldock, J., 2021. Greenhouse Gas Inventory Model for Biochar Additions to Soil. Environmental Science & Technology 55, 14795–14805.[ https://doi.org/10.1021/acs.est.1c02425](https://doi.org/10.1021/acs.est.1c02425)

[^6]: IPCC 2019. Appendix 4 Method for Estimating the Change in Mineral Soil Organic Carbon Stocks from Biochar Amendments: Basis for Future Methodological Development. 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 4 Agriculture, Forestry and Other Land Use. [URL](https://www.ipcc-nggip.iges.or.jp/public/2019rf/pdf/4_Volume4/19R_V4_Ch02_Ap4_Biochar.pdf).

[^7]: Lembrechts et al., Global maps of soil temperature (2021). Global Change Biology. DOI: [10.1111/gcb.16060](https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16060). [URL](https://zenodo.org/records/7134169).

[^8]: Sanei, H., Rudra, A., Przyswitt, Z.M.M., Kousted, S., Sindlev, M.B., Zheng, X., Nielsen, S.B., Petersen, H.I., 2024. Assessing biochar’s permanence: An inertinite benchmark. International Journal of Coal Geology 281, 104409[ https://doi.org/10.1016/j.coal.2023.104409](https://doi.org/10.1016/j.coal.2023.104409)

[^9]: International Committee for Coal and Organic Petrology (ICCP), 2001. The new inertinite classification (ICCP System 1994). Fuel 80, 459–471.[ https://doi.org/10.1016/S0016-2361(00)00102-2](https://doi.org/10.1016/S0016-2361\(00\)00102-2)

[^10]: determined by e.g. thermogravimetric analysis (TGA) or Rock-Eval 6

[^11]: A percentage of verified Rainbow Carbon Credits eliminated from each project and never issued. This acts as a safeguard against uncertainty in GHG reduction quantifications and overestimated carbon removal/avoidance.


# Sampling and measurements

The following indicators shall be measured for each production batch:

* $$H/C\_{\text{org}}$$
* Carbon content (organic and/or total)
* moisture content
* random reflectance and residual organic carbon (only if applying for 1000-year permanence)

Measurements shall be performed by laboratories with at least one quality assurance accreditation, such as:

* ISO/IEC 17025
* CEN/TS 17225-1
* ISO 10694

Unaccredited laboratories from academic settings shall be evaluated on a case by case basis by the VVB and the Rainbow Certification Team.

The sampling procedure detailed in sections below and summarized in Figure 1 is the **recommended approach** for representative sampling. However, Project Developers may implement their own approach if it is detailed in the PDD and in Sampling Records; ensures one representative sample per production batch; addresses samples and composite samples amount and frequency; and ensures homogenization. The VVB and the Rainbow Certification team must validate the rigor and representativeness of the proposed sampling approach.

The recommended approach sampling requirements are based on the following sources:

* [EU Fertilising Products Regulation (EU) 2019/1009](#user-content-fn-1)[^1]
* [European Biochar Certificate Guidelines Annex 4 Representative Sampling](#user-content-fn-2)[^2]

<figure><img src="/files/8TKqusGoWfuUoKr1v4uc" alt=""><figcaption><p>Figure 1: The Rainbow recommended sampling approach is summarized here, and detailed in the text in following sections.</p></figcaption></figure>

#### Representative sampling

One **representative sample per Production Batch** shall be created and sent for laboratory testing. This sample ensures that any within-batch variability is captured in the measurements.

Table 1 details the number of composite samples that shall be taken per Production Batch to obtain one representative sample, based on the [EU Fertilising Products Regulation (EU) 2019/1009](#user-content-fn-1)[^1].

The representative sample size should be be 24 liters \* the *n* number of composite samples per Production Batch detailed in Table 1.

*Table 1 Recommendations for the number of composite samples of biochar to take, based on the site's annual biochar production output.*

| Annual output (tonnes) | Composite samples per Production Batch (n) |
| ---------------------- | ------------------------------------------ |
| ≤ 3 000                | 4                                          |
| 3 001 – 10 000         | 8                                          |
| 10 001 – 20 000        | 12                                         |
| 20 001 – 40 000        | 16                                         |
| 40 001 – 60 000        | 20                                         |
| 60 001 – 80 000        | 24                                         |
| 80 001 – 100 000       | 28                                         |

The [European Biochar Certificate Guidelines Annex 4 Representative Sampling](#user-content-fn-2)[^2] should be followed for **taking composite samples**. Those requirements are summarized below.

{% tabs %}
{% tab title="Continuous production" %}

* The first sample must be taken within 7 days of the start of the Production Batch.
* To prepare **one sample**, 8 sub-samples of 3 liters each are taken at intervals of at least one hour directly at the discharge of the freshly produced material. This shall be repeated for three consecutive days.
* The 24 samples are combined to form one composite sample.
  {% endtab %}

{% tab title="Non-continuous production" %}

* The first sample must be taken within 7 days of the start of the Production Batch.
* Samples may be taken from a well-mixed pile of biochar produced within the last 7 days.
* The amount of biochar used for one sample shall be equivalent to at least one day's production.
* 24 sub-samples of 3 liters each shall be taken from different spots in the pile.
* The 24 subsamples are combined to form one composite sample.
  {% endtab %}
  {% endtabs %}

#### Homogenization

The representative sample shall be homogenized by the Project Developer or by the laboratory that performs testing. The biochar shall be ground to a size of <3 mm.

The ground sample is mixed by shoveling the pile three times from one pile to another.

A sub-sample of 1.5 liters shall be taken from 15 spots in the mixed pile.

The 15 sub-samples are re-combined, and then mixed by shoveling the pile three times from one pile to another.

From the mixed pile of the combined sub-samples, 15 subsamples of 150 ml each should be taken at 15 different spots in the pile and combined. This combined homogenized representative cross sample is used for laboratory testing.

#### Retention samples

A one-liter retention sample shall be collected each day that biochar is produced. These samples should be combined for storage over the calendar month. Retention samples must be stored for a minimum of two years.

#### Sampling records

For **each Production Batch**, Project Developers shall submit a **Sampling Record** for verification to prove their adherence to the requirements above. Sampling Records shall include the following information for each sample taken:

* Date of sampling
* Amount of biochar sampled
* Description of representative sampling process (either followed the recommended approach, or describe the individual approach)
* Sample ID
* Visual description and observation of biochar
* Description of any potential anomalies
* Proof of retention sampling (if performed for that Production Batch)
* Photos showing the date, sample ID, and amount of biochar that is included in the present Sampling Record

[^1]: Regulation (EU) 2019/1009 of the European Parliament and of the Council of 5 June 2019 laying down rules on the making available on the market of EU fertilising products and amending Regulations (EC) No 1069/2009 and (EC) No 1107/2009 and repealing Regulation (EC) No 2003/2003 (Text with EEA relevance), 2024. [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02019R1009-20240703)

[^2]: EBC (2012-2025) ‘European Biochar Certificate – Guidelines for a Sustainable Production of Biochar.’ Carbon Standards International (CSI), Frick, Switzerland.\
    Version 10.5E from 14th August 2025 [URL](https://www.carbon-standards.com/en/standards/service-492~production-of-biochar.html).


# CRCF requirements


# Version history

This page describes the changes in the Biochar application to soils module.

Because this module is considered the V2.0 of the Rainbow BECCS and Biochar V1.0 methodology, the table below also includes changes from the Rainbow BECCS and Biochar V1.0 methodology that are covered in other modules (e.g. [Biomass feedstock](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock)).

<table data-full-width="true"><thead><tr><th width="399">Description of the change</th><th width="292">Justification</th><th width="157">Date</th><th>Version changed to</th></tr></thead><tbody><tr><td>Restructure sections: added Baseline Scope, renamed Eligible technologies to Eligibility and scope, renamed Eligibility criteria to Principles &#x26; requirements, moved Monitoring Plan to Principles &#x26; requirements</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Remove TRL, move Substitution criteria requirements to Baseline Scope section</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>New Certification Scope section with requirements for crediting and monitoring period, project updates with methodology revisions, and site audits.</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Remove limits on number of co-benefits, and require quantification and monitoring of all co-benefits</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Environmental and social risk mitigation plan required for moderate or higher risks, instead of high risk</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Remove project-level reversal risk assessment requirements</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Remove ex-ante validation section</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Change GHG quantification from ecoinvent v3.11 to v3.12 (average change of 0.04±0.2% decrease in total net removals)</td><td>Using more recent version of database</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Specify residual organic carbon measurements needed for 1000-year removal claims</td><td>Provide clearer and more comprehensive instructions</td><td>July 2025</td><td>V2.2</td></tr><tr><td>Re-introduce 100-year carbon degradation model equations based on soil temperature</td><td>Aligning with common biochar modeling practices.</td><td>March 2025</td><td>V2.1</td></tr><tr><td>Changed pollutant requirements from European Biochar Certificate (EBC) thresholds to World Biochar Certificate (WBC) thresholds</td><td>Adding more projects outside Europe, more reasonable and feasible to hold them to worldwide best standards, not European</td><td>March 2025</td><td>V2.1</td></tr><tr><td>Added equations for calculation GHG reductions</td><td>Increased transparency.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Aligned terminology with ISO 14064-2:2019</td><td>Improved consistency with the voluntary carbon market. LCA principles still apply.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Added risk assessment template for environmental and social do no harm</td><td>Provide more detailed and prescriptive assessment framework, clearer instructions for project developers.</td><td>September 2024</td><td>V2.0</td></tr><tr><td><p>Removed text for sections that are the same for all methodologies:</p><ul><li>Measurability</li><li>Real</li><li>Additionality</li><li>Technology readiness level</li><li>Minimum impact</li><li>Independently verified</li></ul></td><td>Repeated text from the Standard Rules.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Added Monitoring Plan section</td><td>Alignment with Rainbow Standard Rules V6.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Remove Rebound Effect and Independently Validated criteria</td><td>Alignment with Rainbow Standard Rules V6.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Added uncertainty assessment section</td><td>Alignment with Rainbow Standard Rules V6.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Infrastructure and machinery quantification expanded and specified, simple option added</td><td>Simplification, results not sensitive to impacts</td><td>September 2024</td><td>V2.0</td></tr><tr><td>New Leakage requirements</td><td>More rigorous eligibility criteria, and clear requirements and instructions for Project Developers</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Allow option for 1000 year removals, measurement of random reflectance</td><td>Updated research</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Added verification of end use reports</td><td>Increased rigor to ensure biochar is used as claimed</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Added precise sampling requirements</td><td>Provide Project Developers with clear expectations, ensure representative sampling</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Allow option to monitor data and quantify GHGs per production batch</td><td>Facilitate data collection and reporting for Project Developers</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Biomass feedstock shall only be waste and biomass cultivated from sustainable production is not allowed</td><td>Increased stringency, following best practice and scientific recommendations</td><td>September 2024</td><td>V2.0</td></tr></tbody></table>


# Appendix

## Appendix 1

The table below presents a non-exhaustive selection of Ecoinvent activities that may be used in the GHG reduction calculations for this module. Additional activities may be used for any project, if the following selection does not cover all relevant activities.

*Table A1 List of ecoinvent 3.12 processes used in the GHG reduction quantification model, all processes are from the cutoff database*

<table><thead><tr><th width="300">Input</th><th>Ecoinvent activity name</th></tr></thead><tbody><tr><td>Peat moss</td><td>peat moss production, horticultural use, RoW</td></tr><tr><td>Perlite</td><td>expanded perlite production, CH</td></tr><tr><td>Lime</td><td>market for lime, RER</td></tr><tr><td>Nitrogen mineral fertilizer</td><td>market for inorganic nitrogen fertiliser, as N, country specific</td></tr><tr><td>Phosphorus mineral fertilizer</td><td>market for inorganic phosphorus fertiliser, as P2O5, country specific</td></tr><tr><td>Potassium mineral fertilizer</td><td>market for inorganic potassium fertiliser, as K2O, country specific</td></tr><tr><td>Mineral NPK fertilizer #1</td><td>market for NPK (26-15-15) fertiliser, RER</td></tr><tr><td>Mineral NPK fertilizer #2</td><td>market for NPK (15-15-15) fertiliser, RER</td></tr></tbody></table>


# Biomass carbon removal and storage (BiCRS)

This methodology covers projects that transform and store biomass into a permanent carbon removal solution, also called biomass carbon removal and storage (BiCRS). This **methodology is composed of modules**, which give more specific requirements and instructions for different parts of project operations. This methodology document provides general requirements and instructions that are relevant for all BiCRS projects, regardless of the specific modules they use.

| **Methodology name** | Biomass carbon removal and storage (BiCRS) |
| -------------------- | ------------------------------------------ |
| **Version**          | 1.1                                        |
| **Methodology ID**   | RBW-BICRS-GEN-V1.1                         |
| **Release date**     | January 21st, 2026                         |
| **Status**           | In use                                     |

## How to use this methodology <a href="#efpqng3v3ute" id="efpqng3v3ute"></a>

This **methodology is composed of modules**, which allows Project Developers to choose the relevant modules for their project depending on their specific operations.

**Modules are arranged into three module categories**: carbon capture, carbon storage, and general Rainbow transformation modules. An example of the modules that can be used in the Rainbow BiCRS methodology are presented in the figure below.

<figure><img src="/files/X0WrsUt37DNx8nfWn1wf" alt=""><figcaption><p>A general overview of the organization of the Rainbow BiCRS modular methodology.</p></figcaption></figure>

**Modules are like mini-methodologies** that only cover a part of the project life-cycle. Combining the relevant modules for a project results in a complete picture of principles and requirements, GHG reduction quantification requirements, required data, monitoring plans, and other instructions for Rainbow certification.

For a given project, multiple modules from each Module category may be selected if they are relevant to the project. For example, most projects will likely use both Transportation and Infrastructure and machinery modules from the Transformation category. At least one module must be selected from the carbon capture, transformation, and carbon storage categories.

**Modules are compiled seamlessly on the Rainbow Certification Platform**. Project Developers only need to select the modules that are relevant for their project.

{% hint style="info" %}
For example, the figure below represents a project that pyrolyzes biomass feedstock to produce biochar, which is then applied to agricultural soils. In this case, five modules are combined to represent the whole project. The principles and requirements from each module can be compiled to obtain the full list of eligibility requirements the Project Developer must respond to.
{% endhint %}

<figure><img src="/files/uA8nq99YrFELWQUNj4Is" alt=""><figcaption><p>An visual example of how a project would combine elements from the relevant modules to obtain a whole-project picture.</p></figcaption></figure>

## Glossary

<table data-header-hidden><thead><tr><th width="216"></th><th></th></tr></thead><tbody><tr><td><strong>Bioenergy</strong></td><td>Renewable energy derived from organic materials, such as plant and animal waste, agricultural crops, and forestry residues, that are converted into heat, electricity, or fuels through processes like combustion, gasification, or fermentation</td></tr><tr><td><strong>BECCS</strong></td><td>BECCS (Bioenergy with Carbon Capture and Storage) is a carbon mitigation technology that combines the use of bioenergy (from biomass) with carbon capture and storage (CCS) to remove and store carbon dioxide (CO2) emissions from the atmosphere</td></tr><tr><td><strong>Biochar</strong></td><td>material that is rich in stable carbon, produced through the thermal conversion of biomass in a low-oxygen environment</td></tr><tr><td><strong>Delivery Risk</strong></td><td>The potential risk that a project will not be able to deliver the anticipated results, such as the projected amount of biochar or carbon sequestration benefits.</td></tr><tr><td><strong>End use application</strong></td><td>The way biochar will be used, such as direct application to soil, mixing with compost and application of the mix to soil, mixing with cement for use in concrete.</td></tr><tr><td><strong>End use point</strong></td><td>The step in the production chain where biochar leaves the direct control of biochar producers, where it is assumed to be incorporated into its final end use application.</td></tr><tr><td><strong>Embodied Transport Emissions</strong></td><td>GHG emissions associated with the production, maintenance, and operation of transportation infrastructure and vehicles across all modes of transport (e.g., road, sea).</td></tr><tr><td><strong>Feedstock</strong></td><td>The organic material used as the raw input for biochar production, such as wood, agricultural residues, or manure.</td></tr><tr><td><strong>Gasification</strong></td><td>high-temperature process that involves the partial oxidation of organic materials in the presence of a controlled amount of oxygen (or air) and a gasification agent</td></tr><tr><td><strong>GVW</strong></td><td>Gross Vehicle Weight is the total weight of a vehicle, including its own weight plus the weight of any cargo</td></tr><tr><td><strong>Loading rate</strong></td><td>Ratio of actual load to the full load or capacity (e.g. mass or volume) that a vehicle carries per trip.</td></tr><tr><td><strong>Molar H/C</strong><sub><strong>org</strong></sub><strong> ratio</strong></td><td>The ratio of hydrogen to organic carbon atoms in biochar, used to assess the stability and quality of biochar; lower ratios indicate higher stability.</td></tr><tr><td><strong>Permanence horizon</strong></td><td>Sequestration horizon, commitment period</td></tr><tr><td><strong>Production batch</strong></td><td>Biochar produced under the same conditions regarding production temperature and feedstock mix. A production batch has a maximum validity of 365 days.</td></tr><tr><td><strong>Production batch ID</strong></td><td>A unique identifier for each production batch.</td></tr><tr><td><strong>Pyrolysis</strong></td><td>thermal decomposition process that occurs in the absence of oxygen</td></tr><tr><td><strong>Random reflectance</strong></td><td>A measure of the reflectivity of biochar under a microscope, indicating the degree of carbonization, inertinite characteristics and permanence of the biochar.</td></tr><tr><td><strong>Segment</strong></td><td>Part of the transportation process involving the movement of inputs or products between point A and point B within the project boundary.</td></tr><tr><td><strong>Transport segment</strong></td><td>One shipment of a fixed amount of material from a known location A to a known location B. It represents a one-way trip.</td></tr><tr><td><strong>Transport Unit</strong></td><td>A general term used to describe any vehicle, vessel, or mode of transportation used to move goods or passengers from one location to another. In this module version, this includes trucks and ships.</td></tr><tr><td><strong>Transport type/ mode of transport</strong></td><td>Type of transport. E.g. by land (truck, rail, pipe), by water (boat, ferry), by air (airplane). This module's first version focuses on road and sea transport type.</td></tr><tr><td><strong>Verification period</strong></td><td>The time period of project activities that a given verification audit and carbon credit issuance covers. For biochar application to soils, this may be one calendar year, or the duration of validity of one production batch.</td></tr></tbody></table>

## Introduction

It is widely acknowledged that in addition to reducing global greenhouse gas (GHG) emissions, [carbon dioxide must be removed from the atmosphere](#user-content-fn-1)[^1] and permanently sequestered. One way to do this is through [Biomass Carbon Removal and Storage (BiCRS)](#user-content-fn-2)[^2], which involves a range of technologies that use plant biomass to remove carbon dioxide (CO$$\_2$$) from the atmosphere and store that CO$$\_2$$ underground or in long-lived products.

This methodology document outlines the general requirements for BiCRS projects certified under the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules). These projects are eligible for removal Rainbow Carbon Credits (RCCs) related to their carbon removals, and avoidance RCCs as a result of generating valuable co-products. Further details for specific technologies are available in module documents.

## Eligibility and scope

### Eligible technologies

All projects certified under this methodology must **convert biomass into permanent carbon storage** solutions.

Avoidance Rainbow Carbon Credits (RCCs) may be issued for eligible project activities, such as energy production.

Any share of removals coming from **non-biogenic carbon are not eligible** for removal RCCs.

Carbon removals shall be ensured for **at least 100 years** under this methodology. Each project shall transparently disclose their permanence horizon of 100 or 1000+ years.

Technologies that are not detailed in a module, but that meet the general requirements of the present methodology, may be considered on a case by case basis.

### Certification requirements

#### **Crediting period duration**

The maximum duration of the crediting period for projects certified under this methodology is 5 years. Upon reaching the maximum duration, a project's crediting period may be renewed, according to the [Crediting Period Renewal](https://docs.rainbowstandard.io/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal) procedure.

#### **Monitoring period duration**

The default monitoring period duration is one year, but may be shorter at the Project Developer's request. Project Developers shall submit a Monitoring Report at least once per 24 months. Failure to do so shall result in the project being [deregistered](https://docs.rainbowstandard.io/rainbow-standard-documents/procedures-manual/project-certification-procedure).

#### **Site audits**

Validation site audits for projects under this methodology may be performed **either remotely or in-person**, depending on the project size. Projects that issue more than 5,000 RCCs per year must undergo an in-person site audit. Projects that issue less than 5,000 RCCs per year may choose between an in-person or remote audit. The Rainbow team may require an in-person site audit for any project, regardless of the size.

#### **Versioning and project compliance**

When this methodology is revised, projects are required to comply with the latest version for subsequent verifications of RCCs.

### Project scope

The default project scope shall be defined in the Carbon storage modules.

### Baseline scope

For **projects that issue only removal RCCs**, the baseline scope represents the permanent carbon removals that would have occurred anyway, without the project intervention.

For **projects that also issue avoidance RCCs**, the baseline scope also includes the GHG emissions from the product or activity that is avoided by the project activity, i.e. the GHG emissions that would have occurred in the absence of the project. Project Developers shall prove that the chosen baseline product or activity is a representative and conservative substitute for the project's product or activity.

Specific instructions for definition and modeling of baseline scenarios are available in the relevant module documents.

The baseline scenario **structure** remains valid for the entire crediting period but may be significantly revised earlier if:

* The Project Developer notifies Rainbow of a substantial change in project operations or baseline conditions, and/or
* The methodology is revised, affecting the baseline scenario.

The **specific values** within the baseline scenario will be updated during each crediting period, using project data to accurately reflect the equivalent of the project’s operations.

## Principles & requirements <a href="#mcckjxeq4h1s" id="mcckjxeq4h1s"></a>

Project Developers shall demonstrate that they comply with all principles and requirements outlined in the applicable version of the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements) and the accompanying BiCRS modules, and described below with a specific focus on BiCRS.

<table data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="files"></th></tr></thead><tbody><tr><td><strong>BiCRS methodology</strong></td><td><ul><li>Additionality</li><li>No double counting</li><li>ESDNH</li><li>Targets alignment</li></ul></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo">/pages/Jy6o8q5Q31d2U0OK7Yuo</a></td><td><a href="/files/4B3R2CjT9hA3bBYbzz1a">/files/4B3R2CjT9hA3bBYbzz1a</a></td></tr><tr><td><strong>Other modules</strong></td><td><ul><li>Permanence</li><li>Substitution</li><li>Co-benefits</li><li>No double counting</li><li>ESDNH</li></ul></td><td></td><td><a href="/pages/eQTO2zpdCEv368f4bRT6">/pages/eQTO2zpdCEv368f4bRT6</a></td><td><a href="/files/CxuE4U5JkYE63biLhW6k">/files/CxuE4U5JkYE63biLhW6k</a></td></tr><tr><td><strong>Rainbow Standard Rules</strong></td><td><ul><li>Measurability</li><li>Real</li><li>TRL</li><li>Minimum impact</li></ul></td><td></td><td><a href="/pages/CRADNrj4mfS258PN3x7N">/pages/CRADNrj4mfS258PN3x7N</a></td><td><a href="/files/gAM5lW5Mf0Lnj63LSqnl">/files/gAM5lW5Mf0Lnj63LSqnl</a></td></tr></tbody></table>

### Additionality

Project Developers shall demonstrate additionality using the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template) and following the requirements of the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#additionality).

{% tabs %}
{% tab title="Regulatory surplus analysis" %}
**Regulatory surplus analysis** shall demonstrate that there are no regulations that require or mandate project activities (for removal and avoidance activities). It is acceptable if regulations promote or set targets for these activities, because the resulting increase in activities shall be accounted for in the [baseline scenario](#id-8422amp7fe3k-1).

At the European Union level, projects automatically pass the regulatory surplus analysis, which has been conducted by the Rainbow Climate Team. Project Developers are only required to provide a country-level regulatory surplus analysis.
{% endtab %}

{% tab title="Investment analysis" %}
**Investment analysis** may be used to prove that revenue from carbon finance is necessary to make the project investment a financially viable and interesting option. The investment may cover:

* The creation and launching of new sites
* Expansion of capacity of existing activities
* Expansion by installing new processes

Business plans shall be provided as initial proof for investment analysis. During verification, audited financial statements shall be used to demonstrate that the initial estimates from the business plan were reasonable, and that carbon finance was used as initially described for the expected investment.

For launching brand new sites, additionality can be simply demonstrated if the business plan shows that carbon finance is expected to make up at least 80% of the company’s revenue, as detailed in the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template).

Note that for investments in expansion, **only the additional carbon reductions enabled by the expansion shall be eligible for Rainbow Carbon Credits.**
{% endtab %}

{% tab title="Barrier analysis" %}
**Barrier analysis** may be used to prove that the project faces financial, institutional, or technological barriers to ongoing operations that can only be overcome using carbon finance. Examples include but are not limited to:

* Financial barrier: financial analysis demonstrating that the project is not financially viable, evidenced by net cash being lower than the working capital requirements, or proof that the project is not meeting the projected financial targets in the business plans and loan documents, and that carbon finance would make it financially viable.
* Institutional barrier: description of new regulation that the project must make costly changes to comply with, financial analysis showing that the project cannot fund the changes on their own, and carbon finance is necessary to make it viable.

For any type of barrier analysis, **audited financial statements must be provided** as proof. These documents should either demonstrate the financial status to prove financial barriers, or show that the project could not independently fund solutions to overcome institutional or technological barriers.
{% endtab %}
{% endtabs %}

### No double counting <a href="#n1iy4xaxuthk" id="n1iy4xaxuthk"></a>

Project Developers shall sign the [Rainbow MRV & Registry Terms & Conditions](/other/terms-and-contracts/terms-and-conditions-for-project-developers-mrv-+-registry), committing to follow the requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules), including not double using or double issuing carbon credits.

BiCRS projects have a risk of double issuance of credits if the user of the removal solution and/or operator of the storage site also seeks credit issuance. Project Developers shall:

* Identify all direct downstream users/buyers/actors in their supply chain, providing the company/organization name, name of an individual contact person at the company/organization, and their contact information (email address at minimum).
* Provide proof that measures have been taken to avoid double issuance with those actors, such as through signed agreements, packaging/marketing material stating carbon credits have already been issued, and/or sales contract clauses.

If the Project Developer proves that the removal solution stays within the project scope all the way through storage, and it is never sold or transferred, then the requirements above may be disregarded.

### Environmental and social safeguards

#### Environmental and social risk assessment

Project Developers shall fill in the[ General BiCRS risk assessment](#risk-evaluation-template), in addition to all module-specific risk assessments, to evaluate the identified environmental and social risks of projects.

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

### Monitoring

The minimum required information to be monitored shall be defined in each module.

Monitoring Plans shall include the following information for each monitored parameter:

* monitoring frequency
* emission sources and sinks
* data source
* measurement methods/procedures, and their accuracy and calibration
* quality assessment or quality control procedures
* responsible party for collecting and archiving data

## GHG quantification

General GHG quantification rules can be found in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules).

Process-specific GHG quantification rules can be found in the accompanying BiCRS [carbon capture](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture), BiCRS [carbon storage](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage), and general Rainbow modules.

The net removals for a project shall be calculated by **summing the emissions and removals of each module** used by that project.

Calculations of GHG emissions for the baseline and project scenarios shall follow a robust, recognized method and good practice guidance. The overall methodological approach is a comparative life cycle assessment (LCA) at the project-scale, based on [ISO 14064-2:2019](#user-content-fn-3)[^3].

BiCRS projects may be eligible for **removal and avoidance Rainbow Carbon Credits**. Removal and avoidance RCCs are calculated and issued according to two completely separate accounting mechanisms, described below. This conservative approach results in double counting the project's induced emissions, and avoids the need for allocation of emissions/removals.

GHG quantifications shall be completed either for each batch (batches are defined in the relevant [carbon storage modules](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage)), or for each calendar year. Carbon storage module documents may provide specific requirements.

### Functional unit <a href="#id-8422amp7fe3k" id="id-8422amp7fe3k"></a>

The functional unit shall be **1 tonne of carbon storage solution** (e.g. 1 tonne of biochar spread on soils, 1 tonne of biomass buried...).

### Co-product allocation

BiCRS projects may result in multiple products in addition to the primary carbon storage component. Emissions from multifunctional processes shared among co-products may be allocated across the respective products. However, emissions from processes exclusive to a single product (e.g., dedicated delivery of carbon storage products) must be fully attributed to that product.

If the **co-product is a nonvaluable waste**, then no allocation is required and all GHG emissions are allocated to the main product.

If the **co-product is valuable and eligible for avoidance RCCs**, then no allocation is performed, and process emissions are counted towards both the avoidance GHG accounting and the removal GHG accounting. This is a conservative approach to separately handling removal and avoidance accounting schemes.

If the **co-product is valuable and eligible for removal RCCs**, then emissions may be allocated between the co-products. It is best practice to perform allocation based on an underlying characteristic that best represents the main function of the products. Here the main function is carbon removal, so allocation shall be based on the proportion of carbon removal of the two products, in tonnes of carbon.

{% hint style="info" %}
For example, if a project's main function is to produce biochar via pyrolysis, they may generate syngas and/or bio-oil co-products.

**Syngas example**

The syngas could be used to produce and export electricity to the grid and be issued avoidance RCCs. Syngas and biochar production share processes such as feedstock production and transport, feedstock shredding, and starting the pyrolyzer. Emissions from these processes would be included in both the removal RCC quantification and avoidance RCC quantification. However, emissions from biochar transport to a farm for spreading would not be accounted for in the syngas avoidance quantification, because it is not a shared process.

***

**Bio-oil example**

The bio-oil could be used for carbon removal and be issued removal RCCs. If the total carbon storage from bio-oil is 400 tonnes CO$$\_2$$eq and from biochar is 600 tonnes CO$$\_2$$eq, then 40% of the GHGs from shared processes would be allocated to bio-oil, and 60% would be allocated to biochar.
{% endhint %}

### Baseline scenario <a href="#id-8422amp7fe3k" id="id-8422amp7fe3k"></a>

The baseline scenario shall be defined in the applicable modules.

### Project scenario <a href="#letyqrgxkbuh" id="letyqrgxkbuh"></a>

Modules include specific instructions on calculating GHG emissions and removals for the relevant processes.

Each project must use **at least one module from the following categories**: carbon capture, transformation and carbon storage.

<details>

<summary><strong>Calculations - Removals</strong></summary>

$$\textbf{(Eq.1)}\ Net\ Removal = R\_{baseline}-R\_{project}-E\_{project}$$

where,

* $$Net\ Removal$$ represents the net removals from the project during the verification period, in tonnes of CO$$\_2$$eq. Its sign is positive.
* $$R\_{baseline}$$ represents any baseline GHG removals from the capture module(s), representing permanent storage that would have occurred in the absence of the project, in tonnes of CO$$\_2$$eq. Its sign is negative.
* $$R\_{project}$$ represents the project's gross GHG removals from the storage module(s) used by the project, in tonnes of CO$$\_2$$eq. Its sign is negative.
* $$E\_{project}$$ represents the project's total induced GHG emissions across the project life cycle, in tonnes of CO$$\_2$$eq. Its sign is positive.

$$\textbf{(Eq.2)}\ E\_{project} = {E}*{project,\ Capture} + {E}*{project,\ Transformation}+ {E}\_{project,\ Storage}$$

where,

* $$E\_{project}$$ was described in Eq. 1.
* $$E\_{project,\ Capture}$$ represents the project's GHG emissions from the capture module(s) used by the project.
* $$E\_{project,\ Transformation}$$ represents the project's GHG emissions from the transformation module(s) used by the project.
* $${E}\_{project,\ Storage}$$ represents the project's GHG emissions from the storage module(s) used by the project.

</details>

<details>

<summary><strong>Calculations - Avoidance</strong></summary>

$$\textbf{(Eq.3)}\ E\_{project} = \Sigma{E}*{P,\ Capture} + \Sigma{E}*{P,\ Transformation} + \Sigma{E}\_{P,\ Storage}$$

where,

* $$E\_{project}$$ represents the induced GHG emissions from the project during the verification period, in tonnes of CO$$\_2$$eq. It does not account for any carbon removals in the storage modules.
* $$E\_{P,\ Capture}$$, $$E\_{P,\ Transformation}$$ and $${E}\_{P, Storage}$$ were described in Equation 1.

$$\textbf{(Eq.4)}\ E\_{baseline} = \Sigma{E}*{B,\ Capture} + \Sigma{E}*{B,\ Transformation} + \Sigma{E}\_{B,\ Storage}$$

where,

* $$E\_{baseline}$$ represents the GHG emissions from the baseline scenario during the verification period, in tonnes of CO$$\_2$$eq.
* $$E\_{B,\ Capture}$$, $$E\_{B,\ Transformation}$$ and $${E}\_{B, Storage}$$ represent GHG emissions from any baseline scenario created in the respective modules.

$$\textbf{(Eq.5)}\ E\_{avoided} = E\_{baseline} - E\_{project}$$

where,

* $$E\_{avoided}$$ represents the avoided GHG emissions from the project scenario, in tonnes of CO$$\_2$$eq.
* $$E\_{baseline}$$ was calculated in Equation 5.
* $$E\_{project}$$ was calculated in Equation 3.

</details>

### Uncertainty assessment

An uncertainty assessment shall be provided in each BiCRS module.

## Risk assessment template

:point\_right: Download the template [here](https://docs.google.com/spreadsheets/d/1Bj7Br4nmekjDhXM5bKjzzEALFFWzTQbGKJuYmH1hJoI/edit?gid=1985359524#gid=1985359524)

{% embed url="<https://docs.google.com/spreadsheets/d/1Bj7Br4nmekjDhXM5bKjzzEALFFWzTQbGKJuYmH1hJoI/edit?gid=1985359524#gid=1985359524>" %}

## Access the modules

{% content-ref url="/pages/V0dXfN5yPUaU1ws1h7sV" %}
[Biomass feedstock](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock)
{% endcontent-ref %}

{% content-ref url="/pages/VTWdCc7guKu1x0azAizi" %}
[Transportation](/modules/transportation)
{% endcontent-ref %}

{% content-ref url="/pages/BTxxPIM3a4Nai1Wkwu2Y" %}
[Processing and energy use](/modules/processing-and-energy-use)
{% endcontent-ref %}

{% content-ref url="/pages/5o87C1B9WEcsBRQuyYwi" %}
[Energy co-products](/modules/energy-co-products)
{% endcontent-ref %}

{% content-ref url="/pages/IwqpSqlee22qTIPti3Sl" %}
[Infrastructure and machinery](/modules/infrastructure-and-machinery)
{% endcontent-ref %}

{% content-ref url="/pages/Om2iC8BSJ1GdkHA5oMoA" %}
[Biochar application to soils](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage/biochar-application-to-soils)
{% endcontent-ref %}

{% content-ref url="/pages/GxlSYzJC7Dkt7JmbJ2y2" %}
[Marine sub-sediment burial](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage/marine-sub-sediment-burial)
{% endcontent-ref %}

## Version history

<table><thead><tr><th width="386.99993896484375">Change</th><th>Justification</th><th>Date</th><th>Version changed</th></tr></thead><tbody><tr><td>Restructure sections: added Baseline Scope, renamed Eligible technologies to Eligibility and scope, renamed Eligibility criteria to Principles &#x26; requirements, moved Monitoring Plan to Principles &#x26; requirements</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V1.0 to 1.1</td></tr><tr><td>Remove TRL and targets alignment criteria, move Substitution criteria requirements to Baseline Scope section</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V1.0 to 1.1</td></tr><tr><td>New Certification Scope section with requirements for crediting and monitoring period, project updates with methodology revisions, and site audits.</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V1.0 to 1.1</td></tr><tr><td>Remove limits on number of co-benefits, and require quantification and monitoring of all co-benefits</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V1.0 to 1.1</td></tr><tr><td>Environmental and social risk mitigation plan required for moderate or higher risks, instead of high risk</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V1.0 to 1.1</td></tr><tr><td>In-person site audit now required for projects issuing 5,000 credits or more annually (changed from 10,000 credits)</td><td>Increase in-person rather than remote site audits</td><td>January 2026</td><td>V1.0 to 1.1</td></tr></tbody></table>

[^1]: IPCC, 2022: Summary for Policymakers. In: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, NY, USA. doi: 10.1017/9781009157926.001

[^2]: Sandalow, David, Aines, Roger, Friedmann, Julio, McCormick, Colin, and Sanchez, Daniel L. Biomass Carbon Removal and Storage (BiRCS) Roadmap. United States: N. p., 2021. Web. doi:10.2172/1763937.

[^3]: ISO 14064-2:2019. Greenhouse gases — Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements.


# Carbon capture modules

Module category

<table data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-cover data-type="files"></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td></td><td>Biomass feedstock</td><td></td><td><a href="/files/GQwFFCmyhtK9q3ZBHm9z">/files/GQwFFCmyhtK9q3ZBHm9z</a></td><td><a href="/pages/V0dXfN5yPUaU1ws1h7sV">/pages/V0dXfN5yPUaU1ws1h7sV</a></td></tr><tr><td></td><td>Biogenic CO<span class="math">_2</span> from flue gas (coming soon)</td><td></td><td><a href="/files/nJYK7GqotRQkb14ITBFk">/files/nJYK7GqotRQkb14ITBFk</a></td><td><a href="/pages/ZvLEzJJrLUMZodurFl70">/pages/ZvLEzJJrLUMZodurFl70</a></td></tr></tbody></table>


# Biomass feedstock

<table data-header-hidden><thead><tr><th width="267"></th><th></th></tr></thead><tbody><tr><td><strong>Module name</strong></td><td>Biomass feedstock</td></tr><tr><td><strong>Module category</strong></td><td>Carbon capture</td></tr><tr><td><strong>Methodology name</strong></td><td>Biomass carbon removal and storage (BiCRS)</td></tr><tr><td><strong>Version</strong></td><td>1.1</td></tr><tr><td><strong>Methodology ID</strong></td><td>RBW-BICRS-CC-BMF-V1.1</td></tr><tr><td><strong>Release date</strong></td><td>January 21st, 2026</td></tr><tr><td><strong>Status</strong></td><td>In use</td></tr></tbody></table>

{% content-ref url="/pages/D1bECpowUAiJorSGzbQY" %}
[Glossary](/glossary)
{% endcontent-ref %}

This is a **Carbon Capture Module** and covers the sourcing of biomass feedstock for carbon storage projects. This module is part of the Rainbow BiCRS methodology, which allows Project Developers to choose the relevant modules for their project, and shall be used with the necessary accompanying modules.

## Eligibility and scope

### Eligible technologies <a href="#uikucys7r1rk" id="uikucys7r1rk"></a>

This module covers use of biomass feedstock for permanent carbon removal and storage.

<table><thead><tr><th width="202">Biomass type</th><th width="315">Description</th><th>Source</th></tr></thead><tbody><tr><td>Forest waste from secondary forest</td><td>Natural but not primary old-growth forest, may still be managed for timber</td><td>Default if no other forest type can be proven</td></tr><tr><td>Forest waste from managed forest</td><td>Managed mixed-use forests that may include agroforestry, plantations or rotational logging</td><td>Must provide proof</td></tr><tr><td>Necessary tree removal from any forest</td><td>Damaged trees, or trees removed for planned forest management such as preventing disease spread or fires</td><td>Must provide proof</td></tr><tr><td>Agricultural residues with value</td><td>Residues left on soil or reapplied to soils for nutrient recycling (e.g. mulching, composting, spreading fast-decaying cellulose-based residues with decay within 5 years)</td><td>Default if prior use could not be determined</td></tr><tr><td>Agricultural residues with no value</td><td>Plowed into soil, burnt in the field, no substantial return of nutrients to soil</td><td>Must provide proof</td></tr><tr><td>Other waste or residue</td><td>To be evaluated on a case by case basis according to criteria outlined in the present document</td><td>Must provide proof</td></tr></tbody></table>

Eligible biomasses are those that:

* could not have been used valuable products (e.g. low quality wood),
* were not grown for the purpose of CDR[^1] or bioenergy production.

For simplification, all feedstocks that meet the above requirements will be referred to hereafter as waste. Biomass feedstocks are categorized accordingly:

<table><thead><tr><th width="202">Biomass type</th><th width="315">Description</th><th>Source</th></tr></thead><tbody><tr><td>Forest waste from secondary forest</td><td>Natural but not primary old-growth forest, may still be managed for timber</td><td>Default if no other forest type can be proven</td></tr><tr><td>Forest waste from managed forest</td><td>Managed mixed-use forests that may include agroforestry, plantations or rotational logging</td><td>Must provide proof</td></tr><tr><td>Necessary tree removal from any forest</td><td>Damaged trees, or trees removed for planned forest management such as preventing disease spread or fires</td><td>Must provide proof</td></tr><tr><td>Agricultural residues with value</td><td>Residues left on soil or reapplied to soils for nutrient recycling (e.g. mulching, composting, spreading fast-decaying cellulose-based residues with decay within 5 years)</td><td>Default if prior use could not be determined</td></tr><tr><td>Agricultural residues with no value</td><td>Plowed into soil, burnt in the field, no substantial return of nutrients to soil</td><td>Must provide proof</td></tr><tr><td>Other waste or residue</td><td>To be evaluated on a case by case basis according to criteria outlined in the present document</td><td>Must provide proof</td></tr><tr><td>Invasive species</td><td>Plants that are not native to the local area and are disruptive or harmful to ecosystems</td><td>Must provide proof</td></tr></tbody></table>

### Certification requirements <a href="#certification-requirements" id="certification-requirements"></a>

The default project scope shall be defined in the [Carbon storage](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage) module.

### Project scope <a href="#project-scope" id="project-scope"></a>

The default project scope shall be defined in the [Carbon storage](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage) module.

### Baseline scope <a href="#project-scope" id="project-scope"></a>

The baseline shall include **any permanent carbon removal that would have occurred in the absence of the project**. For biomass use, this includes permanent carbon storage from the alternate fate of the biomass feedstock used for pyrolysis.

Project Developers shall justify the alternate fate of business-as-usual biomass feedstock use.

* If biomass would have been left on agricultural fields, or otherwise applied to soil to decompose, a default **0.5% of the carbon in the biomass feedstock** is assumed to be permanently stored.
* For any other alternate fate of biomass, it is assumed that no carbon is permanently stored, and no baseline is considered for this module.

It shall be assumed by default that no biomass feedstock would have been used for dedicated carbon removal projects in the absence of the project (i.e. there is no share of the project activity in the baseline scenario).

More conservative baseline scenarios may be applied on a case-by-base basis. They must be representative and transparently justified.

See the [GHG quantification ](#id-4l7lx2ihb6hj-2)section for more details on how baseline removals are calculated.

## Principles & requirements

The principles and requirements specific to this module are detailed in the sections below.

### Environmental and social safeguards <a href="#id-82n4j72vjt9v" id="id-82n4j72vjt9v"></a>

Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.**

Projects must follow all national, local and European (if located in Europe) environmental regulations, including but not limited to those related to biomass harvesting and forest management.

In addition to completing the [Biomass feedstock risk assessment](#esdnh-risk-assessment) described below, Project Developers must prove the following elements.

{% tabs %}
{% tab title="Waste status" %}
Project Developers shall provide proof that the **biomass feedstock is classified as waste**. This can be done via any one of the following three methods:

* **Price**: if Project Developers did not pay for the biomass, or if they were paid to handle it, the biomass can be considered waste. Acceptable proof includes invoices, receipts, or contracts.
* **Contextual analysis**: Project Developers may submit an analysis supported by reputable sources that the biomass 1) could not be used as main material products, and 2) was not grown for the purpose of CDR[^1].
* **Positive list of wastes**: if the biomass is included in the following list, it can be considered waste. Acceptable proof includes invoices, receipts, contracts, or photographic evidence and is required for validation:
  * sawmill residues
  * sawdust
  * shavings
  * bark
  * forestry tops and branches
  * wildfire management residues
  * straw
  * husks
  * corn cobs
  * wood from horticulture (trimmings or whole plants)
  * nut shells
  * bagasse
  * sugar beet pulp
    {% endtab %}

{% tab title="Alternative use" %}
Project Developers shall evaluate the most likely alternative use/s of the biomass in order to assess environmental risks, leakage risks, and to calculate replacement emissions (if applicable). The evaluation shall be transparent and conservative.

The alternative use shall address questions such as:

* was the biomass used for a product or service, that now needs to be replaced?
* was the biomass going to store carbon anyway (in the biomass itself and/or in the soil)?

Proof shall be provided and may include signed statements from the biomass provider, historical records from the biomass provider, regional statistics or reputable reporting.

A short list of likely alternative uses may be provided for descriptive purposes, but for the purpose of further analysis, one single alternative use shall be proposed.
{% endtab %}

{% tab title="Forestry certification" %}
Biomass feedstock originating from forests shall provide at least one of the following forestry sustainability certificates (or similar, with a sufficient justification):

* FSC (Forest Stewardship Council)⁠
* PEFC (Program for the Endorsement of Forest Certification)⁠
* RSB (Roundtable on Sustainable Biomaterials)⁠
* SFI (Sustainable Forestry Initiative)⁠
* SBP (Sustainable Biomass Program)⁠

These certifications are used to prove:

* Legal and transparent chain of custody
* Proper forest regeneration
* Safeguarding biodiversity and soil health
* Historically stable or increasing forest carbon stocks
* Sound socio-environmental practices in forestry operations⁠
  {% endtab %}
  {% endtabs %}

#### Environmental and social risk assessment <a href="#esdnh-risk-assessment" id="esdnh-risk-assessment"></a>

The identified environmental and social risks of this biomass feedstock module are **included in the risk assessment template of the carbon storage module** of the BiCRS methodology and shall be evaluated there. The identified risks include:

* Disruption of soil health when collecting and exporting organic matter
* Presence of heavy metals, toxins or other chemical pollutants in the biomass⁠
* Spread of diseases or invasive species
* Cultivation of feedstock
* Deforestation from use of forestry products as feedstock
* Distant transport of feedstock inputs (>100 km)

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

### Leakage <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

Biomass feedstock sourcing must not contribute to activity shifting leakage.

The requirement that biomass feedstock must be classified as waste prevents activity shifting leakage. Consequently, the evidence provided in the "Environmental and Social Do No Harm" section shall also be applied here to verify that the feedstock is waste.

Several other types of leakage risks are already covered by other components of this module:

* Displacement of soil carbon storage: a small amount of soil carbon storage is assumed and modeled in the Baseline Scenario where relevant, effectively deducted from the project's carbon storage.
* Upstream and downstream emissions: considered in the life-cycle based GHG quantifications in companion modules.

### Monitoring <a href="#snhouoxhyrzi" id="snhouoxhyrzi"></a>

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information **for each monitoring period**:

* Mass, type and source of all biomass feedstocks collected by the project.
* Sustainable forestry certification (if applicable)

Monitoring Plans shall include the following information for each monitored parameter:

* monitoring frequency
* emission sources and sinks
* data source
* measurement methods/procedures, and their accuracy and calibration
* quality assessment or quality control procedures
* responsible party for collecting and archiving data

## GHG quantification

The GHG quantification instructions from all other modules used by the project must be used in conjunction with the present module in order to obtain full life-cycle GHG reduction quantifications.

### Data sources <a href="#kpxsamb8logm" id="kpxsamb8logm"></a>

The **required data from all projects using biomass feedstocks** are presented in Table 2.

*Table 2 Summary of primary data needed from projects and their source for initial project certification and validation. Asterisks (\*) indicate which data are required to be updated annually during verification (see Monitoring Plan section).*

<table><thead><tr><th width="237">Parameter</th><th width="174">Unit</th><th>Source</th></tr></thead><tbody><tr><td>Amount of biomass used*</td><td>Tonnes of fresh matter</td><td>Primary: Internal tracking documents, invoices, contracts</td></tr><tr><td>Carbon content of biomass</td><td>% w/w, fraction, kg/tonne</td><td>Primary or secondary: Laboratory chemical analyses, <a data-footnote-ref href="#user-content-fn-2">scientific publications</a> or local/national agriculture government agencies</td></tr></tbody></table>

### Assumptions <a href="#id-4l7lx2ihb6hj" id="id-4l7lx2ihb6hj"></a>

Major assumptions in this module include:

* The permanent carbon sequestration rate in the [baseline scenario](#id-4l7lx2ihb6hj-2) is 0.5%.

### Project Scenario <a href="#id-4l7lx2ihb6hj" id="id-4l7lx2ihb6hj"></a>

Because the only biomass types allowed are waste, they are assigned no environmental impacts from their production/cultivation stage. Impacts from following stages, such as harvest, transport, and processing, shall be accounted for in the [Processing and energy use](/modules/processing-and-energy-use) module.

### Baseline Scenario <a href="#id-4l7lx2ihb6hj" id="id-4l7lx2ihb6hj"></a>

{% hint style="warning" %}
This section is only required if the feedstock's alternative use was to be **left on the soil or reapplied to soils for nutrient recycling**. Specifically this includes but is not limited to:

* mulching
* composting
* spreading fast-decaying cellulose-based residues (e.g. decay within 5 years)
  {% endhint %}

The Baseline Scenario shall include permanent carbon storage that would have occurred anyway in the absence of the project.

Although most biomass carbon would be released before the CDR project's permanence horizon, a small fraction is stabilized permanently as soil carbon. This portion is accounted for in the Baseline Scenario and deducted from the project's carbon removal capacity.

The uncertainty around biomass carbon being 1) naturally incorporated into the soil and 2) converted to a stable carbon form is high, influenced by factors such as climate, soil type, soil health, and land use, making it hard to estimate for individual projects. Thus, it is assumed that **0.5% of the carbon in the biomass feedstock** left on the soil, or reapplied to soil, will be permanently stored in soils.

<details>

<summary>Calculations- Baseline scenario</summary>

$$\textbf{(Eq.1)}\ {R}*{baseline}= A*{feedstock}\* C \* S\*-1$$

Where,

* $${R}\_{baseline}$$ represents the permanent carbon removal in the baseline scenario in the monitoring period, in t CO$$\_2$$eq. This value shall be applied to Equation 1 from the general [BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals) to calculate total project removals.
* $$A\_{feedstock}$$ represents the amount of biomass feedstock used in the monitoring period, in tonnes of dry matter.
* $$C$$ represents the concentration of carbon in the biomass feedstock, in tonnes of carbon per tonne of dry matter.
* $$S$$ represents the permanent sequestration rate of carbon applied to soils, which is 0.5%, as described in the [Assumptions ](#id-4l7lx2ihb6hj)section.
* It is multiplied by -1 to obtain a negative sign. Removals are reported as a negative value in the [BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals).

</details>

### Uncertainty assessment

See general instructions for uncertainty assessment in the [Rainbow Standard Rules.](/rainbow-standard-documents/rainbow-standard-rules/ghg-quantification#uncertainty-assessment) The outcome of the assessment shall be used to determine the percent of RCCs to eliminate with the [**discount factor**](#user-content-fn-3)[^3].

For projects that include baseline permanent carbon storage, the assumption that 0.5% of carbon is permanently sequestered is has high uncertainty, but the total net project removals is not sensitive to this assumption. Therefore, this translates to an **expected discount factor of at least 3%** for projects that include baseline permanent carbon storage.

## Chemical analyses of feedstock <a href="#ph39su917ek2" id="ph39su917ek2"></a>

Depending on the project type, chemical analyses may be performed on the **biomass feedstock** or the **final carbon storage solution** (e.g. biochar). The accompanying carbon storage module shall specify at which stage chemical analyses should be performed. In all cases, carbon content of biomass feedstock must be provided, although secondary sources may be acceptable (see [Data sources](#kpxsamb8logm)).

If chemical analyses of feedstock are required, Project Developers shall follow the instructions in the [Sampling Requirements](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage/biochar-application-to-soils#sampling-and-measurements) page to ensure a random and representative sampling procedure.

Chemical analyses shall be defined by the carbon storage module and may include but are not limited to:

| Indicator              | Purpose                                                            |
| ---------------------- | ------------------------------------------------------------------ |
| Organic carbon content | Determining amount of carbon removed and carbon removal efficiency |
| Total carbon content   | Determining amount of carbon removed and carbon removal efficiency |
| C:N ratio              | Stability of biomass                                               |
| Moisture content       | Mass conversions                                                   |

## Risk assessment template

:point\_right: Download the template [here](https://docs.google.com/spreadsheets/d/1J2JSxmTxVtfbaNKXyJkwU19DT7Cyvnyf9Q_K5QNmLjU/edit?gid=1281724905#gid=1281724905)

{% embed url="<https://docs.google.com/spreadsheets/d/1J2JSxmTxVtfbaNKXyJkwU19DT7Cyvnyf9Q_K5QNmLjU/edit?gid=1281724905#gid=1281724905>" %}

## Version history

<table><thead><tr><th width="325.33331298828125">Change</th><th>Justification</th><th width="305.3333740234375">Date</th><th>Version changed</th></tr></thead><tbody><tr><td>Restructure sections: added Baseline Scope, renamed Eligible technologies to Eligibility and scope, renamed Eligibility criteria to Principles &#x26; requirements, moved Monitoring Plan to Principles &#x26; requirements</td><td>Align with Standard Rules V7 structure</td><td>January 21st, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>New Certification Scope section with requirements for crediting and monitoring period, project updates with methodology revisions, and site audits.</td><td>Align with Standard Rules V7 structure</td><td>January 21st, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>Environmental and social risk mitigation plan required for moderate or higher risks, instead of high risk</td><td>Align with Standard Rules V7 structure</td><td>January 21st, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>Module first created</td><td>-</td><td>December 4th, 2024</td><td>V1.0</td></tr></tbody></table>

[^1]: Carbon dioxide removal

[^2]: * Fu, B., Chen, L., Huang, H., Qu, P., Wei, Z., 2021. Impacts of crop residues on soil health: a review. Environmental Pollutants and Bioavailability 33, 164–173. [URL](https://doi.org/10.1080/26395940.2021.1948354)
    * Torma, S., Vilček, J., Lošák, T., Kužel, S., Martensson, A., 2018. Residual plant nutrients in crop residues – an important resource. Acta Agriculturae Scandinavica, Section B — Soil & Plant Science 68, 358–366. [URL](https://doi.org/10.1080/09064710.2017.1406134)
    * Wang, X., Yang, Z., Liu, X., Huang, G., Xiao, W., Han, L., 2020. The composition characteristics of different crop straw types and their multivariate analysis and comparison. Waste Management 110, 87–97. [URL](https://doi.org/10.1016/j.wasman.2020.05.018)

[^3]: A percentage of verified Rainbow Carbon Credits eliminated from each project and never issued. This acts as a safeguard against uncertainty in GHG reduction quantifications and overestimated carbon removal/avoidance.


# Carbon storage modules

<table data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-cover data-type="files"></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td>Biochar application to soils</td><td></td><td></td><td><a href="/files/WBbGVKPBjsK4WhkO6UzS">/files/WBbGVKPBjsK4WhkO6UzS</a></td><td><a href="/pages/Om2iC8BSJ1GdkHA5oMoA">/pages/Om2iC8BSJ1GdkHA5oMoA</a></td></tr><tr><td>Marine sub-sediment burial</td><td></td><td></td><td><a href="/files/k13pOQVjlieiKWJxwG2C">/files/k13pOQVjlieiKWJxwG2C</a></td><td><a href="/pages/GxlSYzJC7Dkt7JmbJ2y2">/pages/GxlSYzJC7Dkt7JmbJ2y2</a></td></tr></tbody></table>


# Biochar application to soils

| **Module name**      | Biochar application to soils               |
| -------------------- | ------------------------------------------ |
| **Module category**  | Carbon storage                             |
| **Methodology name** | Biomass carbon removal and storage (BiCRS) |
| **Version**          | 2.3                                        |
| **Methodology ID**   | RBW-BICRS-CS-BCSOIL-V2.3                   |
| **Release date**     | January 21st, 2026                         |
| **Status**           | In use                                     |

{% content-ref url="/pages/D1bECpowUAiJorSGzbQY" %}
[Glossary](/glossary)
{% endcontent-ref %}

This is a **Carbon Storage Module** and covers the biochar application to soils. This module is part of the Rainbow BiCRS methodology, which allows Project Developers to choose the relevant modules for their project, and shall be used with the necessary accompanying modules.

See more details on how modules are organized in the [BiCRS home page](/methodologies/biomass-carbon-removal-and-storage-bicrs#efpqng3v3ute).

<table data-view="cards" data-full-width="false"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="files"></th></tr></thead><tbody><tr><td><strong>How to use this module</strong></td><td></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo#efpqng3v3ute">/pages/Jy6o8q5Q31d2U0OK7Yuo#efpqng3v3ute</a></td><td><a href="/files/0zYtLJBdzIemkx7iKe9C">/files/0zYtLJBdzIemkx7iKe9C</a></td></tr><tr><td><strong>BiCRS Methodology</strong></td><td></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo">/pages/Jy6o8q5Q31d2U0OK7Yuo</a></td><td><a href="/files/4B3R2CjT9hA3bBYbzz1a">/files/4B3R2CjT9hA3bBYbzz1a</a></td></tr></tbody></table>

## Eligibility and scope <a href="#uikucys7r1rk" id="uikucys7r1rk"></a>

### Eligible technologies

This module covers industrial biochar projects that meet all of the following requirements:

<table data-view="cards"><thead><tr><th></th><th></th></tr></thead><tbody><tr><td><strong>Feedstock</strong></td><td><ul><li>Use waste and residual biomass as feedstock, according to the <a href="/pages/V0dXfN5yPUaU1ws1h7sV">Biomass feedstock</a> module.</li></ul></td></tr><tr><td><strong>Processing</strong></td><td><ul><li>Heat biomass to at least <strong>350°C</strong> during production.</li><li>Capture or cleanly burn pyrolysis gasses, as outlined in the <a href="/pages/BTxxPIM3a4Nai1Wkwu2Y#environmental-and-social-do-no-harm">Processing and Energy Use</a> module</li><li>Report methane emissions from pyrolysis, using the <a href="/pages/BTxxPIM3a4Nai1Wkwu2Y#environmental-and-social-do-no-harm">Processing and Energy Use</a> module</li></ul></td></tr><tr><td><strong>Biochar Quality and Use</strong></td><td><ul><li>Produce high-quality biochar with a molar <span class="math">H/C_{\text{org}}</span> below <strong>0.7</strong>.</li><li>Apply biochar to agricultural, forest, or urban soils, ensuring permanent sequestration of its organic carbon content.</li></ul></td></tr></tbody></table>

Projects may be designed to prioritize bio-oil or bioenergy production, where biochar is the co-product. Such projects may still be eligible for removal Rainbow Carbon Credits under this module, if they meet all criteria outlined herein.

This module allows for issuance of **removal RCCs on the basis of biochar end use/delivery**, i.e. application to soils and permanent storage, not on the basis of biochar production.

**Eligible end uses of biochar** include application directly to soils or incorporation into soil-related products, such as soil additives, horticultural substrates, potting soils, fertilizer mixes, or compost.

This module also allows for issuance of **avoidance RCCs on the basis of avoided horticultural products** from the use of biochar (with strict proof of replacement, see the [Baseline Scope](#baseline-scope) section).

The Project Developer and entity eligible for receiving carbon finance may be either:

* the operator of the biochar production site, or
* land owners or managers who purchase biochar and apply it to their soil.

Pyrolysis and gasification equipment manufacturers are not eligible Project Developers.

### Certification requirements

Certification requirements for this module are defined in the [BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#certification-requirements). These cover crediting period duration, monitoring period duration, site audits, and versioning and project compliance.

### Project scope

One project is defined as:

* the operation of one or more pyrolysis units, across one or more sites,
* within a single country,
* using similar types of pyrolysis units,
* using the same carbon removal measurement approach and durability claims, and
* operated at sites that are under the oversight or data access of a single Project Developer, regardless of whether the developer directly owns or manages each site.

The project scope is cradle-to-grave and includes all processes that result from biochar production and application. This includes but is not limited to the following: all removals from biochar production, and all induced emissions related to biomass sourcing, leakage, upstream and downstream transport, embodied emissions from infrastructure and machinery, and onsite process emissions from biomass and biochar processing and energy use.

Any processes that would have occurred regardless of the biochar production and application activities may be excluded from the project scope.

### Baseline scope

Several baselines may be applied depending on the type of credit issued:

**Removal RCCs from biochar carbon removal**:

* the baseline shall include any permanent carbon removal that would have occurred in the absence of the project.
* This includes but is not limited to permanent carbon storage from the alternate fate of the biomass feedstock used for pyrolysis.
* It shall be assumed by default that no biomass feedstock would have been used to produce biochar in the absence of the project (i.e. there is no share of the project activity in the baseline scenario).

**Avoidance RCCs from energy co-products**:

* the baseline shall include the equivalent amount of energy produced and exported by the project.
* The type of energy selected for the baseline shall be representative of the energy produced by the project, and shall be specific and conservative.
* All life cycle emissions from the baseline energy source shall be accounted for, including but not limited to raw material extraction, processing, upgrading, distribution, and if relevant, combustion.

**Avoidance RCCs from horticultural products**:

* the baseline shall include the equivalent amount of horticultural products (e.g. peat, fertilizer...) produced and sold by the project.
* The specific amount and type of avoided products must be **provided by the Project Developer with project-specific documentation**. It must show that the user of the biochar **actually uses less of the horticultural product than they did previously**, as a result of their use of biochar. This must be proven using, for example, operations tracking or invoices from the biochar user. In other words, it is not sufficient to prove that biochar could *technically* substitute products, because there is high uncertainty in which products biochar would *actually* substitute.
* All emissions from the baseline horticultural product life cycle that differ from the biochar life cycle shall be accounted for, including but not limited to raw material extraction and processing. If processes are equivalent between the biochar and horticultural product, such as transport delivery or packaging, they may be excluded from both the project and baseline scope for the purpose of quantifying avoidance RCCs from horticultural products.
* By default, it shall be **assumed that biochar application to soils does not replace any measurable, verifiable product**.

The baseline scenario **structure** remains valid for the entire crediting period but may be significantly revised earlier if:

* The Project Developer notifies Rainbow of a substantial change in project operations or baseline conditions, and/or
* The methodology is revised, affecting the baseline scenario.

The **specific values** within the baseline scenario will be updated during each crediting period, using project data to accurately reflect the equivalent of the project’s operations.

## Production batches <a href="#id-2xck12gc2auz" id="id-2xck12gc2auz"></a>

A production batch is the **biochar produced under the same conditions regarding production temperature and feedstock mix**. It is assumed that all biochar from the same production batch has similar characteristics (i.e. $$H/C\_{\text{org}}$$, moisture content…).

Specifically, the definition of a production batch follows the [European Biochar Certificate Guidelines](#user-content-fn-1)[^1] definition, where pyrolysis temperature and biomass feedstock composition must not change by more than 20%.

Measurements and reporting are performed at the **production batch level**. Verification and credit issuance may be done per production batch, or annually on the cumulative production batches from that year.

{% hint style="info" %}
For example, if the declared pyrolysis temperature is 600 °C, temporary fluctuations between 480 °C and 720 °C are acceptable.

If a mixture of 50% tree clippings and 50% nut shells is pyrolyzed, the proportions can vary between 40% and 60% (±10% of the original 50%)
{% endhint %}

A production batch has a **maximum validity of 365 days**, after which biochar shall be considered part of a different production batch even if conditions are unchanged. In other words, the production batch ID number resets and a new production batch is created, and new monitoring requirements applied, after 365 days, regardless of if feedstock or pyrolysis conditions change or not.

## Principles & requirements

The principles and requirements specific to this module are detailed in the sections below. Other principles and requirements shall be taken from the accompanying modules and methodologies:

<table data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="files"></th></tr></thead><tbody><tr><td><strong>BiCRS methodology</strong></td><td><ul><li>Additionality</li><li>No double counting</li><li>Environmental and social safeguards</li></ul></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo">/pages/Jy6o8q5Q31d2U0OK7Yuo</a></td><td><a href="/files/4B3R2CjT9hA3bBYbzz1a">/files/4B3R2CjT9hA3bBYbzz1a</a></td></tr><tr><td><strong>Other modules</strong></td><td><ul><li>Co-benefits</li><li>No double counting</li><li>Environmental and social safeguards</li><li>Leakage</li></ul></td><td></td><td><a href="/pages/eQTO2zpdCEv368f4bRT6">/pages/eQTO2zpdCEv368f4bRT6</a></td><td><a href="/files/CxuE4U5JkYE63biLhW6k">/files/CxuE4U5JkYE63biLhW6k</a></td></tr></tbody></table>

### Durability <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

#### Durability threshold

All projects certified under this methodology shall prove **durable carbon removals for at least 100 years**. Project Developers may claim an extended durability threshold of 1000 years if they choose the 1000-year pathway for [GHG quantification](#ghg-quantification) and measurements.

#### Reversal risk assessment

The major carbon reversal risks from biochar application to soil are:

1. **Insufficient biochar stability**, where biochar carbon is not sufficiently carbonized and is decomposed by microbes and soil organisms, resulting in re-emission of CO<sub>2</sub>.
2. **Failure to durably incorporate into soils**, where biochar does not end up in a durable storage matrix (e.g. soil or soil-like material) and is instead burned or destroyed, intentionally or unintentionally (e.g. as fuel, in storage fires, or via waste incineration).

This methodology establishes the following mandatory project design requirements to mitigate these risks, detailed in the following sections:

* measuring the durable carbon fraction
* verification of biochar end use

Upon meeting these requirements for each verification and credit issuance, the risk of reversal is considered **negligible** for biochar application to soils. There are no further project requirements to assess reversal risks or conduct post-crediting monitoring for reversals.

All projects certified under this methodology shall contribute the default minimum 2% of their verified removal RCCs to the Rainbow Buffer Pool, as defined in the Rainbow Standard Rules.

#### Risk mitigation: Measuring permanent carbon fraction <a href="#kmzukpswu89" id="kmzukpswu89"></a>

Not all biomass carbon that is converted to biochar is expected to remain durably stored. The durability of biochar carbon depends on the its physicochemical stability, which is influenced by factors such as carbonization temperature and biomass feedstock.

Project Developers shall measure one of the following well-known [proxy indicators](#user-content-fn-2)[^2] of biochar durability for each production batch. These indicators serve both as **eligibility thresholds**, and as inputs to **quantify the permanent fraction of carbon** ($$F\_{perm}$$) expected to remain durably stored beyond the applicable durability threshold.

The fraction of permanently stored carbon shall be quantified using the models and equations specified in the [GHG quantification](#ghg-quantification) section. Only this fraction shall be issued as removal RCCs.

<table><thead><tr><th width="136">Pathway</th><th width="213">Indicator</th><th>Threshold requirement</th></tr></thead><tbody><tr><td>100-year pathway</td><td>Hydrogen-to-organic-carbon atomic ratio (<span class="math">H/C_{\text{org}}</span>)</td><td><span class="math">H/C_{\text{org}}</span> must be less than 0.7</td></tr><tr><td>1000-year pathway</td><td>Random reflectance distribution</td><td><ul><li>The fraction of the biochar residual organic carbon that has a random reflectance of 2% or higher can be considered <a data-footnote-ref href="#user-content-fn-3">inertinite</a>, which is an extremely stable, permanent storage of mineral-like organic carbon.</li><li>Must also have <span class="math">H/C_{\text{org}}</span> less than 0.7</li></ul></td></tr></tbody></table>

The distinction between the 100-year and 1,000-year durability pathways provides supplementary qualitative information and does not affect the inherent attributes of the removal RCC.

These indicators are **suitable proof that a substantial fraction** of the carbon present in biochar is permanently stable. The **specific amount** of permanently stored carbon is determined using the models and equations detailed in the [GHG quantification](#ghg-quantification) section.

<table data-view="cards"><thead><tr><th></th><th></th><th></th></tr></thead><tbody><tr><td></td><td><a href="#risk-evaluation-template">Rainbow Biochar application to soils risk evaluation</a></td><td></td></tr></tbody></table>

These durability indicators shall be monitored for each production batch according to the Rainbow [Sampling Requirements](#sampling-and-measurements).

Issuing removal RCCs only for the verified, highly stable fraction of biochar carbon mitigates the risk of biological decomposition and re-emission after soil application.

#### Risk mitigation: Proof of biochar end use <a href="#id-5a8ye61po9ri" id="id-5a8ye61po9ri"></a>

Project Developers shall prove that all biochar has been used in the intended durable storage application (e.g. incorporated into soils, added to fertilizer mixes…). This shall be done in **Biochar Application Verification Reports** that contain all of the following:

* Tracking records of the purchase and/or delivery of the biochar to its end use point of use, specifying the date, amount of biochar and Production Batch ID.
* GPS coordinates of all end use points with according amounts of biochar, if known to the Project Developer.
* Company name and individual contact information for each buyer/user of biochar, for traceability and random checking by VVBs.
* Photo diary of biochar application, including photos of for example the biochar being delivered, tags/labels with information, road signs during delivery, process of biochar spreading.

Issuing removal RCCs only after verified incorporation into a permanent storage matrix mitigates the risk that biochar is burned, destroyed or otherwise re-emitted.

### No double counting <a href="#id-8f3i2uvmiuhl" id="id-8f3i2uvmiuhl"></a>

See the [BiCRS methodology No double counting](/methodologies/biomass-carbon-removal-and-storage-bicrs#n1iy4xaxuthk) section for general requirements on this topic. Since both **biochar producers and users** are eligible for removal RCCs under this methodology, additional details are provided here.

If **both the biochar producer and the farmer intend to issue carbon credits**, they must agree on how to divide the annual biochar production for credit issuance. The credited biochar amount must be tracked and reported separately, governed by agreements outlining which party receives credits.

{% hint style="info" %}
For example, they might decide that the farmer will issue credits for the biochar produced from January through April (Production Batch #1), while the producer will issue credits for biochar produced from May through December (Production Batch #2).
{% endhint %}

Since both **biochar producers and users** are eligible for removal RCCs under this methodology, additional details are provided here.

If **only one party seeks to issue carbon credits**, this must be proven through signed agreements, minimizing the risk of double counting.

{% hint style="info" %}
For example, if only the biochar producer seeks to issue carbon credits, they must obtain a signed agreement from the farmer whose land biochar will be spread on, stating that the farmer will not also try to issue carbon credits for their use of biochar.
{% endhint %}

If **both the biochar producer and the farmer intend to issue carbon credits**, they must agree on how to divide the annual biochar production for credit issuance. The credited biochar amount must be tracked and reported separately, governed by agreements outlining which party receives credits.

{% hint style="info" %}
For example, they might decide that the farmer will issue credits for the biochar produced from January through April (Production Batch #1), while the producer will issue credits for biochar produced from May through December (Production Batch #2).
{% endhint %}

### Co-benefits <a href="#id-8f3i2uvmiuhl" id="id-8f3i2uvmiuhl"></a>

Projects should support at least two **quantifiable and verifiable** environmental or social co-benefits, aligned with the [UN Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDGs) framework. Any co-benefits claimed by the Project Developer shall be **quantified, monitored, and audited** for each verification and credit issuance.

Common co-benefits under this methodology are detailed in the table below. Project Developers may suggest and prove other co-benefits not mentioned here.

SDG 13 on Climate Action by default is not considered a co-benefit here, since it is implicitly accounted for in the issuance of carbon credits. If the project delivers climate benefits that are not accounted for in the GHG reduction quantifications, then they may be considered as co-benefits.

*Table 1 Common co-benefits that projects under this methodology may provide are detailed, including types of proof that can be used to justify each co-benefit.*

<table><thead><tr><th width="200">UN SDG</th><th width="345">Example</th><th>Proof</th></tr></thead><tbody><tr><td><strong>SDG 2.4:</strong> Ensure sustainable food production systems, increase productivity, help maintain resilient ecosystems, improve land and soil quality.</td><td>Biochar application to agricultural soils can <a data-footnote-ref href="#user-content-fn-4">increase crop yields,</a> therefore reducing the amount of land, pesticides, fertilizer, and other environmentally impactful resources needed to grow food</td><td>Proof of biochar use in agriculture as opposed to other applications: contract, invoices, receipts of sale of biochar to farmers.</td></tr><tr><td><strong>SDG 12.2:</strong> Achieve the sustainable management and efficient use of natural resources</td><td>The project’s <a data-footnote-ref href="#user-content-fn-5">circularity </a>will be measured by the <a data-footnote-ref href="#user-content-fn-6">Material Circularity Indicator (MCI)</a>, according to the Ellen MacArthur Foundation's methodology. The indicator is expected to be 100% circularity for all biochar projects, since they use biomass feedstock and do not landfill or incinerate their product.</td><td>Type of feedstocks used, verification of end use of biochar</td></tr></tbody></table>

### Environmental and social safeguards <a href="#id-82n4j72vjt9v" id="id-82n4j72vjt9v"></a>

Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.**

Projects must follow all national, local, and European (if located in Europe) environmental regulations, including but not limited to those related to pyrolysis, gasification, waste feedstock management, and biochar spreading on soils.

**Feedstock sustainability requirements** shall be taken from the [Biomass feedstock module](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock).

Biochar applied to soils must be below the pollutant concentration thresholds outlined in Table 2, defined by the [World Biochar Certificate Guidelines](#user-content-fn-7)[^7] (for WBC-Agro). This shall be measured for each production batch.

*Table 2 The thresholds for pollutant concentrations allowed in biochar, as detailed in the* [*World Biochar Certificate Guidelines*](#user-content-fn-7)[^7]*.*

<table><thead><tr><th width="353.44439697265625">Substance</th><th>Limit amount (g/tonne dry matter)</th></tr></thead><tbody><tr><td>Pb</td><td>300</td></tr><tr><td>Cd</td><td>5</td></tr><tr><td>Cu</td><td>200</td></tr><tr><td>Ni</td><td>100</td></tr><tr><td>Hg</td><td>2</td></tr><tr><td>Zn</td><td>1000</td></tr><tr><td>Cr</td><td>200</td></tr><tr><td>As</td><td>20</td></tr><tr><td>8 EFSA PAH</td><td>1</td></tr></tbody></table>

{% hint style="info" %}
*Disclaimer: The European Biochar Certificate (EBC) and the World Biochar Certificate (WBC) are independent certification programs designed to ensure the quality of biochar products. These certifications are administered and trademarked by Carbon Standards International (CSI) and are distinct from the Rainbow certification and the issuance of carbon credits.*

*The threshold values provided here are based on the voluntary guidelines of the World Biochar Certificate (WBC), reproduced with permission. While these values have been adopted by the Rainbow standard as pollutant thresholds, they are only indicative. Meeting these thresholds for Rainbow certification does not imply eligibility for or any association with the EBC or WBC programs. Project Developers certified under the Rainbow standard shall not make claims or use any trademarked materials from CSI, unless explicitly allowed by CSI.*

*Voluntary certification under the WBC and EBC schemes is overseen by CSI and includes additional requirements beyond pollutant thresholds.*
{% endhint %}

#### Environmental and social risk assessment

Project Developers shall fill in the [Rainbow Biochar application to soils risk assessment](#risk-assessment-template), to evaluate the identified environmental and social risks of projects. The identified risks include:

* Heavy metal or other pollutants in biochar applied to agricultural soils
* Health risks from exposure to harmful gasses and particles

The risk assessment also includes the identified risks from the [Biomass feedstock ](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock)module and the risks from the [Processing and energy use](/modules/processing-and-energy-use) module relevant for this carbon storage module.&#x20;

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

### Monitoring

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information **for each Production Batch**:

* Description of the pyrolysis conditions (temperature and residence time) and any variability in the process
* Amount of biochar produced, in tonnes of fresh biochar
* Moisture content of biochar
* Organic carbon content
* $$H/C\_{\text{org}}$$ (only for [Approach 1: Modeling 100-year removals with H/C org](#unteq8ror26g))
* Random reflectance ( $$R\_o$$) mean and distribution, and residual carbon content (only for [Approach 2: Estimating 1000-year removals using random reflectance](#id-2rhx2av7of74))
* [Environmental and social safeguards: biochar pollutant measurements](#id-82n4j72vjt9v-1)
* [Biochar Application Verification Reports](#id-5a8ye61po9ri), with names and GPS coordinates of spreading locations, among other information
* [Sampling records](#sampling-records)

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information **for each reporting period**:

* Number of Production Batches
* Total amount of biochar produced per year, in tonnes of fresh biochar
* Co-benefits

Monitoring Plans shall include the following information for each monitored parameter:

* monitoring frequency
* emission sources and sinks
* data source
* measurement methods/procedures, and their accuracy and calibration
* quality assessment or quality control procedures
* responsible party for collecting and archiving data

## GHG quantification

The GHG quantification instructions from all other BiCRS modules used by the project must be used in conjunction with the present module in order to obtain full life-cycle GHG quantifications.

The system boundary of this quantification section starts at the arrival of biochar at the site of permanent incorporation/application (i.e. field for spreading, mixing into potting soil...) and ends at the biochar end of life, after accounting for decay and re-emission in its end use application.

The system boundary of this quantification section starts at the arrival of biochar at the site of permanent incorporation/application (i.e. field for spreading, mixing into potting soil...) and ends at the biochar end of life, after accounting for decay and re-emission in its end use application.

**Quantification shall be done at a minimum for each biochar production batch**, and may be done more frequently for continuous issuance.

GHG emissions covered in this module include:

* Permanent carbon storage modeling
* Production of avoided baseline scenario materials

### Data sources <a href="#kpxsamb8logm" id="kpxsamb8logm"></a>

The required **primary data** for GHG reduction calculations from projects are presented in Table 2. These data shall be provided for each production batch and made publicly available.

*Table 2 Summary of primary data needed from projects and their source for initial project certification and validation. All primary data sources listed here are required to be monitored and updated during verification (see Monitoring Plan section).*

{% tabs %}
{% tab title="Option 1: 100-year removals with H/C" %}

| Parameter                                                              | Unit                   | Source                                                                     |
| ---------------------------------------------------------------------- | ---------------------- | -------------------------------------------------------------------------- |
| Amount of biochar produced\*                                           | Tonnes of fresh matter | Internal tracking documents, invoices, contracts                           |
| Biochar $$H/C\_{\text{org}}$$\*                                        | Ratio                  | Laboratory chemical analyses                                               |
| Organic carbon content                                                 | Percent                | Laboratory chemical analyses                                               |
| Biochar moisture content ($$M\_{\text{%}}$$) \*                        | Percent                | Laboratory chemical analyses                                               |
| [GPS coordinates ](#user-content-fn-8)[^8]of biochar spreading sites\* | coordinates            | Internal tracking documents, invoices, mapping software (e.g. Google Maps) |
| Amount and type of avoided horticultural product (optional)            | kg, tonnes, m3         | Operations tracking and invoices from the product user                     |
| {% endtab %}                                                           |                        |                                                                            |

{% tab title="Option 2: 1000-year removals random reflectance" %}

<table><thead><tr><th width="302">Parameter</th><th width="154">Unit</th><th>Source</th></tr></thead><tbody><tr><td>Amount of biochar produced*</td><td>Tonnes of fresh matter</td><td>Internal tracking documents, invoices, contracts</td></tr><tr><td>Organic carbon content</td><td>Percent</td><td>Laboratory chemical analyses</td></tr><tr><td>Average random reflectance <span class="math">R_o</span></td><td>Percent</td><td>Laboratory chemical analyses</td></tr><tr><td>Fraction of <span class="math">R_o</span> distribution measurements above 2%</td><td>Fraction</td><td>Laboratory chemical analyses</td></tr><tr><td>Residual organic carbon (<span class="math">C_{org,\ \%residual}</span>)</td><td>Fraction</td><td>Laboratory analyses</td></tr><tr><td>Biochar moisture content (<span class="math">M_{\text{%}}</span>)*</td><td>percent</td><td>Laboratory chemical analyses</td></tr><tr><td>Amount and type of avoided horticultural product (optional)</td><td>kg, tonne, m3</td><td>Operations tracking and invoices from the product user</td></tr></tbody></table>
{% endtab %}
{% endtabs %}

The [ecoinvent database](#user-content-fn-9)[^9] version 3.12 (hereafter referred to as ecoinvent) shall be the main source of emission factors unless otherwise specified. Ecoinvent is preferred because it is traceable, reliable, and well-recognized. The ecoinvent processes selected are detailed in [Appendix 1](#appendix).

No other secondary data sources are used in this module.

### Co-product allocation

The rules outlined at the methodology-level in the [BiCRS methodology document](/methodologies/biomass-carbon-removal-and-storage-bicrs) shall be applied for allocating GHG emissions between co-products.

### Assumptions

1. By default, biochar application to soils does not replace any product.
2. The fraction of biochar with an $$R\_o$$ below 2% does not contribute to any permanent carbon storage. This fraction, classified as semi-inertinite rather than inertinite, likely plays a role in long-term carbon storage. However, due to limited research on its quantification, it is conservatively excluded from this analysis.
3. All biochar from the same production batch has the same characteristics (e.g. $$M\_{\text{%}}$$, $$H/C\_{\text{org}}$$, $$R\_o$$).

### Baseline scenario <a href="#ly65klblzpa9" id="ly65klblzpa9"></a>

The baseline scenario for the purpose of Removal vs Avoidance RCCs issuance is detailed below.

{% tabs %}
{% tab title="Removal RCCs" %}
For removal RCCs, there is no baseline from this module because it is assumed that there is no significant share of the project activity already occurring in business-as-usual. Therefore, the baseline for removal credits is zero and is omitted from calculations.

According to the Rainbow Procedures Manual, this assumption shall be re-assessed at a [minimum every 3 years](broken://pages/B6RuQQtXkQShQGfpsbEN#revising-a-methodology) during the mandatory methodology revision process, and any changes to this assumption would be [applied to existing projects](/rainbow-standard-documents/procedures-manual/project-certification-procedure#compliance-and-project-updates).

Note that baseline scenario carbon sequestration may be included for the project from the [biomass feedstock module](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock#ghg-quantification).
{% endtab %}

{% tab title="Avoidance RCCs" %}
By default, it shall be **assumed that biochar application to soils does not replace any measurable, verifiable product**.

If Project Developers can prove that their biochar product replaces a **specific and known amount of a specific product**, then the product may be considered as replaced and avoided.

Examples of ecoinvent processes for these products are presented in [Appendix 1](#appendix).

Note that avoidance from energy co-products is covered in a[ separate module](/modules/energy-co-products).

The equations for calculating avoidance are presented in the [BiCRS methodology ](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals)document and shall be applied here.
{% endtab %}
{% endtabs %}

### Project scenario <a href="#i4figd8ytjua" id="i4figd8ytjua"></a>

Project Developers must choose between one of two approaches to quantify the total carbon removals from their biochar product, as described in the [Durability section](#lc9eewbyvlyk). A single approach must be used consistently throughout each monitoring period, though a different approach may be chosen for subsequent monitoring periods.

1. [Modeling 100-year removals using bulk measurements of $$H/C\_{\text{org}}$$](#unteq8ror26g), or
2. [Estimating 1000-year removals using random reflectance measurements as proxies for inertinite](#id-2rhx2av7of74).

#### Approach 1: Modeling 100-year removals with $$H/C\_{\text{org}}$$ <a href="#unteq8ror26g" id="unteq8ror26g"></a>

This approach is based on research from [Woolf et al., 2021](#user-content-fn-10)[^10], and the [IPCC modeling method](#user-content-fn-11)[^11]. It is rooted in soil ecology and soil biochemistry disciplines. The **permanent fraction** of biochar carbon remaining after 100 years ($$F\_{\text{perm 100}}$$) is modeled according to the local average annual soil temperature.

Soil temperature shall be obtained for the location of each biochar spreading/end use event, using the GPS coordinates provided in the Verification of end use report and the global soil temperature dataset from [Lembrechts et al., 2021](#user-content-fn-12)[^12]. The Rainbow Certification Team can provide soil temperature values for Project Developers based on the provided GPS coordinates.

Project Developers shall provide primary project data in the form of laboratory measurements, following the Sampling requirements.

*Table 3 Soil temperature ranges are categorized and their corresponding c and m regression coefficients are presented, which are used in Eq. 1 below to calculate* $$F\_{perm}$$. Values are taken from [Woolf et al., 2021](#user-content-fn-10)[^10].

| Soil temperature (°C) | c    | m    |
| --------------------- | ---- | ---- |
| <7.49                 | 1.13 | 0.46 |
| 7.5-12.49             | 1.10 | 0.59 |
| 12.5-17.49            | 1.04 | 0.64 |
| 17.5-22.49            | 1.01 | 0.65 |
| >22.5                 | 0.98 | 0.66 |

<details>

<summary><strong>Calculations: 100-year removal credits with</strong> <span class="math">H/C_{org}</span></summary>

$$\textbf{(Eq.1)}\ F\_{perm\ 100} = c - m\*H/C\_{org}$$

where,

* $$F\_{perm\ 100}$$ represents the fraction of biochar carbon remaining after 100 years
* $$c$$ and $$m$$ represent regression coefficients, taken from [Woolf et al., 2021](#user-content-fn-10)[^10], and summarized in Table 3 for the corresponding project's soil temperature.
* $$H/C\_{org}$$ represents the ratio of molar hydrogen to organic carbon in biochar, measured by laboratory analysis for each project.

$$\textbf{(Eq.2)}\ R\_{P,\ Storage\ 100}= F\_{perm\ 100}\*{C\_{org}*A}\_{biochar}*(1 - M\_{%})\*C\ to\ {CO}\_{2}$$

where,

* $$R\_{P,\ Storage\ 100}$$ represents the total carbon removals from biochar during the verification period, in tonnes of CO$$\_2$$eq. This value shall be applied to Equation 1 from the [General BiCRS methodology](broken://pages/IPTw7ScSQWpD4sIH2RfM#calculations-removals) document to calculate total project removals.
* $$F\_{perm\ 100}$$ is calculated in Equation 1
* $$C\_{org}$$ represents the concentration of organic carbon in biochar, on a weight basis.
* $$A\_{biochar}$$ represents the amount of biochar delivered during the verification period, in tonnes of fresh biochar.
* $$M\_{%}$$ represents the moisture content of biochar, on a weight basis (%w/w), so $$1-M\_{%}$$converts to dry mass of biochar
* $$C\ to\ {CO}\_{2}$$ is 44/12 = 3.67, and represents the molar masses of CO$$\_2$$ and C respectively, and is used to convert tonnes C to tonnes of CO$$\_2$$eq.

</details>

#### Approach 2: Estimating 1000-year removals based on inertinite fraction <a href="#id-2rhx2av7of74" id="id-2rhx2av7of74"></a>

This approach is based on the research from [Sanei et al., 2024](#user-content-fn-13)[^13], and is rooted in the organic petrology and geochemistry disciplines. This approach is built upon research showing that fractions of inertinite in biochar samples are:

* [inert and permanent](#user-content-fn-14)[^14] and will not re-release their carbon for at least 1000 years.
* represented by the fraction of residual (i.e. not reactive, not labile) organic carbon in the sample with a Random Reflectance ($$R\_o$$) of [2% or higher](#user-content-fn-13)[^13].

For verification, Project Developers shall provide primary project data in the form of laboratory measurements for $$R\_o$$ distribution, [labile organic carbon content](#user-content-fn-15)[^15], and moisture content for each production batch, following the [Sampling requirements](#sampling-and-measurements).

To determine the inertinite fraction of the biochar's organic carbon, first the labile carbon fraction is measured and subtracted from total organic carbon content, and only the residual organic carbon content is considered.

Next, random reflectance measurements are used to determine the fraction of residual organic carbon that is classified as inertinite:

* The fraction of the distribution with an $$R\_o$$ **above 2%** represents the fraction of the biochar carbon that is stored permanently for 1000 years.
* The fraction of the distribution with an $$R\_o$$ **below 2%** represents the fraction of biochar carbon that is not permanently stored, and for which no removal RCCs are issued.
* $$R\_o$$ distribution shall be based on at least 500 measurements, yielding a frequency distribution diagram similar to the examples in Figure 1a and 1b.

![Figure 1a An example of a random reflectance frequency distribution diagram, with an analysis described below.](/files/RvDwkJem5UkBnsnCmFSv)

{% hint style="info" %}
Example 1: This biochar sample has heterogenous quality and a wide distribution of $$R\_o$$ measurements. The biochar sample has:

* labile organic carbon content of 5%,
* residual organic carbon content of 95%,
* mean $$R\_o$$ of 2.12, and
* 72% of the $$R\_o$$ measurements are above the 2% inertinite threshold.

Therefore, this biochar sample has an $$F\_{\text{perm\ 1000}}$$ of $$0.72 \times 0.95=0.684$$ , so 68.4% of the organic carbon in the sample will be converted to CO$$\_2$$eq and considered as 1000-year carbon removals. The remaining 31.6% of carbon is assumed to decompose within the 1000-year permanence horizon, and is not considered for any removal RCCs.
{% endhint %}

![Figure 1b An example of a random reflectance frequency distribution diagram, with an analysis described below.](/files/zys8iUA26XGiah6RpKoc)

{% hint style="info" %}
Example 2: This biochar sample has rather homogenous quality and a narrow distribution of $$R\_o$$ measurements. The biochar sample has:

* labile organic carbon content of 1%
* residual organic carbon content of 99%
* mean $$R\_o$$ of 2.32, and
* 95% of the $$R\_o$$ measurements are above the 2% inertinite threshold.

Therefore, this biochar sample has an $$F\_{\text{perm\ 1000}}$$ of $$0.99\*0.95=0.94$$, so 94% of the organic carbon in the sample will be converted to CO$$\_2$$eq and considered as 1000-year carbon removals. The remaining 6% of carbon is assumed to decompose within the 1000-year permanence horizon, and is not considered for any removal RCCs.
{% endhint %}

<details>

<summary><strong>Calculations: 1000-year removal credits with random reflectance</strong></summary>

$$\textbf{(Eq.3)}\ F\_{perm\ 1000} = {Sample\ fraction}*{> 2%\ Ro} \times C*{org,\ f\ residual}$$

where,

* $$F\_{perm\ 1000}$$ represents the fraction of biochar carbon remaining after 1000 years.
* $${Sample\ fraction}\_{> 2%\ Ro}$$ represents the fraction of the distribution sample that has a random reflectance ($$R\_O$$) of 2% or higher.
* $$C\_{org,\ f\ residual}$$ represents the fraction of the biochar organic carbon that is residual carbon, as opposed to reactive/labile organic carbon. It may be measured and reported directly, or obtained by subtracting measured *reactive* carbon from 100.

$$\textbf{(Eq.4)}\ R\_{project,\ 1000}=F\_{perm\ 1000}*{C\_{org}*A}\_{biochar}*{(1 - M}*{%})\*C\ to\ {CO}*{2}*-1$$

where,

* $$R\_{project,\ 1000}$$ represents the total carbon removals from biochar during the verification period, in tonnes of CO$$\_2$$eq. This value shall be applied to Equation 1 from the [General BiCRS methodology ](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals)document to calculate overall project removals.
* $$F\_{perm\ 1000}$$ is calculated in Equation 3
* $$C\_{org}$$, $$A\_{biochar}$$, $$M\_{%}$$, and $$C\ to\ {CO}\_{2}$$ are described in Equation 1.
* It is multiplied by -1 to obtain a negative sign. Removals are reported as a negative value in the [BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#calculations-removals).

</details>

Rainbow is actively monitoring ongoing research and seeking expert advice on the potential development of a third approach that uses $$H/C\_{\text{org}}$$ measurements as proxies for inertinite content. For example, if the $$H/C\_{\text{org}}$$ value is less than 0.2, it could be interpreted as indicating that 95% of the biochar is inertinite. While this simplification has been suggested by experts and holds promise, it is currently considered insufficiently rigorous due to a lack of supporting evidence and clear guidance.

#### Future Approach 3: Using H/C as a proxy for inertinite

Rainbow is actively monitoring ongoing research and seeking expert advice on the potential development of a third approach that uses $$H/C\_{org}$$ measurements as proxies for inertinite content. For example, if the $$H/C\_{org}$$ value is less than 0.2, it could be interpreted as indicating that 95% of the biochar is inertinite. While this simplification has been suggested by experts and holds promise, it is currently considered insufficiently rigorous due to a lack of supporting evidence and clear guidance.

### Uncertainty assessment <a href="#dk35zb8m2b1p" id="dk35zb8m2b1p"></a>

An uncertainty assessment is presented below for all aspects of GHG quantification set **at the methodology level**. The findings from this assessment are then applied **at the project level**, where project-specific GHG quantification also undergoes an uncertainty assessment.

The **overall project GHG quantification uncertainty** is determined by qualitatively combining both the methodology-level and project-specific uncertainties for each identified source of uncertainty.

The three assumptions presented in the [Assumptions ](#assumptions)section have moderate uncertainty, but the most conservative approach is taken in the quantifications.

The baseline scenario selection (if applicable) has low uncertainty, because the specific circumstances, amount and type of baseline horticultural material avoided must be proven by the Project Developer.

The equations and models have moderate uncertainty. The model for 100-year permanence from [Woolf et al., 2021](#user-content-fn-10)[^10] has moderate uncertainty because it is a model fitted to experimental data, which always introduces variability. The equations for 1000-year permanence from [Sanei et al., 2024](#user-content-fn-13)[^13] have low uncertainty because they are basic conversion equations.

The uncertainty at the methodology level is estimated to be low. This translates to an **expected discount factor of at least 3%** for projects under this methodology.

## Sampling and measurements

The following indicators shall be measured for each production batch:

* $$H/C\_{\text{org}}$$
* Carbon content (organic and/or total)
* moisture content
* random reflectance and residual organic carbon (only if applying for 1000-year permanence)

Measurements shall be performed by laboratories with at least one quality assurance accreditation, such as:

* ISO/IEC 17025
* CEN/TS 17225-1
* ISO 10694

Unaccredited laboratories from academic settings shall be evaluated on a case by case basis by the VVB and the Rainbow Certification Team.

The sampling procedure detailed in sections below and summarized in Figure 1 is the **recommended approach** for representative sampling. However, Project Developers may implement their own approach if it is detailed in the PDD and in Sampling Records; ensures one representative sample per production batch; addresses samples and composite samples amount and frequency; and ensures homogenization. The VVB and the Rainbow Certification team must validate the rigor and representativeness of the proposed sampling approach.

The recommended approach sampling requirements are based on the following sources:

* [EU Fertilising Products Regulation (EU) 2019/1009](#user-content-fn-16)[^16]
* [European Biochar Certificate Guidelines Annex 4 Representative Sampling](#user-content-fn-17)[^17]

<figure><img src="/files/8TKqusGoWfuUoKr1v4uc" alt=""><figcaption><p>Figure 1: The Rainbow recommended sampling approach is summarized here, and detailed in the text in following sections.</p></figcaption></figure>

#### Representative sampling

One **representative sample per Production Batch** shall be created and sent for laboratory testing. This sample ensures that any within-batch variability is captured in the measurements.

Table 1 details the number of composite samples that shall be taken per Production Batch to obtain one representative sample, based on the [EU Fertilising Products Regulation (EU) 2019/1009](#user-content-fn-16)[^16].

The representative sample size should be be 24 liters \* the *n* number of composite samples per Production Batch detailed in Table 1.

*Table 1 Recommendations for the number of composite samples of biochar to take, based on the site's annual biochar production output.*

| Annual output (tonnes) | Composite samples per Production Batch (n) |
| ---------------------- | ------------------------------------------ |
| ≤ 3 000                | 4                                          |
| 3 001 – 10 000         | 8                                          |
| 10 001 – 20 000        | 12                                         |
| 20 001 – 40 000        | 16                                         |
| 40 001 – 60 000        | 20                                         |
| 60 001 – 80 000        | 24                                         |
| 80 001 – 100 000       | 28                                         |

The [European Biochar Certificate Guidelines Annex 4 Representative Sampling](#user-content-fn-17)[^17] should be followed for **taking composite samples**. Those requirements are summarized below.

{% tabs %}
{% tab title="Continuous production" %}

* The first sample must be taken within 7 days of the start of the Production Batch.
* To prepare **one sample**, 8 sub-samples of 3 liters each are taken at intervals of at least one hour directly at the discharge of the freshly produced material. This shall be repeated for three consecutive days.
* The 24 samples are combined to form one composite sample.
  {% endtab %}

{% tab title="Non-continuous production" %}

* The first sample must be taken within 7 days of the start of the Production Batch.
* Samples may be taken from a well-mixed pile of biochar produced within the last 7 days.
* The amount of biochar used for one sample shall be equivalent to at least one day's production.
* 24 sub-samples of 3 liters each shall be taken from different spots in the pile.
* The 24 subsamples are combined to form one composite sample.
  {% endtab %}
  {% endtabs %}

#### Homogenization

The representative sample shall be homogenized by the Project Developer or by the laboratory that performs testing. The biochar shall be ground to a size of <3 mm.

The ground sample is mixed by shoveling the pile three times from one pile to another.

A sub-sample of 1.5 liters shall be taken from 15 spots in the mixed pile.

The 15 sub-samples are re-combined, and then mixed by shoveling the pile three times from one pile to another.

From the mixed pile of the combined sub-samples, 15 subsamples of 150 ml each should be taken at 15 different spots in the pile and combined. This combined homogenized representative cross sample is used for laboratory testing.

#### Retention samples

A one-liter retention sample shall be collected each day that biochar is produced. These samples should be combined for storage over the calendar month. Retention samples must be stored for a minimum of two years.

#### Sampling records

For **each Production Batch**, Project Developers shall submit a **Sampling Record** for verification to prove their adherence to the requirements above. Sampling Records shall include the following information for each sample taken:

* Date of sampling
* Amount of biochar sampled
* Description of representative sampling process (either followed the recommended approach, or describe the individual approach)
* Sample ID
* Visual description and observation of biochar
* Description of any potential anomalies
* Proof of retention sampling (if performed for that Production Batch)
* Photos showing the date, sample ID, and amount of biochar that is included in the present Sampling Record

## Appendix

The table below presents a non-exhaustive selection of Ecoinvent activities that may be used in the GHG reduction calculations for this module. Additional activities may be used for any project, if the following selection does not cover all relevant activities.

*Table A1 List of ecoinvent 3.12 processes used in the GHG reduction quantification model, all processes are from the cutoff database*

<table><thead><tr><th width="300">Input</th><th>Ecoinvent activity name</th></tr></thead><tbody><tr><td>Peat moss</td><td>peat moss production, horticultural use, RoW</td></tr><tr><td>Perlite</td><td>expanded perlite production, CH</td></tr><tr><td>Lime</td><td>market for lime, RER</td></tr><tr><td>Nitrogen mineral fertilizer</td><td>market for inorganic nitrogen fertiliser, as N, country specific</td></tr><tr><td>Phosphorus mineral fertilizer</td><td>market for inorganic phosphorus fertiliser, as P2O5, country specific</td></tr><tr><td>Potassium mineral fertilizer</td><td>market for inorganic potassium fertiliser, as K2O, country specific</td></tr><tr><td>Mineral NPK fertilizer #1</td><td>market for NPK (26-15-15) fertiliser, RER</td></tr><tr><td>Mineral NPK fertilizer #2</td><td>market for NPK (15-15-15) fertiliser, RER</td></tr></tbody></table>

## Risk assessment template

This module uses the risk assessment template version 1.0.&#x20;

:point\_right: Download the template [here](https://docs.google.com/spreadsheets/d/1URp_Bn8_WLXwN1_oub3Y5yhsZCJw-r-OaxTWT7FHuNc/edit?usp=sharing).&#x20;

{% embed url="<https://docs.google.com/spreadsheets/d/1URp_Bn8_WLXwN1_oub3Y5yhsZCJw-r-OaxTWT7FHuNc/edit?usp=sharing>" %}

## Version history

This page describes the changes in the Biochar application to soils module.

Because this module is considered the V2.0 of the Rainbow BECCS and Biochar V1.0 methodology, the table below also includes changes from the Rainbow BECCS and Biochar V1.0 methodology that are covered in other modules (e.g. [Biomass feedstock](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock)).

<table data-full-width="false"><thead><tr><th width="322.80078125">Description of the change</th><th width="223.83984375">Justification</th><th width="117.15625">Date</th><th width="101.0859375">Version changed to</th></tr></thead><tbody><tr><td>Restructure sections: added Baseline Scope, renamed Eligible technologies to Eligibility and scope, renamed Eligibility criteria to Principles &#x26; requirements, moved Monitoring Plan to Principles &#x26; requirements</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Remove TRL, move Substitution criteria requirements to Baseline Scope section</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>New Certification Scope section with requirements for crediting and monitoring period, project updates with methodology revisions, and site audits.</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Remove limits on number of co-benefits, and require quantification and monitoring of all co-benefits</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Environmental and social risk mitigation plan required for moderate or higher risks, instead of high risk</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Remove project-level reversal risk assessment requirements</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Remove ex-ante validation section</td><td>Align with Standard Rules V7 requirements</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Change GHG quantification from ecoinvent v3.11 to v3.12 (average change of 0.04±0.2% decrease in total net removals)</td><td>Using more recent version of database</td><td>January 2026</td><td>V2.2 to V2.3</td></tr><tr><td>Specify residual organic carbon measurements needed for 1000-year removal claims</td><td>Provide clearer and more comprehensive instructions</td><td>July 2025</td><td>V2.2</td></tr><tr><td>Re-introduce 100-year carbon degradation model equations based on soil temperature</td><td>Aligning with common biochar modeling practices.</td><td>March 2025</td><td>V2.1</td></tr><tr><td>Changed pollutant requirements from European Biochar Certificate (EBC) thresholds to World Biochar Certificate (WBC) thresholds</td><td>Adding more projects outside Europe, more reasonable and feasible to hold them to worldwide best standards, not European</td><td>March 2025</td><td>V2.1</td></tr><tr><td>Added equations for calculation GHG reductions</td><td>Increased transparency.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Aligned terminology with ISO 14064-2:2019</td><td>Improved consistency with the voluntary carbon market. LCA principles still apply.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Added risk assessment template for environmental and social do no harm</td><td>Provide more detailed and prescriptive assessment framework, clearer instructions for project developers.</td><td>September 2024</td><td>V2.0</td></tr><tr><td><p>Removed text for sections that are the same for all methodologies:</p><ul><li>Measurability</li><li>Real</li><li>Additionality</li><li>Technology readiness level</li><li>Minimum impact</li><li>Independently verified</li></ul></td><td>Repeated text from the Standard Rules.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Added Monitoring Plan section</td><td>Alignment with Rainbow Standard Rules V6.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Remove Rebound Effect and Independently Validated criteria</td><td>Alignment with Rainbow Standard Rules V6.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Added uncertainty assessment section</td><td>Alignment with Rainbow Standard Rules V6.</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Infrastructure and machinery quantification expanded and specified, simple option added</td><td>Simplification, results not sensitive to impacts</td><td>September 2024</td><td>V2.0</td></tr><tr><td>New Leakage requirements</td><td>More rigorous eligibility criteria, and clear requirements and instructions for Project Developers</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Allow option for 1000 year removals, measurement of random reflectance</td><td>Updated research</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Added verification of end use reports</td><td>Increased rigor to ensure biochar is used as claimed</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Added precise sampling requirements</td><td>Provide Project Developers with clear expectations, ensure representative sampling</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Allow option to monitor data and quantify GHGs per production batch</td><td>Facilitate data collection and reporting for Project Developers</td><td>September 2024</td><td>V2.0</td></tr><tr><td>Biomass feedstock shall only be waste and biomass cultivated from sustainable production is not allowed</td><td>Increased stringency, following best practice and scientific recommendations</td><td>September 2024</td><td>V2.0</td></tr></tbody></table>

[^1]: *EBC (2012-2023) 'European Biochar Certificate - Guidelines for a Sustainable Production of Biochar.' Carbon Standards International (CSI), Frick, Switzerland. (<http://european-biochar.org>). Version 10.3 from 5th Apr 2022.*

[^2]: * Rodrigues, L., Budai, A., Elsgaard, L., Hardy, B., Keel, S.G., Mondini, C., Plaza, C., Leifeld, J., 2023. The importance of biochar quality and pyrolysis yield for soil carbon sequestration in practice. European Journal of Soil Science 74, e13396. [https://doi.org/10.1111/ejss.1339](https://doi.org/10.1111/ejss.13396)
    * Rudra, A., Petersen, H.I., Sanei, H., 2024. Molecular characterization of biochar and the relation to carbon permanence. International Journal of Coal Geology 291, 104565. <https://doi.org/10.1016/j.coal.2024.104565>
    * Wang, J., Xiong, Z., Kuzyakov, Y., 2016. Biochar stability in soil: meta-analysis of decomposition and priming effects. GCB Bioenergy 8, 512–523. <https://doi.org/10.1111/gcbb.12266>
    * Sanei, H., Rudra, A., Przyswitt, Z.M.M., Kousted, S., Sindlev, M.B., Zheng, X., Nielsen, S.B., Petersen, H.I., 2024. Assessing biochar’s permanence: An inertinite benchmark. International Journal of Coal Geology 281, 104409. <https://doi.org/10.1016/j.coal.2023.104409>

[^3]: Inertinite is a type of maceral. Macerals are the organic compounds in materials like coal and shale, and are extremely permanent. They are analogous to mineral carbon in rocks.

[^4]: * Schmidt, H.-P., Kammann, C., Hagemann, N., Leifeld, J., Bucheli, T.D., Sánchez Monedero, M.A., Cayuela, M.L., 2021. Biochar in agriculture – A systematic review of 26 global meta-analyses. GCB Bioenergy 13, 1708–1730.[ https://doi.org/10.1111/gcbb.12889](https://doi.org/10.1111/gcbb.12889)
    * Joseph, S., Cowie, A.L., Van Zwieten, L., Bolan, N., Budai, A., Buss, W., Cayuela, M.L., Graber, E.R., Ippolito, J.A., Kuzyakov, Y., Luo, Y., Ok, Y.S., Palansooriya, K.N., Shepherd, J., Stephens, S., Weng, Z. (Han), Lehmann, J., 2021. How biochar works, and when it doesn’t: A review of mechanisms controlling soil and plant responses to biochar. GCB Bioenergy 13, 1731–1764.[ https://doi.org/10.1111/gcbb.12885](https://doi.org/10.1111/gcbb.12885)

[^5]: Goddin, J., Marshall, K., Pereira, A., Tuppen, C., Herrmann, S., Jones, S., Krieger, T., Lenges, C., Coleman, B., Pierce, C., Iliefski-Janols, S., Veenendaal, R., Stoltz, P., Ford, L., Goodman, T., Vetere, M., Mistry, M., Graichen, F., Natarajan, A., Sullens, W., 2019. Circularity Indicators: An Approach to Measuring Circularity, Methodology. <https://doi.org/10.13140/RG.2.2.29213.84962>

[^6]: Ellen Macarthur Foundation, ANSYS Granta, 2019. An approach to measuring circularity. Published in 2015, adapted in 2019. [URL](https://emf.thirdlight.com/link/3jtevhlkbukz-9of4s4/@/preview/1?o)

[^7]: WBC (2023): World Biochar Certificate – Guidelines for a Sustainable Production of Biochar and its Certification.' Carbon Standards International, Frick, Switzerland, (<http://www.european-biochar.org>), version 1.1 from 20th December 2024. [URL](https://www.carbon-standards.com/en/standards/service-514~production-of-biochar.html).

[^8]: The coordinates are used by Rainbow Certification Team to obtain the average soil temperature (°C) where the biochar is spread.

[^9]: Wernet, G., Bauer, C., Steubing, B., Reinhard, J., Moreno-Ruiz, E., Weidema, B., 2016. The ecoinvent database version 3 (part I): overview and methodology. Int J Life Cycle Assess 21, 1218–1230. <https://doi.org/10.1007/s11367-016-1087-8>

[^10]: Woolf, D., Lehmann, J., Ogle, S., Kishimoto-Mo, A.W., McConkey, B., Baldock, J., 2021. Greenhouse Gas Inventory Model for Biochar Additions to Soil. Environmental Science & Technology 55, 14795–14805.[ https://doi.org/10.1021/acs.est.1c02425](https://doi.org/10.1021/acs.est.1c02425)

[^11]: IPCC 2019. Appendix 4 Method for Estimating the Change in Mineral Soil Organic Carbon Stocks from Biochar Amendments: Basis for Future Methodological Development. 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 4 Agriculture, Forestry and Other Land Use. [URL](https://www.ipcc-nggip.iges.or.jp/public/2019rf/pdf/4_Volume4/19R_V4_Ch02_Ap4_Biochar.pdf).

[^12]: Lembrechts et al., Global maps of soil temperature (2021). Global Change Biology. DOI: [10.1111/gcb.16060](https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16060). [URL](https://zenodo.org/records/7134169).

[^13]: Sanei, H., Rudra, A., Przyswitt, Z.M.M., Kousted, S., Sindlev, M.B., Zheng, X., Nielsen, S.B., Petersen, H.I., 2024. Assessing biochar’s permanence: An inertinite benchmark. International Journal of Coal Geology 281, 104409[ https://doi.org/10.1016/j.coal.2023.104409](https://doi.org/10.1016/j.coal.2023.104409)

[^14]: International Committee for Coal and Organic Petrology (ICCP), 2001. The new inertinite classification (ICCP System 1994). Fuel 80, 459–471.[ https://doi.org/10.1016/S0016-2361(00)00102-2](https://doi.org/10.1016/S0016-2361\(00\)00102-2)

[^15]: determined by e.g. thermogravimetric analysis (TGA) or Rock-Eval 6

[^16]: Regulation (EU) 2019/1009 of the European Parliament and of the Council of 5 June 2019 laying down rules on the making available on the market of EU fertilising products and amending Regulations (EC) No 1069/2009 and (EC) No 1107/2009 and repealing Regulation (EC) No 2003/2003 (Text with EEA relevance), 2024. [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02019R1009-20240703)

[^17]: EBC (2012-2025) ‘European Biochar Certificate – Guidelines for a Sustainable Production of Biochar.’ Carbon Standards International (CSI), Frick, Switzerland.\
    Version 10.5E from 14th August 2025 [URL](https://www.carbon-standards.com/en/standards/service-492~production-of-biochar.html).


# Bio-oil in asphalt

| **Module name**      | Bio-oil in asphalt                         |
| -------------------- | ------------------------------------------ |
| **Module category**  | Carbon storage                             |
| **Methodology name** | Biomass carbon removal and storage (BiCRS) |
| **Version**          | 1.0                                        |
| **Methodology ID**   | RBW-BICRS-CS-BOIL                          |
| **Release date**     | May 28th , 2026                            |
| **Status**           | Public Consultation                        |

<details>

<summary>Glossary</summary>

|                       |                                                                                                                                                                                                       |
| --------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Crude bio-oil**     | Bio-oil extracted from pyrolysis, that has not been treated                                                                                                                                           |
| **Processed bio-oil** | Crude bio-oil that has been treated to remove water and volatile organic compounds.                                                                                                                   |
| **Bio-bitumen**       | Bio-based binder derived from non-petroleum sources such as bio-oils, lignin, or other organic materials. Used to replace fossil bitumen in asphalt production or as sealant.                         |
| **Fossil bitumen**    | Viscous, black hydrocarbon material refined from crude oil, widely used as a binder in asphalt pavements and as a sealant.                                                                            |
| **Asphalt**           | Composite construction material consisting of mineral aggregates (gravel, sand, crushed stone) bound together with bitumen, used predominantly for road surfacing, airport runways, and parking lots. |

</details>

This is a **Carbon Storage Module** and covers the production of bio-oil and its use in asphalt. This module is part of the Rainbow BiCRS methodology, which allows Project Developers to choose the relevant modules for their project, and shall be used with the necessary accompanying modules.

See more details on how modules are organized in the [BiCRS home page](/methodologies/biomass-carbon-removal-and-storage-bicrs#efpqng3v3ute).

<table data-view="cards" data-full-width="false"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="files"></th></tr></thead><tbody><tr><td><strong>How to use this module</strong></td><td></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo#efpqng3v3ute">/pages/Jy6o8q5Q31d2U0OK7Yuo#efpqng3v3ute</a></td><td><a href="/files/0zYtLJBdzIemkx7iKe9C">/files/0zYtLJBdzIemkx7iKe9C</a></td></tr><tr><td><strong>BiCRS Methodology</strong></td><td></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo">/pages/Jy6o8q5Q31d2U0OK7Yuo</a></td><td><a href="/files/4B3R2CjT9hA3bBYbzz1a">/files/4B3R2CjT9hA3bBYbzz1a</a></td></tr></tbody></table>

## Eligibility and scope <a href="#uikucys7r1rk" id="uikucys7r1rk"></a>

### Eligible technologies

This module covers projects that

* use waste and residual biomass as feedstock, according to the [Biomass feedstock](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock) module; and
* meet all of the following bio-oil requirements:

<table data-view="cards"><thead><tr><th></th><th></th></tr></thead><tbody><tr><td><strong>Bio-oil production</strong></td><td><ul><li>Heat biomass to at least <strong>350°C</strong> during production.</li><li>Capture or cleanly burn pyrolysis gasses, as outlined in the <a href="/pages/BTxxPIM3a4Nai1Wkwu2Y#environmental-and-social-do-no-harm">Processing and Energy Use</a> module.</li><li>Report methane emissions from pyrolysis, using the <a href="/pages/BTxxPIM3a4Nai1Wkwu2Y#environmental-and-social-do-no-harm">Processing and Energy Use</a> module.</li></ul></td></tr><tr><td><strong>Bio-oil</strong> <strong>processing</strong></td><td><ul><li>Treatment of crude bio-oil to remove water and volatile organic components according to the <a href="#kmzukpswu89">Risk mitigation</a> section</li><li>Use processed bio-oil to produce bio-bitumen meeting the <a href="/pages/glF3KEBaQeSfSCpDN62Y#product-use-phase">Product use phase</a> and <a href="#id-82n4j72vjt9v">Environmental and social safeguards</a> requirements</li></ul></td></tr><tr><td><strong>Bio-oil end use</strong></td><td><ul><li>Use bio-bitumen in the eligible permanent end use: asphalt.</li></ul></td></tr></tbody></table>

Projects may be designed to prioritize biochar or bioenergy production, where bio-oil is the co-product of the pyrolysis. Such projects may still be eligible for removal Rainbow Carbon Credits under this module, if they meet all criteria outlined herein.

This module allows for issuance of **removal RCCs on the basis of bio-oil end use/delivery**, i.e. incorporation as bio-bitumen into asphalt, not on the basis of bio-oil production.

**Eligible end uses of bio-oil** under this methodology are limited to the production of bio-bitumen and its use in asphalt for road construction or paving of other areas (e.g. parking lots, airport runways, docks). Any other use of the bio-oil (e.g. as fuel) or of the bio-bitumen (e.g. in roofing applications or for sealing and insulating purposes) is not eligible.

The Project Developer and entity eligible for receiving carbon finance is the operator of the bio-oil production site. Pyrolysis and gasification equipment manufacturers or users of the bio-oil (e.g. bio-bitumen producers that do not produce the bio-oil, road construction companies) are not eligible Project Developers.

### Certification requirements

Certification requirements for this module are defined in the [BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#certification-requirements). These cover crediting period duration, monitoring period duration, site audits, and versioning and project compliance.

### Project scope

One project is defined as:

* the operation of one or more pyrolysis units, across one or more sites,
* within a single country,
* using similar types of pyrolysis units,
* operated at sites that are under the oversight or data access of a single Project Developer, regardless of whether the developer directly owns or manages each site.

The project scope is cradle-to-grave and includes all processes that result from bio-oil production and use. This includes but is not limited to the following: all removals from bio-oil production, and all induced emissions related to biomass sourcing, leakage, upstream and downstream transport, embodied emissions from infrastructure and machinery, and onsite processing and energy use emissions from biomass conversion, bio-oil processing, and bio-bitumen production.

Any processes that would have occurred regardless of the bio-oil production and usage activities may be excluded from the project scope.

### Baseline scope

The baseline for **RCCs from bio-oil carbon removal shall** include any permanent carbon removal that would have occurred in the absence of the project. This includes but is not limited to permanent carbon storage from the alternate fate of the biomass feedstock used for pyrolysis. It shall be assumed by default that no biomass feedstock would have been used to produce bio-oil in the absence of the project (i.e. there is no share of the project activity in the baseline scenario).

#### **Product use phase**

To reduce the environmental impact of asphalt production, bio-oil derived bio-bitumen has been proposed as a **renewable substitute** for fossil bitumen. Project Developers shall identify the type of conventional bitumen and its function that the project's bio-bitumen replaces (e.g. paving grade bitumen, penetration grade bitumen, cutback bitumen, ...). They shall justify that the project's bio-bitumen meets the same quality and performance standards as the conventional bitumen it replaces, considering

* penetration
* softening point
* viscosity
* other relevant performance characteristics related to bio-bitumen use in asphalt

Project Developers shall prove this using representative test results from pilot testing, R\&D laboratories, or full-scale operations.

Project Developers shall ensure compliance of the bio-bitumen with relevant national/regional or industry standards for bitumen (often referred to as binder) in road construction (e.g. [EN 12591:2009](#user-content-fn-1)[^1], [ASTM D946](#user-content-fn-2)[^2]). This shall also include compliance with hazard classification and pollutant levels for bitumen in road construction, as detailed in the [Environmental and social safeguards](#id-82n4j72vjt9v) section.

Compliance shall be demonstrated **once per** [**bio-bitumen batch**](#user-content-fn-3)[^3] (see [Production batches](#id-2xck12gc2auz) for further details on the batch definition).

The baseline scenario **structure** remains valid for the entire crediting period but may be significantly revised earlier if:

* The Project Developer notifies Rainbow of a substantial change in project operations or baseline conditions, and/or
* The methodology is revised, affecting the baseline scenario.

The **specific values** within the baseline scenario will be updated during each crediting period, using project data to accurately reflect the equivalent of the project’s operations.

### Production batches <a href="#id-2xck12gc2auz" id="id-2xck12gc2auz"></a>

A production batch is the [**processed bio-oil**](#user-content-fn-4)[^4] **produced under the same conditions** regarding

* biomass feedstock mix,
* pyrolysis temperature,
* processing of the crude bio-oil (i.e. removal of water and volatile organic compounds, see [Reversal risk assessment](#reversal-risk-assessment) section below).

It is assumed that all bio-oil from the same production batch has similar characteristics (i.e. thermally stable fraction, organic carbon content).

Pyrolysis temperature and biomass feedstock composition must not change by more than 20%.

Measurements and reporting are performed at the **production batch level**. Verification and credit issuance may be done per production batch, or annually on the cumulative production batches from that year.

{% hint style="info" %}
For example, if the declared pyrolysis temperature is 600°C, temporary fluctuations between 480 °C and 720°C are acceptable.

If a mixture of 50% tree clippings and 50% nut shells is pyrolyzed, the proportions can vary between 40% and 60% (±10% of the original 50%)
{% endhint %}

A production batch has a **maximum validity of 365 days**, after which bio-oil shall be considered part of a different production batch even if conditions are unchanged. In other words, the production batch ID number resets and a new production batch is created, and new monitoring requirements applied, after 365 days, regardless of if feedstock, pyrolysis conditions or processing steps change or not.

#### Bio-bitumen batch

A bio-oil production batch may be used to produce one or more bio-bitumen batches. A bio-bitumen batch is defined as all bio-bitumen produced from the **same bio-oil batch** using the same type and amount of additives and the same production conditions (e.g. temperature, mixing time).

Amount and additive composition must not change by more than 20%.

A single bio-oil batch may be turned into multiple bio-bitumen batches if additives or processing conditions change, or correspond to a single bio-bitumen batch if conditions remain unchanged.

## Principles & requirements

The principles and requirements specific to this module are detailed in the sections below. Other principles and requirements shall be taken from the accompanying modules and methodologies:

<table data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="files"></th></tr></thead><tbody><tr><td><strong>BiCRS methodology</strong></td><td><ul><li>Additionality</li><li>No double counting</li><li>Environmental and social safeguards</li></ul></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo">/pages/Jy6o8q5Q31d2U0OK7Yuo</a></td><td><a href="/files/4B3R2CjT9hA3bBYbzz1a">/files/4B3R2CjT9hA3bBYbzz1a</a></td></tr><tr><td><strong>Other modules</strong></td><td><ul><li>Co-benefits</li><li>No double counting</li><li>Environmental and social safeguards</li><li>Leakage</li></ul></td><td></td><td><a href="/pages/eQTO2zpdCEv368f4bRT6">/pages/eQTO2zpdCEv368f4bRT6</a></td><td><a href="/files/CxuE4U5JkYE63biLhW6k">/files/CxuE4U5JkYE63biLhW6k</a></td></tr></tbody></table>

### Durability <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

#### Durability threshold

All projects certified under this module shall prove **durable carbon removals from bio-oil** **for at least 100 years**.

#### Reversal risk assessment

This module covers the production of bio-oil derived bio-bitumen and its use in asphalt.

Asphalt is a composite paving material consisting of mineral aggregates like gravel, crushed stone, and sand, bound together by bitumen, a dark, viscous petroleum-derived binder. It is also referred to as asphalt concrete or blacktop.

Asphalt, more precisely the bitumen in it, **ages continuously from the moment of production**, through mixing and laying, and throughout decades of road service through three main mechanisms:

* distillative aging: The **low-boiling components of the bitumen evaporate,** mainly during hot mixing and paving (*hot mix asphalt*, HMA, up to 190°C) but also to a small extent at elevated temperatures in the use phase.
* oxidative[^5] aging:
* structural[^6] aging:

**Distillative aging** is the most relevant risk of non-permanence for credited carbon removals, as it results in the release of carbon-containing molecules.

Hence, the major carbon reversal risks from bio-oil to bio-bitumen for asphalt are:

1. **Distillative aging of bio-bitumen**, where light organic compounds in the bio-oil used for bio-bitumen production vaporize during the production and use-phase of asphalt due to elevated temperatures, resulting in release of stored carbon.
2. **Failure to durably incorporate bio-oil into asphalt**, where bio-oil does not end up in a durable storage matrix (i.e. as bio-bitumen for asphalt production) and is instead lost or degraded due to inappropriate use (e.g. as fuel) or storage.

This module establishes the following mandatory project design requirements to mitigate these risks, detailed in the following sections:

* using only the thermally stable fraction of bio-oil for crediting
* proof of thermal stability of bio-oil
* verification of bio-oil end use

Upon meeting these requirements for each verification and credit issuance, the risk of reversal is considered **negligible** for bio-bitumen for asphalt mixes. There are no further project requirements to assess reversal risks or conduct post-crediting monitoring for reversals.

All projects certified under this module shall contribute the default minimum 2% of their verified removal RCCs to the Rainbow Buffer Pool, as defined in the Rainbow Standard Rules.

#### Risk mitigation: Thermally stable fraction for crediting <a href="#kmzukpswu89" id="kmzukpswu89"></a>

Not all biomass carbon converted to bio-oil during the pyrolysis is expected to remain durably stored when used as bio-bitumen for asphalt. Only the **thermally stable, heavy fraction is considered durable and eligible for crediting**, as it will not vaporize under the production, use, and recycling conditions of asphalt, which are expected to reach a maximum temperature of 190°C (for hot-mix asphalt).

Project Developers shall demonstrate that all water and volatile organic compounds (VOC) are removed from the crude bio-oil before transforming it into bio-bitumen. This shall be demonstrated by:

* distillation at 200°C; or
* alternative technologies that demonstrate that the remaining organic carbon in bio oil is resistant to temperatures up to 200°C are evaluated on a case-by-case basis.

The organic carbon content of the resulting thermally stable fraction of the bio-oil, hereafter referred to as **processed bio-oil** as opposed to crude bio-oil, shall be measured by elemental analysis and used in the [GHG quantification](#ghg-quantification) section to calculate the total carbon removals of the project.

#### Risk mitigation: Proof of thermal stability of bio-oil <a href="#kmzukpswu89" id="kmzukpswu89"></a>

To cross-validate the successful removal of water and VOC and prove the thermal stability of the processed bio-oil, Project Developers shall conduct the following measurement:

* **Thermogravimetric Analysis (TGA)** under inert gas (e.g. Nitrogen) atmosphere and up to a minimum temperature of 300°C. The cumulative weight loss up to **200°C i**s assumed to be 100% carbon and deducted from the gross carbon removal in Equation 2. Where cumulative weight loss up to 200°C exceeds 5%, the bio-oil batch is not eligible for crediting. Project Developers shall explain the source of any weight loss up to 200°C. See [sampling and measurements](#sampling-and-measurements) section for more details.

These measurements shall be conducted at **validation** and **repeated for every new production batch.**

Limiting RCC issuance to the processed bio-oil carbon mitigates re-emission risks during asphalt production and use.

#### Risk mitigation: Proof of bio-oil end use <a href="#id-5a8ye61po9ri" id="id-5a8ye61po9ri"></a>

Project Developers shall prove that all processed bio-oil has been used in the intended durable storage application (i.e. as bio-bitumen in asphalt). This shall be done in **Bio-oil Use Verification Reports** that contain all of the following:

* Details of the bio-bitumen production, specifying bio-bitumen batch ID, the type and amount of additives used, the production conditions (e.g. temperature, mixing time) and the , and corresponding Production Batch ID of the processed bio-oil used.
* Sales and/or delivery records of the bio-bitumen to asphalt production companies, specifying the date, amount of bio-bitumen and corresponding bio-oil Production Batch ID.
* Signed agreements with the buyer/user of the bio-bitumen, specifying that the bio-bitumen is solely used is asphalt production and not for any other, ineligible use (e.g. roofing, waterproofing).
* Company name and individual contact information for each buyer/user of bio-bitumen, for traceability and random checking by VVBs.

Issuing removal RCCs only after verified incorporation into a permanent storage matrix mitigates the risk that bio-oil is burned, destroyed or used in other, non-permanent end-uses, and the carbon stored in the bio-oil re-emitted.

### No double counting

Project Developers shall sign the [Rainbow MRV & Registry Terms & Conditions](https://docs.rainbowstandard.io/~/changes/229/other/terms-and-contracts/terms-and-conditions-for-project-developers-mrv-+-registry), committing to follow the requirements outlined in the [Rainbow Standard Rules](https://docs.rainbowstandard.io/~/changes/229/rainbow-standard-documents/rainbow-standard-rules), including not double using or double issuing carbon credits.

Project Developers shall prove that they hold the sole ownership of the carbon removal in the asphalt, and that other parties involved in the supply chain (e.g. asphalt mixing company) do not. This includes ensuring that no other party claims the carbon removal through Environmental Product Declarations (EPDs), product-level marketing, or corporate greenhouse gas reporting.

### Co-benefits <a href="#id-8f3i2uvmiuhl" id="id-8f3i2uvmiuhl"></a>

Projects should support at least two **quantifiable and verifiable** environmental or social co-benefits, aligned with the [UN Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDGs) framework. Any co-benefits claimed by the Project Developer shall be **quantified, monitored, and audited** for each verification and credit issuance.

Common co-benefits under this methodology are detailed in the table below. Project Developers may suggest and prove other co-benefits not mentioned here.

SDG 13 on Climate Action by default is not considered a co-benefit here, since it is implicitly accounted for in the issuance of carbon credits. If the project delivers climate benefits that are not accounted for in the GHG reduction quantifications, then they may be considered as co-benefits.

*Table 1 Common co-benefits that projects under this methodology may provide are detailed, including types of proof that can be used to justify each co-benefit.*

<table><thead><tr><th width="200">UN SDG</th><th width="345">Example</th><th>Proof</th></tr></thead><tbody><tr><td><strong>SDG 9.4:</strong> Upgrade infrastructure to make them sustainable</td><td>The use of bio-bitumen in asphalt production replaces fossil bitumen, thereby avoiding/reducing GHG emissions from asphalt production.</td><td>Verification of end use of bio-oil</td></tr><tr><td><strong>SDG 12.2:</strong> Achieve the sustainable management and efficient use of natural resources</td><td>The use of bio-bitumen in asphalt production replaces fossil bitumen, thereby reducing the extraction of and the reliance on non-renewable resources</td><td>Verification of end use of bio-oil</td></tr><tr><td><strong>SDG 12.2:</strong> Achieve the sustainable management and efficient use of natural resources</td><td>Sustainable reuse of biomass, avoiding open field burning of biomass or landfilling.</td><td>Type of feedstock used, verification of end use of bio-oil</td></tr></tbody></table>

### Environmental and social safeguards <a href="#id-82n4j72vjt9v" id="id-82n4j72vjt9v"></a>

Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.**

Projects must follow all national, local, and European (if located in Europe) environmental regulations, including but not limited to those related to pyrolysis, gasification, waste feedstock management, and bitumen and asphalt performance and pollutant thresholds.

#### Hazard comparability assessment

Project Developers shall demonstrate that the bio-bitumen produced from the project's bio-oil is **not more hazardous** than the [conventional product it replaces](#baseline-scope).

The assessment shall be made for every [**bio-bitumen batch**](#user-content-fn-7)[^7] and compared against applicable regulatory classifications and thresholds for the equivalent conventional product. Where bio-bitumen does not meet the applicable requirements, the assessment may instead be applied to the final blended asphalt product, as set out below.

For the assessment, Project Developers shall:

* **Identify the counterfactual product.** The conventional product being replaced shall be identified (e.g. paving grade bitumen, penetration grade bitumen, cutback bitumen, ...) and its applicable [regulatory classification or hazard profile](#user-content-fn-8)[^8] documented.
* **Assess the hazard classification of the bio-bitumen.** The bio-bitumen shall be assessed against the same regulatory frameworks applicable to conventional bitumen. If a national or international bio-bitumen standard exists and is applicable, it shall be cited in preference to petroleum-bitumen standards. The assessment shall at minimum cover PAH content and [bitumen fume emissions](#user-content-fn-9)[^9]. If the bio-bitumen is classified as non-hazardous under those frameworks, the requirement is satisfied and no further assessment is required.
* **Where bio-bitumen does not meet the applicable requirements, apply the assessment to the final asphalt product.** Project Developers shall provide an explanation of why the bio-bitumen does not satisfy the requirements on a standalone basis. They may then instead apply the hazard assessment to the final traceable blended asphalt product in which the bio-bitumen is blended with conventional bitumen. The final asphalt product shall be assessed against the same regulatory thresholds applicable to conventional asphalt. If the final product meets those thresholds and is classified as non-hazardous, the requirement is satisfied.

{% hint style="info" %}
If intermediate products like bio-oil or bio-bitumen carry a hazard classification, this does not automatically disqualify a project.

For example:

* Bio-oil with elevated acidity may still yield compliant bio-bitumen if neutralization steps (e.g. lime addition) are documented and verified.
* Bio-bitumen classified as a hazardous substance may still yield non-hazardous asphalt if dilution in the final mix brings all regulated parameters below threshold.
  {% endhint %}

Acceptable evidence include

* Third-party certification of the final traceable product confirming that the product meets the applicable non-hazardous classification and/or that regulated parameters (e.g. PAH content, fume emission rate, leachate toxicity) are within permitted thresholds.
* Safety Data Sheet (SDS) documents for the project's bio-bitumen as supplied to the asphalt plant, and the finished asphalt mix incorporating it, with an explicit comparison of hazard classifications (GHS/CLP categories) showing the final product is equal to or less hazardous than the conventional product.

#### Environmental and social risk assessment

Project Developers shall fill in the [Rainbow bio-oil to bio-bitumen risk assessment](#risk-assessment-template), to evaluate the identified environmental and social risks of projects. The identified risks include:

* Worker injury or illness due to exposure to hazardous substances in the bio-oil and/or bio-bitumen
* Worker injury or illness due to exposure to hazardous fumes during bio-bitumen production
* Harm to human health and environment due to exposure to hazardous substances and fumes during use-phase of bio-oil
* Leaching of hazardous substances in bio-oil and /or bio-bitumen due to improper storage

The risk assessment also includes the identified risks from the [Biomass feedstock ](https://docs.rainbowstandard.io/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock)module and the risks from the [Processing and energy use](https://docs.rainbowstandard.io/modules/processing-and-energy-use) module relevant for this carbon storage module.

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

### Monitoring

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information **for each Production Batch**:

* Description of the pyrolysis conditions (temperature and residence time) and any variability in the process
* Description of the process to remove water and volatile organic compounds from the crude bio-oil
* Amount of crude bio-oil produced, in tonnes
* Amount of processed bio-oil produced, in tonnes
* Amount of processed bio-oil delivered, in tonnes: [Bio-oil Use Verification Reports](#id-5a8ye61po9ri)
* Organic carbon content of the processed bio-oil
* Cumulative weight loss up to 200°C of the processed bio-oil (TGA)
* [Sampling protocol](#representative-sampling)
* Bio-bitumen batches
  * Number of bio-bitumen batches produced from bio-oil production batch
  * Compliance with [Product use phase ](#product-use-phase)requirements
  * Compliance with [Environmental and social safeguards: Hazard assessment](#id-82n4j72vjt9v) requirements

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information **for each monitoring period**:

* Number of production batches
* Number of bio-bitumen batches
* Total amount of crude bio-oil produced per year, in tonnes
* Total amount of processed bio-oil per year, in tonnes
* Total amount of processed bio-oil delivered per year, in tonnes
* Co-benefits

Monitoring Plans shall include the following information for each monitored parameter:

* monitoring frequency
* emission sources and sinks
* data source
* measurement methods/procedures, and their accuracy and calibration
* quality assessment or quality control procedures
* responsible party for collecting and archiving data

## GHG quantification

The GHG quantification instructions from all other BiCRS modules used by the project must be used in conjunction with the present module in order to obtain full life-cycle GHG quantifications.

The system boundary of this quantification section starts at the recovery of crude bio-oil from the pyrolysis reaction, and ends at the delivery of bio-bitumen to the site of asphalt mixing.

**Quantification shall be done at a minimum for each bio-oil production batch**, and may be done more frequently for continuous issuance.

The following high-level equations shall be used to calculate carbon removals from bio-oil to asphalt projects.

<details>

<summary>Calculation <strong>removals</strong></summary>

Note that Eq. 1 and 2 have been taken directly from the [GHG Quantification section of the BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#ghg-quantification) and are included here to improve clarity.

$$\textbf{(Eq.1)}\ Net\ Removal = R\_{baseline}-R\_{project}-E\_{project}$$

where,

* $$Net\ Removal$$ represents the net removals from the project during the monitoring period, in tonnes of CO$$\_2$$eq. Its sign is positive.
* $$R\_{baseline}$$ represents any baseline GHG removals from the capture module(s), representing permanent storage that would have occurred in the absence of the project, in tonnes of CO$$\_2$$eq. Its sign is negative.
* $$R\_{project}$$ represents the project's gross GHG removals from the carbon capture module(s) used by the project, in tonnes of CO$$*2$$eq. Its sign is negative. In this module, $$R*{project}$$ is calculated using Eq. 4.
* $$E\_{project}$$ represents the project's total induced GHG emissions across the project life cycle, in tonnes of CO$$\_2$$eq. Its sign is positive.

$$\textbf{(Eq.2)}\ E\_{project} = {E}*{project,\ Capture} + {E}*{project,\ Transformation}+ {E}\_{project,\ Storage}$$

where,

* $$E\_{project}$$ was described in Eq. 1.
* $$E\_{project,\ Capture}$$ represents the project's GHG emissions from the capture module(s) used by the project.
* $$E\_{project,\ Transformation}$$ represents the project's GHG emissions from the transformation module(s) used by the project.
* $${E}\_{project,\ Storage}$$ represents the project's GHG emissions from the storage module(s) used by the project.

{% hint style="info" %}
See the Co-product allocation section in the [BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#co-product-allocation) and in [this module](#co-product-allocation) for further information on how baseline removals and project emissions are allocated between co-products (e.g. biochar and bio-oil)
{% endhint %}

GHG quantification is performed for each Production Batch, based on the amount of processed bio-oil, but removal Rainbow Carbon Credits (RCCs) are issued on the basis of processed bio-oil delivery and application in an eligible end use. The following equation is used to determine the number of RCCs to issue per monitoring period, accounting for **a potential delay in bio-oil use after production**. See the [Functional unit](#kpxsamb8logm) section for more details.

$$\textbf{(Eq.3)}\ Removal\ RCCs= \frac{Net\ removal}{tonne\ bio-oil\ produced} \times tonne\ bio-oil\ delivered$$

Where

* $$Removal\ RCCs$$ represents the number of removal credits to be issued at the end of the monitoring period.
* $$Net\ removal$$ is defined in the [GHG Quantification section of the BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#ghg-quantification).
* $$tonne\ bio-oil\ produced$$ represents the amount of processed **bio-oil produced** in the entire Production Batch.
* $$tonne\ bio-oil\ delivered$$ represents the amount of processed **bio-oil delivered in an eligible end use** in the monitoring period, for the given Production Batch.

</details>

### Functional unit <a href="#kpxsamb8logm" id="kpxsamb8logm"></a>

The functional unit shall be **1 tonne of processed bio-oil produced.**

Input data shall be provided for all processes related to bio-oil production in the given Production Batch, and net project removals are first calculated for **all processes across the entire duration of the Production Batch**.

This is normalized to net removals per functional unit by **dividing by the amount of processed bio-oil produced** in the Production Batch.

The number of credits to issue in the given monitoring period is calculated by multiplying the amount of processed bio-oil applied in an eligible end use (i.e. bio-bitumen for asphalt production), by the net removals per tonne of processed bio-oil produced.

This approach is detailed in Eq. 1-3 above .

### Data source

The required **primary data** for GHG reduction calculations from projects are presented in Table 2. These data shall be provided either for each monitoring period or each production batch, as indicted in the table, and made publicly available.

*Table 2 Summary of primary data needed from projects and their source for initial project certification and validation. All primary data sources listed here are required to be monitored and updated during verification (see Monitoring Plan section).*

<table><thead><tr><th width="249">Parameter</th><th>Unit</th><th>Source</th></tr></thead><tbody><tr><td>Total amount of crude bio-oil produced in the monitoring period</td><td>Tonnes</td><td>Internal tracking documents</td></tr><tr><td>Total amount of processed bio-oil produced in the monitoring period</td><td>Tonnes</td><td>Internal tracking documents</td></tr><tr><td>Total amount of processed bio-oil delivered as bio-bitumen to the asphalt producer in the monitoring period</td><td>Tonnes</td><td>Bio-oil use verification record</td></tr><tr><td>Amount of crude bio-oil produced per production batch</td><td>Tonnes</td><td>Internal tracking documents</td></tr><tr><td>Amount of processed bio-oil produced per production batch</td><td>Tonnes</td><td>Internal tracking documents</td></tr><tr><td>Amount of processed bio-oil delivered per production batch</td><td>Tonnes</td><td>Bio-oil use verification record</td></tr><tr><td>Organic carbon content of processed bio-oil per production batch</td><td>Fraction</td><td>Laboratory chemical analysis</td></tr><tr><td>Cumulative weight loss up to 200°C (TGA) of processed bio-oil per production batch</td><td>Fraction</td><td>Laboratory chemical analysis</td></tr></tbody></table>

No other secondary data sources are used in this module.

### Co-product allocation

The rules outlined at the methodology-level in the [BiCRS methodology document](/methodologies/biomass-carbon-removal-and-storage-bicrs) shall be applied for allocating baseline removals and induced GHG emissions from shared processes between pyrolysis co-products (e.g. biochar and bio-oil). This shall include at least the following:

* baseline removals from the [Biomass feedstock module](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock)
* emissions from
  * biomass transport
  * biomass processing
  * methane emissions
  * embodied emissions from infrastructure and machinery

All GHG emissions from processes **after the point of co-product generation** and solely serve the bio-oil are attributed in full to the bio-oil production. This shall include at least the following:

* crude bio-oil processing
* bio-bitumen production
* any transport, e.g. of bio-oil to bio-bitumen production facility, or of bio-bitumen to asphalt mixing company.

{% hint style="info" %}
For example, a project's produces both biochar and bio-oil via pyrolysis. The biochar and the bio-oil can be used for carbon removal and be issued removal RCCs. The total carbon storage from bio-oil is 400 tCO<sub>2</sub> eq (= 40%) and from biochar is 600 tCO<sub>2</sub> eq (= 60%).

**Baseline removals**

In the absence of the project, 10 tCO<sub>2</sub> eq would have remained stored in the soil due to biomass degradation. They are allocated to the co-products based on their total carbon storage capacity.

* Biochar, 60% of total carbon stored = 60% of baseline removals = 6 tCO<sub>2</sub> eq
* Bio-oil, 40% of total carbon stored = 40% of baseline removals = 4 tCO<sub>2</sub> eq

**Shared process emissions**

Emissions from biomass transport, biomass processing, methane emissions from pyrolysis and embodied emissions from infrastructure and machinery amount to 200 tCO<sub>2</sub> eq and are allocated to the co-products accordingly:

* Biochar, 60% of total carbon stored = 60% of emissions from shared processes = 120 tCO<sub>2</sub> eq
* Bio-oil, 40% of total carbon stored = 40% of emissions from shared processes = 80 tCO<sub>2</sub> eq

**Biochar-only emissions**

Emissions of 30 tCO<sub>2</sub> eq from biochar delivery and soil application occur after the co-products are split. The processes serve only the biochar production and are attributed in full to biochar.

**Bio-oil-only emissions**

Crude bio-oil processing, bio-bitumen production and delivery similarly occur after the split point of the co-products and serve only the bio-oil stream. Their full emissions of 20 tCO<sub>2</sub> eq are attributed entirely to the bio-oil production.

**Net removals**

* Biochar production: (- 6 baseline carbon storage - 600 total carbon storage + 150 project emissions) tCO<sub>2</sub> eq = -456 tCO<sub>2</sub> eq
* Bio-oil production: (- 4 baseline carbon storage - 400 total carbon storage + 100 project emissions) tCO<sub>2</sub> eq = -304 tCO<sub>2</sub> eq
  {% endhint %}

### Assumptions

* Asphalt production and any subsequent asphalt recycling cycle happens at a maximum temperature of 190°C.
* Distillation of the crude bio-oil at 200°C (or other similar, approved procedures) removes all water and volatile organic compounds from the crude bio-oil.
* In the TGA measurement, the cumulative weight loss up to 200°C is 100% carbon.
* All processed bio-oil from the same production batch has the same characteristics (e.g. organic carbon content, pollutant levels).

### Baseline scenario

The baseline shall include **any permanent carbon storage that would have occurred in the absence of the project**. It is assumed that there is no significant share of the project activity already occurring in business-as-usual. Therefore, the baseline for removal credits is zero and is omitted from calculations.

The baseline shall be revised at least every 5 years. A more conservative baseline scope may be applied on a case-by-base basis. It must be representative and transparently justified.

Note that baseline scenario carbon sequestration may be included for the project from the [biomass feedstock module](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock#ghg-quantification).

### Project scenario

The total removals of this module are calculated according to the following Equation 4

$$\textbf{(Eq.4)}\ R\_{total}=\sum\_{i=1}^{n} (C\_{org,\ i}\* A\_{bio-oil,\ i}*C\ to\ {CO}\_{2}*(1-W\_{loss, i}))$$

* $$R\_{total}$$ represents the total carbon removals from bio-oil during the monitoring period, in tonnes of CO$$\_2$$eq. This value shall be applied to Equation 1 from the [General BiCRS methodology](/methodologies/biomass-carbon-removal-and-storage-bicrs#letyqrgxkbuh) to calculate total project removals.
* $$n$$ is the total number of production batches $$i$$ from which bio-oil has been delivered during the monitoring period.
* $$C\_{org,\ i}$$ represents the organic carbon content of the processed bio-oil in production batch $$i$$.
* $$A\_{bio-oil,\ i}$$ represents the amount of processed bio-oil produced in production batch $$i$$ during the monitoring period, in tonnes.
* $$C\ to\ {CO}\_{2}$$ is 44/12 = 3.67, and represents the molar masses of CO$$\_2$$ and C respectively, and is used to convert tonnes C to tonnes of CO$$\_2$$eq.
* $$W\_{loss,\ i}$$ represents the cumulative weight loss up to 200°C of the processed bio-oil in production batch $$i$$.

### Uncertainty assessment <a href="#dk35zb8m2b1p" id="dk35zb8m2b1p"></a>

An uncertainty assessment is presented below for all aspects of GHG quantification set **at the methodology level**. The findings from this assessment are then applied **at the project level**, where project-specific GHG quantification also undergoes an uncertainty assessment.

The **overall project GHG quantification uncertainty** is determined by qualitatively combining both the methodology-level and project-specific uncertainties for each identified source of uncertainty.

The uncertainty of the assumptions presented in the [Assumptions ](#assumptions)section are assessed at the methodology level:

* Asphalt is typically produced or recycled via the hot-mix (160–190°C), warm-mix (\~20°C below hot-mix), or cold-mix route (ambient temperature). The assumption carries medium to high uncertainty, as asphalt production mixes are country- or region-specific. However, assuming all asphalt is hot-mix asphalt (HMA) and that bio-bitumen is processed at 190°C throughout its entire life cycle represents the most conservative approach, as asphalt producers are expected to operate at lower temperatures wherever possible to reduce energy consumption. This assumption therefore carries **low uncertainty**.
* Appropriate processing of the crude bio-oil (e.g. distillation at 200°C) removes all water and VOCs, leaving behind only the thermally stable fraction of the bio-oil. This assumption is inherently **high uncertainty**; however, the requirement for thermogravimetric analysis (TGA) to assess the validity of this assumption for each production batch reduces this to **moderate uncertainty**.
* Any cumulative mass loss up to 200°C in TGA is assumed to be 100% carbon. In practice, bio-oil typically contains around 40-70% carbon by weight, the volatile fraction removed below 200°C is therefore not pure carbon. This assumption carries high inherent uncertainty. However, it also underestimates the carbon retained in the bio-bitumen and is therefore considered conservative from a carbon accounting perspective, resulting in **low uncertainty.**
* All processed bio-oil within a production batch is assumed to have uniform characteristics. This assumption carries **moderate uncertainty**.

The uncertainty at the methodology level is estimated to be medium. This translates to an **expected discount factor of at least 6%** for projects under this methodology.

## Sampling and measurements

The following indicators shall be measured for each production batch:

* Amount of processed bio-oil produced and delivered
* Organic carbon content of processed bio-oil
* Cumulative weight loss up to 200°C (TGA) of processed bio-oil

Measurements shall be performed by laboratories with at least one quality assurance accreditation, such as:

* ISO/IEC 17025
* CEN/TS 17225-1
* ISO 10694

Unaccredited laboratories from academic settings shall be evaluated on a case by case basis by the VVB and the Rainbow Certification Team.

#### Representative sampling

Bio-oil composition is variable and changes over time due to its reactive nature. The following requirements ensure that samples are **representative of the bio-oil material that enters bio-bitumen production**, and that measurements are sufficiently frequent to capture this variability.

* A sample shall be taken **once every 100 tonnes of processed bio-oil produced**, or once per production batch, whichever comes first, for the first 1,000 tonnes of production.
* After 1,000 tonnes of processed bio-oil have been produced, the sampling frequency may be **relaxed to once every 250 tonnes**, provided that measurement stability has been demonstrated. To demonstrate stability, Project Developers shall conduct a statistical analysis of prior measurements and show that results do not vary by more than ±5%. If this criterion is not met, the reduced frequency is not permitted.
* Samples shall be taken and analyzed after a storage duration equal to the average storage duration of bio-oil before it enters bio-bitumen production, within a tolerance of ±1 week.
* Samples shall be taken from a homogeneous portion of the bio-oil, ensuring that all phases and solids are fully blended prior to sampling.

For each production batch, Project Developers shall provide a sampling protocol that includes, at minimum:

* the number of samples taken per production batch;
* a statistical analysis of the variability of measurement results;
* the average storage duration of bio-oil prior to bio-bitumen production;
* the duration between bio-oil production and sampling for every sample;
* description of the sampling procedure.

#### Measurements

* The **organic carbon content** of the bio-oil shall be determined by elemental analysis following the [ASTM D5291](#user-content-fn-10)[^10] standard test method or equivalent, if justified and documented. The measurement shall be done in replicates of three.
* Thermogravimetric analysis shall be conducted in a temperature range from room temperature to a minimum of 300°C under an inert gas atmosphere (e.g. N<sub>2</sub>) and with a temperature ramp rate of 10°C/min. The measurement shall be done in replicates of three and the cumulative weight loss up to 200°C reported.

## Risk assessment template

This module uses the risk assessment template version 1.0

:point\_right: Download the template [here](https://docs.google.com/spreadsheets/d/1lRkrxT1KtSSpsNSHPdBnFCEK3yjRoxQBQ-tftxiDacs/edit?usp=sharing)

{% embed url="<https://docs.google.com/spreadsheets/d/1lRkrxT1KtSSpsNSHPdBnFCEK3yjRoxQBQ-tftxiDacs/edit?usp=sharing>" %}

[^1]: EU standard: Bitumen and bituminous binders - Specifications

    for paving grade bitumens, [URL](https://webgate.ec.europa.eu/circabc-ewpp/d/d/workspace/SpacesStore/397bb835-6152-4bdc-8816-08b5838d675f/download)

[^2]: US standard: Paving Grade Bitumen, [URL](https://bernetbitumen.com/bitumen-standards-and-grades/astm-bitumen-standards/)

[^3]: A bio-bitumen batch is defined as all bio-bitumen produced from the **same bio-oil production batch** using identical additives and production conditions (e.g. temperature, mixing time).

[^4]: as opposed to crude bio-oil. Bio-oil that has been processed to remove water and volatile organic compounds.

[^5]: Dominant long-term aging mechanism but also present during mixing and laying of asphalt.\
    \
    Atmospheric oxygen reacts with hydrocarbons in the bitumen. The carbon in the bitumen is chemically transformed but remains stored.

[^6]: Slow structural change of bitumen during extended service life, also called physical hardening. Asphaltenes are formed and are no longer held in solution by the remaining maltenes.

[^7]: A bio-bitumen batch is defined as all bio-bitumen produced from the **same bio-oil batch** using identical additives and production conditions (e.g. temperature, mixing time). See [Production batches](#id-2xck12gc2auz) section for further details.

[^8]: Bitumen:

    * e.g. EN 12591 (bitumen for road construction);
    * applicable SDS/GHS classification under CLP Regulation (EU) 1272/2008 or equivalent;
    * REACH substance registration where applicable.

    Asphalt:

    * e.g. EN 13108 series (asphalt mix standards);
    * workplace exposure limit (WEL) / occupational exposure limit (OEL) for bitumen fume, typically expressed as inhalable fraction;
    * polycyclic aromatic hydrocarbon (PAH) content thresholds under relevant national road authority or environmental permitting requirements

[^9]: Bitumen fume emissions are the volatile organic and inorganic compounds released when bitumen (also known as asphalt) is heated during road construction, roofing, waterproofing, and other industrial processes.

[^10]: Standard Test Methods for Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and Lubricants, [URL](https://store.astm.org/d5291-21.html)


# Marine sub-sediment burial

| **Module name**      | Marine sub-sediment burial                 |
| -------------------- | ------------------------------------------ |
| **Module category**  | Carbon storage                             |
| **Methodology nam**e | Biomass carbon removal and storage (BiCRS) |
| **Version**          | 1.0                                        |
| **Methodology ID**   | RBW-BICRS-CS-MSSB-V1.0                     |
| **Release date**     | August 28th, 2025                          |
| **Status**           | In use                                     |

{% content-ref url="/pages/D1bECpowUAiJorSGzbQY" %}
[Glossary](/glossary)
{% endcontent-ref %}

<details>

<summary>Acknowledgements <span data-gb-custom-inline data-tag="emoji" data-code="1f91d">🤝</span></summary>

This module was developed by Rainbow with support from [Sinkco Labs](https://www.sinkcolabs.com/), particularly their science team, Brenna Boehman (Ph.D.) and Daniel Babin (Ph.D.), who provided fundamental scientific knowledge on storage in sub-sediment anoxic conditions. We extend our gratitude to [EcoEngineers ](https://www.ecoengineers.us/)and [David Harning, PhD](https://www.colorado.edu/instaar/david-harning), for their expert review. Rainbow sincerely appreciates the valuable contributions of all involved in this work.

</details>

This is a **Carbon Storage Module** and covers Marine sub-sediment burial. This module is part of the Rainbow BiCRS methodology, which allows Project Developers to choose the relevant modules for their project, and shall be used with the necessary accompanying modules.

See more details on how modules are organized in the [BiCRS home page](/methodologies/biomass-carbon-removal-and-storage-bicrs#efpqng3v3ute).

<table data-view="cards" data-full-width="false"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="files"></th></tr></thead><tbody><tr><td><strong>How to use this module</strong></td><td></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo#efpqng3v3ute">/pages/Jy6o8q5Q31d2U0OK7Yuo#efpqng3v3ute</a></td><td><a href="/files/0zYtLJBdzIemkx7iKe9C">/files/0zYtLJBdzIemkx7iKe9C</a></td></tr><tr><td><strong>BiCRS Methodology</strong></td><td></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo">/pages/Jy6o8q5Q31d2U0OK7Yuo</a></td><td><a href="/files/4B3R2CjT9hA3bBYbzz1a">/files/4B3R2CjT9hA3bBYbzz1a</a></td></tr></tbody></table>

## Eligible technologies

#### Project type <a href="#uikucys7r1rk" id="uikucys7r1rk"></a>

This module covers marine sub-sediment burial projects that inject waste and residual biomass feedstock inputs directly into the [**anoxic** ](#user-content-fn-1)[^1]layer of [marine sub-sediments](#user-content-fn-2)[^2]. Projects shall meet all of the following criteria:

* Demonstrate capability to perform MRV as agreed upon in the validated project documentation
* Demonstrate a net-negative project carbon footprint based on initial LCA estimates of induced emissions and initial CDR estimates based on modeling
* Projects that **sink** biomass to the seafloor but do not bury and embed it into marine sub-sediments are **not eligible**.
* The entity eligible for receiving carbon finance is the operator performing storage at the sub-sediment burial site. Biomass producers and sub-sediment burial machinery manufacturers are not eligible Project Developers.

#### Project scope <a href="#gs84uiswpg2k" id="gs84uiswpg2k"></a>

A project is defined as **all burial activities that take place from one port** over the project lifetime (by default a maximum of 5 years, [renewable](/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal)), and all removal that occurs as a result of that burial, plus the upstream/downstream activities associated with that burial (e.g. GHG emissions from feedstock sourcing, transport...).

See the [Storage batch](#ad7rimjzuv5e) section for more details on how a project is organized into different burial areas and burial events.

#### Eligible sites <a href="#aih0rwwz5szx" id="aih0rwwz5szx"></a>

Storage must be done in [**anoxic** ](#user-content-fn-1)[^1]conditions.

Storage must be done in **existing accessible** [**marine sub-sediment**](#user-content-fn-2)[^2]. Projects that excavate, dredge or build wells for the sole purpose of accessing sub-sediments or creating sub-sediment conditions are not eligible, due to the associated environmental risks.

See the [Site characterization](#id-9yt6lk62t36) section for more specific requirements.

#### Eligible feedstock <a href="#ja1qpxfjotc" id="ja1qpxfjotc"></a>

Only [particulate terrestrial biomass](#user-content-fn-3)[^3] feedstock that also meets the requirements of the[ BiCRS Biomass Feedstock module](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock) is eligible in this module. Injection of liquefied or gaseous CO$$\_2$$ into sediments is outside the scope of this module.

See the [BiCRS Biomass Feedstock module](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock) for more specific feedstock requirements.

## Crediting timeline and process <a href="#vqih1nxeqk4n" id="vqih1nxeqk4n"></a>

{% stepper %}
{% step %}
**Pre-project sampling**

Before or in parallel to validation with Rainbow, the Project Developer shall obtain the necessary permits, and take measurements and samples, and gather secondary sources, for the [Site Characterization Report](#id-9yt6lk62t36-1) and feedstock characterization, and propose a [sampling plan](#aklb6qbc2jek).
{% endstep %}

{% step %}
**Project validation**

The Project Developer submits required documentation and undergoes an ex-ante validation audit. The project documentation is made available on the registry, and expected CDR volume is estimated and displayed for pre-purchase agreements. Specific prerequisites include:

* [Permissions ](#o97hd5b4ge3i)have been granted to operate at the storage site, and to monitor the site up to 12-months after storage.
* The storage points are technically appropriate and can allow for permanent carbon storage. This is proven by generating the [Site Characterization Report](#id-9yt6lk62t36-1), demonstrating adherence to all requirements in the [Storage site requirements](#id-9yt6lk62t36-1) section.
* The biomass feedstock has been secured and a preliminary assessment of organic carbon content has been made.
* Expected project-scale CDR is modeled using equations in the [GHG quantification](/methodologies/battery-second-life/ghg-quantification) section.
  {% endstep %}

{% step %}
**Burial events**

The feedstock mixture is buried in the predefined storage points. Visual proof of each burial event and site closure is required, via imagery documented and verified in Monitoring Reports, to confirm that the site is well-sealed by surrounding sediments or other surface enhancements (e.g. rocks/rubble, clay caps) and confirm closure.
{% endstep %}

{% step %}
**(Optional) Monitoring: first measurement, verification and credit issuance**

Between 1-3 months after burial, Project Developers may conduct first monitoring by following the [Monitoring Plan](#snhouoxhyrzi) and the [Sampling Plan](#aklb6qbc2jek) to measure organic carbon content in buried biomass for each storage batch. Additional storage points may be added within the validated storage sites. CDR estimates and permanence are [updated with verified real data](#bpf7f2gx9dj5).

Project Developers may choose to either use:

* **50/50 issuance:** undergo a verification audit by a VVB at the first measurement step and issue the first 50% of removal RCCs on the Rainbow registry. Repeat the audit after the following step (Step 5) to issue the remaining 50%, or
* **One-time issuance:** skip this first measurement and verification step, and wait to issue 100% of RCCs at the second measurement stage described below (Step 5).
  {% endstep %}

{% step %}
**Monitoring: second measurement, verification and credit issuance**

Project Developers conduct the second monitoring at least 12 months after burial, following the [Monitoring Plan](#snhouoxhyrzi) and the [Sampling Plan](#aklb6qbc2jek), to measure organic carbon content in buried biomass for each storage batch. CDR estimates and permanence are [updated with verified real data](#bpf7f2gx9dj5), and verified by the VVB.

* **50/50 issuance:** the remaining credits are issued. Any discrepancies in earlier results, for example as a result of degradation, shall be accounted for by updating CDR calculations and following the [over/under crediting mechanism](broken://pages/RdrWiIQKe1CrCOIWJKCK#under-overachievement) in the Rainbow Procedures Manual.
* **One-time issuance:** all credits are issued for that storage batch based on the 12-month measurements.
  {% endstep %}

{% step %}
**Ongoing project operations**

Steps 3 through 5 are repeated throughout the 5-year project crediting period for as many storage batches as the Project Developer completes.
{% endstep %}

{% step %}
**End of project and renew the crediting period**

Monitoring and verification continues for a maximum of 5 years until the end of the crediting period. The Project Developer may choose to [renew the project's crediting period](/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal) to extend the Monitoring Plan and continue repeating steps 3 through 5.
{% endstep %}
{% endstepper %}

## Storage batches <a href="#ad7rimjzuv5e" id="ad7rimjzuv5e"></a>

Measurements and reporting are performed for **storage batches**. Verification and credit issuance is done at the reporting period scale (by default, annually), and groups results for all storage batches concerned during that reporting period. The organization of a project into **storage batches**, **sites** and **points** is described below, and depicted in Figure 1.

<table data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td>A <strong>storage batch</strong> is all burial events of homogenous feedstock mixtures at one storage site over a maximum of 31 days.</td></tr><tr><td>A <strong>storage site</strong> is a group of similar storage points within 24 km<span class="math">^2</span> of one another with similar site characteristics.</td></tr><tr><td>A <strong>storage point</strong> is the precise spot where a burial event occurs. Similar storage points may be grouped into a storage site.</td></tr></tbody></table>

<figure><img src="/files/FDPjAjZKnsxIN3gdWzHS" alt=""><figcaption><p>Figure 1 This figure illustrates how a project is organized into storage batches, storage sites, and storage points. Storage Batch #1 and Storage Batch #2 differ because Storage Batch #1 exceeded the 31-day limit and rolled over into a new batch. Storage Batch #1 and Storage Batch #3 occur over the same dates but are stored at different sites under distinct conditions. Meanwhile, Storage Batch #3 and Storage Batch #4 represent a shift in feedstock mixture, which defines a new storage batch, even though the previous batch did not reach the full 31-day duration.</p></figcaption></figure>

Sedimentary conditions for storage points within one storage site must be within the following ranges (data requirements are outlined in the [Data Sources](#g6ohrisnjsbj) section):

* **Grain size:** Grain size must be predominantly (> 50%) mud (< 63 µm grain size in diameter)
* **Water depth** at storage point: At water depths 1-20 m, water depths must be within 0.5 m. At water depths 20-200 m, water depths must be within 5 m.
* **Sub-sediment depth** of storage: At sub-sediment depths 2-3 m, storage depths must be within 0.5 m. At sub-sediment depths >3 m, storage depths must be within 1 m.

Ongoing burial into the sub-sediment shall last no longer than [**31 days per storage batch**](#user-content-fn-4)[^4], to standardize sampling timescales. If burial continues after 31 days, it shall be considered a separate storage batch.

One project may work with different storage batches simultaneously. **Each storage batch shall be monitored and reported separately** within the same Monitoring Report. Storage batch information shall be monitored and reported at least once per calendar year.

Information about storage batches may be monitored and [**issued credits continuously**](/rainbow-standard-documents/procedures-manual/project-certification-procedure#continuous-issuance) by Project Developers by uploading claim information to the Rainbow MRV platform.

## Feedstock mixture <a href="#id-9yt6lk62t36" id="id-9yt6lk62t36"></a>

A feedstock mixture is defined as one biomass feedstock or uniform mixtures of feedstocks. One feedstock mixture may be used across several storage batches, but any time the feedstock mixture of one storage batch changes, a new storage batch shall be started.

Any water used in the feedstock mixture must come from within the 24 km$$^2$$ storage batch area.

The feedstock mixture composition may vary by no more than 20% to be considered the same homogeneous feedstock mixture, where the composition is made of feedstocks of a specific type from a specific supplier.

See the [Pre-burial sampling](#pre-burial-sampling) section for requirements on feedstock sampling.

{% hint style="info" %}
For example, if a feedstock mixture is composed of 50% sawdust and 50% shredded straw, the proportions can vary between 40% and 60% (±10% of the original 50% for both inputs).

If a feedstock mixture is composed of 50% sawdust from Supplier A and and 50% from Supplier B, the proportions can vary between 40% and 60% (±10% of the original 50% for both inputs).
{% endhint %}

## Storage site and storage point requirements <a href="#id-9yt6lk62t36" id="id-9yt6lk62t36"></a>

Storage points must meet the criteria outlined in Table 1 to be eligible. The criteria are set to ensure storage points are suitable for permanent carbon storage, are anoxic, and have low reversal risks.

All criteria shall be outlined in the **Site Characterization Report**, prepared before any burial events occur and submitted with the PDD for the validation audit. In addition, the Site Characterization Report shall provide GPS coordinates of each planned storage point, and a GIS-generated map showing each storage point and the delineation of the associated storage site.

{% hint style="info" %}
Additional storage sites and points may be proposed after project operations begin and credits are issued, provided no burial occurs at the new sites or points before they are validated. To add new storage sites and points, the Project Developer must update the Site Characterization Report with the required details. A VVB shall audit the report to ensure compliance with requirements in Table 1. Once approved, the new sites and points must adhere to the monitoring plan requirements.
{% endhint %}

Data sources characterizing storage points must be, in the following order of preference:

1. primary data from a pilot survey e.g. site surveys, in situ measurements and measurements on samples collected at the project site, delivered by the Project Developer, or
2. secondary data from the specific area concerned (e.g. published peer-reviewed literature or database measurements) or
3. secondary data from an area that is proven to be sufficiently representative and similar to the project area in the appropriate factors that relate to permanent storage.

*Table 1 The required measurements and information for a storage site that must be presented in the Site Characterization Report, before any burial occurs, to justify that the storage site is appropriate for permanent CDR via marine sub-sediment burial.*

<table><thead><tr><th width="162">Criteria</th><th>Description</th></tr></thead><tbody><tr><td><strong>Marine water</strong></td><td>Must be in coastal, sea or ocean waters with a salinity greater than zero. Freshwater burial is not currently eligible.</td></tr><tr><td><strong>Anoxic Sediment Layer</strong></td><td><p>Must reach deep enough into the sub-sediment to reach the <a data-footnote-ref href="#user-content-fn-2">anoxic zone</a>. This shall be <strong>at least 2 m into the sediment</strong> (see <a href="#dg5ezfux812d">Appendix </a>D for justification), but actual depth to achieve this varies by site and shall be justified for each project.</p><p>The depth must remain anoxic year-round, accounting for bioturbation or increased advection/diffusion into sediments. The sub-sediment area must be stable with low likelihood of re-exposure, proven via established tools for determining sediment stability such as 210Pb or other geochronology tools.</p></td></tr><tr><td><strong>Water depth</strong></td><td>Must ensure the surface of the water bottom (seafloor or sediment surface) is not exposed to the air during tidal fluctuations. At water depths 1-20 m, water depths must be within 0.5 m. At water depths 20-200 m, water depths must be within 5 m</td></tr><tr><td><strong>Methane diffusion</strong></td><td>Methane must not be diffusing out of the sediment-water interface. This is measured using <a data-footnote-ref href="#user-content-fn-5">oxygen penetration depth</a> as a proxy for methane diffusion. This requirement is to ensure that if any buried feedstock mixture degrades, it would not be emitted as the stronger GHG methane, and would instead be emitted as CO<span class="math">_2</span>. In any case, loss of organic carbon from the biomass would be detected.</td></tr><tr><td><strong>Potential gas exchange</strong></td><td><p>Project Developers shall use all criteria mentioned above to calculate potential gas exchange from embedded depth into the atmosphere, to justify that there will be minimal gas exchange of any evolved gases with the atmosphere during a 1000 year period.</p><p>This requirement ensures that if any buried feedstock mixture degrades, the CO<span class="math">_2</span> generated will likely remain trapped in the sediment and remain stored, rather than <a data-footnote-ref href="#user-content-fn-6">diffusing </a>through the water column into the atmosphere.</p></td></tr><tr><td><strong>Shelf slope</strong></td><td>Sediment or seafloor gradation must be &#x3C;1:100 to prevent sediment <a data-footnote-ref href="#user-content-fn-7">slumping</a>.</td></tr><tr><td><strong>Sediment grain size</strong></td><td>At the target sub-sediment depth, at least 50% of sediment grains must be maximum 63 µm particle size.</td></tr><tr><td><strong>Authorization and access</strong></td><td>Project Developers must be authorized by jurisdictional authorities to operate, perform burial events and complete monitoring at the given geographic coordinates.</td></tr><tr><td><strong>Potential for Future Disturbance</strong></td><td>This shall be qualitatively and transparently discussed in the Site Characterization Report to determine if sediment disturbance may occur in the next 40 years, due to deep-sea mining, oil and gas extraction, trawling from fishing vessels, other resource exploitation, or any other use-conflict that might lead to reversal of storage. The site lease agreement should implement suitable barriers to such disturbance events.</td></tr><tr><td><strong>Marine life</strong></td><td>Characterize the biodiversity of marine life at the storage site, considering species type and abundance. This is used to 1) identify any sensitive biodiversity hotspots and 2) as a benchmark to compare identify any environmental damages after post-burial. Jurisdictional permitting and Environmental Impact Assessment procedures should already cover this, so this is implemented as an abundance of caution.</td></tr></tbody></table>

## Sampling requirements <a href="#aklb6qbc2jek" id="aklb6qbc2jek"></a>

Sampling occurs at two stages of the project: sampling of the feedstock mixture before burial to establish organic carbon buried, and sampling the feedstock mixture after burial to check for any reversals (i.e. carbon degradation or diffusion). At both stages of sampling, laboratory testing shall provide the following measurements of the feedstock mixture:

* % organic carbon content of the solid biomass
* % moisture content of the feedstock mixture
* density of the feedstock mixture

### **Pre-burial sampling**

Two representative samples of the feedstock mixture shall be prepared and sent for laboratory testing per storage batch: one at the beginning (day one) and one at the end of the storage batch (day 31, or an earlier date when the storage batch is complete).

### **Post-burial monitoring and sampling**

Post-burial monitoring and sampling shall occur:

* at least 12 months after the burial event, and
* optionally, may also be performed within 1-3 months after the burial event if the Project Developer chooses the 50/50 credit issuance approach. See the [Crediting timeline and process ](#vqih1nxeqk4n)section for more details.

Post-burial monitoring and sampling should be completed using sediment coring, to access the buried biomass, extract samples, and send them to a laboratory to measure the organic content of the solid biomass. Alternative approaches may be considered on a case by case basis, and approved by the VVB, the Rainbow Certification team and, if deemed necessary by the Rainbow Certification team, an expert peer reviewer.

**Sampling and laboratory testing shall be done separately for each storage point**. At least three sub-samples shall be taken from each storage point and mixed together to obtain one composite sample for the storage point. Samples can not be mixed from all storage points in one storage site to perform laboratory tests on a composite sample.

### Sampling plan

Project Developers shall prepare an **ex-ante** **Sampling Plan** before any burial events occur, and submit it with the PDD for the validation audit. The Sampling Plan shall describe:

* how representative samples will be taken of the feedstock mixture in pre-burial sampling
* how to preserve moisture content of feedstock mixture while sending it to the lab
* number of samples used for post-burial sampling
* strategy for ensuring random/representative/unbiased sampling locations for post-burial sampling

### **Sampling procedure**

The Sampling Plan described above is developed ex-ante during validation and outlines the *intended* sampling approach. During monitoring and ex-post verification, Project Developers must provide a **Sampling Procedure**, described in the [Monitoring Report](/rainbow-standard-documents/procedures-manual/project-certification-procedure#monitoring-plan), which documents the actual sampling approach that was implemented.

Ideally, the Sampling Procedure should align exactly with the Sampling Plan. However, given real-world challenges that may arise during monitoring, deviations are expected. The purpose of documenting the Sampling Procedure ex-post is to ensure transparency by capturing any adjustments made to the original plan.

The **Sampling Procedure shall include all elements listed in the Sampling Plan components** section.

## Eligibility criteria <a href="#id-8818d1p2uq2v" id="id-8818d1p2uq2v"></a>

The eligibility criteria requirements specific to this module are detailed in the sections below. Other eligibility criteria requirements shall be taken from the accompanying modules and methodologies:

<table data-view="cards"><thead><tr><th></th><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="files"></th></tr></thead><tbody><tr><td><strong>BiCRS methodology</strong></td><td><ul><li>Additionality</li><li>No double counting</li><li>Targets alignment</li><li>ESDNH</li></ul></td><td></td><td><a href="/pages/Jy6o8q5Q31d2U0OK7Yuo">/pages/Jy6o8q5Q31d2U0OK7Yuo</a></td><td><a href="/files/4B3R2CjT9hA3bBYbzz1a">/files/4B3R2CjT9hA3bBYbzz1a</a></td></tr><tr><td><strong>Other modules</strong></td><td><ul><li>Substitution</li><li>Co-benefits</li><li>No double counting</li><li>ESDNH</li><li>Leakage</li></ul></td><td></td><td><a href="/pages/eQTO2zpdCEv368f4bRT6">/pages/eQTO2zpdCEv368f4bRT6</a></td><td><a href="/files/CxuE4U5JkYE63biLhW6k">/files/CxuE4U5JkYE63biLhW6k</a></td></tr><tr><td><strong>Rainbow Standard Rules</strong></td><td><ul><li>Measurability</li><li>Real</li><li>TRL</li><li>Minimum impact</li></ul></td><td></td><td><a href="https://github.com/riverse-carbon/standard-documentation/blob/main/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage/broken-reference/README.md">https://github.com/riverse-carbon/standard-documentation/blob/main/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage/broken-reference/README.md</a></td><td></td></tr></tbody></table>

### Permanence <a href="#id-6mhy92a80ym0" id="id-6mhy92a80ym0"></a>

Removal Rainbow Carbon Credits (RCCs) issued from marine sub-sediment burial have a permanence horizon of 1000 years.

Permanence is assessed at two points during project certification:

* at ex-ante validation it is **estimated using site requirements that identify suitable sites for permanent burial**
* during verification it is **demonstrated using direct measurements**.

Requirements for each stage are detailed below.

#### Estimating permanence at validation <a href="#k1tsrh5yuegy" id="k1tsrh5yuegy"></a>

To demonstrate that carbon in sub-sediment burial will remain permanently stable, indicators from the [Storage site and storage point requirements ](#id-9yt6lk62t36-1)section must be provided at validation, in the Site Characterization Report, demonstrating compliance with the requirements. These indicators are **suitable proof that a substantial fraction** of the buried carbon will be permanently stable.

These indicators are **suitable proof that a substantial fraction** of the buried carbon is permanently stable. The amount of permanently stored carbon is determined using the models and equations detailed in the [GHG reduction quantification](#uua77odyg1lf) section.

#### Demonstrating permanence at verification <a href="#bpf7f2gx9dj5" id="bpf7f2gx9dj5"></a>

At verification, it is assumed that **92% of organic carbon still remaining in the feedstock mixture 12 months after burial will remain permanently stored over 1000 years**. This is based on modeled results for oxic marine sediments, and likely overestimate the non-permanent fraction of organic carbon in anoxic marine sediments, as required under this module.

At verification, the organic carbon content in the buried feedstock mixture of each storage batch is measured via sampling, and observed via remote sensing, at 1-3 months (optional) and 12 months (mandatory) to ensure permanent storage and negligible risk of reversal.

If measured organic carbon loss at 3 or 12 months **exceeds 2% of the initially buried carbon**, degradation/reversal may be triggered. In this case, the project is considered compromised, and carbon credit issuance for the affected storage batches will be paused. The Rainbow Certification team will collaborate with Project Developers to determine the cause of the unexpected loss and decide on appropriate corrective actions, including canceling issued credits according to the [Rainbow Procedures Manual](https://app.gitbook.com/o/zK7HMMBIcwhOSDhxzqPO/s/E1FUJsBoIj20nqp3CtMf/~/changes/185/rainbow-standard-documents/procedures-manual/rcc-management-avoiding-over-crediting#cancelation) and suspension of future credit issuance.

The amount of **permanently stored carbon that is issued credits** is conservatively modeled, as detailed in the [GHG quantification section](#fd0bgrymvc5j). Note that when default literature values for biomass are used, the modeled fraction of organic carbon that is still stored after 1000 years is 92%.

{% hint style="warning" %}
If measured organic carbon loss, at 3 or 12 months, exceeds 2% of the initially buried carbon, degradation may be triggered. In this case, the project is considered compromised, and carbon credit issuance for the affected storage batches will be paused. The Rainbow Certification team will collaborate with Project Developers to determine the cause of the unexpected loss and decide on appropriate corrective actions, including canceling issued credits according to the [Rainbow Procedures Manual](broken://pages/RdrWiIQKe1CrCOIWJKCK#cancelation).
{% endhint %}

{% hint style="info" %}
This use of the proposed model is conservative because it models carbon degradation in **oxic** marine sub-sediments, whereas projects certified under this methodology are required to bury biomass in **anoxic** marine sub-sediments, where microbial activity and degradation are lower.
{% endhint %}

Project Developers shall fill in the Methodology Risk evaluation template at the link below to **evaluate the risk of carbon storage reversal**, based on social, economic, natural, and delivery risks.

Project Developers shall assign a likelihood and severity score to each risk, and provide an explanation of their choices. The Rainbow Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

The Project Developer, Rainbow Certification team, or the third-party auditor may suggest additional risks to be considered for a specific project.

Each reversal risk with a **high or very risk score** is subject to:

* **risk mitigation plan**, developed by the Project Developer, that details the long-term strategies and investments for preventing, monitoring, reporting and compensating carbon removal reversal, OR
* **additional contributions to the buffer pool**, at a rate of 3% of verified removal Rainbow Carbon Credits for each high or very high risk

<table data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><a href="#risk-evaluation-template"><strong>Marine sub-sediment burial risk evaluation template</strong></a></td></tr></tbody></table>

All projects under this module are estimated to have a material reversal risk, due to

* risk of degradation from improper burial in oxic conditions
* risk of physical leakage from burial sites
* the novelty of the technology, meaning the abovementioned points have not been proven as consistent and reliable.

Therefore, the risk mitigation plan includes adhering to all site characteristics, plus a reversal monitoring requirement. At least 5 years after burial, Project Developers shall

* at a subset of storage sites, measure remaining organic carbon in feedstock samples
* at all storage sites, confirm the presence and extent of buried feedstock using radar

All projects under this module are estimated to have a material reversal risk, due to

* risk of degradation from improper burial in oxic conditions
* risk of physical leakage from burial sites
* the novelty of the technology, meaning the abovementioned points have not been proven as consistent and reliable.

Therefore, the **risk mitigation plan** includes adhering to all site characteristics, plus a **reversal monitoring requirement**. At least 5 years after burial, Project Developers shall:

* at a **subset of storage sites**, measure remaining organic carbon in feedstock samples, and
* at **all storage sites**, confirm the presence and extent of buried feedstock using radar.

Any identified carbon removal reversals shall result in canceled credits according to the [Rainbow Procedures Manual](broken://pages/RdrWiIQKe1CrCOIWJKCK#cancelation).

### Co-benefits <a href="#jrm3oypynw1w" id="jrm3oypynw1w"></a>

Project Developers shall prove that their project provides **at least 2 co-benefits** from the [UN Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDGs) framework (and no more than 4).

Common co-benefits of Marine sub-sediment burial projects, and their sources of proof, are detailed in Table 2. Project Developers may suggest and prove other co-benefits not mentioned here.

*Table 2 Summary of common co-benefits provided by Marine sub-sediment burial projects. Co-benefits are organized under the United Nation Sustainable Development Goals (UN SDGs) framework.*

<table><thead><tr><th width="158">UN SDG</th><th width="292">Example</th><th>Proof</th></tr></thead><tbody><tr><td><p><strong>SDG 9</strong>: Industry,</p><p>innovation, and</p><p>infrastructure</p></td><td>The use of offshore technology, such as oil and gas exploration and exploitation equipment, retrofitting maritime vessels to use for more sustainable application than fossil fuel extraction and merchant transport.</td><td>Project Developers standard operating procedure (SOP) for the disposal and burial of biomass feedstock.</td></tr><tr><td><strong>SDG 14</strong>: Aquatic life</td><td>Project Developers can develop long-term ecological monitoring stations to support monitoring of sub-sediment burial and support regional monitoring for ocean health indicators.</td><td>Project Developers demonstrate collaborations with regional universities or governmental institutions for collaborative long-term monitoring, and measurements to be completed. Relevant data should be open source.</td></tr></tbody></table>

### Environmental and social do no harm <a href="#amkr8oso802r" id="amkr8oso802r"></a>

Project Developers shall prove that the project does not contribute to substantial environmental and social harms.

Projects must follow all national, local, and European (if located in Europe) environmental regulations related to the project activities.

Feedstock sustainability requirements shall be taken from the [Biomass feedstock module](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock).

Project Developers shall measure heavy metal content from biomass samples and demonstrate that it is below thresholds set by the relevant jurisdiction.

#### ESDNH risk assessment

Project Developers shall fill in the Rainbow Marine sub-sediment burial [risk assessment template](#risk-evaluation-template) to evaluate the identified environmental and social risks of Marine sub-sediment burial projects. The identified risks include:

* Release of biomass via improper embedding
* Release of aqueous CO$$\_2$$ or methane at sediment-water interface
* Release of hydrogen sulfide at oxic-anoxic transition zone
* Project activities impacting benthic life
* Transfer of harmful pollutants in biomass feedstock
* Marine pollution due to ship time spent over storage site

The risk assessment also includes the identified risks from the [Biomass feedstock ](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock)module and the risks from the [Processing and energy use](/modules/processing-and-energy-use) module relevant for this carbon storage module.&#x20;

Additional optional environmental impacts to monitor are described in [Appendix C](#pcoc1dv4wl45-1).

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

#### Permitting <a href="#o97hd5b4ge3i" id="o97hd5b4ge3i"></a>

Project Developers must follow all relevant laws and legal requirements for reporting operations to local, federal and international governing bodies. Project Developers must follow the requirements outlined in their permit relating to the amount of tonnes injected if specified, and geographic area permitted for operations.

Permits are typically required for accessing coastal marine sediments and performing sub-sediment burial. The Project Developer must provide written authorization by either 1) the permit granting regulatory authority or 2) by the partner providing the permit demonstrating freedom to operate and perform sub-sediment burial in the geographic area defined in the PDD.

#### Environmental Impacts Assessment (EIA) <a href="#bcjgj9hknk0a" id="bcjgj9hknk0a"></a>

Typically, the EIA should be completed in advance of obtaining permitting for credit generation, and will be completed over the course of operations and reported to Rainbow.

EIA may not be required for all permits for storage. When EIA is not required for permitting (e.g. for a research permit or permit exemption), the Project Developer shall demonstrate that a baseline environmental survey has been completed, assessing the elements listed below, and that the potential impacts have been considered to be within regulatory guidelines. This justification shall be evaluated by both the VVB and the Rainbow Certification Team. Project Developers shall provide the same information as they would in a full EIA to Rainbow for project validation, and cover aspects including:

* Marine protected areas
* Benthic habitat
* Fishing grounds
* Shipping lanes
* Subsea infrastructure
* Materials of historical significance

Baseline environmental survey and/or EIA must address how the project adheres to regulatory requirements such as limitations on sediment resuspension and habitat destruction due to seabed intervention.

## GHG quantification <a href="#uua77odyg1lf" id="uua77odyg1lf"></a>

<figure><img src="/files/PmDblzP4u9jTyvrtQkYs" alt=""><figcaption><p>Figure 2 An example of the project process and possible operations, highlighting the Rainbow BiCRS modules that correspond to each process: biomass feedstock, transport, infrastructure and machinery, processing and energy use, and the present module marine sub-sediment burial.</p></figcaption></figure>

The system boundary of this quantification section starts after burial of feedstock mixture and covers carbon storage through end of life after 1000 years, and accounts for potential re-emission and decay modeled for 1000+ years. Sources of GHG emissions covered in this module include only permanent carbon storage modeling. Other GHG emissions shall be taken from the accompanying modules.

{% hint style="info" %}
There is no baseline from this module because it is assumed that there is no significant share of the project activity already occurring in business-as-usual. Therefore, the baseline for removal credits is zero and is omitted from calculations.

According to the Rainbow Procedures Manual, this assumption shall be re-assessed at a [minimum every 3 years](https://docs.rainbow.io/Rainbow-standard-documents/procedures-manual/documentation-and-methodologies-management#revising-a-methodology) during the mandatory methodology revision process, and any changes to this assumption would be [applied to existing projects](https://docs.rainbow.io/Rainbow-standard-documents/procedures-manual/project-certification-procedure#compliance-and-project-updates).

Note that baseline scenario carbon sequestration or leakage impacts may be included for the project from the [biomass feedstock module](https://docs.rainbow.io/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock#ghg-quantification).
{% endhint %}

### Assumptions <a href="#snal78yaa2vf" id="snal78yaa2vf"></a>

1. The rate of organic carbon degradation under oxic conditions is greater than the rate under anoxic conditions.
2. 12 months is an appropriate and sufficiently long timeframe to determine if carbon degradation will likely occur over 1000 years, given that organic carbon degradation is [front-loaded and logarithmic](#user-content-fn-8)[^8].
3. Biomass degradation can be measured by tracking organic carbon content of samples of the buried feedstock mixture over time.
4. Storage points will not experience re-suspension or re-working such that burial biomass is exposed to the water column over 1000 years.
5. The site characteristics and requirements detailed in Table 1 are suitable to identify sub-sediment areas that are anoxic.
6. Any organic carbon degradation from the buried biomass leads to CO$$\_2$$ released to the water column, and eventually back to the atmosphere, via diffusive transport. This is a conservative assumption, because degraded carbon may remain trapped permanently in the sediment matrix as CO$$\_2$$. Indeed, the site requirements are set to ensure that CO$$\_2$$ diffusion out of the sediment matrix is minimized.
7. Methane diffusion can be measured using oxygen penetration depth as a proxy. If O$$\_2$$ is measurable in the surface layer of marine sediments, methane is unable to diffuse out of the sediment-water interface.

### Data sources <a href="#g6ohrisnjsbj" id="g6ohrisnjsbj"></a>

The required **primary data** for GHG reduction calculations from projects are presented in Table 3. These data shall be included in the project’s PDD and made publicly available.

*Table 3 Summary of primary data needed from projects and their source for project validation and verification. See the* [*Monitoring Plan* ](#snhouoxhyrzi)*section for more details on monitoring and verification requirements. Asterisks (\*) indicate which data shall be updated for each storage batch.*

<table><thead><tr><th width="183">Parameter</th><th width="125">Unit</th><th>Source proof</th></tr></thead><tbody><tr><td>Sediment grain size</td><td>mm</td><td><ul><li>primary data from a pilot survey of the site</li><li>secondary data from the specific area concerned (e.g. published peer-reviewed literature or database measurements)</li><li>secondary data from an area that is proven to be sufficiently representative and similar to the project area in the appropriate factors that relate to permanent storage</li><li>reported in the <a href="#id-9yt6lk62t36-1">Site Characterization Report</a></li></ul></td></tr><tr><td>Sub-sediment depth (X)</td><td>m</td><td>Same as above</td></tr><tr><td>Water depth</td><td>m</td><td>Same as above</td></tr><tr><td>Volume of feedstock mixture buried per storage batch*</td><td>m<span class="math">^3</span></td><td>Equipment logs on machinery delivering the burial</td></tr><tr><td>Organic carbon content of feedstock mixture*</td><td>% organic carbon, dry mass basis</td><td><ul><li>Laboratory testing of <a href="#aklb6qbc2jek">feedstock mixture samples</a></li><li>Measured per storage batch, <a href="#pre-burial-sampling">2x pre-burial</a> and <a href="#post-burial-monitoring-and-sampling">1-2x post-burial</a> (1-3 months, and 12 months)</li><li>Reported in the Feedstock Characterization Report for each storage batch</li></ul></td></tr><tr><td>Bulk density of dry feedstock*</td><td>tonne/m<span class="math">^3</span></td><td>Same as above</td></tr><tr><td>Solids mass fraction*</td><td>fraction</td><td><ul><li>Laboratory testing of <a href="#aklb6qbc2jek">feedstock mixture samples</a></li><li>Measured per storage batch, upon burial</li><li>Reported in the Feedstock Characterization Report for each new storage batch</li></ul></td></tr></tbody></table>

**Secondary data** taken from the literature may be used to define default values for the parameters outlined in Table 4. If instead, project incubation experiments or *in situ* experiments are used to provide values for $$G$$ and $$k$$ parameters, these experiments must either 1) be scientifically peer reviewed and published in academic journals, or 2) undergo independent external peer review for the specific project.

*Table 4 Values from scientific literature that may be used instead of primary data, for validation stage ex-ante carbon degradation modeling.*

<table data-full-width="false"><thead><tr><th width="169">Parameter</th><th width="152">Variable</th><th>Source proof</th></tr></thead><tbody><tr><td>Fractional pools of complex organic carbon</td><td><span class="math">G_{int,1},\ G_{int,2}</span> and <span class="math">G_{res}</span></td><td><p>Project Developers may choose between three sources for these values:</p><ul><li><a data-footnote-ref href="#user-content-fn-9">literature </a>(oxic biomass bale sinking experiment, values for maize are 0.012, 0.091, 0.897 for each <span class="math">G</span> variable, respectively).</li><li>project incubation experiments with the feedstock mixture in representative marine sub-sediments.</li><li><em>in situ</em> experiments with the biomass feedstock mixture in representative marine sediments.</li></ul></td></tr><tr><td>Rate constants</td><td><span class="math">k_{int1},\ k_{int2}</span> and <span class="math">k_{res}</span></td><td><p>Same options as above.</p><p><a data-footnote-ref href="#user-content-fn-9">Literature </a>values for maize are 0.04, 0.002, and 0 for each <span class="math">k</span> variable, respectively</p></td></tr></tbody></table>

### Carbon storage <a href="#cxpdobk03o90" id="cxpdobk03o90"></a>

Carbon storage is calculated by multiplying the fraction of organic carbon still stored over 1000 years, by the amount of initially buried organic carbon (Eq 1). Each component is described in the following sections.

#### Carbon burial

The amount of carbon initially buried shall be calculating using using primary data, measured by Project Developers, for each storage batch, following Eq. 2 below.

#### Carbon degradation <a href="#fd0bgrymvc5j" id="fd0bgrymvc5j"></a>

A small fraction of the buried organic carbon may be decomposed by microbes in the sub-sediment. This is expected to be small because of:

1. the site requirements that ensure anoxic conditions, preventing degradation,
2. use of terrestrial biomass in marine settings, where microbial communities are not well adapted to degrade terrestrial biomass (see Appendix B), and
3. sediment conditions in the site requirements, ensuring that if degradation occurs, any evolved CO$$\_2$$ would likely stay trapped in the sub-sediment. Nevertheless, the calculations conservatively assume that any CO$$\_2$$ degraded is diffused out of the sub-sediment.

Carbon degradation is conservatively modeled using a [multi-G kinetic model](#user-content-fn-10)[^10] as shown in Eq. 3 (see justification in [Appendix A](#appendix-a-scientific-basis-of-sub-sediment-biomass-storage) and [Appendix B](#pcoc1dv4wl45)).

{% hint style="warning" %}
Empirical peer-reviewed research has only covered rate constants for organic matter degradation ($$k$$) for use in the [multi-G kinetic model](#user-content-fn-10)[^10] under marine sediment **oxic conditions**, but the projects covered under this methodology occur in marine sub-sediment **anoxic conditions**.

In absence of resources covering anoxic conditions, oxic-environment rate constants shall be used by default in the model for crediting, which is a conservative approach because this is expected to overestimate potential degradation in the sub-sediment burial anoxic conditions. As described in the[ Data sources](#g6ohrisnjsbj) section, Project Developers may provide project-specific anoxic rate constants, under certain conditions.

A literature review is described in [Appendix B](#appendix-a-scientific-basis-of-sub-sediment-biomass-storage) justifying the use of the proposed multi-G kinetic model and rate constants, comparing them to empirical findings of biomass buried in non-oxic conditions.
{% endhint %}

<details>

<summary>Calculations: Carbon removal for credit issuance and permanence check</summary>

$$\textbf{(Eq.1)}\ R\_{P,\ Storage}=C\_{buried} \times F\_{perm}$$

Where

* $$R\_{P,\ Storage}$$ represents the total carbon removed in the present [Carbon Storage](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage) module on marine sub-sediment burial. It is used in Eq. 1 in the [Removals Calculations](broken://pages/IPTw7ScSQWpD4sIH2RfM#calculations-removals) section of the [BiCRS methodology](broken://pages/IPTw7ScSQWpD4sIH2RfM). It is calculated for each storage batch.
* $$C\_{buried}$$ represents the tonnes of CO$$\_2$$eq in the buried feedstock mixture, calculated below in Eq. 2.
* $$F\_{perm}$$ represents the fraction of initially buried organic carbon that remains permanently buried after 1000 years, and is modeled according to Eq.3.

$$\textbf{(Eq.2)}\ C\_{buried}=V\_{FM}\times w\_{s,\ FM} \times \rho\_{feedstock} \times C\_{org,\ feedstock} \times C\ to\ CO\_2$$

Where

* $$C\_{buried}$$ is described in Eq. 1.
* $$V\_{FM}$$ represents the total volume of feedstock mixture buried in m$$^3$$. Note that this represents solid biomass feedstock mixed with water in a slurry.
* $$w\_{s,\ FM}$$ represents the solid mass fraction of the feedstock mixture, as a unitless fraction
* $$\rho\_{feedstock}$$ represents the bulk density of the dry feedstock in tonnes/m$$^3$$
* $$C\_{org,\ feedstock}$$ represents the organic carbon content in the solid fraction of the feedstock mixture, in % dry mass (e.g. g organic carbon/g dry feedstock mixture). At validation, this value should be conservatively estimated.
* $$C\ to\ {CO}\_{2}$$ is 44/12 = 3.67, and represents the molar masses of CO$$\_2$$ and C respectively, and is used to convert tonnes C to tonnes of CO$$\_2$$eq.

$$\textbf{(Eq.3)}\ F\_{perm}= G(t,1000)=G\_{int,1}e^{-k\_{int1}t}+G\_{int,2}e^{-k\_{int2}t}+G\_{res}e^{-k\_{res}t}$$

Where

* $$F\_{perm}$$ was described in Eq. 1. It represents carbon degradation over 1000 years, calculated using the following [multi-G degradation model](#user-content-fn-8)[^8].
* $$t$$ represents time. The equations presented can be time-integrated from 0 to 1000 years, calculating carbon degradation/storage continuously. For the purpose of issuing RCCs under this module, only results at time $$t$$ = 1000 years are used.
* $$G(t,1000)$$ represents the fraction of organic carbon originally buried in the feedstock biomass remaining after 1000 years. Also called $$F\_{perm}$$.
* $$G\_{int,1},\ G\_{int,2}$$ and $$G\_{res}$$ are the fractional pools (in tonnes of organic carbon) of intermediate 1, intermediate 2, and residual, described in Table 4.
* $$k\_{int1},\ k\_{int2}$$ and $$k\_{res}$$ are rate constants for each fractional pool, described in Table 4.
* Note that using default literature values presented in Table 4 results in a $$F\_{perm}$$ of 0.92.

Although carbon storage at 1000 years is conservatively modeled according to Eq. 3 for the purpose of **issuing credits**, carbon loss at each verification and credit issuance (1-3 and 12 months after burial) is measured using samples of biomass feedstock to **check the permanence of storage at each storage point**, and confirm the eligibility of removal at each storage site, as described in the [Permanence](#bpf7f2gx9dj5) section.

$$\textbf{(Eq.4)}\ F\_{loss}= (C\_{org,\ feedstock}-C\_{org,\ feedstock,\ t}) \div C\_{org,\ feedstock}$$

Where

* $$F\_{loss,\ t}$$ represents the fraction of organic carbon originally buried that has been lost via degradation, at time $$t$$. This shall be proven to be >0.02 during 1-3 or 12 month monitoring (i.e. 2% of buried organic carbon has degraded), in order to issue RCCs.
* $$C\_{org,\ feedstock}$$ was described in Eq. 2.
* $$C\_{org,\ feedstock,\ t}$$ represents the organic carbon content in the solid fraction of the feedstock mixture, in % dry mass, at time $$t$$.

$$\textbf{(Eq.5)}\ C\_{stored,\ t}=C\_{buried} \* (1-F\_{loss})$$

JUST FOR OSCAR, TO REMOVE LATER

* $$C\_{stored,\ t}$$ is additional info for projects, to be shown in the mrv output, showing the acutal estimated carbon removals (interesting to compare to the conservatively calculated/credited removals based on models)

</details>

## Uncertainty assessment <a href="#bwkjzyy06l35" id="bwkjzyy06l35"></a>

See general instructions for uncertainty assessment in the [Rainbow Standard Rules](https://github.com/riverse-carbon/standard-documentation/blob/main/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-storage/broken-reference/README.md). The outcome of the assessment shall be used to determine the percent of RCCs to eliminate with the [**discount factor**](#user-content-fn-11)[^11].

The uncertainty in this module is assessed below for each component.

{% tabs %}
{% tab title="Baseline" %}
The baseline scenario selection has low uncertainty: it is rather certain that the share of project technology occurring in a Business as Usual scenario is very low.
{% endtab %}

{% tab title="Equations" %}

* [Carbon burial](#cxpdobk03o90) measurements consists of basic conversions with low uncertainty.
* [Carbon degradation](#fd0bgrymvc5j) modeling consists of the [multi-G degradation model](#user-content-fn-8)[^8], with low uncertainty given that this is a foundational and commonly accepted model in biogeochemistry.
  {% endtab %}

{% tab title="Secondary data" %}
The secondary data used for all projects under this methodology are the $$G$$ and $$k$$ constants presented in Table 4. The use of these constants has moderate uncertainty, because they are not specifically adapted to project designs and biomass feedstock types. This uncertainty is mitigated and considered acceptable because they are conservative assumptions, representing oxic conditions where carbon degradation is assumed to be higher than in the anoxic conditions required for burial under the present module.
{% endtab %}

{% tab title="Assumptions" %}
**Low Uncertainty**

* Biomass degradation can be tracked by measuring organic carbon over time.
* Organic carbon degrades faster in oxic than anoxic conditions.
* The site traits outlined in Table 1 are suitable for identifying anoxic sub-sediment areas.
* Oxygen penetration depth can be used to estimate methane diffusion.

**Moderate Uncertainty**

* Organic carbon degrades quickly at first, following a logarithmic trend; 12 months is a suitable measurement period.
* Storage points will remain undisturbed, preventing biomass exposure.
* Any degradation releases CO$$\_2$$ to the water, then the atmosphere, via diffusion (a conservative assumption).
  {% endtab %}
  {% endtabs %}

The uncertainty at the module level is estimated to be low. This translates to an expected **discount factor of at least 3%** for projects under this module.

## Risk assessment template

This module uses the risk assessment template version 1.0.&#x20;

:point\_right: Download the template [here](https://docs.google.com/spreadsheets/d/1RHk7aHLzqfASGgy2ylwPoMV6sEu622_Rgx4jgJoWgOw/edit?usp=sharing)

{% embed url="<https://docs.google.com/spreadsheets/d/1RHk7aHLzqfASGgy2ylwPoMV6sEu622_Rgx4jgJoWgOw/edit?usp=sharing>" %}

## Monitoring plan <a href="#snhouoxhyrzi" id="snhouoxhyrzi"></a>

The Project Developer is the party responsible for adhering to the Monitoring Plan.

Monitoring Plans to issue credits for this module shall include, but are not limited to, tracking of the following information **for each new Storage Batch**:

<table><thead><tr><th width="216">Data/Indicator</th><th width="139">Purpose</th><th>Frequency of Measurement</th></tr></thead><tbody><tr><td>Volume of feedstock mixture buried per storage batch</td><td>To calculate <span class="math">C_{buried}</span></td><td>Each burial event</td></tr><tr><td>Organic carbon content of solid fraction of feedstock mixture</td><td>To calculate <span class="math">C_{buried}</span></td><td><p>Each storage batch, including:</p><ul><li>Day 1 and last day of burial, and</li><li>12 months post-burial, and</li><li>1-3 months post-burial (optional, for <a href="#vqih1nxeqk4n">50/50 credit issuance</a>)</li></ul></td></tr><tr><td>Solid mass fraction of feedstock mixture</td><td>To calculate <span class="math">C_{buried}</span></td><td><p>Each storage batch, including:</p><ul><li>Day 1 and last day of burial, and</li><li>12 months post-burial, and</li><li>1-3 months post-burial (optional, for <a href="#vqih1nxeqk4n">50/50 credit issuance</a>)</li></ul></td></tr><tr><td>Bulk density of the feedstock mixture</td><td>To calculate <span class="math">C_{buried}</span></td><td><p>Each storage batch, including:</p><ul><li>Day 1 and last day of burial, and</li><li>12 months post-burial, and</li><li>1-3 months post-burial (optional, for <a href="#vqih1nxeqk4n">50/50 credit issuance</a>)</li></ul></td></tr><tr><td>Visual proof of burial (e.g. photos or video taken during the burial event, satellite imagery)</td><td>To confirm that the storage site is closed.</td><td><p>Each burial event, including:</p><ul><li>During burial, and</li><li>12 months post-burial, and</li><li>1-3 months post-burial (optional, for <a href="#vqih1nxeqk4n">50/50 credit issuance</a>)</li></ul></td></tr></tbody></table>

**Reversal Monitoring Plans** to check for reversals shall include, but are not limited to, tracking of the following information for a representative sample of storage sites:

<table><thead><tr><th width="216">Data/Indicator</th><th width="139">Purpose</th><th>Frequency of Measurement</th></tr></thead><tbody><tr><td>Organic carbon content of solid fraction of feedstock mixture</td><td>To calculate <span class="math">C_{buried}</span></td><td>5 years after burial, for a representative sample of storage sites</td></tr><tr><td>Solid mass fraction of feedstock mixture</td><td>To calculate <span class="math">C_{buried}</span></td><td>5 years after burial, for a representative sample of storage sites</td></tr><tr><td>Bulk density of the feedstock mixture</td><td>To calculate <span class="math">C_{buried}</span></td><td>5 years after burial, for a representative sample of storage sites</td></tr><tr><td>Visual proof of burial (e.g. photos or video taken during the burial event, satellite imagery)</td><td>To confirm that biomass remains physically buried.</td><td>5 years after burial, for all storage sites</td></tr></tbody></table>

## Appendix <a href="#dk8b5sw92isc" id="dk8b5sw92isc"></a>

#### **Appendix A: Scientific Basis of Marine Sub-Sediment Burial**

This appendix outlines the scientific foundation for marine sub-sediment biomass storage, summarizing key research on organic carbon degradation and preservation in marine sediments. While no studies directly replicate the conditions described in this module, relevant literature on similar processes is compiled.

#### **Introduction**

Marine sediments serve as the final carbon sink, storing 150–200 billion tons of organic carbon in their upper layers ([Hedges & Keil, 1995](https://www.sciencedirect.com/science/article/abs/pii/030442039500008F); [Hedges, Keil & Benner, 1997](https://www.sciencedirect.com/science/article/abs/pii/S0146638097000661); [Atwood et al., 2020](https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2020.00165/full)). The **biological pump** transfers oceanic carbon to sediments via microbial fixation, food chain dynamics, and sinking particulate matter. Despite its inefficiency—only \~1% of sinking carbon reaches sediments, and just 0.1% is buried long-term ([Burdige, 2007](https://pubs.acs.org/doi/10.1021/cr050347q); [LaRowe et al., 2012](https://www.sciencedirect.com/science/article/abs/pii/S0016703711000378))—this process significantly influences atmospheric CO<sub>2</sub> levels.

Biomass degrades rapidly in oxygenated sediments, but in anoxic environments, it can persist for millennia. **Oxygen exposure time (OET)** controls degradation: prolonged exposure breaks macromolecules into labile forms, accelerating conversion to CO<sub>2</sub> . Reducing OET preserves biomass, as seen in bog bodies and historic wooden structures preserved in compacted, oxygen-deprived sediments ([Ceccato et al., 2014](https://associazionegeotecnica.it/wp-content/uploads/2017/05/rig_2_2014_ceccato_analysis_of_degradation_effect_on_the_wooden_foundations_in_venice_.pdf); [Macchioni et al., 2016](https://www.sciencedirect.com/science/article/abs/pii/S0950061816302057)).

#### **Organic Carbon Preservation in Marine Sediments**

Decades of research ([Hedges & Keil, 1995](https://www.sciencedirect.com/science/article/abs/pii/030442039500008F); [Arndt et al., 2013](https://www.sciencedirect.com/science/article/abs/pii/S0012825213000512); [LaRowe et al., 2020](https://www.sciencedirect.com/science/article/pii/S0012825219305720?casa_token=Jn1H3dyaNnAAAAAA:Tgq2PF0zEmcw5lXn9Hhlo1yzRPWjMrywh2m_XnMCHGKUzdL3VhiNnBrUXyYf2qbnaZHWCnM1pM0)) indicate that organic carbon degrades slowly in anoxic sediments due to low substrate availability, microbial competition, mineral protection, and biochemical inaccessibility ([Kristensen & Holmer, 2001](https://www.sciencedirect.com/science/article/abs/pii/S0016703700005329); [LaRowe et al., 2022](https://www.sciencedirect.com/science/article/pii/S0012825219305720?casa_token=Jn1H3dyaNnAAAAAA:Tgq2PF0zEmcw5lXn9Hhlo1yzRPWjMrywh2m_XnMCHGKUzdL3VhiNnBrUXyYf2qbnaZHWCnM1pM0)).

Biomass preservation for over 1,000 years is common in coastal zones with high sedimentation rates and low OET. For example, rapid burial in the Bay of Bengal (30 cm/yr sedimentation) protects wood from microbial degradation, preserving organic material for millions of years ([Lee et al., 2019](https://www.pnas.org/doi/full/10.1073/pnas.1913714116)). Similarly, wood fragments up to 11,900 years old have been recovered from the Gulf of Mexico ([Schwab et al., 1996](https://pubs-geoscienceworld-org.libproxy.mit.edu/sepm/jsedres/article/66/5/916/98826/Sediment-mass-flow-processes-on-a-depositional)), and entire ancient forests remain buried off the Alabama coast ([Delong et al., 2021](https://onlinelibrary.wiley.com/doi/epdf/10.1111/bor.12524?getft_integrator=sciencedirect_contenthosting\&src=getftr\&utm_source=sciencedirect_contenthosting); [Moran et al., 2024](https://www.sciencedirect.com/science/article/pii/S0025322724001865)).

Studies show organic carbon degradation slows exponentially over time, with rates up to 1,000× lower in anoxic sediments than in oxic environments ([Kristensen & Holmer, 2001](https://www.sciencedirect.com/science/article/abs/pii/S0016703700005329); [Keil et al., 2010](https://www.sciencedirect.com/science/article/abs/pii/S0304420310000903); [LaRowe et al., 2012](https://www.sciencedirect.com/science/article/abs/pii/S0016703711000378); [Arndt et al., 2013](https://www.sciencedirect.com/science/article/abs/pii/S0012825213000512)). This supports the assumption that degradation rates in oxic conditions ([Keil et al., 2010](https://www.sciencedirect.com/science/article/abs/pii/S0304420310000903)) represent a worst-case scenario for anoxic sub-sediment burial.

#### **Biomass Degradation in Marine Sediments**

Biomass degradation begins with extracellular enzymatic hydrolysis, where aerobic microbes break down macromolecules into small organic compounds. These are further processed via anaerobic fermentation into substrates for redox reactions. However, without sufficient OET, enzymatic hydrolysis cannot begin, preventing degradation ([Hartnett et al., 1998](https://www.nature.com/articles/35351); [Hedges et al., 1999](https://earth.geology.yale.edu/~ajs/1999/07-09.1999.02Hedges.pdf)). Ligno-cellulosic biomass requires longer OET than algal biomass to initiate breakdown.

In deep sediments, sulfate reduction is the dominant degradation process, accounting for 50% of total biomass decomposition globally (Jorgensen et al., 2019). This slow, energy-limited process produces CO<sub>2</sub> and hydrogen sulfide (HS). CO<sub>2</sub> diffuses upward, where it may be fixed by microbes or released at the sediment-water interface. Worst-case CO<sub>2</sub> diffusion rates align with modern dissolved inorganic carbon (DIC) fluxes ([Krumins et al., 2013](https://bg.copernicus.org/articles/10/371/2013/)). CO<sub>2</sub> accumulates due to compaction, it can form hydrates at depths >10 m in cold marine sediments (Eccles & Pratson, 2012; Velaga et al., 2011).

Hydrogen sulfide (HS), though toxic, is rapidly oxidized in oxygenated environments, preventing marine toxicity. Additionally, 10–20% of HS reacts with iron hydrates to form pyrite (FeS), further stabilizing organic matter (Barber et al., 2017; Baumgartner et al., 2023).

Methanogenesis, consuming 15% of CO<sub>2</sub> from sulfate oxidation, contributes to organic carbon degradation (Regnier et al., 2011). Over time, sediment compaction reduces porosity, slowing diffusion and promoting FeS formation. This further limits CO<sub>2</sub> and methane movement, allowing microbial utilization.

#### **Conclusion**

Long-term biomass preservation in marine sediments is driven by **low OET, rapid burial, and anoxic conditions**. Anoxic degradation is significantly slower than oxic processes, enhancing the stability of buried carbon. Existing research supports the feasibility of sub-sediment biomass storage as a durable carbon sequestration strategy.

***

#### Appendix B: Incubations, models, and field evidence support minimal carbon loss in buried wood <a href="#pcoc1dv4wl45" id="pcoc1dv4wl45"></a>

*Written by Daniel Babin (Ph.D.), Head of Science, Sinkco Labs. See reference list at the end of the Appendix.*

Marine sub-sediment burial is a carbon storage method that stores waste biomass products in anoxic marine sediment to prevent rot. This carbon storage method is supported by laboratory incubations, biogeochemical models, and numerous natural examples of well-preserved, million-old subfossil wood found in sediment around the world. The purpose of this annex is to:

1. Provide general evidence of the feasibility of permanent carbon removal from biomass burial in or below aquatic sediments,
2. Use model and literature data to determine a target preservation threshold for a 1 year monitoring period that justifies claims of 1000 year permanent removals.
3. Assess an appropriate and conservative estimate for how much carbon will remain stored after 1000 years based on biogeochemical models and chemical and physical data subfossil wood preservation from the literature.

A model for organic matter decay based on laboratory incubations indicates 92% of organic carbon will remain after 1000 years. This aligns with findings on the decay of subfossil wood in a wide variety of geologic settings that indicate preservation 88-97% preservation on the timescale of thousands of years.

**Introduction**\
Marine sediment has the potential to lock away carbon for millennia. Marine sediments are the final resting place for terrestrial and marine carbon with 150-200 billion tons stored in top meters of marine sediments globally (Hedges & Keil, 1995; Hedges et al., 1997; Atwood et al., 2020). However, the pathway to permanent storage in sediments is relatively inefficient — only 0.1% will ultimately be buried for millions of years due microbial activity in both the water column and the upper few centimeters of sediment where oxygen is present (Burdige, 2007; LaRowe et al., 2012).

At depth in marine sediments, organic matter is much better preserved. This environment is typically anoxic or hypoxic, cold, and saline. Dissolved oxygen is consumed rapidly near the surface, and below a few centimeters, decomposition relies on less efficient anaerobic processes . Additionally, cooler temperatures slow microbial enzyme activity, further decelerating decomposition (Bulesco et al. 2019). The combined effect of low oxygen, high salinity, and low temperatures means that marine sediments preserve OM far longer than soils or freshwater sediments.

Marine sub-sediment burial (MSSB) as a carbon removal protocol leverages the geochemical stability of carbon at depth in anoxic marine sediments by placing biomass even deeper beneath layers of sediment where microbial access and oxygen infiltration are virtually nonexistent. To store carbon, low-value agricultural and forestry residues (normally burned or landfilled) are mixed into a slurry and injected more than 15 feet down into sediments.

The durability of this carbon storage technique is further enhanced because marine sediment microbial communities are adapted primarily to marine-derived organic matter—not to the complex compounds typical of terrestrial plant biomass (like lignin and cellulose) often used in MSSB. These microbes often lack the necessary enzymatic pathways to efficiently degrade such materials . Recent studies show that when terrestrial-derived organic substrates (e.g., lignin, cellulose-rich material) enter marine sediments, only select microbial clades—usually rare or uncultured—respond, and even then, degradation is slow (Bulesco et al. 2019).

***Predicting carbon loss in marine sediments***\
To predict the amount of carbon degradation, the MSSB protocol draws on sediment biogeochemistry models. A particularly relevant framework is the multi-G kinetic model of organic matter degradation, originally developed for marine sediments. As reviewed by Arndt *et al.* (2013), the multi-G model assumes organic matter comprises multiple discrete pools (“G” classes), each with its own characteristic degradation rate (Arndt *et al.* 2013). Rapidly decaying compounds are exhausted early, leaving progressively more refractory fractions that break down extremely slowly. This multi-component kinetic formulation quantifies how overall reactivity declines with depth and time in sediment burial (Arndt *et al.* 2013). The model has been successful in simulating long-term carbon preservation in many sedimentary settings (Arndt *et al.* 2013), making it a promising tool to predict the fate of buried biomass carbon. The model is the closest fit to MSSB projects, although it assesses degradation in shallow layers of marine sediment, where more degradation is expected to occur than in MSSB projects, which bury organic matter deeper in sub-sediment layers. Because the model was calibrated in oxic conditions and MSSBs projects are required to bury biomass in anoxic conditions, the mullti-G model predictions are expected to be a maximum degradation rate.

Empirical evidence for long-term stability of buried organic carbon comes from deep-sea experiments, and corroborates results from the model described above. Keil *et al.* (2010) applied a multi-G type analysis to test burying crop residues in marine sediment. In a 700-day incubation using marine sediments, an initial brief pulse of decay oxidized <1% of the added plant material in the first week Keil *et al.* (2010). Thereafter, degradation virtually stalled: over the following two years only 3–8% of the terrestrial biomass (soy straw, corn stover, wood chips) was re-mineralized. This decay rate is much lower than the 19% lost from more labile, marine-native plankton material (Keil *et al.* 2010). The fitted kinetic parameters (e.g. approximately 0.004 yr<sup>-1</sup> for terrestrial plant carbon) were orders of magnitude lower than typical decay rates for fresh organic matter (Keil *et al.* 2010).

For this study, we use the decay rate fit for alder wood from the laboratory experiments of Kiel et al. (2010) (Figure A1). Plankton, maize, and soy were also tested in their experiments, but alder was selected as the best representation of woody biomass (Figure A1). In Kiel et al. (2010), decay of alder is modeled as:

<p align="center"><span class="math">G(t)=G_{int,1,0}e^{-k_{int1}t}+G_{int,2,0}e^{-k_{int2}t}+G_{res,0}e^{-k_{res}t}</span></p>

Where *G(t)* is the fraction of carbon left at time *t*, and *G*<sub>*int2*</sub> = 0.088, *G*<sub>*res*</sub> = 0.911, *k*<sub>*int2*</sub> = 0.003, and *k*<sub>*res*</sub> = 0 (Kiel et al. 2010).

<figure><img src="/files/BlrfXwdevI8DEyGJaZOt" alt=""><figcaption><p>Figure A1: Decay rates measured by Kiel et al. (2010) on different biomass types (maize, soy, alder, plankton) modeled out to 1000 years. Note that all terrestrial biomass types are far less degraded than marine biomass (plankton).</p></figcaption></figure>

The purpose of this annex is to validate the multi-G model’s predictions against real-world data from long-buried wood on land. We compiled carbon-loss measurements from subfossil wood recovered in a wide variety of settings (terrestrial and marine burial, archaeological settings, anaerobic bogs, landfills) to see if observed decay over years to millennia aligns with the multi-G kinetic curve. By comparing these field and laboratory observations to model expectations, we test whether biomass buried in marine sub-sediments can achieve the ultra-long-term carbon stability that the multi-G framework – and prior marine experiments – suggest.

<details>

<summary><strong>Methods and Data Collection</strong></summary>

We assembled a dataset of published studies reporting the decomposition of wood buried in anoxic environments. The dataset encompasses a range of contexts – from timber excavated out of landfills to ancient logs preserved in waterlogged sediments – along with the age of burial and measures of wood degradation. We selected studies that quantified wood chemical composition (e.g. lignin and cellulose content) and/or physical loss (mass or density reduction) after burial. Each study entry was reviewed to extract the percentage of carbon loss from the wood over the reported burial duration.

*Short term burial (0-1 year)*\
For the shortest burial times (0–1 year; Table 2), studies have examined wood under artificially created and natural anoxic conditions to simulate initial decay processes. For example, Holt and Jones (1983) buried freshly cut beech (*Fagus sylvatica*) and Scots pine (*Pinus sylvestris*) blocks below 10 cm of black sulfide mud layer (\~0.1 m depth) for up to one year, simulating storage in an anoxic, waterlogged environment. Kuptz et al. (2020) stored Norway spruce (*Picea abies*) samples in sealed anaerobic containers for around 4–5 months to observe early-stage decay under oxygen-free conditions.

*Decadal scale (1-100 years)*\
In the 1–100 year range (Table 2), field studies have examined wood buried for several decades in landfill and soil contexts. Ximenes et al. (2015) excavated wood samples of a wide variety of species from Australian landfills after approximately 44 years of burial beneath 4-5 m of clay cover in anaerobic conditions.

*Centennial scale (100-1000 years)*\
Over multi-century timescales (100–1000 years; Table 2), researchers have found wood preserved in natural waterlogged sites and archaeological contexts. Uçar and Yılgör (1995) described fir wood that had been submerged in a Turkish lake for roughly 300 years. Möttönen et al. (2022) analyzed a \~700-year-old Scots pine (*Pinus sylvestris*) trunk recovered from oxygen-poor lake sediments in Finland. In an archaeological example, Ghavidel et al. (2020) investigated oak timber posts buried for about 600–700 years in damp, low-oxygen soil at a 14th-century site in Romania.

*Millennial Scale (1000-10,000 years)*\
At the longest burial durations we surveyed (1,000–10,000 years; Table 2), numerous studies document ancient wood preserved in anoxic sediments across the world. Zeng et al. (2024) reported an Eastern red cedar trunk approximately 3,800 years old that was preserved below 2 m of clay deposits in Quebec. Subfossil wood a few millennia old has been found on multiple continents: for instance, oak logs \~1,000–2,800 years old recovered from riverbank sediments in the Czech Republic (Baar et al. 2019) and a \~2,500-year-old Sitka spruce (*Picea sitchensis*) in waterlogged river deposits of Washington State (Hedges et al. 1985). Mid‐Holocene examples (several thousand years old) have also been reported – Pan et al. (1990) documented a \~6,600-year-old hardwood (*Bischofia polycarpa*) buried in a Chinese riverbed, and Solar et al. (1987) described an oak about 8,100 years old found buried 16 m deep in soil sediments. In addition, Bednar and Fengel (1974) reported an oak (*Quercus*) trunk \~8,500 years old uncovered 10 m below ground in an Austrian gravel pit. Some exceptionally ancient wood specimens even extend beyond ten millennia – Fejfer et al. (2014) noted a pine log \~12,500 years old in Poland , and swamp-preserved kauri logs in New Zealand have been dated to approximately 30,000 years old (Freedland et al. 1994).

*Burial Conditions*\
The studies sourced from the literature span a wide range of environmental settings. With studies of wood preserved in natural settings for thousands of years, the burial history and geochemical environment of the wood is poorly controlled. Incomplete burial, exposure to oxygen during the transport and burial process, intermittent re-exposure to surface conditions or oxygenated ground water are a possibility for most samples sourced from the literature.

MSSB differs in that fresh biomass is delivered directly to fully anoxic pockets within marine sub-sediments. This control on transport and storage means **MSSB projects are expected to provide greater permanence than estimates** sourced from natural settings. Estimates derived from these literature examples should therefore be treated as conservative in nature.

***Carbon Loss Estimation***\
For studies providing chemical composition, we estimated carbon loss using a conservative lignin-based approach following Ximenes *et al.* (2015) and Zeng *et al.* (2024). In essence, we assumed the wood’s lignin – a decay-resistant polymer – remained intact during burial, so any decrease in holocellulose (combined cellulose and hemicellulose) reflects carbon that was lost as CO<sub>2</sub> or CH<sub>4</sub>. This method uses the increase in relative lignin content to infer how much of the original carbon has decomposed. Carbon loss is calculated using the lignin-anchor fraction:

<p align="center"><span class="math">F= L_{fresh} \div L_{buried}</span></p>

Where *L*<sub>*fresh*</sub> and *L*<sub>*buried*</sub> are the lignin concentrations in the fresh and buried wood samples. The preserved holocellulose fraction (*P*) can then be calculated as:

<p align="center"><span class="math">P= H_{buried} \div H_{fresh} \times F</span></p>

Where *H*<sub>*buried*</sub> and *H*<sub>*fresh*</sub> represent holocellulose concentrations in the buried and fresh wood sample. With these factors and the fraction of carbon in these components (0.447 in holocellulose and 0.6 in lignin), carbon loss can be calculated as:

<p align="center"><span class="math">C-loss(\%)= {\frac {H_{fresh}\times0.447\times(1-P)} {H_{fresh}\times0.447 + L_{fresh}\times0.600}} \times100</span></p>

For studies that directly reported wood density or total mass loss, we equated the percent mass loss to percent carbon loss, assuming carbon content per wood mass stays roughly constant. This is reasonable because wood is approximately 50% carbon by weight initially (Thomas and Martin, 2012), and if a certain fraction of the wood mass is gone (mostly via carbon-containing compounds), a similar fraction of the carbon should be gone as well. If either biomass compositional, mass, or density measurements indicated a theoretical gain in carbon, carbon loss was reported as 0.

**Grouping and Analysis:** To compare with the multi-G model, we grouped the burial cases by order-of-magnitude age ranges: 0–1 year, 1–100 years, 100–1000 years, and 1000–10,000 years. This binning strategy captures early-stage decay (months to \~1 year), intermediate-term decay (years to decades), longer-term decay (centuries), and millennial-scale preservation in separate categories. For each age bin, we computed the average carbon loss (%) observed across studies in that group, and the sample standard deviation to indicate variability. These mean values at four increasing time scales serve as a condensed representation of the empirical carbon loss vs. time curve. Finally, we plotted the binned results against the multi-G model’s predicted decay trend for woody biomass (Equation 1). We compared the model’s curve to the averaged observations to assess agreement.

</details>

*Table A1: Summary comparing the conditions and parameters of 1) the multi-G model with input parameters from Keil et al. 2010, 2) empirical studies measuring carbon loss in buried wood, and 3) the requirements for marine sub-sediment burial projects under the present methodology.*

<table><thead><tr><th width="146">Characteristic</th><th width="181">Model</th><th width="208">Buried wood studies</th><th>MSSB projects</th></tr></thead><tbody><tr><td><strong>Geochemical environment</strong></td><td>Oxygenated marine sediment incubation</td><td>Poorly constrained, potentially oxygenated (floodplains, swamps, landfills, lakes, riverbeds, clays)</td><td>Site requirements of fully anoxic, leading to less decomposition than model and empirical results</td></tr><tr><td><strong>Type of biomass</strong></td><td>Alder (a type of tree/wood) results modeled here, study also tested agricultural residue and plankton</td><td>Variety of wood (see Table A2)</td><td>Wood dust, chips, or bark</td></tr><tr><td><strong>Time scale</strong></td><td>Modeled results at 1, 100, 1000 years</td><td>One month to 30,000 years (see Table A2)</td><td>Require measurements at 1 year to prove aligned with modeled stable-removal results, make 1000 year claims.</td></tr></tbody></table>

**Results**\
The results are illustrated in a comparative plot (grouped data vs. model, Figure A2) which shows observed carbon loss at each timescale alongside the multi-G model prediction. Each empirical data point represents the mean percent carbon loss for one of the four age bins (0-1, 1-100, 100-1000, 1000-10,000 years), with error bars indicating the variability among studies in that bin. Light grey dots represent individual samples from studies measuring decay. The decay curve predicted by the multi-G model is overlaid for reference. The trajectory of the decay curve falls within the range of observations of subfossil wood, indicating that the multi-G kinetic model reproduces the real-world decay of buried wood within the margin of experimental error.

<figure><img src="/files/rMgVztw0GVd2P0upWFso" alt=""><figcaption><p>Figure A2: Studies on carbon preservation in buried subfossil wood (grey dots), summary statistics (black dots, error bars) for the same studies by binned by age interval (0-1, 1-100, 100-1000, and 1000-10,000 years) and predictions of the rate of decay in wood (alder) made by multi-G kinetic model (black curve) using parameters from Kiel et al. (2010).</p></figcaption></figure>

Quantitatively, very little carbon loss is observed in the early stages of burial, consistent with model expectations of initial rapid stability. In the 0–1 year group, the carbon loss was 1.2% ± 1.3% (Figure A2). Several studies reported essentially no measurable mass loss during the first year of anoxic burial. The multi-G model supports this, predicting negligible decay in year one due to the rapid exhaustion of only the most labile components. These observations suggest that if a maximum of <2.5% (1.2% + 1.3%) of carbon loss is observed in MSSB batches after 1 year, decay is consistent with empirical evidence for carbon loss in buried wood, and long-term storage can be estimated using model results. **This directly supports purpose #2 of this annex**—determining a <2.5% annual loss is a reasonable proxy for predicting 1,000-year carbon permanence.

Even after centuries of burial (100–1000 years bin), the compiled data show that most of the wood’s carbon is still retained (with 5.2% ± 3.3% lost), aligning with the model’s slow exponential decay phase (8% lost). **The close alignment of model results (92% remaining) and empirical data (minimum 91.5% remaining) supports purpose #3 of this annex**. Available evidence suggests that permanent carbon removal using MSSB is estimated to be a maximum of 91.5%.

**Discussion**\
These findings have positive implications for the long-term stability of buried woody biomass as a climate mitigation strategy. The close match between the multi-G kinetic model and real-world subfossil wood data validates that the model’s core assumption – a small labile fraction decays quickly, leaving a large refractory fraction that persists – holds true in practice. In other words, once the readily degradable components of wood are consumed (typically within the first months of burial), the remaining bulk of the carbon becomes extraordinarily stable. This outcome is consistent with previous research on wood in landfills: studies have concluded that wood disposed under anaerobic conditions effectively acts as a “long-term reservoir of carbon” with extremely slow decay. Ximenes *et al.* (2015), for instance, documented minimal decomposition of wood even after decades in well-managed landfills, confirming that most of the carbon is retained over time. Likewise, the observation of a >3,000-year-old buried log with only \~5% carbon loss underscores how durable buried biomass can be when oxygen and microbes are severely limited (Zheng et al. 2024). The reason is straightforward – lignin-rich wood in anoxic, water-saturated or clay-sealed environments does not readily support the microbial activity needed for decay. Our results reinforce that under such conditions, burial effectively “vaults” carbon out of the atmosphere for millennia.

For the release of carbon credits, we propose a monitoring period with a 1-year duration, with results that match evidence from subfossil wood and the multi-G kinetic model. The compiled literature and our analysis indicate that no more than 2.5% of carbon is lost in the first year of anoxic wood burial. If chemical data from storage batches align with literature and model estimates, then decay can be expected to match literature and model examples, which show 92% of wood carbon will stay sequestered on the timescale of thousands of years. The excellent agreement between the multi-G model and observed subfossil wood decay affirms storage of wood in anoxic sediment as a durable form of carbon removal.

<details>

<summary><em>Table A2: Summary of sub-fossil wood studies</em></summary>

<table data-full-width="true"><thead><tr><th>Reference</th><th width="96">Age (yr)</th><th width="117">Location</th><th width="119">Species</th><th width="110">Setting</th><th>Data Type*</th><th>Carbon loss</th></tr></thead><tbody><tr><td>Freedland et al. 1994</td><td>30000</td><td>New Zealand</td><td>Agathis australis</td><td>Buried in swamp</td><td>Composition</td><td>7.63</td></tr><tr><td>Fejfer et al. 2014</td><td>12500</td><td>Poland</td><td>Pinus sylvestris</td><td>Buried stumps in floodplain</td><td>Composition</td><td>20.25</td></tr><tr><td>Bednar &#x26; Fengel 1974</td><td>8500</td><td>Austria</td><td>Quercus</td><td>Buried in gravel pit</td><td>Composition</td><td>1.67</td></tr><tr><td>Solar et al. 1987</td><td>8100</td><td>Austria</td><td>Q. robur</td><td>Buried deep in soil</td><td>Composition</td><td>14.18</td></tr><tr><td>Pan et al. 1990</td><td>6600</td><td>China</td><td>Bischofia polycarpa</td><td>Buried in riverbed</td><td>Composition</td><td>0.49</td></tr><tr><td>Zeng et al. 2024</td><td>3775</td><td>Quebec</td><td>Eastern red cedar</td><td>Buried in clay</td><td>Composition</td><td>4.53</td></tr><tr><td>Baar et al. 2019</td><td>2800</td><td>Czech</td><td>Q. robur</td><td>Buried in river bank</td><td>Composition</td><td>8.65</td></tr><tr><td>Hedges et al. 1985</td><td>2500</td><td>Washington State</td><td>Picea sitchensis</td><td>Buried in river bank</td><td>Composition</td><td>9.16</td></tr><tr><td>Baar et al. 2019</td><td>1900</td><td>Czech</td><td>Q. robur</td><td>Buried in river bank</td><td>Composition</td><td>6.13</td></tr><tr><td>Möttönen et al. 2022</td><td>1600</td><td>Finland</td><td>Pinus sylvestris</td><td>Submerged in lake</td><td>Composition</td><td>11.75</td></tr><tr><td>Baar et al. 2019</td><td>1000</td><td>Czech</td><td>Q. robur</td><td>Buried in river bank</td><td>Composition</td><td>5.52</td></tr><tr><td>Möttönen et al. 2022</td><td>700</td><td>Finland</td><td>Pinus sylvestris</td><td>Submerged in lake</td><td>Composition</td><td>8.37</td></tr><tr><td>Ghadviel et al. 2020</td><td>700</td><td>Romania</td><td>Quercus</td><td>Buried fence posts</td><td>Composition</td><td>1.71</td></tr><tr><td>Ucar &#x26; Yilgor 1995</td><td>300</td><td>Turkey</td><td>Abies sp.</td><td>Submerged in lake</td><td>Composition</td><td>3.93</td></tr><tr><td>Horisawa et al. 2025</td><td>55</td><td>Japan</td><td>Larix kaempferi</td><td>Buried poles</td><td>Density</td><td>5.09</td></tr><tr><td>Ximenes et al. 2015</td><td>44</td><td>Australia</td><td>Agathis sp.</td><td>Buried in clay</td><td>Composition</td><td>0</td></tr><tr><td>Ximenes et al. 2015</td><td>44</td><td>Australia</td><td>Pinus sylvestris</td><td>Buried in clay</td><td>Composition</td><td>0</td></tr><tr><td>Ximenes et al. 2015</td><td>44</td><td>Australia</td><td>Pseudotsuga menziesii</td><td>Buried in clay</td><td>Composition</td><td>0</td></tr><tr><td>Ximenes et al. 2015</td><td>44</td><td>Australia</td><td>Eucalyptus sp.</td><td>Buried in clay</td><td>Composition</td><td>0</td></tr><tr><td>Ximenes et al. 2015</td><td>44</td><td>Australia</td><td>Eucalyptus sp.</td><td>Buried in clay</td><td>Composition</td><td>0</td></tr><tr><td>Ximenes et al. 2015</td><td>44</td><td>Australia</td><td>Eucalyptus sp.</td><td>Buried in clay</td><td>Composition</td><td>0</td></tr><tr><td>Ximenes et al. 2015</td><td>44</td><td>Australia</td><td>Tsuga heterophylla</td><td>Buried in clay</td><td>Composition</td><td>0.28</td></tr><tr><td>Ximenes et al. 2015</td><td>44</td><td>Australia</td><td>Picea sp.</td><td>Buried in clay</td><td>Composition</td><td>3.9</td></tr><tr><td>Ximenes et al. 2015</td><td>44</td><td>Australia</td><td>Pinus radiata</td><td>Buried in clay</td><td>Composition</td><td>0.89</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>0.03</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>0</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>4.36</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>1.96</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>1.89</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>0.95</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>1.23</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>2.52</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>4.09</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>2.92</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>0.75</td></tr><tr><td>Holt and Jones 1983</td><td>1</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>0</td></tr><tr><td>Holt and Jones 1983</td><td>0.5</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>0.04</td></tr><tr><td>Holt and Jones 1983</td><td>0.5</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>0</td></tr><tr><td>Holt and Jones 1983</td><td>0.5</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>2.91</td></tr><tr><td>Holt and Jones 1983</td><td>0.5</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>2.67</td></tr><tr><td>Holt and Jones 1983</td><td>0.5</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>2.53</td></tr><tr><td>Holt and Jones 1983</td><td>0.5</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>0.39</td></tr><tr><td>Holt and Jones 1983</td><td>0.25</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>0</td></tr><tr><td>Holt and Jones 1983</td><td>0.25</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>0</td></tr><tr><td>Holt and Jones 1983</td><td>0.25</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>2.58</td></tr><tr><td>Holt and Jones 1983</td><td>0.25</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>2.1</td></tr><tr><td>Holt and Jones 1983</td><td>0.25</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>0</td></tr><tr><td>Holt and Jones 1983</td><td>0.25</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>0</td></tr><tr><td>Holt and Jones 1983</td><td>0.08333333</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>0</td></tr><tr><td>Holt and Jones 1983</td><td>0.08333333</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>0</td></tr><tr><td>Holt and Jones 1983</td><td>0.08333333</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>0.98</td></tr><tr><td>Holt and Jones 1983</td><td>0.08333333</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>1.03</td></tr><tr><td>Holt and Jones 1983</td><td>0.08333333</td><td>England</td><td>Fagus sylvatica</td><td>Black sulfide mud</td><td>Mass</td><td>0</td></tr><tr><td>Holt and Jones 1983</td><td>0.08333333</td><td>England</td><td>Pinus sylvestris</td><td>Black sulfide mud</td><td>Mass</td><td>0</td></tr><tr><td>Kuptz et al. 2020</td><td>0.43</td><td>Lab</td><td>Picea abies</td><td>Anaerobic storage container</td><td>Mass</td><td>1.4</td></tr><tr><td>Kuptz et al. 2020</td><td>0.43</td><td>Lab</td><td>Picea abies</td><td>Anaerobic storage container</td><td>Mass</td><td>0.4</td></tr><tr><td>Kuptz et al. 2020</td><td>0.37</td><td>Lab</td><td>Picea abies</td><td>Anaerobic storage container</td><td>Mass</td><td>2</td></tr><tr><td>Kuptz et al. 2020</td><td>0.37</td><td>Lab</td><td>Picea abies</td><td>Anaerobic storage container</td><td>Mass</td><td>2.2</td></tr></tbody></table>

\* **Composition** = lignin and holocellulose data reported, carbon loss with lignin conservation calculations used. **Density** = density loss reported. **Mass** = mass change reported.

</details>

<details>

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Hedges, J. I., Cowie, G. L., Ertel, J. R., James Barbour, R., & Hatcher, P. G. (1985). Degradation of carbohydrates and lignins in buried woods. *Geochimica et Cosmochimica Acta*, *49*(3), 701–711. <https://doi.org/10.1016/0016-7037(85)90165-6>

Hedges, J. I., & Keil, R. G. (1995). Sedimentary organic matter preservation: An assessment and speculative synthesis. *Marine Chemistry*, *49*(2), 81–115. <https://doi.org/10.1016/0304-4203(95)00008-F>

Hedges, J. I., Keil, R. G., & Benner, R. (1997). What happens to terrestrial organic matter in the ocean? *Organic Geochemistry*, *27*(5), 195–212. <https://doi.org/10.1016/S0146-6380(97)00066-1>

Holt, D. M., & Jones, E. B. (1983). Bacterial degradation of lignified wood cell walls in anaerobic aquatic habitats. *Applied and Environmental Microbiology*, *46*(3), 722–727. <https://doi.org/10.1128/aem.46.3.722-727.1983>

Keil, R. G., Nuwer, J. M., & Strand, S. E. (2010). Burial of agricultural byproducts in the deep sea as a form of carbon sequestration: A preliminary experiment. *Marine Chemistry*, *122*(1–4), 91–95. <https://doi.org/10.1016/j.marchem.2010.07.007>

Kuptz, D., Lesche, S., Mendel, T., Mack, R., Rist, E., Schön, C., & Hartmann, H. (2020). Fuel properties, dry matter losses and combustion behavior of wood chips stored at aerobic and anaerobic conditions. *Biomass and Bioenergy*, *142*, 105745. <https://doi.org/10.1016/j.biombioe.2020.105745>

LaRowe, D. E., & Van Cappellen, P. (2011). Degradation of natural organic matter: A thermodynamic analysis. *Geochimica et Cosmochimica Acta*, *75*(8), 2030–2042. <https://doi.org/10.1016/j.gca.2011.01.020>

Möttönen, V., Helama, S., Pranovich, A., Korotkova, E., Xu, C., Herva, H., Heräjärvi, H., Mäkinen, H., Nöjd, P., & Jyske, T. (2022). Subfossil Scots Pine (Pinus sylvestris L.) Wood from Northern Finland—Physical, Mechanical, and Chemical Properties and Suitability for Specialty Products. *Forests*, *13*(5), Article 5. <https://doi.org/10.3390/f13050704>

Pan, D., Tai, D., Chen, C.-L., & Robert, D. (1990). Comparative Studies on Chemical Composition of Wood Components in Recent and Ancient Woods of *Bischofia polycarpa*. *Holzforschung*, *44*(1), 7–16. <https://doi.org/10.1515/hfsg.1990.44.1.7>

Solar, R., Reinprecht, L., KACIK, F., MELCER, J., & HORSKY, D. (1987). Comparison of some physico-chemical and chemical properties of carbohydrate and lignin part of contemporary and subfossile oak wood. *Comparison of Some Physico-Chemical and Chemical Properties of Carbohydrate and Lignin Part of Contemporary and Subfossile Oak Wood*, *21*(5), 513–524.

Thomas, S. C., & Martin, A. R. (2012). Carbon Content of Tree Tissues: A Synthesis. Forests, 3(2), Article 2. <https://doi.org/10.3390/f3020332>

Ximenes, F. A., Gardner, W. D., & Cowie, A. L. (2008). The decomposition of wood products in landfills in Sydney, Australia. *Waste Management*, *28*(11), 2344–2354. <https://doi.org/10.1016/j.wasman.2007.11.006>

Ximenes, F., Björdal, C., Cowie, A., & Barlaz, M. (2015). The decay of wood in landfills in contrasting climates in Australia. *Waste Management*, *41*, 101–110. <https://doi.org/10.1016/j.wasman.2015.03.032>

Zeng, N., Zhao, X., Poisson, G., Clifford, B., Liu, Y., Liu, H., Meng, T., Picard, L., Zeng-Mariotti, E., Zaitchik, B., & Hu, L. (2024). 3775-year-old wood burial supports “wood vaulting” as a durable carbon removal method. *Science*, *385*(6716), 1454–1459. <https://doi.org/10.1126/science.adm8133>

</details>

***

#### Appendix C: Additional optional ESDNH indicators to monitor <a href="#pcoc1dv4wl45" id="pcoc1dv4wl45"></a>

ESDNH indicators may be measured by the Project Developer within the validation stage to reduce project risk, and suggested monitoring during the verification stage.

To monitor environmental risk, Project Developers should understand the biogeochemical zonation of sediment depths where biomass is stored. In anoxic marine sediments, organic molecules degrade via sulfate reduction, producing hydrogen sulfide (H$$\_2$$S), which diffuses upward and oxidizes to sulfate in oxygen-rich layers. In the absence of sulfate, methanogenesis dominates, producing methane (CH$$\_4$$). Both processes can generate H$$\_2$$S or CH$$\_4$$, posing environmental risks.

* Hydrogen sulfide is toxic to benthic life, and excessive production may exceed oxidation rates, increasing ecological risk.
* Methane, a potent greenhouse gas, can also impact benthic organisms if released.

To mitigate risks, H$$\_2$$S and CH$$\_4$$emissions at the sediment-water interface should remain below environmental thresholds. Project Developers are encouraged to measure dissolved sulfate, H$$\_2$$S, and CH$$\_4$$concentrations in target sediment layers before burial and include these gases in their monitoring plans to ensure environmental safety.

**Suggested monitoring plan additions to monitor environmental harms**

| Data/Indicator                                                                                           | Purpose                                                                                                                                      | Frequency of measurement                                                           |
| -------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------- |
| Dissolved hydrogen sulfide (H$$\_2$$S) in storage batch sediment porewaters at 1- and 12-month intervals | To detect microbial activity that might indicate increased environmental risk, even without %OC changes                                      | Each storage batch, 12 months after burial                                         |
| Dissolved sulfate in the sediment porewaters                                                             | To determine that the depth of storage has > 1 Mm of sulfate for organic carbon degradation to proceed using sulfate as an electron acceptor | Each storage batch, 12 months after burial                                         |
| Methane (if dissolved sulfate is not measurable)                                                         | To assess methane production, which would indicate the use of methanogenesis rather than sulfate reduction                                   | Each storage batch, 12 months after burial, if dissolved sulfate is not measurable |

***

#### Appendix D Reasoning for 2 m burial depth <a href="#dg5ezfux812d" id="dg5ezfux812d"></a>

In addition to reaching below the maximum oxygen penetration depth at any season, there is a required sub-sediment depth of at least 2 m depth into the sediment is required due to risk of reversal, due to maximum 2m sediment scouring during tropical zones, and infilling of previously scoured areas due to resuspension due to storms ([Morton, 1979](https://www.researchgate.net/profile/Robert-Morton-9/publication/250082056_Temporal_and_Spatial_Variations_in_Shoreline_Changes_and_their_Implications_Examples_from_the_Texas_Gulf_Coast/links/60181d8892851c2d4d0bb75f/Temporal-and-Spatial-Variations-in-Shoreline-Changes-and-their-Implications-Examples-from-the-Texas-Gulf-Coast.pdf); [Sherwood et al., 1994](https://www.sciencedirect.com/science/article/abs/pii/0278434394900299)), fluid-mud flows ([Wheatcroft, 2000](https://www.sciencedirect.com/science/article/abs/pii/S0278434300000625)), and erosion ([Morton, 1979](https://www.researchgate.net/profile/Robert-Morton-9/publication/250082056_Temporal_and_Spatial_Variations_in_Shoreline_Changes_and_their_Implications_Examples_from_the_Texas_Gulf_Coast/links/60181d8892851c2d4d0bb75f/Temporal-and-Spatial-Variations-in-Shoreline-Changes-and-their-Implications-Examples-from-the-Texas-Gulf-Coast.pdf), [Harris & Wiberg, 2001](https://www.sciencedirect.com/science/article/abs/pii/S0098300400001229?via%3Dihub)).

On the continental shelf, seafloor sediments are eroded and reworked by bottom currents and wave action, a process known as “scouring” ([Flood et al. 1983](https://doi.org/10.1130/0016-7606\(1983\)94%3C630:COSFAA%3E2.0.CO;2)). This creates linear or lobate depressions shaped by dominant environmental forces. Channel-shaped scours, or furrows, range from 10–100 meters wide and 100–1000 meters long, with coarse sand or gravel floors. Larger lobate deposits (100–500 meters wide) are often filled with mega-rippled coarse sand, forming "Rippled Scour Depressions" ([Davis et al. 2013](https://doi.org/10.1016/j.csr.2013.09.010)). Major storms can also transport large amounts of sediment to the deep sea without leaving scours ([Teague et al. 2006](https://doi.org/10.1029/2005GL025281)).

Scouring and sediment resuspension pose risks to carbon storage in shelf sediments, as buried biomass must remain covered to prevent oxygen exposure. To assess this risk, we reviewed 29 studies on sediment furrows and ripple scour depressions across various depths and oceanographic settings (Figure A3, Table A3). Reported scour depths, including those from extreme events (e.g., Hurricanes Katrina, Ivan, Sandy), inform our recommendation of a >2-meter burial depth for carbon storage. While regional variation is significant, findings from [Ferinni et al (2005)](https://doi.org/10.1016/j.csr.2005.07.002) suggest that wider continental shelves may offer greater protection from erosion.

<figure><img src="/files/QcGFO8tEjxMXWgZ8h7wv" alt=""><figcaption><p><strong>Figure A3 Summary of scour depths in sediment furrows and rippled scour deposits in shelf sediments.</strong> Vertical bars represent observed scour depth ranges. Observations are grouped by continent and ocean basin.</p></figcaption></figure>

*Table A3: Summary of observation of furrowing and rippled scour depressions in literature*

| **Location**                | **Water Depth** | **Scour Depth (cm)** | **Width (m)** | **Reference**                                                                                          |
| --------------------------- | --------------- | -------------------- | ------------- | ------------------------------------------------------------------------------------------------------ |
| Central CA, USA             | 30-70           |                      | 5-500         | [Cacchione et al. 1984](https://doi.org/10.1306/212F85BC-2B24-11D7-8648000102C1865D)                   |
| Onslow Bay, NC, USA         | 0-20            |                      | 20            | [MacIntyre et al. 1969](https://www.erudit.org/en/journals/ageo/1969-v5-n1-ageo_5_1/ageo05_1rep07.pdf) |
| Rio Balsas, Mexico          | 0-30            |                      | 50-100        | [Reimnitz et al. 1976](https://doi.org/10.1130/0091-7613\(1976\)4%3C395:PRCOFB%3E2.0.CO;2)             |
| Middle Atlantic Bight, USA  | 5-30            |                      | 10-100        | [Swift et al. 1978](https://doi.org/10.1306/212F7653-2B24-11D7-8648000102C1865D)                       |
| Southern Rhode Island, USA  | 0-10            |                      | 50            | [Morang et al. 1980](https://doi.org/10.1306/212F7AFE-2B24-11D7-8648000102C1865D)                      |
| Port Clarence, AK, USA      | 4-15            |                      | 10-500        | [Hunter et al. 1981](https://pubs.usgs.gov/publication/70011805)                                       |
| Southampton                 | 1-12            | 10-60                | 100-300       | [Flood et al. 1981](https://doi.org/10.1111/j.1365-3091.1981.tb01699.x)                                |
| California Coast, CA, USA   | 0-100           | 40-100               |               | [Davis et al. 2013](https://doi.org/10.1016/j.csr.2013.09.010)                                         |
| Shinnecock Inslet, NY, USA  | 3-9             | 50                   | 30            | [Ferrini et al. 2005](https://doi.org/10.1016/j.csr.2005.07.002)                                       |
| Gray's Harbor, WA, USA      | 10-16           | 100                  | 10-90         | [Ferrini et al. 2005](https://doi.org/10.1016/j.csr.2005.07.002)                                       |
| Humboldt Bay, CA, USA       | 16-36           | 100                  |               | [Ferrini et al. 2005](https://doi.org/10.1016/j.csr.2005.07.002)                                       |
| Rhone Island Sound, RI, USA | 0-42            | 50-80                |               | [McMullen et al. 2015](https://doi.org/10.1007/s00367-014-0392-0)                                      |
| Malin Shelf, Ireland        | 80-120          | 50-100               | 100           | [Evans et al. 2015](https://doi.org/10.1080/17445647.2014.956820)                                      |
| Drowned Forest, AL, USA     | 20              | 100                  |               | [Moran et al. 2024](https://doi.org/10.1016/j.margeo.2024.107402)                                      |
| Dauphin Island, AL, USA     | 60              | 30-36                |               | [Teague et al. 2006](https://doi.org/10.1029/2005GL025281)                                             |
| Innisfail, QLD, AUS         | 28-35           | 15                   | 40-150        | [Carter et al. 2009](https://doi.org/10.1016/j.margeo.2009.08.009)                                     |
| York River, VA, USA         |                 | 5-100                |               | [Dellapenna et al. 2001](https://doi.org/10.2307/1352946)                                              |
| Copper Harbon, MI, USA      | 100             | 50                   | 3-5           | [Viekman et al. 1992](https://doi.org/10.4319/lo.1992.37.4.0797)                                       |
| English Channel, UK         |                 | 50-200               | 10-20         | [Flood et al. 1983](https://doi.org/10.1130/0016-7606\(1983\)94%3C630:COSFAA%3E2.0.CO;2)               |
| Western Sahara              |                 | 100                  | 20            | [Flood et al. 1983](https://doi.org/10.1130/0016-7606\(1983\)94%3C630:COSFAA%3E2.0.CO;2)               |
| New Jersey, USA             |                 | 100-150              | 5-15          | [Flood et al. 1983](https://doi.org/10.1130/0016-7606\(1983\)94%3C630:COSFAA%3E2.0.CO;2)               |
| Los Angeles, CA, USA        |                 | 100-200              | 15-50         | [Flood et al. 1983](https://doi.org/10.1130/0016-7606\(1983\)94%3C630:COSFAA%3E2.0.CO;2)               |
| Mississippi, USA            |                 | 100-200              | 5-10          | [Flood et al. 1983](https://doi.org/10.1130/0016-7606\(1983\)94%3C630:COSFAA%3E2.0.CO;2)               |
| Bolivar Peninsula, TX, USA  | 3.5             | 100                  |               | [Goff et al. 2015](https://doi.org/10.1190/geo2014-0136.1)                                             |
| Fire Island, NY, USA        | 5-30            | 100                  |               | [Warner et al. 2017](https://doi.org/10.1016/j.csr.2017.02.003)                                        |
| Barataria Bight, LA, USA    | 10-40           | 2-15                 |               | [Allison et al. 2007](https://doi.org/10.1061/40926\(239\)67)                                          |

## Version history

<table data-full-width="true"><thead><tr><th width="237">Description of the change</th><th width="492">Justification</th><th width="165">Date</th><th>Version changed to</th></tr></thead><tbody><tr><td>Module created</td><td>--</td><td>August 2025</td><td>V1.0</td></tr></tbody></table>

[^1]: **Anoxic:** The absence of oxygen. In marine sediments, anoxic layers contain no detectable oxygen, as the rate of oxygen diffusion into these layers is slower than its consumption. In these conditions, microbial activity and organic matter degradation occur at significantly slower rates compared to oxic environments.

[^2]: A layer of sediment that is not exposed to the overlying water column, does not hold multicellular life and does not experience re-suspension. There is no exchange with marine water and the overlying water column.

[^3]: \>63um, as opposed to dissolved biomass

[^4]: This has been determined because continuous burial over one calendar month is expected to cover at maximum 24 km$$^2$$, which was deemed an appropriate threshold for when sedimentary conditions likely change.

[^5]: If O$$\_2$$ is measurable in the surface layer of marine sediments, methane diffusion is unable to occur due to aerobic oxidation of methane ([Mao et al., 2022](https://www.nature.com/articles/s41467-022-35082-y)). Aerobic oxidation of methane consumes the majority of evolved sedimentary methane before outgassing from marine sediments ([Dale et al., 2008](https://www.sciencedirect.com/science/article/abs/pii/S0012821X07006097?via%3Dihub); [Egger et al., 2018](https://www.sciencedirect.com/science/article/abs/pii/S0012821X07006097?via%3Dihub)).

[^6]: Nevertheless, it shall be conservatively assumed that any measured organic carbon loss in buried feedstock mixture is emitted to the atmosphere as biogenic CO$$\_2$$ and the corresponding carbon removal is not permanent and not issued credits.

[^7]: * Lykousis, V., Roussakis, G., Sakellariou, D., 2009. Slope failures and stability analysis of shallow water prodeltas in the active margins of Western Greece, northeastern Mediterranean Sea. Int J Earth Sci (Geol Rundsch) 98, 807–822. <https://doi.org/10.1007/s00531-008-0329-9>
    * Chen, B., Zhu, C., Feng, Y., Han, X., Zeng, W., Xing, C., Lin, S., Liu, G., 2021. Underestimated angle of submarine slope at failure: A short discussion, in: E3S Web of Conferences. EDP Sciences, p. 02057. <https://doi.org/10.1051/e3sconf/202129302057>

[^8]: Arndt, S., Jørgensen, B.B., LaRowe, D.E., Middelburg, J.J., Pancost, R.D., Regnier, P., 2013. Quantifying the degradation of organic matter in marine sediments: A review and synthesis. Earth-Science Reviews 123, 53–86. [URL](https://doi.org/10.1016/j.earscirev.2013.02.008).

    \
    Stolpovsky, K., Dale, A.W., Wallmann, K., 2018. A new look at the multi-G model for organic carbon degradation in surface marine sediments for coupled benthic–pelagic simulations of the global ocean. Biogeosciences 15, 3391–3407. [URL](https://doi.org/10.5194/bg-15-3391-2018).

    Westrich, J.T., Berner, R.A., 1984. The role of sedimentary organic matter in bacterial sulfate reduction: The G model tested. Limnology and Oceanography 29, 236–249. [URL](https://doi.org/10.4319/lo.1984.29.2.0236).

[^9]: Keil, R.G., Nuwer, J.M., Strand, S.E., 2010. Burial of agricultural byproducts in the deep sea as a form of carbon sequestration: A preliminary experiment. Marine Chemistry 122, 91–95. [URL](https://doi.org/10.1016/j.marchem.2010.07.007).

[^10]: *The multi-G model is a canonical modeling tool used to conservatively assess organic matter degradation potential. The explicit assumptions in this model are that organic carbon degradation proceeds by multiple kinetic relationships with defined rate constants (k) and proportions of the organic matter that are degraded using discrete rate constants (k) that can be measured and modelled by assessing organic carbon degradation over extended temporal monitoring.*

[^11]: A percentage of verified Rainbow Carbon Credits eliminated from each project and never issued. This acts as a safeguard against uncertainty in GHG reduction quantifications and overestimated carbon removal/avoidance.


# Biogenic carbon capture and storage (BioCCS)

This methodology covers durable carbon removal through the point-source capture and geological storage of biogenic CO<sub>2</sub> from an eligible biomass feedstock.

<table data-header-hidden><thead><tr><th width="234"></th><th></th></tr></thead><tbody><tr><td><strong>Methodology name</strong></td><td>Biogenic carbon capture and storage</td></tr><tr><td><strong>Version</strong></td><td>1.0</td></tr><tr><td><strong>Methodology ID</strong></td><td>RBW-BCCS-V1.0</td></tr><tr><td><strong>Release date</strong></td><td>June 29th, 2026</td></tr><tr><td><strong>Status</strong></td><td>In use</td></tr></tbody></table>

<details>

<summary>Acknowledgements <span data-gb-custom-inline data-tag="emoji" data-code="1f91d">🤝</span></summary>

*This methodology was developed by Rainbow with valuable input and support from the Rainbow BioCCS Working Group members and other expert contributors.*

*We would like to thank Jean-Lucien Fonquergne (New Mexico Tech), Tadeg Grall, Karim Rahmani (Carbon Impact) and Chris Malins (Cerulogy) for their insights and contributions throughout the development process.*

</details>

See the glossary for methodology-specific terminology :point\_down:

## Glossary

<table data-search="false"><thead><tr><th width="284">Term</th><th>Description</th></tr></thead><tbody><tr><td><strong>Additional biomass</strong></td><td>A biomass fraction of a retrofit project, defined as any biomass used above the amount of biomass consumed in the baseline.</td></tr><tr><td><strong>Associated CO</strong><sub><strong>2</strong></sub> </td><td>Fossil CO<sub>2</sub> emitted as a result of the capture process. </td></tr><tr><td><strong>Baseline biomass</strong></td><td>A biomass fraction of a retrofit project, defined as the amount of biomass consumed by the underlying facility as it existed prior to the retrofit.</td></tr><tr><td><strong>BioCCS</strong></td><td>The process of capturing biogenic CO<sub>2</sub> at a point-source, transporting and securely storing it for over 1,000 years in a geological storage reservoir that is permitted under a relevant international or national regulation.</td></tr><tr><td><strong>Bioenergy</strong></td><td>Renewable energy derived from organic materials, such as plant and animal waste, agricultural and forestry residues, that are converted into heat, electricity, or fuels through processes like combustion, gasification, oxidation, anaerobic digestion and fermentation.</td></tr><tr><td><strong>Biogenic CO</strong><sub><strong>2</strong></sub></td><td>CO<sub>2</sub> originating from biomass sources. It is produced by chemical or biological conversion of biomass through combustion, oxidation, anaerobic digestion and fermentation. Its capture and storage leads to net carbon removals, and is eligible for removal carbon credits.</td></tr><tr><td><strong>Biomass category</strong></td><td>The qualitative type and source of biomass eligible under this methodology.</td></tr><tr><td><strong>Biomass fraction</strong></td><td>An accounting construct to delineate which fraction of biomass is used for what purpose: baseline vs additional biomass (retrofit); biomass allocated to CO<sub>2</sub> generation vs allocated to bioenergy generation vs parasitic load biomass (greenfield).</td></tr><tr><td><strong>Capture facility</strong></td><td>The facility that captures a biogenic CO<sub>2</sub>-containing stream from a point-source and processes it into a transport- or storage-ready form, meeting CO<sub>2</sub> purity and pressure requirements.</td></tr><tr><td><strong>Captured CO</strong><sub><strong>2</strong></sub></td><td>CO<sub>2</sub> captured and concentrated from a point-source of CO<sub>2</sub>. This can include both biogenic and fossil CO<sub>2</sub>.</td></tr><tr><td><strong>CRCF</strong></td><td>The European Commission's Regulation 2024/3012 on establishing a Union certification framework for permanent carbon removals, carbon farming and carbon storage in products, also called <em>Carbon Removal and Carbon Farming regulation</em>. <a href="https://eur-lex.europa.eu/eli/reg/2024/3012/oj/eng">URL</a></td></tr><tr><td><strong>Embodied emissions</strong></td><td>Emissions associated with the construction of infrastructure and machinery attributed to the BioCCS project.</td></tr><tr><td><strong>Exit point</strong></td><td>A point at which CO<sub>2</sub> is transferred out of the capture facility for the purpose of either transport or storage, which excludes any smokestack, flue or other outlet at the capture facility from which CO<sub>2</sub> is released into the atmosphere.</td></tr><tr><td><strong>Fossil CO</strong><sub><strong>2</strong></sub></td><td>CO<sub>2</sub> originating from fossil fuels. Its capture and storage is not eligible for removal carbon credits.</td></tr><tr><td><strong>Fugitive CO</strong><sub><strong>2</strong></sub><strong> emissions</strong></td><td>Irregular or unintended CO<sub>2</sub> emissions from sources that are not localized, or are too diverse or not substantial enough to be monitored individually (e.g. equipment like reactors, pipelines, trucks). </td></tr><tr><td><strong>Geological storage</strong></td><td>Storage of CO<sub>2</sub> at a geological storage site permitted under a relevant international or national regulation.</td></tr><tr><td><strong>Greenfield</strong> </td><td>A project setup, defined as the installation of a new facility, where biomass conversion and CO<sub>2</sub> capture are co-designed. </td></tr><tr><td><strong>Heat</strong></td><td>Also referred to as useful heat. Generated to satisfy an economically justifiable demand for heat, for heating or cooling purposes.</td></tr><tr><td><strong>Induced GHG emissions</strong></td><td>Increase in direct and indirect greenhouse gas emissions over the entire lifecycle of a BioCCS project due to the implementation of the project.</td></tr><tr><td><strong>Leakage</strong></td><td>Displacement of emitting activities from the project scope to areas outside the project scope, resulting in an indirect transfer of GHG emissions rather than the absolute removal of emissions.</td></tr><tr><td><strong>Marginal energy crop</strong></td><td>A biomass category for energy crops grown on marginal, degraded or contaminated land, or as a cover crop or intermediary crop.</td></tr><tr><td><strong>Mixed stream</strong></td><td><p>A mixed stream is either</p><ul><li><strong>CO</strong><sub><strong>2</strong></sub><strong> streams generated and captured together:</strong> a stream of mixed fossil and biogenic CO<sub>2</sub>, generated from feedstock that includes a share of fossil-based material, or</li><li><strong>CO</strong><sub><strong>2</strong></sub><strong> streams generated separately, and captured together</strong>: the co-capture of the project CO<sub>2</sub> stream and one or more CO<sub>2</sub> streams from project-unrelated sources at the same capture facility. This includes fossil CO<sub>2</sub>, biogenic CO<sub>2</sub> from sustainable (zero-rated) biomass and biogenic CO<sub>2</sub> from unsustainable (non-zero-rated) biomass. </li></ul></td></tr><tr><td><strong>Nameplate energy generation capacity</strong></td><td>Maximum theoretical (power) output of a facility, determined by the operator and registered with authorities.</td></tr><tr><td><strong>Non-segregated CO</strong><sub><strong>2</strong></sub><strong> stream</strong></td><td>Project's captured CO<sub>2</sub> that is mixed with other CO<sub>2</sub> streams for any transport or injection step.</td></tr><tr><td><strong>Operator</strong></td><td>A natural or legal person, or public entity, that operates or controls the carbon removal project (i.e the capture facility), or holds decisive economic power over the technical functioning of the project. </td></tr><tr><td><strong>Point-source</strong></td><td>A localized, identifiable origin of CO<sub>2</sub> emissions from which a concentrated CO<sub>2</sub> stream can be captured.</td></tr><tr><td><strong>Post-crediting monitoring period</strong></td><td>Period up until the point at which responsibility for all geological storage sites used by the activity has been transferred to the relevant competent national authorities, in accordance with national regulations.</td></tr><tr><td><strong>Primary energy crop</strong></td><td>A biomass category for energy crops grown as main crop on agricultural land, if this land has been repeatedly cultivated for energy crops for at least 20 years prior to the start of the project's activity.</td></tr><tr><td><strong>RED</strong></td><td>The European Commission's amended Directive 2018/2001 on the promotion of use of energy from renewable sources, also called <em>Renewable Energy Directive III</em>. <a href="https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02018L2001-20240716">URL</a></td></tr><tr><td><strong>Retrofit</strong> </td><td>A project setup, defined as the addition of a carbon capture unit to an existing biomass conversion site.</td></tr><tr><td><strong>Segregated CO</strong><sub><strong>2</strong></sub><strong> stream</strong></td><td>Project's captured CO<sub>2</sub> that is at all times transported and injected separately from other CO<sub>2</sub> streams.</td></tr><tr><td><strong>Vented CO</strong><sub><strong>2</strong></sub><strong> emissions</strong></td><td>Intentional release of CO<sub>2</sub> for operational or safety reasons.</td></tr><tr><td><strong>Zero-rated biomass</strong> </td><td>Biomass certified under the EU's Renewable Energy Directive. More precisely, it is biomass compliant with Article 38, Paragraph 5 of the EU's Implementing Regulation 2018/2066, <a href="https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02018R2066-20250527#anx_IV">URL</a>, which mirrors the sustainability requirements in Article 29 of the RED</td></tr></tbody></table>


# Eligibility and scope

## Eligible technologies

All projects certified under this methodology must cause [additional ](#user-content-fn-1)[^1]carbon removals by

* capturing biogenic CO<sub>2</sub> at a point-source resulting from the processing of an [eligible biomass feedstock](#eligible-biomass), and
* permanently storing this biogenic CO<sub>2</sub> for over 1,000 years in [eligible geological storage sites](#eligible-storage).

Project Developers may transfer all or part of the captured CO<sub>2</sub> to storage sites for permanent storage to issue removal Rainbow Carbon Credits (RCCs). If part of the captured CO<sub>2</sub> is transferred for Carbon Capture and Utilization (CCU), no removal RCCs will be issued for that fraction of the CO<sub>2</sub>.

The Project Developer and entity receiving carbon finance is the **operator of the** [**capture facility**](#user-content-fn-2)[^2]. An operator is a natural or legal person, or public entity, that operates or controls the carbon removal project, or holds decisive economic power over the technical functioning of the project. Storage site operators are not eligible Project Developers.

Carbon removals under this methodology are estimated to have a permanence horizon of **at least 1000 years**. Reversal risks and baseline removals are assessed according to this duration.

### Eligible CO<sub>2</sub> sources

Captured CO<sub>2</sub> shall be a by-product of production of goods, energy and services, and shall not be generated for the sole purpose of the BioCCS project.

The following CO<sub>2</sub> point-sources are eligible, if they are generated from [eligible biomass feedstock:](#eligible-biomass)

* biogenic CO<sub>2</sub> from thermochemical treatment of biomass (e.g. combustion at bioenergy facilities, pyrolysis, gasification)
* biogenic CO<sub>2</sub> from biochemical treatment of biomass (e.g. anaerobic digestion at biogas facilities, fermentation)
* biogenic CO<sub>2</sub> from treatment of biomass mixed with other waste substances (e.g. municipal solid waste incineration)
* biogenic CO<sub>2</sub> from other industrial processes on a case-by-case basis.

At the capture site, the project's biogenic CO<sub>2</sub> **may be captured alongside ineligible CO**<sub>**2**</sub>. Only the biogenic part of the project's captured CO<sub>2</sub> shall be issued credits. This includes:

* Capture of fossil CO<sub>2</sub> generated by the capture process, called **associated CO**<sub>**2**</sub>
* Capture of **CO**<sub>**2**</sub>**&#x20;from a mixed stream**. This is defined as
  * **CO**<sub>**2**</sub>**&#x20;streams generated and captured together:** a stream of mixed fossil and biogenic CO<sub>2</sub>, generated from feedstock that includes a share of fossil-based material, or
  * **CO**<sub>**2**</sub>**&#x20;streams generated separately, and captured together**: the co-capture of the project CO<sub>2</sub> stream and one or more CO<sub>2</sub> streams from project-unrelated sources at the same capture facility. This includes fossil CO<sub>2</sub>, biogenic CO<sub>2</sub> from sustainable (zero-rated[^3]) biomass and biogenic CO<sub>2</sub> from unsustainable (non-zero-rated[^4]) biomass.

{% hint style="info" %}
For example, the liquefaction unit of a BioCCS project at a biogas production site is powered by electricity from a diesel generator. The emissions of fossil CO<sub>2</sub> from that generator are captured alongside the biogenic CO<sub>2</sub> and transported for permanent storage.

* This is **associated fossil CO**<sub>**2**</sub> emitted as a result of the capture process

For example, a waste incineration plant burns municipal solid waste, generating a CO<sub>2</sub> stream containing both fossil and biogenic CO<sub>2</sub> The BioCCS project captures the mixed stream, liquefies it and sends it for transport and permanent storage.

* This is **CO**<sub>**2**</sub>**&#x20;from a mixed stream**, generated and captured together

For example, a BioCCS project at a biogas site shares its liquefaction unit with neighboring biogas sites that are *not* registered under the project. The project's CO<sub>2</sub> is co-liquefied with CO<sub>2</sub> from these unregistered sites. Even though that CO<sub>2</sub> is biogenic and from sustainable biomass, it is ineligible because its source is not registered under the project.

* This is **CO**<sub>**2**</sub>**&#x20;from a mixed stream**, generated separately and captured together
  {% endhint %}

The CO<sub>2</sub> stream composition shall comply with all applicable legal, regulatory, and [third-party operator](#user-content-fn-5)[^5] requirements.

<details>

<summary>🇪🇺<strong>CRCF requirement:</strong> Confirmation of the origin of the CO<sub>2</sub> stream</summary>

If the facility at which the CRCF-project captures CO<sub>2</sub> is not subject to monitoring of the biogenic CO<sub>2</sub> amount under the EU Emission Trading System (EU-ETS), Project Developers shall provide access, immediately at request, to representatives of the VVB, Rainbow or relevant national authorities to allow unannounced C14 testing of the CO<sub>2</sub> stream leaving the facility, and if relevant, prior to being mixed with any separately captured fossil CO<sub>2</sub> stream. If the biogenic origin cannot be confirmed, then no credits shall be issued for the corresponding monitoring period.

</details>

### Eligible biomass

The following requirements determine **project eligibility**, and apply to all [biomass fractions](#user-content-fn-6)[^6]. Separate [Leakage](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#lc9eewbyvlyk-2) and [Environmental and social safeguard](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#id-82n4j72vjt9v) requirements also apply to specific biomass types.

Project Developers shall demonstrate that biomass:

* could not have been used as main material products (e.g. wood for construction), and
* falls into one of the categories listed below.

The entire project is ineligible if **any fraction of the CO**<sub>**2**</sub>**&#x20;generated from the underlying facility** comes from biomass

* not listed below, or
* derived from soybean cultivation and palm oil plantation (see the [Leakage](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#indirect-land-use-change) section on indirect land use change for more information).

Biomass shall be categorized accordingly:

<table data-search="false"><thead><tr><th width="144.974365234375">Biomass type</th><th width="594.5479736328125">Description</th></tr></thead><tbody><tr><td>Forest waste</td><td><ul><li><strong>Secondary forest waste:</strong> Natural but not primary old-growth forest, may still be managed for timber</li><li><strong>Managed forest waste:</strong> Managed mixed-use forests that may include agroforestry, plantations or rotational logging</li></ul></td></tr><tr><td>Necessary tree removal</td><td><strong>Necessary tree removal from any forest:</strong> Damaged trees, or trees removed for planned forest management such as preventing disease spread or wildfires</td></tr><tr><td>Agro-food waste</td><td><ul><li><strong>Residues otherwise left on soil</strong> or reapplied to soils for nutrient recycling, through mulching, composting, or spreading</li><li><strong>Residues otherwise burnt in the field</strong>, with no substantial return of nutrients or organic carbon to soil</li><li><strong>Food processing facility</strong> waste</li></ul></td></tr><tr><td>Municipal solid waste</td><td>Solid waste collected by or on behalf of municipal authorities, and disposed of through waste management systems.</td></tr><tr><td>Municipal sludge</td><td>Sewage sludge and biosolids recovered from municipal wastewater treatment systems.</td></tr><tr><td>Animal waste</td><td>Animal manure and slurry.</td></tr><tr><td>Invasive species</td><td>Woody or herbaceous plants proven to be locally or regionally invasive (non-native and causing environmental or human harm).</td></tr><tr><td>Marginal energy crops</td><td><p>Energy crops grown</p><ul><li>on marginal, degraded or contaminated land, or</li><li>as a cover crop or intermediary crop.</li></ul></td></tr><tr><td>Primary energy crops</td><td><p>Energy crops grown as main crop on agricultural land, if this land has been repeatedly cultivated for energy crops for at least 20 years prior to the start of the project's activity.</p><p>This biomass type is eligible for BioCCS projects capturing CO<sub>2</sub> from <strong>anaerobic digestion</strong> (biogas) only.</p></td></tr></tbody></table>

### Eligible storage

All BioCCS project activities, including capture, transport and storage, shall be located in jurisdictions with established regulations for the geological storage of CO<sub>2</sub>, namely countries of the European Economic Area (EEA), the United Kingdom and the USA. In Canada, geological storage is permitted in the province of Alberta, while capture and transport activities are allowed nationwide. These regulations[^7] mandate:

* **Full site characterization and risk assessment** as a precondition for storage permits,
* **Continuous monitoring** for fugitive CO<sub>2</sub> leaks during and after injection, with regular reporting to authorities, and
* **Enforceable corrective measures** and long-term liability provisions to detect and mitigate any potential reversals.

Project Developers shall provide a **valid and current regulatory control document** proving the storage site is approved for geological storage of CO<sub>2</sub> under the relevant national or local regulation. This can be in the form of a permit, license or authorization.

The capture facility of a BioCCS project is allowed to be located in a different country from the storage site/s used by that project, provided they are all eligible under this methodology.

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Eligible storage</summary>

For CRCF-projects, the capture facility shall be located in the European Union and the storage site(s) shall be permitted under the ​[Directive (EU) 2009/31/EC](https://eur-lex.europa.eu/eli/dir/2009/31/oj/eng) on the geological storage of carbon dioxide.

</details>

## Certification requirements

#### **Crediting period duration**

The maximum duration of the crediting period for projects certified under this methodology is 15 years. Upon reaching the maximum duration, a project's crediting period may be renewed **twice**, according to the [Crediting Period Renewal](https://docs.rainbowstandard.io/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal) procedure.

#### **Monitoring period duration**

The default [monitoring period](#user-content-fn-8)[^8] duration is one year, but may be shorter at the Project Developer's request. Project Developers shall submit a Monitoring Report **at least once per 12 months**. Failure to do so shall result in the project being [deregistered](https://docs.rainbowstandard.io/rainbow-standard-documents/procedures-manual/project-certification-procedure).

#### **Post-crediting monitoring period**

The **post-crediting** monitoring period shall be the duration until responsibility for all geological storage sites used by the project has been transferred to the relevant competent national authorities, in accordance with the applicable national storage site regulation[^7].

#### **Site audits**

Validation site audits for projects under this methodology shall be performed **in-person at the capture site** and follow the requirements in the Rainbow Procedures Manual section on [site audits](/rainbow-standard-documents/procedures-manual/project-certification-procedure#site-audit). Where a project comprises multiple capture sites, the Validation and Verification Body (VVB, the auditor) shall visit all sites.

#### **Versioning and project compliance**

When this methodology is revised, projects are allowed to **continue under the previous methodology version used for their initial validation** for subsequent verifications of RCCs. However, Project Developers are strongly encouraged to update their projects to comply with the latest requirements whenever possible.

## Project scope

One project is defined as:

* the operation of one or more CO<sub>2</sub> capture facilities,
  * capturing CO<sub>2</sub> from the same type of point-source (e.g. anaerobic digestion, biomass combustion)
  * using the same CO<sub>2</sub> capture, purifying and cleaning technology
  * located within a single country,
* the storage of CO<sub>2</sub> at one or more storage site(s) complying with the rules in [Eligible storage](#eligible-storage)
* operated at sites that are under the oversight or data access of a single Project Developer, regardless of whether the developer directly owns or manages each site.

The project scope is cradle-to-grave and includes all processes associated with the capture, transport and storage of CO<sub>2</sub>. This includes but is not limited to the following:

* all removals from storing the eligible fraction of CO<sub>2</sub>,
* all project emissions from the capture, transport and storage processes that are **additional to the business-as-usual scenario**, including
  * emissions from CO<sub>2</sub> generation (if applicable, see [Generation of CO<sub>2</sub>](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#generation-of-co2)),
  * embodied emissions from infrastructure and machinery used by the project,
  * emissions from energy and material use along the entire supply-chain,
  * emissions from biomass sourcing (if applicable, see [Biomass fractions](#biomass-fractions))
  * leakage emissions (if applicable, see [Biomass fractions](#biomass-fractions) and [Leakage](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#lc9eewbyvlyk-2)).

See the GHG quantification [Project Scenario](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#i4figd8ytjua) section for more details.

## Baseline scope <a href="#project-scope" id="project-scope"></a>

The standardized baselines presented below shall be revised at least every 5 years. A more conservative baseline scope may be applied on a case-by-base basis. It must be representative and transparently justified.

#### Baseline carbon removal

The baseline shall include **any permanent carbon storage of the generated CO**<sub>**2**</sub>**&#x20;that would have occurred in the absence of the project**. For BioCCS projects, a **standardized baseline of zero** **removals** is set, assuming that no carbon capture activity would have occurred under business-as-usual conditions.

Permanent carbon storage from the **alternate fate of the biomass feedstock** used by the project is addressed in [Leakage](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#lc9eewbyvlyk-2).

#### Baseline CO<sub>2</sub> generating activity

Project Developers shall categorize the project's carbon capture site either as a

* **Retrofit project**, retrofit/additional to existing site, or
* **Greenfield project**, installation of a new site. Projects qualify as a greenfield if the time between the start of operations of the biomass conversion facility and the start of the BioCCS project (i.e. installation of the carbon capture unit) does not exceed four years, unless the Project Developer can prove that biomass conversion and carbon capture were not co-designed.

Project Developers shall prove the extent of existing operations of any connected activities using historical proof of operations of the existing site/s. These **existing operations are excluded from the project scope**, and considered to be part of the business-as-usual baseline scope, because they would have occurred anyway in the absence of the project.

See the [GHG quantification: Capture stage emissions ](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#capture-stage-emissions)section for more details.

{% hint style="info" %}
For example, if the project is a **retrofit** adding CO<sub>2</sub> capture to an existing bioenergy plant:

* the embodied emissions from infrastructure for the underlying bioenergy plant are not counted towards project emissions, and
* the emissions from biomass production, supply and conversion, used to generate bioenergy and the captured CO<sub>2</sub>, are not counted towards project emissions

because **they would have been generated anyway for the business-as-usual** bioenergy plant operations.

A fraction of emissions from the above-mentioned processes may still be included in the project scope if the project uses a fraction of the site's bioenergy to power the capture unit. This bioenergy fraction is called the parasitic load. The parasitic load energy is attributed a fraction of the bioenergy site's total emissions, including from infrastructure, biomass cultivation, and other processes.
{% endhint %}

## Biomass fractions

Biomass is subject to different methodology requirements including:

* **Project eligibility**, in [Eligible Biomass](#eligible-biomass): Biomass types, from with the CO<sub>2</sub> captured by the projects is generated.
* **Sustainability**, in [Environmental and Social safeguards](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#id-82n4j72vjt9v): compliance with a set of criteria for each biomass category to demonstrate sustainability.
* **Project emissions**, in [GHG Quantification](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification): Emissions from production, supply and conversion of biomass for the generation of CO<sub>2</sub> that shall be accounted for in the project's GHG quantification.
* **Leakage**: Biomass-related [leakage emissions](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#lc9eewbyvlyk-2) driven by biomass demand from the project. Types of leakage include counterfactual carbon storage, diversion of biomass and indirect land use change emissions.

The methodology requirements apply to different **biomass fractions** (defined below) depending on the baseline scenario (i.e. retrofit or greenfield).

The different components are summarized below:

<table data-view="cards"><thead><tr><th></th><th></th><th></th></tr></thead><tbody><tr><td><strong>Biomass type</strong></td><td>The qualitative type and source of biomass</td><td><ul><li><p>waste</p><ul><li>forestry waste, necessary tree removal, agro-food waste, invasive species, municipal solid waste and sludge, animal waste</li></ul></li><li><p>energy crops</p><ul><li>primary and marginal energy crops</li></ul></li></ul></td></tr><tr><td><strong>Biomass fraction</strong></td><td>An accounting construct to delineate which fraction of biomass is used for what purpose</td><td><ul><li>baseline vs additional biomass (retrofit)</li><li>biomass allocated to CO<sub>2</sub> generation vs allocated to bioenergy generation vs parasitic load biomass (greenfield)</li></ul></td></tr><tr><td><strong>Biomass requirements</strong></td><td>The Rainbow crediting and eligibility requirements that the given biomass fraction and category are subject to</td><td><ul><li>Project eligibility</li><li>Sustainability</li><li>Project emissions</li><li>Leakage</li></ul></td></tr></tbody></table>

### **Biomass fractions for retrofit scenario**

In a retrofit scenario, two biomass fractions can be defined:

* **Baseline biomass:** The biomass consumed by the underlying facility as it existed prior to the retrofit.
* **Additional biomass**: Any extra biomass used in addition to the baseline quantity defined above. This includes extra biomass procured for the following purposes:
  * meeting the energy demand of the carbon capture equipment (also called the parasitic load), or
  * compensating for any decrease in net energy output resulting from the retrofit.

Table 1 below sets out the requirements for biomass fractions in **retrofit projects**.

| Requirement               | Additional biomass | Baseline biomass\*        |
| ------------------------- | ------------------ | ------------------------- |
| **Project eligibility**   | Yes                | Yes (all biomass)         |
| **Sustainability**        | Yes                | Yes (all biomass)         |
| **Project** **emissions** | Yes                | Yes (parasitic load only) |
| **Leakage**               | Yes                | Yes (parasitic load only) |

\*If the energy demand of the capture unit is covered internally by the parasitic load, then the corresponding parasitic load biomass is subject to the Project emissions and Leakage requirements. If the energy demand is covered through external energy sourcing, then there is no parasitic load, and the baseline biomass is only subject to Project eligibility and Sustainability requirements.

### **Biomass fractions for greenfield scenario**

In a greenfield scenario, there is no baseline biomass, because the entire site is new and there is no business-as-usual biomass consumption. Biomass consumption is driven and motivated by the mixture of co-products from the multifunctional site, and its emissions shall be [allocated as such](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#generation-of-co2). The multiple functions that drive biomass demand include

* the carbon removal project (CO<sub>2</sub> generation for capture and storage),
* and other functions such as energy generation or waste management.

In this scenario, three biomass fractions are defined:

* **Biomass allocated to CO**<sub>**2**</sub>**&#x20;generation:** The share of biomass whose production, supply and conversion emissions are allocated to CO<sub>2</sub> generation, and counted in the project scope.
* **Biomass allocated to product generation:** The share of biomass whose production, supply and conversion emissions are allocated to the generation of other products such as bioenergy, and excluded from the project scope.
* **Parasitic load biomass:** The share of total biomass consumed by the facility that is used to meet the energy demand of the capture unit (the parasitic load), and whose production, supply and conversion emissions are counted in the project scope. The parasitic load biomass fraction cannot generally be attributed to either of the other two fractions because it is initially used for product generation (making bioenergy), and is then diverted to the project (as the parasitic load energy use). It is therefore treated as a standalone fraction.

Table 2 sets out the applicable requirements for the biomass fractions in **greenfield projects**.

| Requirement             | Biomass allocated to CO2 generation | Biomass allocated to product generation | Parasitic load biomass |
| ----------------------- | ----------------------------------- | --------------------------------------- | ---------------------- |
| **Project eligibility** | Yes                                 | Yes                                     | Yes                    |
| **Sustainability**      | Yes                                 | Yes                                     | Yes                    |
| **Project emissions**   | Yes                                 | No                                      | Yes                    |
| **Leakage**             | Yes                                 | No                                      | Yes                    |

[^1]: beyond what would have happened in the business-as-usual, baseline scenario

[^2]: The facility that captures a biogenic CO<sub>2</sub>-containing stream from a point-source and processes it into a transport- or storage-ready form, meeting CO<sub>2</sub> purity and pressure requirements.

[^3]: Biomass compliant with the EU RED sustainability criteria.

[^4]: Biomass not compliant with the EU RED sustainability criteria.

[^5]: i.e. transport or storage site operators

[^6]: An accounting construct to delineate which fraction of biomass is used for what purpose:

    * baseline vs additional biomass (retrofit)
    * biomass allocated to CO<sub>2</sub> generation vs allocated to bioenergy generation vs parasitic load (greenfield)

    Further information in the [Biomass fractions](#biomass-fractions) section.

[^7]: European Economic Area (EEA):

    [Directive 2009/31/EC](https://eur-lex.europa.eu/eli/dir/2009/31/oj/eng) on the geological storage of carbon dioxide

    \
    United States of America (USA):

    [EPA’s Class VI rules (2010](https://www.epa.gov/sites/default/files/2015-07/documents/epa816b14003.pdf)) (federal level) or relevant state level regulations

    United Kingdom (UK):

    The Storage of Carbon Dioxide Regulations, [2010](https://www.legislation.gov.uk/uksi/2010/2221/contents) (Licensing) and [2011](https://www.legislation.gov.uk/uksi/2011/2305/contents) (Access to Infrastructure)\
    \
    Canada, province of Alberta: Alberta Energy Regulator on [CCUS](https://www.aer.ca/data-and-performance-reports/statistical-reports/alberta-energy-outlook-st98/carbon-capture-utilization-and-storage-ccus?utm_source=chatgpt.com)

[^8]: The period of time covered by a project's Monitoring Report, for which they have monitored operations following the Monitoring Plan, and undergo verification audit and are issued credits.


# Principles & requirements

Project Developers shall demonstrate that they comply with all principles and requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements), and described below with a specific focus on BioCCS.

{% content-ref url="/pages/CRADNrj4mfS258PN3x7N" %}
[Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules)
{% endcontent-ref %}

## Additionality

Project Developers shall follow the additionality requirements in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#additionality) and fill out the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template).

{% tabs %}
{% tab title="Regulatory surplus analysis" %}
**Regulatory surplus analysis** shall demonstrate that there are no regulations that require or mandate project activities. It is acceptable if regulations promote or set targets for these activities, because the resulting increase in activities shall be accounted for in the [baseline scenario](/methodologies/biogenic-carbon-capture-and-storage-bioccs/eligibility-and-scope#project-scope-1).

At the European Union level, projects automatically pass the regulatory surplus analysis, which has been conducted by the Rainbow Team. Project Developers are only required to provide a country-level regulatory surplus analysis.
{% endtab %}

{% tab title="Investment analysis" %}
**Investment analysis** shall be used to prove that revenue from carbon finance is necessary to make the project investment a financially viable and interesting option, and that the project would not have been viable through government support or compliance market payments alone. The investment may cover:

* The creation and launching of new **carbon capture** **sites** (i.e. greenfields)
* Expansion of capacity of existing **carbon capture** activities
* Expansion by installing new **carbon capture processes** onto existing CO<sub>2</sub> generating sites (i.e. retrofits)

Business plans shall be provided as initial proof for investment analysis. During subsequent verifications, audited financial statements shall be used to demonstrate that the initial estimates from the business plan were reasonable, and that carbon finance was used as initially described for the expected investment.

Project Developers shall use Internal Rate of Return (IRR) or Net Present Value (NPV) as financial indicators for any investment analyses.

Note that for investments in expansion, **only the additional carbon removals enabled by the expansion shall be eligible for Rainbow Carbon Credits.**
{% endtab %}
{% endtabs %}

## Durability <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

### Durability threshold

The durability of carbon removal for projects certified under this methodology is **1000+ years**.

### Reversal risk assessment

The major carbon reversal risks from BioCCS is at the CO<sub>2</sub> storage site in geological formations, where fugitive CO<sub>2</sub> leaks may occur due to e.g. natural or induced seismicity, lateral migration of the CO<sub>2</sub> plume, degrading confining systems, faults and fractures at infrastructure.

Project design requirements largely reduce reversal risks by restricting the [eligible carbon storage](/methodologies/biogenic-carbon-capture-and-storage-bioccs/eligibility-and-scope#eligible-storage) to countries with established storage regulations.

In addition to storing CO<sub>2</sub> at a regulated storage site, Project Developers shall:

* prove access to storage capacity for the projected amount of CO<sub>2</sub> captured during the facility's operating lifetime through contracts with storage providers,
* prove compliance with national storage regulations (in the [Storage Plan](#lc9eewbyvlyk-1)),
* establish a post-crediting reversal monitoring plan (in the [Storage Plan](#lc9eewbyvlyk-1)),

Upon meeting the above-mentioned requirements, the risk of reversal for carbon storage in geological formations is considered negligible. There are **no further requirements to assess reversal risks** at the project-level.

All projects certified under this methodology shall contribute the default minimum 2% of their verified removal RCCs to the [Rainbow Buffer Pool](/rainbow-standard-documents/procedures-manual/rainbow-carbon-credits#buffer-pool), as defined in the Rainbow Standard Rules.

### Storage Plan <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

The assumption that reversal risk is negligible in geological storage relies on storage sites being **rigorously selected, characterized, and monitored,** both during operations and after site closure. As part of the validation audit, Project Developers are required to provide a **storage plan**, including but not limited to the following information:

<table><thead><tr><th width="198.1973876953125">Section of Storage Plan</th><th>Required content</th></tr></thead><tbody><tr><td><strong>Site suitability</strong></td><td><ul><li>applicable regulations governing the geological storage site</li><li>characterization of the storage site (i.e potential storage complex and surrounding area),</li><li>assessment methods and data used to determine suitability for geological storage,</li><li>risk assessment for the potential of leakage from the storage site, including risk magnitude, timing and frequency.</li></ul></td></tr><tr><td><strong>Monitoring procedures</strong></td><td><ul><li>technologies used</li><li>frequency of monitoring</li><li><p>The list of monitored parameters shall at least comprise</p><ul><li>the gas flow rate,</li><li>the chemical composition of the injected CO<sub>2</sub> stream</li><li>the pressure and temperature at the injection wellhead, at the reservoir and/or along the well (where accessible)</li></ul></li><li><strong>Normal, alert and threshold values</strong> for monitored parameters procedures implemented in case the alert or threshold values are reached.</li></ul></td></tr><tr><td><strong>Reversal monitoring plan scope</strong></td><td><p>Plans to monitor the injection facility, the storage complex, including the CO<sub>2</sub> plume where possible, and its <a data-footnote-ref href="#user-content-fn-1">surroundings</a>, covering at least the following points:</p><ul><li>changes in the actual and modeled behavior of CO<sub>2</sub>,</li><li>any irregularities,</li><li>migration and leakage of CO<sub>2</sub>,</li><li>negative effects on the surrounding environment,</li><li>structural integrity of the infrastructure,</li><li>location and extent of the area monitored</li></ul></td></tr><tr><td><strong>Reversal response protocol</strong></td><td><p>Outlining actions taken if a reversal event is detected (i.e. timeline for response steps, corrective measures, documentation of any reversal events). This protocol shall be in accordance with the <a href="/pages/PFnP2GjoQlU2GAENGCg3#cancelation">Rainbow Cancelation Procedure</a> and its <a data-footnote-ref href="#user-content-fn-2">Cancelation Notice</a>.</p><p><br>Project Developers shall establish an agreement with the storage operator to ensure compliance with the above mentioned requirements, if the Project Developer is not the storage provider.</p></td></tr><tr><td><strong>Post-closure procedure</strong></td><td><p>Description of procedures and liability transfer process, in accordance with applicable regulatory frameworks. This shall at least cover</p><ul><li>post-closure monitoring,</li><li>reporting and corrective measures,</li><li>conditions for liability transfer.</li></ul></td></tr><tr><td><strong>Liability</strong></td><td>In the case that the <strong>Project Developer is not the storage operator</strong>, the Project Developer shall provide a clear division of responsibilities and liabilities between the Project Developer and the external storage operator.</td></tr></tbody></table>

{% hint style="info" %}
Note that all required information shall comply with the requirements from relevant **local or national regulations**. If such regulations do not provide specifications, it shall be based on **industry best practices or peer-reviewed scientific literature.**
{% endhint %}

## No double counting <a href="#n1iy4xaxuthk" id="n1iy4xaxuthk"></a>

Project Developers shall sign the [Rainbow MRV & Registry Terms & Conditions](/other/terms-and-contracts/terms-and-conditions-for-project-developers-mrv-+-registry), committing to follow the requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules), including not double using or double issuing carbon credits.

BioCCS projects have multiple process steps, with each step potentially operated or managed by parties other than the Project Developer. To avoid double counting, Project Developers shall provide proof, through contracts with all parties involved in the supply chain, that they are the sole owner of the RCCs associated with the storage activity, and ensure that no other party claims carbon removals associated to the activity.

Any allocation applied for co-products in the [GHG Quantification](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification) section of this methodology shall be **consistent with any other GHG accounting performed by the operator**, whether voluntary or required under applicable law. Specifically, this means that removals assigned to the BioCCS activity shall not also be deducted or claimed as avoided in a product carbon footprint, Environmental Product Declaration, or corporate GHG inventory for the primary product(s).

#### CO<sub>2</sub> Traceability

**Mass balance for non-segregated streams**

If the project CO<sub>2</sub> is mixed with CO<sub>2</sub> from other sources at any point after leaving the capture site, the CO<sub>2</sub> injected at the storage site cannot be directly linked to the BioCCS project. In the case of this so-called [**non-segregated stream scenario**](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#non-segregated-stream), Project Developers shall use contractual agreements with the transport and/or storage operators to **link a quantity of CO**<sub>**2**</sub>**&#x20;being injected at a storage site with an equivalent quantity of CO**<sub>**2**</sub>**&#x20;captured at the capture site** by the BioCCS project (minus any transport and storage losses), even if the exact physical location of the captured CO<sub>2</sub> molecules is unknown. No other CO<sub>2</sub> stored or leaving the shared system shall be linked to the same captured quantity.

Project Developers shall provide evidence, or arrange for the transport and/or storage operators to provide it, showing that all of the following mass balance rules are met:

* Each quantity of CO<sub>2</sub> entering the transport or storage system can only be counted as stored or discharged once.
* The total CO<sub>2</sub> entering any transport segment or storage site in a given period must equal the total CO<sub>2</sub> leaving or being stored at that same segment or site in the same period. Small differences are allowed to account for CO<sub>2</sub> actively in transit or undergoing storage processes at the end of the period, and for measurement uncertainty.
* Where CO<sub>2</sub> from a project is mixed with CO<sub>2</sub> from other sources, and the mixed stream is then split across more than one transport segment or storage site, Project Developers shall agree with other parties which portion of the transferred CO<sub>2</sub> is treated as coming or partially coming from the BioCCS project.
* Where CO<sub>2</sub> is transferred into a shared transport network and mixed with CO<sub>2</sub> from other sources, Project Developers do not need to track the exact transit time. Any equivalent quantity of CO<sub>2</sub> leaving the network after the project's CO<sub>2</sub> entered may be treated as the project's CO<sub>2</sub>, as long as the CO<sub>2</sub> is not assumed to have traveled against the flow direction.

{% hint style="info" %}
For example, a BioCCS project at a biogas facility captures 1,000 tCO<sub>2</sub> and injects it into a shared pipeline network already carrying CO<sub>2</sub> from two other industrial sources.

The three CO<sub>2</sub> streams mix in the pipeline. It's not possible to track exactly which molecules came from the BioCCS project.

Applying the methods to calculate transport losses, 8 tCO<sub>2</sub> associated with the project CO<sub>2</sub> was lost in transit. Under a contractual agreementt, the BioCCS project and the storage site operator agree in writing that:

* 992 tCO<sub>2</sub> injected at the storage site is attributed to the BioCCS project (1,000 t captured minus 8 t transport losses)
* That 992 tCO<sub>2</sub> is counted as permanently stored by the BioCCS project
* No other party can claim those same 992 tCO<sub>2</sub> as their stored quantity

The contract doesn't require the BioCCS project to prove its specific CO<sub>2</sub> molecules are the ones stored, just that the mass balance adds up and no double-counting occurs across all users of the shared system
{% endhint %}

## Co-benefits <a href="#id-8f3i2uvmiuhl" id="id-8f3i2uvmiuhl"></a>

Projects should support at least two **quantifiable and verifiable** environmental or social co-benefits, aligned with the [UN Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDGs) framework. Any co-benefits claimed by the Project Developer shall be **quantified, monitored, and audited** for each verification and credit issuance.

Common co-benefits under this methodology are detailed in the table below. Project Developers may suggest and prove other co-benefits not mentioned here.

SDG 13 on Climate Action by default is not considered a co-benefit here, since it is implicitly accounted for in the issuance of carbon credits. If the project delivers climate benefits that are not accounted for in the GHG reduction quantifications, then they may be considered as co-benefits.

*Table 1 Common co-benefits that projects under this methodology may provide are detailed, including types of proof that can be used to justify each co-benefit.*

<table><thead><tr><th width="205.4730224609375">UN SDG</th><th width="345">Example</th><th>Proof</th></tr></thead><tbody><tr><td><strong>SDG 7.2.</strong> Increase the share of renewable energy in the global energy mix.</td><td>BioCCS projects classified as greenfield projects produce renewable bioenergy (heat, electricity, biogas), and contribute to increasing the share of renewable energy.</td><td>Energy produced (kWh), injection receipts from electricity/heat/gas network</td></tr><tr><td><strong>SDG 9.4:</strong> Upgrade infrastructure and retrofit industries to make them sustainable.</td><td>Retrofits and additions to existing facilities support sustainable industrialization by operating scalable, innovative carbon-negative solutions.</td><td>Project description</td></tr><tr><td><strong>SDG 11.6:</strong> Reduce adverse environmental impact of cities</td><td>By capturing flue gas from municipal solid waste management sites, BioCCS projects may capture harmful pollutants alongside CO<sub>2,</sub> thereby improving urban air quality.</td><td>Analysis and quantification of captured flue gas</td></tr><tr><td><strong>SDG 12.2:</strong> Achieve sustainable management and efficient use of natural resources.</td><td>BioCCS project capturing CO<sub>2</sub> from <a data-footnote-ref href="#user-content-fn-3"><strong>waste-only</strong></a> biomass ensures that no additional land or resources are required for feedstock. This approach maximizes resource efficiency, avoids competition with food production and promotes circular economy principles.</td><td>Biomass invoices and supplier contracts</td></tr></tbody></table>

## Environmental and social safeguards <a href="#id-82n4j72vjt9v" id="id-82n4j72vjt9v"></a>

Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.**

Projects shall follow all national, local and European (if located in Europe) environmental and social regulations for the **capture, transport and storage of CO**<sub>**2**</sub>, and prove such compliance using, for example, permits, certifications, or licenses.

Project Developers shall comply with the following biomass sustainability requirements, and complete the [BioCCS risk assessment](#esdnh-risk-assessment) described below.

### Biomass sustainability

The following requirements apply to all [biomass fractions](#user-content-fn-4)[^4]:

* Project Developers shall transparently report on the **mass, type and source of biomass** to the level required in regulations[^5], national guidance and relevant industrial standards.
* Project Developers shall prove that biomass complies with the requirements for different types of biomass outlined below.

<details>

<summary>Forestry waste</summary>

Eligible sources of [forestry waste](#user-content-fn-6)[^6] and downstream wood processing waste are:

* **Secondary forest:** Natural but not primary old-growth forest, may still be managed for timber
* **Managed forest:** Managed mixed-use forests that may include agroforestry, plantations or rotational logging

Forestry waste and downstream wood processing waste shall meet all of the following requirements:

* Biomass shall **not be sourced from a** [**primary forest**](#user-content-fn-7)[^7].
* Biomass shall be proven to be waste, following the [proof of waste status](#proof-of-waste-status) requirements below.
* Biomass shall hold at least one of the following **forestry sustainability certificates**:
  * FSC (Forest Stewardship Council)⁠
  * PEFC (Program for the Endorsement of Forest Certification)⁠
  * RSB (Roundtable on Sustainable Biomaterials)⁠
  * SFI (Sustainable Forestry Initiative)⁠
  * SBP (Sustainable Biomass Program)⁠
* Biomass shall be sourced from an area with **stable or increasing carbon stocks**. Assessment of forest carbon stocks shall be evidenced by one of the following approaches:
  * **Sourcing area assessment:** An independent third-party assessment demonstrating that the net change in forest carbon stocks within the [sourcing region ](#user-content-fn-8)[^8]has not decreased during the last five years for which data is available, compared to the average forest carbon stocks in the previous 5-year period. The assessment shall be based on public inventory data and shall include live, above-ground biomass. Deadwood pools may be included if reliable data is available.
  * **Jurisdictional assessment:** Evidence that the net LULUCF[^9] emissions of the jurisdiction, as reported to the UNFCCC, are zero or negative (i.e. a net carbon sink) over a r[olling average](#user-content-fn-10)[^10] not exceeding 10 years, using the most recently available primary data. Net emissions shall include both forest land and harvested wood products as reported within the LULUCF sector. Where biomass is sourced from jurisdictional territories exceeding 5 million km<sup>2</sup>, additional evidence that forest carbon stocks in the sourcing are not decreasing over the same period shall be provided.

</details>

<details>

<summary>Necessary tree removal</summary>

**Necessary tree removal from any forest** includes damaged trees, or trees removed for planned forest management such as preventing disease spread or wildfires.

Project Developer shall

* prove that the biomass comes from a necessary tree removal activity. Evidence includes official documentation from a competent governmental authority confirming the necessity of tree removal, stating the forest health objective (such as fire risk reduction, pest control, or disease containment), together with chain-of-custody records linking the biomass to the designated intervention area, and
* prove that the biomass is classified as **waste**, following the [proof of waste status](#proof-of-waste-status) requirements below, and
* provide an **Ecosystem Restoration Plan** outlining all of the following:
  * the extent of tree removal, and how much biomass is left on the ground after harvesting
  * impacts on biodiversity and habitat loss
  * impacts on ecosystem carbon loss

</details>

<details>

<summary>Agro-food waste</summary>

Agro-food waste may originate from the field, or from food processing facilities. It shall be proven to be waste, following the [Proof of waste status](#proof-of-waste-status) requirements below.

If agro-food waste originates from the field, it shall be harvested in a way that preserves soil carbon stocks and soil quality. Evidence may include national or regional regulations, policies or local residue harvesting plans, provided these include some form of monitoring and enforcement.

</details>

<details>

<summary>Municipal solid waste (MSW)</summary>

Municipal solid waste shall not be generated for the purpose of generating CO<sub>2</sub> and/or for CDR.

MSW sites shall prove sustainable management of any hazardous waste, following the applicable regulations.

The biomass shall also be proven to be waste, following the [proof of waste status](#proof-of-waste-status) requirements below.

</details>

<details>

<summary>Municipal sludge</summary>

Municipal sludge such as sewage sludge and biosolids shall not be generated for the purpose of generating CO<sub>2</sub> and/or for CDR.

Sites handling municipal sludge shall prove sustainable management of any hazardous waste, following the applicable regulations.

The biomass shall also be proven to be waste, following the [proof of waste status](#proof-of-waste-status) requirements below.

</details>

<details>

<summary>Animal waste</summary>

Animal waste such as manure and slurry shall not be generated for the purpose of generating CO<sub>2</sub> and/or for CDR.

The biomass shall also be proven to be waste, following the [proof of waste status](#proof-of-waste-status) requirements below.

</details>

<details>

<summary>Invasive species</summary>

Project Developers shall **provide proof of invasive species status** for any biomass feedstock categorized as invasive species. This may include but is not limited to peer-reviewed scientific literature documenting the species as invasive in the specific region, national or regional government invasive species lists or registers, regional intergovernmental lists (e.g. IUCN Invasive Species Specialist Group database), or local official weed management orders.

Project Developers shall provide an **Ecosystem Restoration Plan**, outlining all of the following:

* the extent of invasive species harvesting, and how much biomass is left in the field after harvesting
* procedures to ensure only targeted invasive species are harvested
* impacts on biodiversity and habitat loss
* impacts on ecosystem carbon loss

</details>

<details>

<summary>Marginal energy crops</summary>

To avoid competition with food and feed production, marginal energy crops are defined as crops that are:

* grown on [**marginal**](#user-content-fn-11)[^11]**,** [**degraded**](#user-content-fn-12)[^12] **or contaminated land**, not suitable for food or feed production; or
* grown as a **cover crop or intermediary crop**, on agricultural land suited for food and feed production.

Project Developers shall demonstrate compliance with the following sustainability criteria:

* The classification of land as marginal, degraded or contaminated shall be recognized by a local competent authority.
* Marginal energy crops shall not be cultivated on land classified as [highly biodiverse land](#user-content-fn-13)[^13], or [high carbon stock land](#user-content-fn-14)[^14] in or after January 2008. Land use maps, land register extracts or other official documentation shall be provided as evidence.
* Marginal energy crops shall be cultivated under an agronomic **monitoring or management plan** that preserves or improves soil quality and soil carbon. Acceptable proof includes national or regional regulations, policies or local harvesting plans, provided these include some form of monitoring and enforcement.
* Cultivation of intermediary or cover crops shall comply with applicable local or regional regulations governing the cultivation of this crop type for bioenergy applications, ensuring that the crop is not the primary driver of land use and does not trigger demand for additional land. Acceptable proof includes feedstock traceability records, identifying each feedstock batch by plot of origin and delivery date. Access to feedstock sourcing history at farm level shall be made available upon request.

</details>

<details>

<summary>Primary energy crops</summary>

Primary energy crops are grown as a [main crop](#user-content-fn-15)[^15] on agricultural land that is suited for food and feed production.

This biomass type is eligible only for BioCCS projects capturing CO<sub>2</sub> from **anaerobic digestion,** and shall not exceed 15% of the total mass of the feedstock mix.

Project Developers shall demonstrate compliance with the following sustainability criteria:

* To avoid competition with food and feed production, primary energy crops shall be grown on land that was in [**repeated cultivation for energy crops**](#user-content-fn-16)[^16] **for at least 20 years** prior to the project start date.
* Primary energy crops shall not be cultivated on land classified as [highly biodiverse land](#user-content-fn-13)[^13], or [high carbon stock land](#user-content-fn-14)[^14] in or after January 2008. Land use maps, land register extracts or other official documentation shall be provided as evidence.
* Primary energy crops shall be cultivated under an agronomic **monitoring or management plan** that preserves or improves soil quality and soil carbon. Acceptable proof includes national or regional regulations, policies or local harvesting plans, provided these include some form of monitoring and enforcement.

</details>

#### Proof of waste status

Biomass types categorized above as waste shall be **proven to be waste** using any one of the following three methods:

1. **Price**: if Project Developers did not pay for the biomass, or if they were paid to handle it, the biomass can be considered waste. Acceptable proof includes invoices, receipts, or contracts.
2. **Contextual analysis**: Project Developers may submit an analysis supported by reputable sources that the biomass 1) could not be used as main material products, and 2) was not grown for the purpose of CDR or bioenergy generation.
3. **Positive list of wastes**: if the biomass is included in the following list, it can be considered waste. Acceptable proof includes invoices, receipts, contracts, or photographic evidence and is required for validation:

{% columns %}
{% column %}

* sawmill residues
* sawdust
* shavings
* bark
* forestry tops and branches
* wildfire management residues
* straw
* husks
  {% endcolumn %}

{% column %}

* corn cobs
* wood pruning from horticulture
* nut shells
* bagasse
* sugar beet pulp
* municipal solid waste
* municipal sludge and biosolids
* animal manure and slurry
  {% endcolumn %}
  {% endcolumns %}

***

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Biomass sustainability</summary>

In addition to meeting all requirements outlined above, Projects seeking certification under the CRCF shall also comply with the following:&#x20;

#### **RED-certified biomass**

Project shall use biomass that is compliant with the EU's [Renewable Energy Directive](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32023L2413\&qid=1699364355105) (RED) III. Specifically, this means that &#x20;

* biomass shall be compliant with the sustainability requirements set out in Article 29 of the RED for the purposes referred to in Article 29, Paragraph 1 (a), (b) and (c), even if the project does not generate renewable energy that is taken into account under the RED.
* the requirements on GHG savings set out in Article 29, Paragraph 10 shall only be met if the CO<sub>2</sub> is captured at a facility producing heat, electricity or a biofuel, bioliquid or biogas. The GHG savings criteria apply to the product of the facility.&#x20;
* biomass from waste or residues from agricultural, aquaculture, fisheries and forestry residues are subject to the sustainability requirements set out in Article 29, Paragraphs 2 to 7. Other biomass types are not subject to the requirements in these paragraphs.

Compliance shall be demonstrated by certification of the biomass from&#x20;

* [voluntary schemes](https://energy.ec.europa.eu/topics/renewable-energy/bioenergy/voluntary-schemes_en) approved by the Commission in accordance with Article 30, Paragraph 4 of RED, or
* national schemes recognized by the Commission in accordance with Article 30, Paragraph 6 of RED, or
* schemes recognized by the competent national authority in the state where the BioCCS capture facility is located.

#### **Additional biomass sustainability requirements**

Project Developers shall also demonstrate that

* biomass is not identified as being produced from a high indirect land use change risk feedstock, as defined in the [Delegated Regulation 2019/807](https://eur-lex.europa.eu/eli/reg_del/2019/807/oj/eng) to the RED.
* if biomass is sourced from areas designated by the national competent authority for

  conservation, including areas covered by the national restoration plan established under

  [Regulation (EU) 2024/1991](https://eur-lex.europa.eu/eli/reg/2024/1991/oj/eng), or in habitats that are protected, the sourcing shall be in

  accordance with the conservation and restoration objectives for those areas.

#### **CO**<sub>**2**</sub>**&#x20;captured from energy production covered under RED**

If CO<sub>2</sub> is captured from an energy production process covered by the RED, Project Developers shall demonstrate that

* the national implementation of that directive applies to the operator of the energy production process and that the operator complies with this national implementation.
* the operator complies with any measures in that national implementation that ensure that woody biomass is used according to the [list of priorities](#user-content-fn-17)[^17] established in Article 3, Paragraph 3 of the RED, including any derogations introduced by Member States under Article 3, Paragraph 3 (a), if the operator benefits from a relevant support scheme for energy production.
* the operator does not receive direct financial support from Member States for the use of saw logs, veneer logs, industrial grade roundwood, stumps and roots to produce energy, in line with Article 3, Paragraph 3 (c)&#x20;

Facilities regulated under the RED undergo periodic assessment of compliance with the sustainability requirements by Member State competent authorities. This periodic assessment shall not prevent the compliance assessment conducted by the VVB for approval of credit issuance. In practice, this means that the VVB does not need to wait for the completion of an ongoing RED assessment of compliance before assessing the BioCCS project and approving credit issuance. However, if the Member State assessment results in any non-conformity with Article 29 of the RED, Project Developers shall notify Rainbow and the VVB immediately.&#x20;

#### **Voluntary compensation of biomass**

To support the regeneration of natural carbon stocks used for the generation of permanent carbon removals, Project Developers may purchase [carbon farming sequestration units](#user-content-fn-18)[^18] and report the amount in the monitoring report.&#x20;

</details>

#### **Biomass conversion efficiency**

For projects that capture CO<sub>2</sub> from a facility that primarily converts biomass to heat and/or electricity, Project Developers **shall not make operational changes that reduce the efficiency of the biomass-to-bioenergy conversion process**, i.e. requiring greater biomass consumption in favor of higher CO<sub>2</sub> generation.

Project Developers shall prove one of the following:

* The facility's [nameplate energy generation capacity](#user-content-fn-19)[^19] has not increased by more than what is needed **to power the capture process.** This shall be assessed relative to the facility's nameplate capacity either at the time it began operating, or three years prior to the start of the project's certification period.
* The facility would remain economically viable without carbon removal, if it is
  * a [newly-constructed facility](#user-content-fn-20)[^20] that became operational not more than one year before the start of the BioCCS project; or
  * a facility that previously consumed fossil fuel feedstock, either partly or entirely, and that was adjusted to increase the share of biomass in the feedstock mix not more than one year before the start of the BioCCS project.

The above requirements do not apply if the project captures CO<sub>2</sub> from:

* waste-to-energy facilities combusting wastes or residues other than agricultural, aquaculture, fisheries, and forestry residues (e.g. municipal waste incineration);
* facilities using biomass for **non-energy applications** or where heat/electricity are **not the primary outputs** (e.g., biofuel or biogas production);
* facilities using biomass as part of an **industrial chemical process** to produce a product other than heat or electricity, even if energy is also extracted.

{% hint style="info" %}
**Example**

A bioenergy plant, built in 2015, has a nameplate energy generation capacity of 50 MW, which has remained unchanged since it began operating. In 2022, the facility was retrofitted with a carbon capture unit, which requires 3 MW of energy to operate, and captures **18,000 tCO**<sub>**2**</sub>**/year**. The plant consumes 100,000 tonnes/year of woody biomass.

* **Scenario 1:** The plant’s nameplate capacity increased by 3 MW, from 50 MW (2019, three years prior to the start of the project) to 53 MW, due to an increased consumption of biomass. The capacity increase **exactly matches the energy needed to power the capture process**. No other operational changes were made.
  * ✅ **This scenario is eligible** because the increase only covers the energy demand of the capture unit.
* **Scenario 2:** The plant’s nameplate capacity increased by 6 MW, from 50 MW (2019) to 56 MW, **exceeding the 3 MW required for the capture process**. Since the increase is greater than what is needed to power the capture unit, it suggests that biomass consumption was increased not only to power the capture unit, but also to generate more CO<sub>2</sub> for capture.
  * ❌ **This scenario is ineligible** because the capacity increase goes beyond the needs of the capture process.
* **Scenario 3:** In 2025, the Project Developer installs an additional heat recovery system that improves the plant's overall thermal efficiency, allowing more CO<sub>2</sub> to be captured from the same flue gas stream. Biomass consumption remains unchanged at 100,000 tonnes/year, but the capture unit can now process a greater share of the flue gas, increasing captured CO<sub>2</sub> to 20,000 tCO<sub>2</sub>/year
  * ✅ **This scenario is eligible**. Although the operational changes increased CO<sub>2</sub> generation per unit of output, this results from an improvement in process efficiency, not from additional biomass consumption

***

A biogas plant produces biomethane through anaerobic digestion of agricultural residues. CO<sub>2</sub> is captured from the upgrading process, where it is separated from the raw biogas stream. The plant's primary output is biomethane for grid injection. In 2024, the plant increases its feedstock consumption by 20%, from 50,000 to 60,000 tonnes/year of agricultural residues, in order to produce more biomethane. As a result, more CO<sub>2</sub> is available for capture.

* ✅ **This scenario is not subject to the requirements above**. The facility's primary purpose is biomethane production, not heat or electricity generation. The additional CO2 captured is a co-product of biomethane production expansion, not the result of an operational adjustment made solely to increase CO<sub>2</sub> availability.
  {% endhint %}

### Environmental and social risk assessment <a href="#esdnh-risk-assessment" id="esdnh-risk-assessment"></a>

Project Developers shall fill in the [BioCCS risk assessment template](/methodologies/biogenic-carbon-capture-and-storage-bioccs/risk-assessment-template), to evaluate the identified environmental and social risks of projects. The identified risks include:

For biomass

* Disruption of soil health when collecting and exporting organic matter
* Deforestation from use of forestry products as feedstock
* Distant transport of feedstock inputs (>100 km)

For CCS

* Generation of hazardous liquid and solid wastes and exhaust gases during capture process
* CO<sub>2</sub> stream impurities
* CO<sub>2</sub> leakage during transport
* CO<sub>2</sub> migration or leakage to surface or near-surface at storage site
* Contamination of groundwater due to leakage of CO<sub>2</sub> from storage reservoir
* Induced seismicity

<details>

<summary>🇪🇺 <strong>CRCF requirement</strong>: Risk assessment </summary>

Project Developers seeking compliance with the EU's CRCF shall additionally evaluate and address the following risks.

#### **Climate change adaptation**

To comply with the *do-no-significant-harm to climate change adaptation* criteria, Project Developers shall identify the physical climate risks that are material to the project from those listed in Section II of Appendix A to Annex 1 of the [Commission Delegated Regulation (EU) 2021/2139](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02021R2139-20260101#app_A) and perform a robust climate risk and vulnerability assessment following the steps outlined in Section I of that same appendix.

#### **Sustainable use and protection of water and marine resources**

Any potential risks due to the project to the good status or the good ecological potential of bodies of water, including surface water and groundwater, or to the good environmental status of marine waters. In the case that pollutants that are scrubbed from flue gases in order to reduce air pollution may be released to a body of water, the air pollution benefit and the availability of alternative discharge strategies shall be taken into consideration when evaluating the impact on water quality.&#x20;

Addressing the following [Minimum environmental and social risks](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment) defined in the Rainbow Standard Rules is equivalent to addressing this risk:

* Minimize pollutant discharges to water, noise and vibration&#x20;
* Avoid and/or minimize negative impacts on terrestrial and marine biodiversity and ecosystems
* Minimize water consumption and stress in the project&#x20;

#### **Circular economy, efficient use of sustainably sourced bio-based materials**

Any potential risks to the circular economy objectives from the projects, considering&#x20;

* the project leads to significant inefficiencies in the use of materials or in the direct or indirect use of natural resources such as non-renewable energy sources, raw materials, water and land at one or more stages of the life cycle of products, including in terms of durability, reparability, upgradability, reusability or recyclability of products
* the project leads to a significant increase in the generation, incineration or disposal of waste, with the exception of the incineration of non-recyclable hazardous waste
* the long-term disposal of waste may cause significant and long-term harm to the environment

#### **Pollution prevention and control**

Any potential risks to generate a significant increase in the emissions of pollutants to air, water or land from the project. Where facilities are within the scope of [Directive 2010/75/EU](#user-content-fn-21)[^21] they shall comply with all requirements arising from that Directive.&#x20;

Where facilities are not in the scope of that Directive, addressing the following [Minimum environmental and social risks](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment) defined in the Rainbow Standard Rules is equivalent to addressing this risk.

* Minimize pollutant emissions to air
* Minimize pollutant discharges to water, noise and vibration&#x20;
* Minimize generation of waste and release of hazardous materials, chemical pesticides and fertilizers

#### **Protection and restoration of biodiversity and ecosystems**

Any potential risks from the project to the good condition or resilience of ecosystems or to the conservation status of habitats and species, including those of Union interest or to the achievement of targets or obligations set out in national restoration plans established under [Regulation (EU) 2024/1991](https://eur-lex.europa.eu/eli/reg/2024/1991/oj/eng).

Addressing the following [Minimum environmental and social risks](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment) defined in the Rainbow Standard Rules is equivalent to addressing this risk. Note that any potential risk to targets or obligations in national restoration plans shall be addressed separately.&#x20;

* &#x20;Avoid and/or minimize negative impacts on terrestrial and marine biodiversity and ecosystems
* Protect the habitats of rare, threatened, and endangered species, including areas needed for habitat connectivity
* Do not convert natural forests, grasslands, wetlands, or high conservation value habitats
* Minimize soil degradation and soil erosion
* Minimize water consumption and stress in the project

</details>

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

## Leakage <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

According to the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#leakage), carbon removal projects shall minimize leakage, where carbon-emitting activities are displaced or shifted outside of the project boundary.

Project Developers shall assess and, if identified to be material, quantify the leakage caused by the BioCCS project. This shall be done by first identifying the alternative fate of biomass, and then assessing the leakage risks from the following identified leakage sources:

1. Counterfactual carbon storage
2. Diversion of biomass
3. Indirect land use change
4. Diversion of bioenergy and biomaterial

Biomass-related leakage requirements (leakage sources 1-3) apply to the following [biomass fractions](#user-content-fn-4)[^4]:

* Greenfield:
  * Biomass fraction allocated to CO<sub>2</sub> generation
  * Parasitic load biomass fraction
* Retrofit:
  * Baseline biomass fraction (if used for parasitic load)
  * Additional biomass fraction

Any leakage GHG emissions are calculated according to the [Leakage emissions](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#leakage-emissions) section and deducted from the project GHG quantification.

The **leakage assessment is valid for 5 years**, provided the biomass type and [sourcing region](#user-content-fn-22)[^22] remain unchanged. After 5 years, upon verification, a new leakage assessment shall be conducted for the project with updated context and proof.

The Project Developer is responsible for reporting any significant change in biomass type or sourcing region in their monitoring report **at each verification**. Where such a change is identified, a reassessment of leakage impacts is required, even if the project's 5-year leakage assessment is still valid.

### Alternative fate of biomass

Project Developers shall evaluate the most likely alternative use/s of the biomass in order to assess leakage risks associated with **the counterfactual carbon storage and the diversion of biomass**. The assessment shall be transparent and conservative.

Alternative uses of the biomass include but are not limited to:

{% columns %}
{% column %}

* incineration
* energy combustion
* left on field / in forest
* animal bedding
  {% endcolumn %}

{% column %}

* animal feed
* mulching
* landfill
* other (specified by Project Developers)
  {% endcolumn %}
  {% endcolumns %}

Proof shall be provided and may include signed statements from the biomass provider, historical records from the biomass provider, regional statistics or reputable reporting.

A short list of likely alternative uses may be provided for descriptive purposes, but for the purpose of further analysis, one single alternative use shall be proposed.

### Counterfactual carbon storage

The climate benefit of a BioCCS project, i.e. the actual removal of CO<sub>2</sub> from the atmosphere, only occurs when the carbon in the biomass feedstock would have been released to the atmosphere in the absence of the project. In other words, for the period that carbon would have remained stored in the biomass in its alternative use/counterfactual scenario, any project CO<sub>2</sub> permanently stored represents CO<sub>2</sub> that would not yet have been emitted.

The timing of this release depends on the type of biomass and its alternative fate. It can be rapid, where the counterfactual involves fast decay or combustion, or it can span decades, as with woody biomass in cool or dry environments.

Although these decay timescales are negligible relative to the 1,000+ year durability of BioCCS carbon removal, **only the removal of biogenic CO**<sub>**2**</sub>**&#x20;otherwise released in the near-term is additional and can be credited**. This ensures that the project delivers a near-term benefit for climate change mitigation.

The assessment of counterfactual carbon storage is informed by the biomass's alternative fate scenario:

* No baseline carbon storage is considered for feedstock whose alternative fate fully releases its carbon in the near-term. This includes
  * incineration
  * energy combustion
  * necessary tree removal under a wildfire mitigation program.
* For all other alternative fate scenarios, counterfactual carbon storage is assumed to be non-negligible and shall be quantified according to the [Counterfactual carbon storage](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#counterfactual-carbon-storage) section in the GHG Quantification.

### Diversion of biomass

BioCCS projects capture CO<sub>2</sub> from sustainable biomass, a scarce resource, that may otherwise have been used elsewhere. Demand from the project's activity risks displacing biomass from an existing use, forcing other actors to use high-emission alternatives.

Leakage from the diversion of biomass feedstock can be assumed to be **negligible** if Project Developers can demonstrate one of the following cases:

<table data-full-width="false"><thead><tr><th width="366.44677734375">Description</th><th>Proof</th></tr></thead><tbody><tr><td>The project is a retrofit and the biomass feedstock consumed by the project did not change in quantity compared to the business-as-usual scenario over the last 3 years prior to retrofitting.</td><td>Calculation of the <a data-footnote-ref href="#user-content-fn-23">baseline consumption rate</a></td></tr><tr><td>The feedstock is agricultural or forestry waste that would have been burnt on the field or elsewhere.</td><td>Historic proof of disposal from feedstock supplier (e.g. contract with disposal or end-use sites)</td></tr><tr><td>The feedstock is whole trees from <a data-footnote-ref href="#user-content-fn-24">necessary tree removal</a> and is unsuitable for bioenergy or material production.</td><td><p>Justification and proof of</p><ul><li>necessary tree removal</li><li>unsuitability for bioenergy and material production</li></ul><p>Historic proof of disposal from feedstock supplier (e.g. contract with disposal or end-use sites)</p></td></tr></tbody></table>

If none of the cases can be demonstrated, leakage from the diversion of biomass shall be quantified for each feedstock type and source according to the rules set out in the [Diversion of biomass](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#biomass-diversion) section of the GHG Quantification and deducted from the total GHG removals of the project.

### Indirect land-use change

Indirect land use change can occur when land that was previously used to produce food or feed is converted to produce biomass for bioenergy. As the demand for food and feed still needs to be met, this can lead to agricultural land being extended into areas with high carbon stocks, such as forests, wetlands and peatlands, causing additional emissions.

Projects that use any fraction of biomass input that derives from oil palm plantations and soybean cultivation are ineligible due to the [high risk of indirect land-use change](#user-content-fn-25)[^25] (iLUC) associated to this feedstock type.

Project Developers shall quantify iLUC leakage emissions following the rules in the [Indirect land use change](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#indirect-land-use-change-emissions) section of the GHG Quantification, where required by the table below.

<table data-search="false"><thead><tr><th width="194.016357421875">Biomass type</th><th>iLUC risk</th></tr></thead><tbody><tr><td>Forestry waste</td><td>Mitigated through compliance with sustainability criteria.</td></tr><tr><td>Necessary tree removal</td><td>Mitigated through compliance with sustainability criteria.</td></tr><tr><td>Agro-food waste</td><td><p>Mitigated, if Project Developers can demonstrate one of the following:</p><ul><li>they did not pay for the biomass, or</li><li>they were paid to handle the biomass, or</li><li>residue sales do not exceed 50% of the feedstock supplier's revenues, evidenced by assessing the <strong>relative income of the feedstock supplier from residue sales</strong> to the BioCCS project using farm records or analysis of <a data-footnote-ref href="#user-content-fn-26">secondary data</a>.</li></ul><p>If not, <strong>quantify iLUC leakage</strong>.</p></td></tr><tr><td>Municipal solid waste</td><td>Mitigated through compliance with sustainability criteria.</td></tr><tr><td>Municipal sludge</td><td>Mitigated through compliance with sustainability criteria.</td></tr><tr><td>Animal waste</td><td>Mitigated through compliance with sustainability criteria.</td></tr><tr><td>Invasive species</td><td>Mitigated through compliance with sustainability criteria.</td></tr><tr><td>Marginal energy crops</td><td>Mitigated through compliance with sustainability criteria.</td></tr><tr><td>Primary energy crops</td><td>Quantify iLUC leakage.</td></tr></tbody></table>

### Diversion of bioenergy and biomaterial

The assessment of leakage from the diversion of bioenergy and biomaterial depends on the chosen baseline scenario, and shall be quantified according to the rules set out in the [Diversion of Bioenergy and biomaterial](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#diversion-of-bioenergy-and-biomaterial) section in the GHG Quantification:

* For **greenfield** BioCCS facilities, no leakage due to diversion of bioenergy and biomaterial is considered because there are no such outputs in the business-as-usual (BAU) scenario.
* For **retrofits/ additions on top of existing sites** that:
  * produce an equivalent or increased amount of bioenergy or biomaterial (e.g. through improvement of efficiency), there is no diversion of bioenergy/biomaterial leakage.
  * produce and export less energy or material than the BAU, and that reduction is directly linked to the retrofitting of the facility (e.g. reduced energy export due to high internal energy consumption of the CCS equipment), leakage shall be quantified for the displaced provisioning of the marginal energy or material.

## Monitoring <a href="#snhouoxhyrzi" id="snhouoxhyrzi"></a>

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information **for each monitoring period**:

{% tabs %}
{% tab title="Segregated CO2 streams" %}
**For** [**segregated streams**](#user-content-fn-27)[^27]:

Biomass assessment

* [Environmental and Social Safeguards: Biomass sustainability](#biomass-sustainability)

Carbon storage measurements

* amount of CO<sub>2</sub> injected at the storage site
  * mass or volumetric flow, density and concentration of CO<sub>2</sub> in injected stream
* amount of CO<sub>2</sub> captured at the capture site
  * mass or volumetric flow, density and concentration of CO<sub>2</sub> of captured stream
* amount of ineligible CO<sub>2</sub> captured at the capture site, if applicable
  * amount of [associated CO<sub>2</sub>](#user-content-fn-28)[^28]
  * amount of [CO<sub>2</sub> from a mixed stream](#user-content-fn-29)[^29]

GHG quantification

* emissions associated with [CO<sub>2</sub> generation](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#generation-of-co2), if applicable
* amount and type of fuel, energy, chemicals and other inputs used by the capture process
  * [parasitic load biomass](#user-content-fn-30)[^30] and associated emissions, if applicable
* emissions associated with CO<sub>2</sub> transport
  * for transportation via pipeline networks, per segment:
    * amount and type of fuel or energy used by the pipeline network
  * for transportation via road, rail or ship, per segment:
    * distance traveled, weight of CO<sub>2</sub> transported and type of vehicle, or
    * amount and type of fuel consumed, type of vehicle and number of trips
* amount and type of fuel or energy used at storage site
* embodied emissions from infrastructure and machinery at capture, transport and storage stage
* amount of [associated CO<sub>2</sub>](#user-content-fn-31)[^31] captured and stored, if applicable

Proof of delivery

* contractual agreement with storage site operator confirming the amount of CO<sub>2</sub> injected, proof of injection.

Co-benefits
{% endtab %}

{% tab title="Non-segregated CO2 streams" %}
**For** [**non-segregated streams**](#user-content-fn-32)[^32]**:**

Biomass assessment

* [Environmental and Social Safeguards: Biomass sustainability](#biomass-sustainability)

Carbon storage measurements

* amount of CO<sub>2</sub> captured at the capture site
  * mass or volumetric flow, density and concentration of CO<sub>2</sub> of captured stream
* amount of ineligible CO<sub>2</sub> captured at the capture site, if applicable
  * amount of [associated CO<sub>2</sub>](#user-content-fn-28)[^28]
  * amount of [CO<sub>2</sub> from a mixed stream](#user-content-fn-29)[^29]
* fraction of eligible biogenic CO<sub>2</sub> sent for permanent carbon storage and not used for other purposes (i.e. utilization)
* amount of CO<sub>2</sub> lost during the transport stage
* amount of CO<sub>2</sub> lost during the storage stage

GHG quantification

* emissions associated with [CO<sub>2</sub> generation](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#generation-of-co2), if applicable
* amount and type of fuel, energy, chemicals and other inputs used by the capture process
  * [parasitic load biomass](#user-content-fn-30)[^30] and associated emissions, if applicable
* emissions associated with CO<sub>2</sub> transport
  * for transportation via pipeline networks, per segment:
    * amount and type of fuel or energy used by the pipeline network
  * for transportation via road, rail or ship, per segment:
    * distance traveled, weight of CO<sub>2</sub> transported and type of vehicle, or
    * amount and type of fuel consumed, type of vehicle and number of trips
* amount and type of fuel or energy used at storage site
* embodied emissions from infrastructure and machinery at capture, transport and storage stage
* amount of [associated CO<sub>2</sub>](#user-content-fn-31)[^31] captured and stored, if applicable

Proof of delivery

* contractual agreement with transport and/or storage operators, linking an amount of CO<sub>2</sub> injected at a storage site to an equivalent amount of CO<sub>2</sub> captured at the capture site (minus any losses), proof of injection.

Co-benefits
{% endtab %}
{% endtabs %}

Monitoring Plans for this methodology shall also include, **at least once every 5 years**:

* updated leakage assessment and quantification of leakage emissions, if applicable (see [Leakage](#lc9eewbyvlyk-2))
* updated economic value of CO<sub>2</sub> and primary product or service of facility, if applicable (see [CO<sub>2</sub> generation](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#generation-of-co2))

Monitoring Plans shall include the following information for each monitored parameter:

* monitoring frequency
* emission sources and sinks
* data source
* measurement methods/procedures, and their accuracy and calibration
* quality assessment or quality control procedures
* responsible party for collecting and archiving data

[^1]: often defined as *active/maximum monitoring area,* usually upon to 1 km around maximum CO2 plume extension.

[^2]: The Project Developer must submit a **Cancelation Notice** to notify Rainbow within **30 calendar days** of becoming aware of the reversal event.

[^3]: Classified as waste according to the [Biomass sustainability](#biomass-sustainability) section.

[^4]: An accounting construct to delineate which fraction of biomass is used for what purpose:

    * baseline vs additional biomass (retrofit)
    * biomass allocated to CO<sub>2</sub> generation vs allocated to bioenergy generation vs parasitic load (greenfield)

    Further information in the [Biomass fractions](/methodologies/biogenic-carbon-capture-and-storage-bioccs/eligibility-and-scope#biomass-fractions) section.

[^5]: e.g. the [Renewable Energy Directive](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02018L2001-20240716#art_29) reporting in the EU

[^6]: collected directly from forest land

[^7]: Primary forest is defined as a forest that has never been logged and has developed following natural disturbances and under natural processes, regardless of its age.

[^8]: A continuous geographic area from which biomass is harvested, with similar ecological characteristics (e.g. species composition and biodiversity) as defined by the relevant regional authorities. Definition from Carbon Direct's Guide to Sustainable Biomass Sourcing (2025). [URL](https://www.carbon-direct.com/research-and-reports/2025-guide-to-sustainable-biomass-sourcing)

[^9]: Land-use, land-use change and forestry: A sector of national greenhouse gas inventories, as reported to the UNFCCC, that accounts for carbon stock changes and GHG emissions and removals resulting from land use and land management activities. A net negative LULUCF value indicates that the land sector is functioning as a net carbon sink

[^10]: An average calculated using the most recently available data over a defined period (here, 10 years).

[^11]: The definition of marginal land varies depending on the geography and economy.\
    Marginality is generally determined by two main dimensions:

    * biophysical constraints, such as low fertility, poor drainage, shallowness, salinity, steepness of terrain or unfavorable climatic conditions
    * socio-economic constraints, such as the absence of markets, difficult accessibility, restrictive land tenure, small holdings, poor infrastructure or unfavorable output/input ratios

[^12]: Degraded land is land that, for a significant period of time, has either been significantly salinated or presented significant low organic matter and has been severely degraded.

    Definition of "severely degraded land" from the EU's RED, [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02018L2001-20240716#anx_V)

[^13]: * Primary/old-growth forests
    * Species-rich forests identified as highly biodiverse
    * Legally protected nature areas or areas protecting endangered species
    * Natural or species-rich highly biodiverse grassland
    * Heathland

    as identified by the relevant competent authority

[^14]: wetlands, peatlands and forests.

[^15]: *Main crop* as opposed to *intermediary* or *cover crop*. This includes energy crops grown as part of a crop rotation practice.

[^16]: for example energy crops grown as part of a crop rotation.

[^17]: (a)  wood-based products;

    (b)  extending the service life of wood-based products;

    (c)  re-use;

    (d)  recycling;

    (e)  bioenergy;

    (f)  disposal.

[^18]: Temporary carbon credits issued under the carbon farming branch of the CRCF that certify the removal and storage of CO2 through land-based activities such as soil carbon sequestration, agroforestry, and peatland rewetting.

[^19]: The *nameplate energy generation capacity* is the maximum theoretical (power) output of a facility, determined by the operator and registered with authorities. The actual output can be different.

[^20]: This could be a

    * greenfield facility, or
    * a retrofit facility if it can be demonstrated that the biomass conversion and carbon capture were not co-designed

    see [Baseline CO2 generating activity](/methodologies/biogenic-carbon-capture-and-storage-bioccs/eligibility-and-scope#baseline-co2-generating-activity) for more details.

[^21]: Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial and livestock rearing emissions (integrated pollution prevention and control), [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02010L0075-20240804)

[^22]: A continuous geographic area from which biomass is harvested, with similar ecological characteristics (e.g. species composition and biodiversity) as defined by the relevant regional authorities. Definition from Carbon Direct's Guide to Sustainable Biomass Sourcing (2025). [URL](https://www.carbon-direct.com/research-and-reports/2025-guide-to-sustainable-biomass-sourcing)\
    \
    A change in supplier alone does not constitute a change in source.

[^23]: biomass feedstock consumed in the 3 years prior to retrofitting, calculated following [Calculation: additional biomass](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#calculation-additional-biomass)

[^24]: damaged trees, or trees removed for planned forest management such as preventing disease spread or fires

[^25]: A crop whose production area has expanded significantly into land with high carbon stock (i.e. forests, wetlands, or peatland).

    This means that

    * More than 10% of the crop's global production area has expanded into high-carbon-stock land since 2008, and
    * that expansion is happening at an average rate of more than 1% per year.

    This definition is adopted from the EU's RED II Delegated Regulation 2019/807, [URL](https://eur-lex.europa.eu/eli/reg_del/2019/807/oj/eng).

[^26]: e.g. regional market prices and agricultural statistics

[^27]: Project's captured CO<sub>2</sub> that is at all times transported and injected separately from other CO<sub>2</sub> streams.

[^28]: Fossil CO<sub>2</sub> generated by the capture process

[^29]: This includes:

    * **CO**<sub>**2**</sub>**&#x20;streams generated and captured together**: a stream of mixed fossil and biogenic CO2, generated from feedstock that includes a share of fossil-based material, or
    * **CO**<sub>**2**</sub>**&#x20;streams generated separately, and captured together:** the co-capture of the project CO2 stream and one or more CO2 streams from project-unrelated sources at the same capture facility. This includes fossil CO2, biogenic CO2 from sustainable (zero-rated) biomass and biogenic CO2 from unsustainable (non-zero-rated) biomass.

[^30]: The biomass that is converted at the facility to provide energy consumed by the capture unit, see [Internal energy and parasitic load](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#internal-energy-and-parasitic-load).

[^31]: Fossil CO<sub>2</sub> generated by the capture process. See [Storage of associated CO<sub>2</sub>](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#storage-of-associated-co2)

[^32]: Project's captured CO<sub>2</sub> that is mixed with other CO<sub>2</sub> streams for any transport or injection step.


# GHG quantification

General GHG quantification rules can be found in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules).

Calculations of GHG emissions for the baseline and project scenarios shall follow a robust, recognized method and good practice guidance. The overall methodological approach is a comparative life cycle assessment (LCA) at the project-scale, based on [ISO 14064-2:2019](#user-content-fn-1)[^1].

This methodology shall be used in conjunction with the Rainbow modules listed below. **Modules are like mini-methodologies** that only cover a part of the project life-cycle. Combining the relevant modules for a project results in a complete picture of the required data, calculations, monitoring plans, and other information needed for a full GHG quantification.

<table data-view="cards"><thead><tr><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="image">Cover image</th></tr></thead><tbody><tr><td>Processing and energy use</td><td><a href="/pages/BTxxPIM3a4Nai1Wkwu2Y">/pages/BTxxPIM3a4Nai1Wkwu2Y</a></td><td><a href="/files/xqDoBuMbX7fcBqJ8AanC">/files/xqDoBuMbX7fcBqJ8AanC</a></td></tr><tr><td>Transportation</td><td><a href="/pages/VTWdCc7guKu1x0azAizi">/pages/VTWdCc7guKu1x0azAizi</a></td><td><a href="/files/XAxrYlLSh0qtvbDkKkqp">/files/XAxrYlLSh0qtvbDkKkqp</a></td></tr><tr><td>Infrastructure and machinery</td><td><a href="/pages/IwqpSqlee22qTIPti3Sl">/pages/IwqpSqlee22qTIPti3Sl</a></td><td><a href="/files/gE6Zo8o6awA0p9LnSTnF">/files/gE6Zo8o6awA0p9LnSTnF</a></td></tr></tbody></table>

GHG quantifications shall be completed for **each monitoring period**.

## Functional unit <a href="#id-8422amp7fe3k" id="id-8422amp7fe3k"></a>

The functional unit shall be **1 tonne of carbon dioxide stored** in a geological reservoir.

## Data sources <a href="#kpxsamb8logm" id="kpxsamb8logm"></a>

The required data for GHG removal calculations from projects are presented below.

* Table 1 and 2 list the data required for the calculation of **project removals** for segregated[^2] and non-segregated[^3] streams, respectively.
* Table 3 lists the primary data measured on a CO<sub>2</sub> stream required to determine the amount of CO<sub>2</sub> in tonnes. Further details on the measurements are provided in the [Sampling and measurements](/methodologies/biogenic-carbon-capture-and-storage-bioccs/sampling-and-measurements) section.
* Table 4-7 list the data required for the calculation of project emissions. Further details are provided in the respective Emission sections in this methodology and the Rainbow Transformation modules.

Note that the table **does not include all information needed for project monitoring and verification— only the data inputs for ongoing GHG quantification**. The full list of information is provided in the minimum requirements for a [Monitoring Plan](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#snhouoxhyrzi).

#### Data sources for project removals

<details>

<summary><strong>Removals:</strong> Segregated CO<sub>2</sub> stream</summary>

The following data shall be provided for projects that transport and store CO<sub>2</sub> as a segregated stream. This means that the project's captured CO<sub>2</sub> is at all times separate from other CO<sub>2</sub> streams.

*Table 1 for **segregated streams**: Summary of **removal data** needed from projects and their source for initial project certification and validation. All data sources listed here are required to be monitored and updated during verification (see Monitoring Plan section).*

| Parameter                                               | Variable                         | Unit     | Source                                                                                                           |
| ------------------------------------------------------- | -------------------------------- | -------- | ---------------------------------------------------------------------------------------------------------------- |
| Amount of CO<sub>2</sub> injected at storage site       | $$CO\_{2 \ injected}$$           | tonnes   | Primary data, collect all data listed in [Amount of CO<sub>2</sub>](#removals-amount-of-co2)                     |
| Total amount of CO<sub>2</sub> captured at capture site | $$CO\_{2 \ captured, total}$$    | tonnes   | Primary data, collect all data listed in [Amount of CO<sub>2</sub>](#removals-amount-of-co2)                     |
| Amount of co-captured associated CO<sub>2</sub>         | $$CO\_{2 \ assoc, co-captured}$$ | tonnes   | Primary data, collect all data listed in [Amount of CO<sub>2</sub>](#removals-amount-of-co2)                     |
| Amount of associated CO<sub>2</sub> captured separately | $$CO\_{2 \ assoc, source}$$      | tonnes   | Primary data, collect all data listed in [Amount of CO<sub>2</sub>](#removals-amount-of-co2)                     |
| Biogenic fraction of mixed stream                       | $$F\_{B}$$                       | fraction | <p>Primary data, measured at capture site via</p><ul><li>mass balance approach, or</li><li>C14 testing</li></ul> |

</details>

<details>

<summary><strong>Removals:</strong> Non-segregated CO<sub>2</sub> streams</summary>

The following data shall be provided for projects in which the Project's captured CO<sub>2</sub> is mixed with other CO<sub>2</sub> streams for any transport or injection step.

*Table 2 For **non-segregated streams**: Summary of **removal data** needed from projects and their source for initial project certification and validation. All data sources listed here are required to be monitored and updated during verification (see Monitoring Plan section). Note that only one of the approaches marked with an asterisk (\*) is required for reporting transport losses data.*

<table data-search="false"><thead><tr><th>Parameter</th><th>Variable</th><th>Unit</th><th>Source</th></tr></thead><tbody><tr><td>Fraction of captured biogenic CO<sub>2</sub> transferred for permanent storage, as opposed to CO<sub>2</sub> use (CCU)</td><td><span class="math">F_{RCC}</span></td><td>fraction</td><td>Choice of Project Developer</td></tr><tr><td>Total amount of CO<sub>2</sub> captured at capture site</td><td><span class="math">CO_{2 \ captured, total}</span></td><td>tonnes</td><td>Primary data, collect all data listed in <a href="#removals-amount-of-co2">Amount of CO<sub>2</sub></a></td></tr><tr><td>Amount of co-captured associated CO<sub>2</sub></td><td><span class="math">CO_{2 \ assoc, co-captured}</span></td><td>tonnes</td><td>Primary data, collect all data listed in <a href="#removals-amount-of-co2">Amount of CO<sub>2</sub></a></td></tr><tr><td>Amount of associated CO<sub>2</sub> captured separately</td><td><span class="math">CO_{2 \ assoc, source}</span></td><td>tonnes</td><td>Primary data, collect all data listed in <a href="#removals-amount-of-co2">Amount of CO<sub>2</sub></a></td></tr><tr><td>Biogenic fraction of mixed stream</td><td><span class="math">F_{B}</span></td><td>fraction</td><td><p>Primary data, measured at capture site via</p><ul><li>mass balance approach, or</li><li>C14 testing</li></ul></td></tr><tr><td>Allocation fraction in transport segment <span class="math">S</span> (ratio project CO<sub>2</sub> to total CO<sub>2</sub> transported)</td><td><span class="math">F_{S}</span></td><td>fraction</td><td>Provided by transport operator if independently verified, or calculated according to <a href="#calculation-allocation-fraction">Calculation: Allocation fraction <span class="math">F_S</span></a></td></tr><tr><td><strong>Mass balance approach</strong>: Amount of CO<sub>2</sub> entering transport segment <span class="math">S</span>*</td><td><span class="math">CO_{2 \ in, S}</span></td><td>tonnes</td><td>Primary data, collect all data listed in <a href="#removals-amount-of-co2">Amount of CO<sub>2</sub></a></td></tr><tr><td><strong>Mass balance approach:</strong> Amount of CO<sub>2</sub> leaving transport segment <span class="math">S</span>*</td><td><span class="math">CO_{2 \ out, S}</span></td><td>tonnes</td><td>Primary data, collect all data listed in <a href="#removals-amount-of-co2">Amount of CO<sub>2</sub></a></td></tr><tr><td><strong>Individual monitoring approach:</strong> average emission factor per component <span class="math">c</span> in transport segment <span class="math">S</span> per time period*</td><td><span class="math">EF_{c,S}</span></td><td>tCO<sub>2</sub>eq per time unit</td><td>Technical specifications, documents from transport operator</td></tr><tr><td><strong>Individual monitoring approach:</strong> number of components <span class="math">c</span> in transport segment <span class="math">S</span>, multiplied by number of time periods*</td><td><span class="math">N_{c,S}</span></td><td>dimensionless</td><td>Technical specifications, documents from transport operator</td></tr><tr><td>Total amount of CO<sub>2</sub> injected into permanent storage at storage site <span class="math">K</span></td><td><span class="math">CO_{2\ injected, K}</span></td><td>tonnes</td><td>Primary data, collect all data listed in <a href="#removals-amount-of-co2">Amount of CO<sub>2</sub></a></td></tr><tr><td>Amount of project CO<sub>2</sub> injected at storage site <span class="math">K</span></td><td><span class="math">CO_{2\ project, injected, K}</span></td><td>tonnes</td><td>Contractual agreements with storage site operator</td></tr><tr><td>Total amount of CO<sub>2</sub> entering storage site <span class="math">K</span></td><td><span class="math">CO_{2\ in, K}</span></td><td>tonnes</td><td>Primary data, collect all data listed in <a href="#removals-amount-of-co2">Amount of CO<sub>2</sub></a></td></tr><tr><td>Sum of fugitive emissions of CO<sub>2</sub> at storage site <span class="math">K</span></td><td><span class="math">CO_{2 \ fugitive,K}</span></td><td>tonnes</td><td>Provided by storage site operator</td></tr><tr><td>Sum of vented emissions of CO<sub>2</sub> at storage site <span class="math">K</span></td><td><span class="math">CO_{2 \ vented,K}</span></td><td>tonnes</td><td>Provided by storage site operator</td></tr></tbody></table>

</details>

<details>

<summary><strong>Removals:</strong> Amount of CO<sub>2</sub></summary>

Depending on the type of stream (segregated vs. non-segregated) and the type of CO<sub>2</sub> captured (biogenic CO<sub>2</sub> vs. ineligible CO<sub>2</sub>), Project Developers shall determine the amount of CO<sub>2</sub> at different points during capture, transport and storage of the project's CO<sub>2</sub>. To determine the amount of CO<sub>2</sub> in tonnes, the following primary data on the stream shall be provided. See [Measurement of injected CO<sub>2</sub>](#amount-of-co2-injected) for further details.

*Table 3: Summary of primary data measured on a CO*<sub>*2*</sub>*&#x20;stream.*

<table><thead><tr><th>Parameter</th><th width="130.73931884765625">Variable</th><th width="124.3699951171875">Unit</th><th>Source</th></tr></thead><tbody><tr><td>total mass or volumetric flow of stream</td><td><span class="math">m_{stream}</span> or <span class="math">V_{stream}</span></td><td>tonne or m<sup>3</sup></td><td>primary data measured at storage site</td></tr><tr><td>concentration of CO<sub>2</sub> in the stream</td><td><span class="math">F_{mass,\ CO2}</span></td><td>wt%</td><td>primary data measured at storage site</td></tr><tr><td>density of stream (for volumetric flow measurements)</td><td><span class="math">\rho_{stream}</span></td><td>t/m<sup>3</sup></td><td>primary data measured at storage site</td></tr></tbody></table>

</details>

***

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Data sources</summary>

In addition to the data listed in the table above, Project Developers of CRCF-projects shall additionally monitor and update the fraction of injected CO<sub>2</sub> dedicated for carbon removals under the CRCF, $$F\_{CRCF}$$.

</details>

#### Data sources for project emissions

<details>

<summary><strong>Emissions:</strong> Shared data sources</summary>

The following data shall be provided by all projects, regardless of the baseline scenario (i.e. retrofit or greenfield project, CO<sub>2</sub> generation), or energy source (external vs. internal, parasitic load).

*Table 4: Summary of **emission data needed from all projects** and their source for initial project certification and validation. All data sources listed here are required to be monitored and updated during verification (see Monitoring Plan section). Those marked with an asterisk (\*) shall be provided once, during validation. Note that only one of the approaches marked with two asterisks (\*\*) is required for reporting mobile transport data.*

<table data-search="false"><thead><tr><th width="142">Life cycle stage</th><th width="214">Parameter</th><th>Unit</th><th>Source</th></tr></thead><tbody><tr><td>CO<sub>2</sub> capture</td><td><p>Type of input used by capture process, e.g.</p><ul><li>fuel</li><li>electricity</li><li>heat</li><li>chemicals (solvents, sorbents, etc.)</li></ul></td><td>Text description</td><td>Internal process documents</td></tr><tr><td>CO<sub>2</sub> capture</td><td>Amount of fuel or energy used by capture process</td><td>liter, kWh, MWh, GWh, kJ, MJ</td><td>Meter readings, bills, internal tracking documents, invoices</td></tr><tr><td>CO<sub>2</sub> capture</td><td>Amount of energy (heat or electricity) recovered from capture process and exported</td><td>kWh, MWh, GWh, kJ, MJ</td><td>Meter readings, bills, internal tracking documents, invoices</td></tr><tr><td>CO<sub>2</sub> capture</td><td>Amount of chemicals or other inputs used by capture process</td><td>kg, liter</td><td>Bills, internal tracking documents, invoices</td></tr><tr><td>CO<sub>2</sub> capture</td><td>Material type*</td><td>Selection</td><td>Technical specifications, bill of materials, invoices, building design documents</td></tr><tr><td>CO<sub>2</sub> capture</td><td>Material amount*</td><td>kg, tonne, m<sup>3</sup></td><td>same as above</td></tr><tr><td>CO<sub>2</sub> capture</td><td>Item lifetime* (optional)</td><td>years</td><td>same as above</td></tr><tr><td>Transport stage, mobile**<br>distance based approach</td><td>Distance traveled per transport segment</td><td>km</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport stage, mobile,**<br>distance based approach</td><td>Weight of CO<sub>2</sub> transported per segment</td><td>tCO<sub>2</sub></td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport stage, mobile,**<br>distance based approach</td><td>Vehicle type</td><td>Category</td><td>Vehicle documents or photos</td></tr><tr><td>Transport stage, mobile, **<br>fuel amount approach</td><td>Fuel quantity consumed per transport segment</td><td>kg or kWh</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport stage, mobile, **<br>fuel amount approach</td><td>Fuel type and (optional) geography</td><td>Category</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport stage, mobile, **<br>fuel amount approach</td><td>Number of trips per transport segment</td><td>Unit</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport stage, mobile, **<br>fuel amount approach</td><td>Vehicle type</td><td>Category</td><td>Vehicle documents or photos</td></tr><tr><td>Transport stage, infrastructure</td><td><p>Type of input used by stationary transport process, e.g.</p><ul><li>fuel</li><li>electricity</li></ul></td><td>Text description</td><td>Internal process documents</td></tr><tr><td>Transport stage, infrastructure</td><td>Amount of fuel or energy used by stationary transport process</td><td>liter, kWh, MWh, GWh</td><td>Meter readings, bills, internal tracking documents, invoices</td></tr><tr><td>CO<sub>2</sub> storage</td><td><p>Type of input used by storage process, e.g.</p><ul><li>fuel</li><li>electricity</li></ul></td><td>Text description</td><td>Internal process documents</td></tr><tr><td>CO<sub>2</sub> storage</td><td>Amount of energy used by storage process</td><td>liter, kWh, MWh, GWh</td><td>Bills, internal tracking documents, invoices</td></tr><tr><td>CO<sub>2</sub> storage</td><td>Material type*</td><td>Selection</td><td>Technical specifications, bill of materials, invoices, building design documents</td></tr><tr><td>CO<sub>2</sub> storage</td><td>Material amount*</td><td>kg, tonne, m<sup>3</sup></td><td>same as above</td></tr><tr><td>CO<sub>2</sub> storage</td><td>Item lifetime* (optional)</td><td>years</td><td>same as above</td></tr></tbody></table>

</details>

<details>

<summary><strong>Emissions:</strong> CO<sub>2</sub> generation</summary>

Emissions from [CO<sub>2</sub> generation](#generation-of-co2) are allocated to the project if

* the project is a greenfield, or
* the project is a retrofit that sources additional biomass above its [baseline biomass consumption](#user-content-fn-4)[^4] for purposes other than meeting the [parasitic load](#user-content-fn-5)[^5].

The following data shall be provided.

*Table 5: Summary of **CO***<sub>***2***</sub>***&#x20;generation emission data needed** and their source for initial project certification and validation. All data sources listed here are required to be monitored and updated **at least every five years** during verification* *(see Monitoring Plan section). Those marked with an asterisk (\*) shall be provided once, during validation. Note that only one of the approaches marked with two asterisks (\*\*) is required for reporting transport data.*

<table data-search="false"><thead><tr><th width="164">Stage</th><th>Parameter</th><th width="145">Unit</th><th>Source</th></tr></thead><tbody><tr><td>CO<sub>2</sub> allocation</td><td>Economic allocation fraction for CO<sub>2</sub> generation</td><td>fraction</td><td>Calculated using prevailing market prices</td></tr><tr><td>CO<sub>2</sub> allocation</td><td>Total amount of biomass consumed</td><td>tonnes</td><td>Operational records, conservative justified estimates</td></tr><tr><td>CO<sub>2</sub> allocation</td><td><em>Retrofit only:</em> Baseline biomass consumption</td><td>tonnes</td><td>Operational records or regional market analysis</td></tr><tr><td>Biomass production</td><td>Amount of biomass produced, per type</td><td>kg</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Direct land-use change</td><td>Carbon stock per unit area associated with the reference land use</td><td>tCO<sub>2</sub>eq</td><td>Calculated following the <a data-footnote-ref href="#user-content-fn-6">guidelines for the calculation of land carbon stocks</a></td></tr><tr><td>Direct land-use change</td><td>Carbon stock per unit area associated with the actual land use</td><td>tCO<sub>2</sub>eq</td><td>Calculated following the <a data-footnote-ref href="#user-content-fn-6">guidelines for the calculation of land carbon stocks</a></td></tr><tr><td>Direct land-use change</td><td>Productivity of the biomass crop, per type</td><td>MJ / area and year</td><td>Operational records, peer-reviewed literature</td></tr><tr><td>Direct land-use change</td><td>Lower heating value of biomass, per type</td><td>MJ / tonne of biomass</td><td>Operational records, peer-reviewed literature</td></tr><tr><td>Biomass processing</td><td>Amount of biomass processed, per type</td><td>kg</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Biomass processing</td><td>Amount and type of energy and material used in processing step, if no appropriate emission factor available</td><td>kg, liter, kWh, MWh, GWh</td><td>Meter readings, bills, internal tracking documents, invoices</td></tr><tr><td>Biomass transport, distance based approach**</td><td>Biomass transported, per type</td><td>kg</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Biomass transport, distance based approach**</td><td>Distance traveled</td><td>km</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Biomass transport, distance based approach**</td><td>Vehicle type</td><td>Category</td><td>Vehicle documents, photos</td></tr><tr><td>Biomass transport, fuel amount based approach**</td><td>Fuel quantity consumed</td><td>kg or kWh</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Biomass transport, fuel amount based approach**</td><td>Fuel type and (optional) geography</td><td>Category</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Biomass transport, fuel amount based approach**</td><td>Number of trips</td><td>Unit</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Biomass transport, fuel amount based approach**</td><td>Vehicle type</td><td>Category</td><td>Vehicle documents, photos</td></tr><tr><td>Biomass storage</td><td>Amount biomass stored, per type</td><td>kg</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Biomass storage</td><td>Time biomass is stored, per type</td><td><ul><li>manure, slurry: days</li><li>other: months (rounded up)</li></ul></td><td>Operational records, conservative justified estimates</td></tr><tr><td>Biomass storage</td><td>Carbon content of biomass stored (for biomass other than manure or slurry), per type</td><td>mass%</td><td>Measurements, conservative justified estimates</td></tr><tr><td>Biomass conversion</td><td>Amount of biomass converted, per type</td><td>kg</td><td>Operational records</td></tr><tr><td>Biomass conversion</td><td>Amount of energy used in biomass conversion</td><td>kWh, MWh, GWh</td><td>Meter readings, bills, internal tracking documents, invoices</td></tr><tr><td>Biomass conversion</td><td>Amount of material used in biomass conversion</td><td>kg, liter</td><td>Meter readings, bills, internal tracking documents, invoices</td></tr><tr><td>Biomass conversion</td><td>Amount of fugitive emissions (e.g. CH<sub>4</sub>, N<sub>2</sub>O) from biomass conversion, per type</td><td>tCO<sub>2</sub>eq / t biomass</td><td>Flue gas measurements, conservative justified estimates</td></tr><tr><td>Biomass conversion, embodied emissions (only for biogas sites, simplified approach)</td><td>External volume of site's main digester*</td><td>m<sup>3</sup></td><td>Licensing or official design document containing this parameter</td></tr><tr><td>Biomass conversion, embodied emissions</td><td>Item type*</td><td>Selection</td><td>NA</td></tr><tr><td>Biomass conversion, embodied emissions</td><td>Material type*</td><td>Selection</td><td>Technical specifications, bill of materials, invoices, building design documents</td></tr><tr><td>Biomass conversion, embodied emissions</td><td>Material amount*</td><td>kg, tonne, m<sup>3</sup></td><td>same as above</td></tr><tr><td>Biomass conversion, embodied emissions</td><td>Item lifetime (optional)*</td><td>years</td><td>same as above</td></tr><tr><td>Biomass conversion, embodied emissions</td><td>List of items that were excluded*</td><td>Selection</td><td>Description of the system and transparent justification</td></tr></tbody></table>

</details>

<details>

<summary><strong>Emissions:</strong> Parasitic load</summary>

In a BioCCS project, the energy consumed by the CO<sub>2</sub> capture process may be sourced internally from the facility's own energy output. Emissions from this so called [parasitic load](#internal-energy-and-parasitic-load) are allocated to the project.

The following data shall be provided.

*Table 6: Summary of emission data needed to calculate **parasitic load emissions** and their source for initial project certification and validation. All data sources listed here are required to be monitored and updated during verification (see Monitoring Plan section). Note that only one of the approaches marked with an asterisk (\*) is required for reporting parasitic load emissions.*

<table data-search="false"><thead><tr><th>Parameter</th><th>Unit</th><th>Source</th></tr></thead><tbody><tr><td>Electricity consumed by capture unit</td><td>kWh, MJ</td><td>Meter readings, internal tracking documents</td></tr><tr><td>Total electricity produced by facility</td><td>kWh, MJ</td><td>Operational records</td></tr><tr><td>Amount of biomass used to produce electricity</td><td>tonnes</td><td>Operational records</td></tr><tr><td>Heat consumed by capture unit</td><td>kWh, MJ</td><td>Meter readings, internal tracking documents</td></tr><tr><td>Total heat produced by facility</td><td>kWh, MJ</td><td>Operational records</td></tr><tr><td>Average temperature of heat</td><td>K</td><td>Temperature measurements</td></tr><tr><td>Amount of biomass used to produce heat</td><td>tonnes</td><td>Operational records</td></tr><tr><td>Lower heating value of biomass</td><td>kJ or MJ or kWh or MWh per kg or tonne</td><td>Operational records, peer-reviewed literature</td></tr><tr><td><strong>Simplified approach:</strong> Verified emission factor for facility electricity production*</td><td>kWh/ tCO<sub>2</sub>eq or MJ/ tCO<sub>2</sub>eq</td><td>Official facility certifications</td></tr><tr><td><strong>Simplified approach:</strong> Verified emission factor for facility heat production*</td><td>kWh/ tCO<sub>2</sub>eq or MJ/ tCO<sub>2</sub>eq</td><td>Official facility certifications</td></tr><tr><td><strong>Full approach</strong>: Data inputs listed in <a href="#emissions-co2-generation">Table 5: CO<sub>2</sub> generation</a> for stages other than <em>CO</em><sub><em>2</em></sub><em> allocation</em></td><td>/</td><td>/</td></tr></tbody></table>

</details>

<details>

<summary><strong>Emissions:</strong> Leakage</summary>

Leakage emissions shall be quantified where required by the rules in the [Leakage](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#lc9eewbyvlyk) section. The following data shall be provided.

Table 7: *Summary of emission data needed to calculate **leakage emissions** and their source for initial project certification and validation. All data sources listed here are required to be monitored and updated **at least every five years** during verification (see Monitoring Plan section)*

<table data-search="false"><thead><tr><th>Leakage emissions</th><th>Parameter</th><th width="142.22442626953125">Unit</th><th>Source</th></tr></thead><tbody><tr><td>Counterfactual carbon storage</td><td>Carbon content of biomass</td><td>tonnes</td><td>Laboratory measurements, modeled, or representative secondary data</td></tr><tr><td>Counterfactual carbon storage</td><td>Estimated fraction of biomass carbon stored at 15 years in the counterfactual</td><td>fraction</td><td>Peer-reviewed literature, modeled, or representative secondary data, recognized national or regional GHG inventory reports, documented industry data or direct measurements</td></tr><tr><td>Counterfactual carbon storage</td><td>Estimated fraction of biomass carbon emitted within 15 years in the counterfactual, per type of GHG</td><td>fraction</td><td>Peer-reviewed literature, modeled, or representative secondary data, recognized national or regional GHG inventory reports, documented industry data or direct measurements</td></tr><tr><td>Counterfactual carbon storage</td><td>Estimated fraction of biomass carbon stored at 50 years in the counterfactual</td><td>fraction</td><td>Peer-reviewed literature, modeled, or representative secondary data, recognized national or regional GHG inventory reports, documented industry data or direct measurements</td></tr><tr><td>Biomass diversion</td><td>Amount of biomass diverted from valuable alternative use, per type</td><td>tonnes</td><td>Operational records</td></tr><tr><td>iLUC</td><td>Lower heating value of biomass, per type</td><td>MJ/tonne</td><td>Laboratory measurements</td></tr><tr><td>Bioenergy and biomaterial diversion</td><td>Electricity output of facility in the business-as-usual (BAU)</td><td>kWh, MJ</td><td>Operational records</td></tr><tr><td>Bioenergy and biomaterial diversion</td><td>Electricity output of facility after retrofit (BAU)</td><td>kWh, MJ</td><td>Operational records</td></tr><tr><td>Bioenergy and biomaterial diversion</td><td>Heat output of facility in the business-as-usual (BAU)</td><td>kWh, MJ</td><td>Operational records</td></tr><tr><td>Bioenergy and biomaterial diversion</td><td>Heat output of facility after retrofit (BAU)</td><td>kWh, MJ</td><td>Operational records</td></tr><tr><td>Bioenergy and biomaterial diversion</td><td>Material output of facility in the business-as-usual (BAU)</td><td>appropriate unit</td><td>Operational records</td></tr><tr><td>Bioenergy and biomaterial diversion</td><td>Material output of facility after retrofit (BAU)</td><td>appropriate unit</td><td>Operational records</td></tr></tbody></table>

</details>

The [ecoinvent database](#user-content-fn-7)[^7] version 3.12 (hereafter referred to as ecoinvent) shall be the main source of emission factors unless otherwise specified. Ecoinvent is preferred because it is traceable, reliable, and well-recognized. The ecoinvent processes selected are detailed in the [Appendix](/methodologies/biogenic-carbon-capture-and-storage-bioccs/appendix#ecoinvent-activities).

## Assumptions <a href="#id-4l7lx2ihb6hj" id="id-4l7lx2ihb6hj"></a>

* The [Baseline scope](/methodologies/biogenic-carbon-capture-and-storage-bioccs/eligibility-and-scope#project-scope) assumes no carbon capture activity would have occurred under business-as-usual conditions.
* For projects sourcing CO<sub>2</sub> from anaerobic digestion of manure or slurry
  * Emissions of N<sub>2</sub>O and methane due to manure and slurry storage before the digestion process are linearly related to the amount of days manure and slurry are stored on site. If Project Developers do not have an estimation of this value, an average of 15 days is assumed. In the baseline scenario, this is assumed to be 180 days.
  * Emissions of N<sub>2</sub>O from slurry storage [*are sufficiently small (0.01-0.05% life cycle GHG emissions)*](#user-content-fn-8)[^8] that they can be excluded. This is because N<sub>2</sub>O emissions from slurry storage are generally small, plus the shortened storage duration in the project scenario minimizes them further.
  * Manure and slurry from pigs, horses, sheep, and other animals are modeled using the same characteristics as cow manure. Only chicken manure is treated differently, due to its high nitrogen content (Table A1 and A2).
  * Embodied emissions from the underlying biogas production sites are modeled and extrapolated from the main digester exterior volume and buildings and main infrastructure at the underlying biogas site have an assumed lifetime of 20 years.

## Baseline scenario <a href="#ly65klblzpa9" id="ly65klblzpa9"></a>

A project's [Baseline scope](/methodologies/biogenic-carbon-capture-and-storage-bioccs/eligibility-and-scope#project-scope) is either a retrofit/addition on top of an existing site, or a greenfield, i.e. the installation of a new site. For both scopes, this methodology has a standardized baseline of 0 tCO<sub>2</sub>eq stored from BioCCS. Therefore, there are no GHG quantifications for the baseline scenario.

Note that counterfactual carbon storage from alternate biomass use is treated in this methodology under [Leakage](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#counterfactual-carbon-storage).

## Project scenario <a href="#i4figd8ytjua" id="i4figd8ytjua"></a>

The project scenario is broken down into four main life cycle stages, detailed in the following sections and shown in the figures below

* CO<sub>2</sub> removal
* Emissions from CO<sub>2</sub> capture
* Emissions from CO<sub>2</sub> transport
* Emissions from CO<sub>2</sub> storage
* Emissions from leakage

Figure 1 shows the system diagram of a greenfield project. Figure 2 shows the system diagram of a retrofit project sourcing no additional biomass above its baseline consumption (see [baseline biomass fraction](#user-content-fn-9)[^9]). Figure 3 shows that of a retrofit project sourcing additional biomass only to cover the parasitic load (see [additional biomass fraction](#user-content-fn-9)[^9]).

<figure><img src="/files/rA9Jno6is5mxZ25t7vBi" alt=""><figcaption><p><em>Figure 1: System diagram for a greenfield bioenergy and BioCCS project. Emissions from the generation of CO</em><sub><em>2</em></sub><em> are allocated to the project based on the economic value of the co-products (i.e. CO</em><sub><em>2</em></sub><em>, bioenergy, other services).</em></p></figcaption></figure>

<figure><img src="/files/3XQwYwyEFik6XjpL1GOv" alt=""><figcaption><p><em>Figure 2: System diagram of a retrofit bioenergy site and BioCCS project sourcing no additional biomass. In this example, the parasitic load energy demand is covered by the baseline energy generation, resulting in a reduced output of that energy compared to the baseline, and corresponding leakage emissions. Emissions associated with the generation of the parasitic load are allocated to the project. See Figure 1 for a detailed list of what's included in the CO</em><sub><em>2</em></sub><em> generation stages.</em></p></figcaption></figure>

<figure><img src="/files/AL7PjMjiJOpyoTp4Emh0" alt=""><figcaption><p><em>Figure 3: System diagram of a retrofit bioenergy site and BioCCS project sourcing biomass additional to its baseline consumption, for example to compensate for the parasitic load energy demand. All emissions associated with the sourcing of the additional biomass and its CO</em><sub><em>2</em></sub><em> generation are allocated to the project. See Figure 1 for a detailed list of what's included in the CO</em><sub><em>2</em></sub><em> generation stages.</em></p></figcaption></figure>

The total net carbon removal of the BioCCS project is calculated according to Eq. 1.

$$\textbf{(Eq.1)}\ Net\ Removal = R\_{baseline}-R\_{project}-E\_{project}$$

* $$R\_{baseline}$$ represents any baseline GHG removals, representing permanent storage that would have occurred in the absence of the project, in tonnes of CO<sub>2</sub>eq. According to the [Baseline scope](/methodologies/biogenic-carbon-capture-and-storage-bioccs/eligibility-and-scope#project-scope), no removals are considered in the absence of the project, hence $$R\_{baseline} = 0$$.
* $$R\_{project}$$ represents the project's gross GHG removals, in tonnes of CO<sub>2</sub>eq and is calculated according to the rules set out it [Project CO<sub>2</sub> removal](#project-co2-removal). Its sign is negative.
* $$E\_{project}$$ represents the project's total induced GHG emissions across the project life cycle including leakage emissions if applicable, in tonnes of CO<sub>2</sub>eq. Its sign is positive.

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Recognition under different schemes</summary>

Project Developers can choose to credit part of net carbon removal under a scheme other than the CRCF. In this case, the fraction credited under the CRCF, $$F\_{CRCF}$$ shall be applied to the net removal calculation in Eq. 1 .

</details>

The project's total induced GHG emissions are calculated according to Eq. 2:

$$\textbf{(Eq.2)}\ E\_{project} = E\_{capture}+E\_{transport}+E\_{storage}+E\_{leakage}$$

* $$E\_{capture}$$ represents the project's GHG emissions in the capture stage, in tonnes of CO<sub>2</sub>eq.
* $$E\_{transport}$$ represents the project's GHG emissions in the transport stage, in tonnes of CO<sub>2</sub>eq.
* $$E\_{storage}$$ represents the project's GHG emissions in the storage stage, in tonnes of CO<sub>2</sub>eq.
* $$E\_{leakage}$$ represents the project's leakage emissions, in tonnes of CO<sub>2</sub>eq.

The project's GHG emissions shall include emissions from all additional sources caused by the project mitigation activity. Any emission sources identified by the Project Developer and not listed in the GHG emission sections below shall be reported to the Rainbow Certification team and accounted for.

According to the methodology [Certification requirements](/methodologies/biogenic-carbon-capture-and-storage-bioccs/eligibility-and-scope#certification-requirements), each monitoring period and GHG quantification shall cover a maximum duration of **12-months of CO**<sub>**2**</sub>**&#x20;capture activities**. If Project Developers are not able to precisely identify the moment when captured CO<sub>2</sub> enters permanent storage, they may count all associated GHG emissions downstream related to the storage of that CO<sub>2</sub> by applying default emission inventory data from the monitoring period, regardless of whether those downstream emissions occurred in the same 12-month period.

## Project CO<sub>2</sub> removal

The project's CO<sub>2</sub> removals shall be calculated differently depending on whether or not the project's captured CO<sub>2</sub> stream is at all times transported and injected separately (i.e. segregated) from other CO<sub>2</sub> streams in the transport and storage facilities.

* For **segregated streams**, the amount of CO<sub>2</sub> removed is measured directly at **injection** **at the storage site**,
* For **non-segregated streams**, it is calculated using the measured amount of CO<sub>2</sub> captured **at the capture site**, minus CO<sub>2</sub> losses during transport and at the storage site.

### Segregated stream

A segregated CO<sub>2</sub> stream is one where the project's CO<sub>2</sub> injected at the storage site can be directly attributed to the BioCCS project (i.e. the project's captured CO<sub>2</sub> is at all times transported and injected separately from other CO<sub>2</sub> streams). CO<sub>2</sub> removal for segregated streams shall be calculated by **multiplying the amount of CO**<sub>**2**</sub>**&#x20;injected by the fraction eligible biogenic CO**<sub>**2**</sub>**&#x20;captured.**

#### Amount of CO<sub>2</sub> injected

To quantify the amount of CO<sub>2</sub> injected at each storage site, $$CO\_{2 \ injected}$$, Project Developers shall measure either the **mass flow or volumetric flow and density** of the stream, and multiply it with the CO<sub>2</sub> concentration. Details on the measurement method is provided in the [Sampling and measurement](/methodologies/biogenic-carbon-capture-and-storage-bioccs/sampling-and-measurements) section.

#### Eligible biogenic fraction of CO<sub>2</sub>

To determine the fraction of $$CO\_{2 \ injected}$$ eligible for RCCs, Project Developers shall determine the **eligible biogenic fraction in the total amount of CO**<sub>**2**</sub>**&#x20;captured** at the capture site. The calculation approach depends on whether the project captures only eligible biogenic CO<sub>2</sub>, or CO<sub>2</sub> from [ineligible sources](#user-content-fn-10)[^10] along with it.

* **Capture of only biogenic CO**<sub>**2**</sub>: All CO<sub>2</sub> captured is eligible biogenic CO<sub>2</sub>. The total amount of CO<sub>2</sub> captured $$CO\_{2\ captured, total}$$ is defined as the sum of all CO<sub>2</sub> leaving the capture facility at each exit point. Project Developers shall prove there are no ineligible sources of CO<sub>2</sub> in the captured stream through [operational data records](#user-content-fn-11)[^11].
* **Capture of ineligible CO**<sub>**2**</sub>**&#x20;alongside biogenic CO**<sub>**2**</sub>: If the project captures CO<sub>2</sub> from ineligible sources alongside eligible biogenic CO<sub>2</sub>, Project Developers shall measure the amount of CO<sub>2</sub> from ineligible sources and subtract it from the total amount of CO<sub>2</sub> captured, to obtain the eligible amount.

<details>

<summary><strong>Calculation:</strong> Segregated stream removals</summary>

$$\textbf{(Eq.3)}\ R\_{Project, segregated} = \frac{CO\_{2\ captured, biogenic}} {CO\_{2\ captured, total}} \ \times\sum\_{K}CO\_{2 \ injected, \ K}\times-1$$

* $$R\_{Project, segregated}$$ represents the total project removals for a segregated stream, in tCO<sub>2.</sub> It is used in Eq. 1.
* $$CO\_{2\ captured, biogenic}$$ represents the amount of eligible biogenic CO<sub>2</sub> captured at the capture site, in tCO<sub>2</sub>. Calculated according to Eq. 7.
* $$CO\_{2\ captured, total}$$ represents the total amount of CO<sub>2</sub> captured at the capture site, in tCO<sub>2</sub>. Calculated according to Eq. 4.
* $$CO\_{2 \ injected, \ K}$$ represents the total amount of CO<sub>2</sub> injected at the storage site $$K$$, in tCO<sub>2</sub>. Calculated according to Eq. 5 (mass flow approach) or 6 (volume flow approach).
* It is multiplied by -1 to obtain a negative sign. Removals are reported as a negative value.

The total amount of CO<sub>2</sub> captured at the capture facility that is transferred for transport and storage is defined as

$$\textbf{(Eq.4)}\ CO\_{2\ captured,total} = \sum\_{i} CO\_{2\ OUT,project,i}$$

* $$CO\_{2\ captured,total}$$ is defined in Eq. 3.
* $$CO\_{2\ OUT,project,i}$$ represents the amount of captured CO<sub>2</sub> that leaves the capture facility at each exit point $$i$$, in tCO<sub>2</sub>. It shall be directly measured following the same approach for $$CO\_{2 \ injected}$$ outlined below.

***

$$CO\_{2 \ injected}$$ is calculated using either the Mass flow measurement approach or Volumetric flow and density measurement approach below.

**Mass flow measurement approach**:

$$\textbf{(Eq.5)}\ CO\_{2 \ injected} = \sum\_{i\ = 1}^{N}(m\_{stream, \ i}\ \times F\_{mass,\ CO2,\ i} )$$

* $$\ CO\_{2 \ injected}$$ is defined in Eq. 3.
* $$N$$ is the number of days in the monitoring period.
* $$m\_{stream, \ i}$$ represents the aggregated mass flow of the stream on day $$i$$ , in tonnes.
* $$F\_{mass,\ CO2,\ i}$$ the [**weighted average**](#user-content-fn-12)[^12] **daily concentration** of CO<sub>2</sub> in the stream, in wt%, reported as fraction.

**Volumetric flow and density measurement approach**:

$$\textbf{(Eq.6)}\ CO\_{2 \ injected} = \sum\_{i\ = 1}^{N}(V\_{stream, \ i}\times\rho\_{stream, \ i} \times F\_{mass,\ CO2,\ i})$$

* $$\ CO\_{2 \ injected}$$ is defined in Eq. 3.
* $$N$$ is defined in Eq. 5.
* $$V\_{stream,\ i}$$ represents the aggregated volumetric flow of the stream on day $$i$$, at standard temperature and pressure, in m<sup>3</sup>.
* $$\rho\_{stream, \ i}$$ represents the density of the stream at standard temperature and pressure on day $$i$$, in t/m<sup>3</sup>.
* $$F\_{mass,\ CO2,\ i}$$ the [**weighted average**](#user-content-fn-12)[^12] **daily concentration** of CO<sub>2</sub> in the stream, in wt%, reported as fraction.

</details>

<details>

<summary><strong>Calculation:</strong> Eligible biogenic fraction of CO<sub>2</sub></summary>

The amount of biogenic CO<sub>2</sub> eligible for crediting is defined as

$$\textbf{(Eq.7)}\ CO\_{2\ captured,biogenic} = CO\_{2\ captured, total} - CO\_{2\ captured, ineligible}$$

* $$CO\_{2\ captured, biogenic}$$ is defined in Eq. 3.
* $$CO\_{2\ captured,total}$$ is defined in Eq. 3.
* $$CO\_{2\ captured, ineligible}$$ represents the total amount CO<sub>2</sub> from [ineligible sources](#user-content-fn-10)[^10] that is captured at the capture facility, in tCO<sub>2</sub>. It is calculated according to Eq. 8 below.

$$\textbf{(Eq.8)}\ CO\_{2 \ captured, ineligible} = CO\_{2 \ captured,assoc} + CO\_{2 \ captured,mixed}$$

* $$CO\_{2\ captured, assoc}$$ represents the amount of [associated CO<sub>2</sub>](#user-content-fn-13)[^13], in tCO<sub>2</sub>. It is calculated according to Eq. 9 below.
* $$CO\_{2\ captured, mixed}$$ represents the amount of ineligible CO<sub>2</sub> captured from a mixed stream, in tCO<sub>2</sub>. It is calculated according to Eq. 10 below.

**Associated CO**<sub>**2**</sub> can be either captured separately from the biogenic CO<sub>2</sub> or simultaneously (i.e. co-captured) with the capture of the biogenic CO<sub>2</sub>, and shall be calculated according to

$$\textbf{(Eq.9)}\ CO\_{2\ captured,assoc} = CO\_{2 \ assoc,co\text{-}captured} + \sum\_{sources} CO\_{2 \ assoc,source}$$

* $$CO\_{2 \ assoc,co\text{-}captured}$$ represents the amount of associated CO<sub>2</sub> that is co-captured with the biogenic CO<sub>2</sub>, in tCO<sub>2</sub>. It shall not be more than the total amount of fossil CO<sub>2</sub> emissions reported for the capture stage in the calculation of the project's associated GHG emissions. It shall be measured following the Mass flow measurement approach or Volumetric flow and density measurement approach in Eq 5 and 6.
* $$CO\_{2 \ assoc,source}$$ represents the amount of associated CO<sub>2</sub> that is captured separately from the biogenic CO<sub>2,</sub> in tCO<sub>2</sub>. It shall be measured following the Mass flow measurement approach or Volumetric flow and density measurement approach in Eq 5 and 6.

**The amount of CO**<sub>**2**</sub>**&#x20;from a mixed stream, generated and captured together** shall be calculated as follows

$$\textbf{(Eq.10)}\ CO\_{2 \ captured,mixed} = (1 - F\_B) \times \left( CO\_{2\ captured,total} - CO\_{2 \ captured,assoc} \right)$$

* $$F\_B$$ is the eligible biogenic fraction of the mixed CO<sub>2</sub> stream, measured according to the [Sampling and measurements](/methodologies/biogenic-carbon-capture-and-storage-bioccs/sampling-and-measurements#determination-of-biogenic-fraction-of-co2).
* $$CO\_{2 \ captured, total }$$ is defined in Eq. 3.
* $$CO\_{2 \ captured, assoc}$$ is defined in Eq. 9.

</details>

### Non-segregated stream

If the CO<sub>2</sub> injected at the storage site cannot be directly linked to the BioCCS project, due to logistical or other operational reasons (i.e. the project's captured CO<sub>2</sub> is mixed with other CO<sub>2</sub> streams for any transport or injection step), project removals are calculated using the **amount of biogenic CO**<sub>**2**</sub>**&#x20;captured minus CO**<sub>**2**</sub>**&#x20;losses during transport and storage** prior to entering permanent storage.

#### Calculation of transport losses

Transport losses include eligible biogenic CO<sub>2</sub> lost during transport from the capture to the storage site. Transport losses shall be calculated for each transport segment.

**A transport segment** is a section of the transportation process involving the movement of CO<sub>2</sub> from point A to point B. Transport segments divide up the transportation process so that losses and emissions can be correctly allocated to each part of it.

* If CO<sub>2</sub> captured by the BioCCS project is the only CO<sub>2</sub> passing through the relevant transport infrastructure, the whole transportation process from capture to storage can be counted as a single transport segment. Otherwise, the transportation process shall be divided into a series of transport segments.
* A new transport segment shall be defined if
  * two or more CO<sub>2</sub> streams from different sources are merged together
  * two or more CO<sub>2</sub> streams from different sources are split up
  * the project's CO<sub>2</sub> stream is split up (e.g. when sent to multiple storage sites)
  * the [mode of transport](#user-content-fn-14)[^14] changes

Transport losses shall be calculated using one of the following approaches. Different approaches can be used for different segments.

1. **Mass balance approach:** Using the overall mass balance of all input and output streams across a segment.
2. **Individual monitoring approach**: Monitoring fugitive, vented and leaked emissions individually across a segment, using the following sources:
   1. **Fugitive emissions**: measurements at seals, measurement devices, valves, intermediate compressor stations or intermediate storage sites, and calculated in Eq. 15.
   2. **Vented emissions**: calculated for each transport segment $$S$$ based on the expected venting identified for that transport segment by the [operator of the transport network](#user-content-fn-15)[^15]. If this is not available, venting emissions shall be allocated by segment on a reasonable basis agreed on by the Project Developer and the Rainbow Certification team in agreement with the VVB[^16].
   3. **Transport leakage emissions**: calculated for each transport segment $$S$$ based on the amount identified by the [operator of the transport network](#user-content-fn-15)[^15]. If this is not available, transport leakage emissions shall be allocated by segment on a reasonable basis agreed on by the Project Developer and the Rainbow Certification team in agreement with the VVB[^16].

#### Calculation of storage losses

Storage losses are defined as the amount of eligible biogenic CO<sub>2</sub> lost at the storage site before entering permanent storage. Storage losses shall be calculated for each storage site.

To allocate storage losses between the project CO<sub>2</sub> and CO<sub>2</sub> from other sources injected at the storage site, an allocation fraction is defined.

<details>

<summary><strong>Calculation:</strong> Non-segregated stream removals</summary>

$$\textbf{(Eq.11)}\ R\_{project, \ non-segregated} = (F\_{RCC} \* CO\_{2 \ captured, biogenic} \ - \sum CO\_{2 \ transport\ losses } \ - \ CO\_{2 \ storage \ losses})\*-1$$

* $$R\_{project, non-segregated}$$ represents the total project removals for a non-segregated stream, in tCO<sub>2</sub>. It is used in Eq. 1.
* $$F\_ {RCC}$$ represents the fraction of the captured biogenic CO<sub>2</sub> transferred for permanent storage and RCC issuance, and not used for other purposes (i.e. utilization).
* $$CO\_{2\ captured, biogenic}$$ represents the amount of eligible biogenic CO<sub>2</sub> captured at the capture site, in tCO<sub>2</sub>.
  * For purely purely biogenic CO<sub>2</sub> streams, it is calculated according to Eq. 4.
  * For capture of ineligible CO<sub>2</sub> alongside biogenic CO<sub>2</sub>, it is calculated according to Eq. 7-10.
* $$CO\_{2 \ transport\ losses }$$ represents the amount of eligible biogenic CO<sub>2</sub> lost during transport from the capture to the storage site, in tCO<sub>2</sub>. It shall be summed for all transport segments, calculated in Eq. 12 and/or 14.
* $$CO\_{2 \ storage\ losses }$$ represents the amount of eligible biogenic CO<sub>2</sub> lost at the storage site prior to entering permanent geological storage, in tCO<sub>2</sub>.
* It is multiplied by -1 to obtain a negative sign. Removals are reported as a negative value.

***

**Transport losses: Mass balance approach**

$$\textbf{(Eq.12)}\ CO\_{2\ transport,losses} = F\_{RCC} \times \frac{CO\_{2\ captured,biogenic}}{CO\_{2\ project}}\times\sum\_{S}( F\_{S} \times ( CO\_{2\ in,S} - CO\_{2 \ out,S}))$$

* $$F\_{RCC}$$ is defined in Eq. 11.
* $$CO\_{2\ captured,biogenic}$$ is defined in Eq.3.
* $$CO\_{2\ project}$$ represents the CO<sub>2</sub> from the project leaving the capture facility and being transferred for storage, in tCO<sub>2</sub>. It is calculated according to Eq. 13 below.
* $$F\_{S}$$ represents the fraction of all CO<sub>2</sub> in a given transport segment $$S$$ that is from the project. It may be
  * provided by the transport operator, if independently verified, or
  * calculated according to [Calculation: Allocation fraction $$F\_S$$](#calculation-allocation-fraction)
* $$CO\_{2\ in,S}$$ represents the total amount of CO<sub>2</sub> entering the transport segment $$S$$, in tCO<sub>2</sub>. It shall be measured according to the Mass flow measurement approach or Volumetric flow and density measurement approach in Eq. 5 and 6.
* $$CO\_{2\ out,S}$$ represents the total amount of CO<sub>2</sub> leaving the transport segment $$S$$, in tCO<sub>2</sub>.It shall be measured according to the Mass flow measurement approach or Volumetric flow and density measurement approach in Eq. 5 and 6.

The amount of CO<sub>2</sub> counted as transported by the project includes the eligible biogenic CO<sub>2</sub> captured and the [associated CO<sub>2</sub>](#user-content-fn-17)[^17] captured. It is calculated as:

$$\textbf{(Eq.13)}\ CO\_{2,\ project} = F\_{RCC} \times ( CO\_{2\ captured,biogenic} + CO\_{2\ captured,assoc})$$

* $$F\_{RCC}$$ is defined in Eq. 11.
* $$CO\_{2\ captured,biogenic}$$ is defined in Eq. 3.
* $$CO\_{2\ captured,assoc}$$ is defined in Eq. 9.

**Transport losses: Individual monitoring approach**

$$\textbf{(Eq.14)}\ CO\_{2 \ transport,losses} =F\_{RCC} \times \frac{\ CO\_{2\ captured,biogenic}}{CO\_{2\ project}}\times \sum\_{S} \ ( F\_{S} \times ( CO\_{2 \ fugitive,S} + CO\_{2\ vented,S} + CO\_{2 \ transport \ leakage,S}))$$

* $$F\_{RCC}$$ is defined in Eq. 11.
* $$CO\_{2\ captured,biogenic}$$ is defined in Eq. 3.
* $$CO\_{2\ project}$$ is defined in Eq. 13.
* $$F\_{S}$$ represents the fraction of all CO<sub>2</sub> in a given transport segment $$S$$ that is from the project. Project Developers can **use** $$F\_{S}$$ **values provided by the transport operator** if those values are independently verified, or calculate it according to Eq. 19.
* $$CO\_{2 \ fugitive,S}$$ represents the sum of fugitive emissions from CO<sub>2</sub> transported in transport segment $$S$$, in tCO<sub>2</sub>, at seals, measurement devices, valves, intermediate compressor stations or intermediate storage sites. It shall be calculated using Eq. 15.
* $$CO\_{2 \ vented,S}$$ represents the sum of vented emissions from CO<sub>2</sub> transported in transport segment $$S$$, in tCO<sub>2</sub>.
* $$CO\_{2 \ transport\ leakage,S}$$ represents the sum of CO<sub>2</sub> transported in transport segment $$S$$, that was emitted as a result of the failure of one or more components of the transportation network, in tCO<sub>2</sub>.

$$\textbf{(Eq.15)}\ CO\_{2 \ fugitive,\ S} = \sum\_{c} ( EF\_{c,S} \* N\_{c,S} )$$

* $$EF\_{c,S}$$ represents the average emission factor per component $$c$$ in the transport segment $$S$$ per time period, in tCO<sub>2</sub> per unit time. The factor shall be reviewed at least every 5 years based on newly available techniques and knowledge.
* $$N\_{c,S}$$ represents the number of components $$c$$ in the transport segment $$S$$, multiplied by the number of time periods.

***

**Storage losses**

$$\textbf{(Eq.16)}\ CO\_{2\ storage,losses} = F\_{RCC} \* \frac{CO\_{2 \ captured,biogenic}}{CO\_{2 \ project}} \*\sum\_{K}( F\_{K} \*( CO\_{2 \ fugitive,K} + CO\_{2\ vented,K} ))$$

* $$F\_{RCC}$$ is defined in Eq. 11.
* $$CO\_{2\ captured,biogenic}$$ is defined in Eq. 3.
* $$CO\_{2\ project}$$ is defined in Eq. 13.
* $$F\_{K}$$ is the allocation fraction for each storage site $$K$$ and represents the fraction of CO<sub>2</sub> stored at storage site $$K$$ that is associated with the project. It is calculated according to Eq. 18.
* $$CO\_{2 \ fugitive,K}$$ represents the sum of fugitive emissions of CO<sub>2</sub> at the storage site $$K$$, in tCO<sub>2</sub>. It is based on data recorded by the storage site operator in accordance with the [European Commission Implementing Regulation 2018/2066](#user-content-fn-18)[^18], Annex IX, Section 23, subsection B.1.
* $$CO\_{2 \ vented,K}$$ represents the sum of vented emissions of CO<sub>2</sub> at the storage site $$K$$, in tCO<sub>2</sub>. It is based on data recorded by the storage site operator in accordance with the [European Commission Implementing Regulation 2018/2066](#user-content-fn-18)[^18], Annex IX, Section 23, subsection B.1.

At each storage site $$K$$, the sum of fugitive and vented emissions shall be equal to the difference between the measured amount of CO<sub>2</sub> entering the storage site and the measured amount of CO<sub>2</sub> injected at the storage site, according to the following equation.

$$\textbf{(Eq.17)}\ CO\_{2\ fugitive,K} + CO\_{2\ vented,K} = CO\_{2\ in,K} - CO\_{2 \ injected,K}$$

* $$CO\_{2 \ fugitive,K}$$ is defined in Eq. 16.
* $$CO\_{2 \ vented,K}$$ is defined in Eq. 16.
* $$CO\_{2\ in, K}$$ represents the total amount of CO<sub>2</sub> entering the storage site $$K$$, in tCO<sub>2</sub>. It shall be measured according to the Mass flow measurement approach or Volumetric flow and density measurement approach in Eq. 5 and 6.
* $$CO\_{2\ injected, K}$$ represents the total amount of CO<sub>2</sub> from all sources that is stored at site $$K$$ during the monitoring period, in tCO<sub>2</sub>. It shall be measured according to the Mass flow measurement approach or Volumetric flow and density measurement approach in Eq. 5 and 6.

The fraction allocating storage losses between the project CO<sub>2</sub> and CO<sub>2</sub> from other sources injected at the storage site, is defined as

$$\textbf{(Eq.18)}\ F\_{K} = \frac{CO\_{2 \ project,injected, K}}{CO\_{2 \ injected,K}}$$

* $$F\_{K}$$ is defined in Eq. 16.
* $$CO\_{2\ project, injected, K}$$ represents the amount of CO<sub>2</sub> associated with the project that is stored at the storage site $$K$$ during the monitoring period, in tCO<sub>2</sub>. It is determined applying the mass balance approach in the [CO<sub>2</sub> traceability](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#co2-traceability) section.
* $$CO\_{2\ injected, K}$$ is defined in Eq. 17

</details>

<details>

<summary><strong>Calculation:</strong> Allocation fraction <span class="math">F_S</span></summary>

To allocate transport losses between the project CO<sub>2</sub> and other CO<sub>2</sub> transported in a segment, an allocation fraction is defined. If independently verified values provided by the transport operator are not available, $$F\_{S}$$ shall be calculated.

$$\textbf{(Eq.19)}\ F\_{S} = \frac{CO\_{2 \ project,S}}{CO\_{2 \ total,S}}$$

* $$F\_{S}$$ is defined in Eq. 12.
* $$CO\_{2\ project, S}$$ represents the amount of CO<sub>2</sub> associated with the project, that is passing through the transport segment $$S$$ during the monitoring period, in tCO<sub>2</sub>. It is calculated differently for the first than for the following transport segments, as described below.
* $$CO\_{2\ total, S}$$ represents the total amount of CO<sub>2</sub> from all sources passing through the transport segment $$S$$ during the monitoring period, in tCO<sub>2</sub>. It shall be measured according to the Mass flow measurement approach or Volumetric flow and density measurement approach in Eq. 5 and 6.

**Project CO**<sub>**2**</sub>**&#x20;in the first transport segment (S=1)**

For the first transport segment $$S = 1$$, $$CO\_{2\ project, S}$$ is equal to $$CO\_{2\ project}$$, the amount of CO<sub>2</sub> associated with the project, leaving the capture facility and being transferred for storage, and calculated according to Eq. 13.

**Project CO**<sub>**2**</sub>**&#x20;in following transport segments (S>1)**

For subsequent transport segments $$S > 1$$, $$CO\_{2\ project, S}$$ is equal to the amount of project CO<sub>2</sub> entering the previous transport segment minus any CO<sub>2</sub> losses in that previous segment.

If the [Mass balance approach](#transport-losses-overall-mass-balance-approach) is chosen for the calculation of the transport losses, then Eq. 20 shall be used.

$$\textbf{(Eq.20)}\ CO\_{2\ project,S} = CO\_{2\ project,S-1} -(F\_{S-1}\* (CO\_{2\ in,S-1} - CO\_{2 \ out,S-1}))$$

* $$CO\_{2\ project,S-1}$$ represents the amount of CO<sub>2</sub> associated with the project, passing through the previous transport segment, in tCO<sub>2</sub>.
* $$F\_{S-1}$$ represents the allocation fraction of the previous transport segment.
* $$CO\_{2\ in,S-1}$$ represents the total amount of CO<sub>2</sub> entering the previous transport segment, in tCO<sub>2</sub>.
* $$CO\_{2\ out,S-1}$$ represents the total amount of CO<sub>2</sub> leaving the previous transport segment, in tCO<sub>2</sub>.

If the [Individual monitoring approach](#transport-losses-individual-monitoring-approach) is chosen for the calculation of the transport losses, then Eq. 21 shall be used.

$$\textbf{(Eq.21)}\ CO\_{2\ project,S} = CO\_{2\ project,S-1} -(F\_{S-1}\* ( CO\_{2 \ fugitive,S-1} + CO\_{2\ vented,S-1} + CO\_{2 \ transport\ leakage,S-1}))$$

* $$CO\_{2\ project,S-1}$$ is defined in Eq. 20.
* $$F\_{S-1}$$ is defined in Eq. 19.
* $$CO\_{2 \ fugitive,S-1}$$ represents the sum of fugitive emissions from CO<sub>2</sub> transported in the previous transport segment, in tCO<sub>2</sub>.
* $$CO\_{2 \ vented,S-1}$$ represents the sum of vented emissions from CO<sub>2</sub> transported in the previous transport segment, in tCO<sub>2</sub>.
* $$CO\_{2 \ transport\ leakage,S-1}$$ represents the sum of CO<sub>2</sub> transported in the previous transport segment, that was emitted as a result of the failure of one or more components of the transportation network, in tCO<sub>2</sub>.

Where the CO<sub>2</sub> stream is split at a node and sent to multiple storage sites, the project CO<sub>2</sub> shall be allocated across the number of transport segments leaving that node.

{% hint style="info" %}
For example, a biomass capture plant captures 1,000 t biogenic CO<sub>2</sub>, no associated CO<sub>2</sub>, and sends 100% of this CO<sub>2</sub> for permanent storage.

The plant sends its CO<sub>2</sub> into a shared pipeline, carrying 500t CO<sub>2</sub> from an unrelated fossil capture plant. The Project Developers uses the Overall mass balance approach for transport losses.

According to Eq. 12, transport losses for the **first segment** are: $$CO\_{2\ transport,losses} = F\_{RCC} \* \frac{CO\_{2,captured,biogenic}}{CO\_{2,project}} \*( F\_{S=1} \* ( CO\_{2\ in,S=1} - CO\_{2 \ out,S=1})$$

* $$F\_{RCC}$$ is 1
* $$CO\_{2,captured,biogenic}$$ is 1,000 t CO<sub>2</sub>
* $$CO\_{2,project}$$ is 1,000 t, according to Eq. 13.
* $$F\_{S=1} = \frac{CO\_{2 \ project,S=1}}{CO\_{2 \ total,S=1}}=\frac{1,000 t\ CO\_2}{1,500 t\ CO\_2}= 0.67$$
* $$CO\_{2\ in,S=1}$$ is measured to be 1,500 t CO<sub>2</sub>
* $$CO\_{2\ out,S=1}$$ is measured to be 1,470 t CO<sub>2</sub>

By substituting the terms with the corresponding values in Eq. 12, the transport losses in the first segment can be calculated as 20.1 t CO<sub>2</sub>

The CO<sub>2</sub> is entering a **second segment** when being transferred from the to a pipeline operated by a different entity.

The project CO<sub>2</sub> entering this new segment 2 is calculated according to Eq. 20:

$$CO\_{2,project,S=2} = CO\_{2,project,S=1} -(F\_{S=1}\* (CO\_{2\ in,S=1} - CO\_{2 \ out,S=1}))=1,000t \ CO\_2 \ -\ 0.67\*(1,500t\ CO\_2- 1,470t\ CO\_2)=979.9 \ CO\_2$$
{% endhint %}

</details>

## Capture stage emissions

Capture stage emissions are calculated as the sum of emissions from CO<sub>2</sub> generation and CO<sub>2</sub> capture. If the project captures and stores [associated CO<sub>2</sub>](#user-content-fn-19)[^19] alongside the biogenic CO<sub>2</sub>, the amount of the stored associated CO<sub>2</sub> is deducted from the capture stage emissions.

<details>

<summary><strong>Calculation:</strong> Capture stage emissions</summary>

$$\textbf{(Eq.22)}\ E\_{capture} = F\_{RCC}*(E\_{CO2 \ generation}\ +F\_{CO2\ capture}*(\ E\_{CO2\ capture} -CO\_{2, stored, assoc}))$$

* $$E\_{capture}$$ is defined in Eq. 2.
* $$F\_{RCC}$$ is defined in Eq. 11.
* $$E\_{CO2\ generation }$$ represents the operational and embodied emissions associated with the generation of CO<sub>2</sub>, in tCO<sub>2</sub>eq. It includes all processes described in the [CO<sub>2</sub> generation and biomass allocation](#co2-generation-and-biomass-allocation) section. It is calculated in Eq. 24.
* $$F\_{CO2\ capture}$$ represents the allocation fraction for the emissions from CO<sub>2</sub> capture, between the eligible project CO<sub>2</sub> and any other CO<sub>2</sub> captured alongside it. It is determined according to the table below.
* $$E\_{CO2\ capture }$$ represents the operational and embodied emissions associated with the capture of CO<sub>2</sub> after its generation, in tCO<sub>2</sub>eq. This includes emissions from energy and material use and embodied emissions.
* $$CO\_{2 stored, assoc}$$ represents the amount of [associated CO<sub>2</sub>](#user-content-fn-20)[^20] stored, in tCO<sub>2</sub>eq. It is calculated according to the [Storage of associated CO<sub>2</sub>](#storage-of-associated-co2) section.

| Type of captured CO2                                                                             | Emission allocation                                                                                                                            | Allocation fraction                                             |
| ------------------------------------------------------------------------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------- |
| eligible biogenic CO<sub>2</sub>                                                                 | No allocation: all emissions attributed to the BioCCS project.                                                                                 | $$F\_{CO2\ capture}=1$$                                         |
| eligible biogenic CO<sub>2</sub> and associated CO<sub>2</sub>                                   | No allocation: all emissions attributed to the BioCCS project.                                                                                 | $$F\_{CO2\ capture}=1$$                                         |
| eligible biogenic CO<sub>2</sub> and CO<sub>2</sub> from mixed stream                            | Allocation: emissions associated with the capture of the eligible biogenic CO<sub>2</sub> attributed to the BioCCS project.                    | $$F\_{CO2\ capture}=F\_B$$, as defined in Eq. 10                |
| eligible biogenic CO<sub>2</sub>, associated CO<sub>2</sub> and CO<sub>2</sub> from mixed stream | Allocation: emissions associated with the capture of the eligible biogenic and the associated CO<sub>2</sub> attributed to the BioCCS project. | $$F\_{CO2\ capture}=F\_{B, assoc}$$ as defined in Eq. 23, below |

The allocation fraction $$F\_{B, assoc}$$ is calculated according to the following equation:

$$\textbf{(Eq.23)} \ F\_{B,assoc} = (1 - \frac{CO\_{2\ captured,mixed}}{CO\_{2 \ captured,total}})$$

* $$F\_{B,assoc}$$ represents the allocation fraction for emissions from CO<sub>2</sub> capture, when associated CO<sub>2</sub> and CO<sub>2</sub> from a mixed stream are captured alongside eligible biogenic CO<sub>2</sub>.
* $$CO\_{2 \ captured,mixed}$$ is defined in Eq. 10.
* $$CO\_{2 \ captured, total}$$ is calculated in Eq. 4.

***

$$\textbf{(Eq.24)}\ E\_{CO2 \ generation} = Q\_{biomass\ CO2\ generation} \times EF\_{biomass}$$

* $$Q\_{biomass\ CO2\ generation}$$ represents the tonnes of biomass used by the underlying site allocated to the project for CO<sub>2</sub> generation, calculated in Eq. 32 for greenfield projects and Eq. 31 for retrofit projects.
* $$EF\_{biomass}$$ represents the emission factor for all processes related to biomass used at the site from biomass production, in tCO<sub>2</sub>eq/tonne of biomass.

$$\textbf{(Eq.25)}\ EF\_{biomass} = (E\_{b,\ production}+E\_{dLUC}+E\_{b,\ processing}+E\_{b,\ transport}+E\_{b,\ storage}+E\_{b,conversion}+E\_{b,\ leakage}) \div Q \_{biomass,total}$$

* $$E\_{b,\ production}$$ represents the emissions from biomass production for all biomass used at the site in the monitoring period, in tCO<sub>2</sub>eq. It is calculated in the [Processing and energy use](/modules/processing-and-energy-use) module by multiplying one of the eligible emission factors in the [Calculation of CO<sub>2</sub> generation / Biomass production](#calculation-of-co2-generation-emissions) section by $$Q \_{biomass,total}$$.
* $$E\_{dLUC}$$ represents the emissions from direct land use change for all biomass used at the site in the monitoring period, in tCO<sub>2</sub>eq. It shall be calculated using Eq. 33.
* $$E\_{b,\ processing}$$ represents the emissions from processing biomass used at the site in the monitoring period, in tCO<sub>2</sub>eq. It is calculated in the [Processing and energy use](/modules/processing-and-energy-use) module by multiplying an emission factor for one of the processes described in the [Calculation of CO<sub>2</sub> generation / Biomass processing](#calculation-of-co2-generation-emissions) section by $$Q \_{biomass,total}$$.
* $$E\_{b,\ transport}$$ represents emissions from transport of biomass from the sourcing location to the facility and shall be accounted for in the [Transportation](/modules/transportation) module.
* $$E\_{b,\ storage}$$ represents emissions from storage of biomass and shall be calculated using Eq. 35 and 36 for manure and slurry, and Eq. 34 for all other types of biomass.
* $$E\_{b,\ conversion}$$ represent any material, energy, fugitive, or embodied emissions from the biomass conversion process for the entire site (e.g., from anaerobic digestion, municipal incineration, bioenergy combustion...), using the [Processing and energy use](/modules/processing-and-energy-use) and [Infrastructure and machinery](/modules/infrastructure-and-machinery) modules.
* $$E\_{b,\ leakage}$$ represents the leakage emissions related to biomass, from the Leakage emission section and calculated in Eq. 26.
* $$Q\_{biomass, total}$$ represents the total amount biomass consumed by the underlying facility during the monitoring period, in tonnes.

$$\textbf{(Eq.26)}\ E\_{b,\ leakage} = C\_{counterfactual }+E\_{biomass\ diversion}+E\_{iLUC}$$

* $$C\_{counterfactual}$$ represents the counterfactual carbon storage, in tCO<sub>2</sub>eq. It is described in the [#counterfactual-carbon-storage](#counterfactual-carbon-storage "mention") section and calculated in Eq. 48-49.
* $$E\_{biomass\ diversion }$$ represents the leakage emissions from biomass diversion, in tCO<sub>2</sub>eq. It is described in the [#biomass-diversion](#biomass-diversion "mention") section and calculated in Eq. 50.
* $$E\_{iLUC}$$ represents the indirect land use change emissions, in tCO<sub>2</sub>eq. It is described in the [#indirect-land-use-change-emissions](#indirect-land-use-change-emissions "mention") section and calculated in Eq. 51.

***

$$\textbf{(Eq.27)}\ E\_{CO2\ capture}= E\_{external\ energy}+E\_{parasitic\ load}+ E\_{capture,\ materials}+E\_{embodied}$$

* $$E\_{external\ energy}$$ represents emissions from all external energy consumption used to power the carbon capture unit in the monitoring period in tCO<sub>2</sub>eq. It is described in the [External energy](#external-energy) section, and calculated in the [Processing and energy use](/modules/processing-and-energy-use) module.
* $$E\_{parasitic\ load}$$ is calculated using either the simplified approach in Eq. 42 or the full approach in Eq. 43.
* $$E\_{capture,\ materials}$$ represents emissions from all materials used the carbon capture unit in the monitoring period in tCO<sub>2</sub>eq. It is described in the [Material consumption](#material-consumption-in-capture-process) section, and calculated in the [Processing and energy use](/modules/processing-and-energy-use) module.
* $$E\_{embodied}$$ represents emissions from all infrastructure and machinery used the carbon capture unit in the monitoring period in tCO<sub>2</sub>eq. It is described in the [Embodied emissions in capture process](#embodied-emissions-in-capture-process) section, and calculated in the [Infrastrucutre and machinery](/modules/infrastructure-and-machinery) module.

</details>

### CO<sub>2</sub> generation and biomass allocation

Depending on the context, CO<sub>2</sub> shall be counted as either

* a waste, and enter the project system boundary burden-free, or
* a co-product of the underlying system, and be allocated a share of emissions from its generation.

Under some circumstances, CO<sub>2</sub> can be considered a co-product and not a waste, and the emissions from the CO<sub>2</sub>-generating activity at the underlying facility shall be shared between the CO<sub>2</sub>/bioCCS project and the primary product. Emissions from CO<sub>2</sub> generation include all upstream emissions up to the point of physical separation of the co-products, such as **biomass supply and conversion steps upstream of CO**<sub>**2**</sub>**&#x20;capture**.

CO<sub>2</sub> allocation follows biomass allocation. The share of biomass attributed to the BioCCS project is determined in two steps:

1. identifying the quantity of biomass corresponding to the CO<sub>2</sub> considered to be a co-product rather than a waste,
2. applying economic allocation between the BioCCS project and the underlying facility.

#### **Determine the biomass quantity corresponding to CO**<sub>**2**</sub>**&#x20;generation**

The biomass quantity subject to allocation differs by project type.

**Retrofit projects:** Prior to the retrofit, the CO<sub>2</sub> was generated anyway, not used, and was treated as a waste stream (e.g. vented to atmosphere).

* If the facility increased its biomass consumption after the retrofit by more than what is needed to meet the parasitic load, for eligible reasons outlined in [Biomass conversion efficiency](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#biomass-conversion-efficiency), the excess above the parasitic load (referred to as the additional biomass) is the quantity subject to CO<sub>2</sub> generation emissions allocation.
* If the facility did not increase its biomass consumption after the retrofit, or increased its consumption only by the amount needed for the parasitic load, the **generation of all CO**<sub>**2**</sub>**&#x20;is considered burden-free.** No biomass is subject to CO<sub>2</sub> generation emissions allocation. Note that emissions from the parasitic load energy use are accounted for separately in the [Internal energy and parasitic load](#internal-energy-and-parasitic-load) section. Project Developers shall prove that:
  * The biomass consumption did not increase above the baseline consumption rate, or
  * The amount of additional biomass consumed above the baseline consumption rate corresponds to the [parasitic load biomass](#calculation-amount-of-biomass-corresponding-to-the-parasitic-load).

**Greenfield projects:** If carbon capture and primary production are co-designed, the facility simultaneously produces CO<sub>2</sub> and one or more primary products or services. The total biomass consumed is the quantity subject to CO<sub>2</sub> allocation.

#### Economic allocation of emissions

The amount of biomass whose supply and conversion emissions are allocated to the BioCCS project is multiplied by the economic allocation factor, representing the **economic value of CO**<sub>**2**</sub>**&#x20;and RCC issuance relative to other products and services of the underlying facility**. The economic value of the co-products shall be determined at the site level.

* **The CO**<sub>**2**</sub>**&#x20;price** shall be based on the project's average annual revenue from BioCCS carbon removal credits over the past 3 years. If such data is not available for the first verification, the price shall be based on final financial projections of the expected revenues, as presented to investors.
* **The price of the primary product or service** shall be based on annual average project-specific data over the past 3 years. If such data is not available the use of secondary market data is allowed for the first verification.

Project Developers shall provide documentation and justification of the calculations, conservativeness of the values and sources used.

The validity of the economic values of the co-products is **5 years**. Project Developers may update the values at each monitoring period.

The economically-allocated amount of biomass counted for the project for CO<sub>2</sub> generation is multiplied by the biomass' [supply and conversion emission factor](#user-content-fn-21)[^21], $$EF\_{biomass}$$, calculated in Eq. 25.

<details>

<summary><strong>Calculation:</strong> Economic allocation of biomass for CO<sub>2</sub> generation</summary>

**Retrofit: Additional biomass**

In a retrofit scenario, the amount of biomass consumed above the baseline biomass consumption rate is considered additional biomass and defined as:

$$\textbf{(Eq.28)} \ Q\_{additional \ biomass } = Q\_{biomass, total}-Q\_{baseline\ biomass}$$

* $$Q\_{additional \ biomass }$$ represents the fraction of biomass consumed above the baseline biomass consumption rate in the monitoring period, in tonnes. This is the [**additional biomass**](#user-content-fn-9)[^9]**.**
* $$Q\_{biomass, total}$$ represents the total amount biomass consumed during the monitoring period, in tonnes.
* ​$$Q\_{baseline\ biomass}$$ represents the baseline biomass consumption rate scaled to the same period, in tonnes. This is the [**baseline biomass**](#user-content-fn-9)[^9]. It shall be provided from:
  * The average annual biomass consumption of the facility over the three years prior to the start of the project activity, derived from primary operational records; or
  * If site specific data is not available, a [regional market analysis](#user-content-fn-22)[^22] shall be used to demonstrate that the feedstock type, quantity, and alternative fate are representative of the local market conditions prior to the retrofit.

If any of the additional biomass consumed is used for purposes other than meeting the parasitic load, emissions from the generation of CO<sub>2</sub> from that biomass shall be economically allocated between the CO<sub>2</sub> and the primary product or service.

The share of additional biomass used for other purposes is calculated as:

$$\textbf{(Eq.29)} \ Q\_{additional\ biomass, other}=Q\_{additional\ biomass} -Q\_{parasitic\ load, biomass}$$

* $$Q\_{additional\ biomass, other}$$ represents the share of additional biomass that is used for other purposes than meeting the parasitic load, and that is allocated to the project, in tonnes. This value is used in Eq. 24 to calculate $$E\_{CO2\ generation }$$.
* $$Q\_{additional\ biomass}$$ is defined in Eq. 28.
* $$Q\_{parasitic\ load, biomass}$$ represents the amount of biomass needed to meet the parasitic load, in tonnes. Calculated according to the rules set out in [Internal energy and parasitic load](#internal-energy-and-parasitic-load).

**Economic allocation of biomass**

$$\textbf{(Eq.30)} F\_{economic,\ CO2}= \frac{Revenue\_{CO2,\ RCC}}{Revenue\_{CO2,\ RCC}+Revenue\_{primary\ product}}$$

* $$F\_{economic, \ CO2}$$ represents the economic allocation fraction for CO<sub>2</sub> generation, determined following the rules set out in [Determination of the economic value](#economic-value-of-co-products).
* $$Revenue\_{CO2,\ RCC}$$ represents the annual revenue of the site from carbon finance from the equivalent amount of RCCs issued from CO<sub>2</sub> capture and storage.
* $$Revenue\_{primary\ product}$$ represents the annual revenue of the site from generation and sale of other primary product/s and/or service/s.

For retrofit projects:

$$\textbf{(Eq.31)} \ Q\_{biomass, \ CO2\ generation } = F\_{economic,\ CO2}\*Q\_{additional\ biomass, other }$$

* $$Q\_{biomass, \ CO2\ generation }$$ represents the amount of biomass whose supply and conversion emissions are allocated to the BioCCS project, in tonnes.
* $$F\_{economic, \ CO2}$$ is calculated in Eq. 30.
* $$Q\_{additional\ biomass, other }$$ is calculated in Eq. 29.

For greenfield projects:

$$\textbf{(Eq.32)} \ Q\_{biomass, \ CO2\ generation } = F\_{economic,\ CO2}\*Q\_{biomass, total}$$

* $$Q\_{biomass, \ CO2\ generation }$$ is defined in Eq. 31. This is the [**biomass fraction**](#user-content-fn-9)[^9] **allocated to CO**<sub>**2**</sub>**&#x20;generation**.
* $$F\_{economic, \ CO2}$$ is calculated in Eq. 30.
* $$Q\_{biomass, total }$$ represents the total amount of biomass consumed in the monitoring period, in tonnes.

</details>

#### Calculation of CO<sub>2</sub> generation emissions

Emissions shall be calculated for each biomass type, and include all sourcing steps upstream of the conversion site, detailed in the following sections.

**Biomass production**

[Waste and residues](#user-content-fn-23)[^23] are considered to have zero biomass production emissions up to the point of collection of those materials.

Production emissions of non-waste biomass (i.e. energy crops) shall cover both cultivation and harvesting. This includes all inputs associated with growing and collecting the biomass, such as fertilizer production and application, fuel and energy use for agricultural machinery, pesticide or herbicide use, any on-site storage or handling operations prior to biomass transport to the BioCCS site.

Project Developers shall determine the emissions from biomass production by multiplying the mass of biomass used with an appropriate emission factor. Emission factors shall be sourced from:

* [**RED III**](#user-content-fn-24)[^24] **disaggregated default values for term&#x20;*****e***<sub>***ec***</sub>, where available in Annex V or Annex VI of the Directive; or
* **Default values at regional level (NUTS2)**, where reported by the relevant countries and recognized by the European Commission (available [here](https://energy.ec.europa.eu/topics/renewable-energy/bioenergy/biofuels_en#reports-on-emissions-from-cultivation-of-raw-materials-for-use-in-biofuels)); or
* **representative emission factors** from databases or peer-reviewed literature (e.g. [ecoinvent database](#user-content-fn-7)[^7] 3.12).

Where values are expressed per unit of energy output, Project Developers shall convert to emissions per unit of feedstock consumed.

<details>

<summary>🇪🇺 <strong>CRCF requirement</strong>: Emission factors biomass production</summary>

For CRCF-compliant projects, Project Developers shall follow the hierarchical list below for selecting biomass production emission factors:

1. RED III disaggregated default values for term *e*<sub>*ec,*</sub>
2. Default values at regional level (NUTS2),
3. Calculate averages based on local farming practices based on e.g. data of a group of farms, as an alternative to using a single actual value

Note that the use of representative emissions factors from other databases or literature is not allowed under the CRCF.

</details>

**Direct land-use change**

Biomass cultivation may cause direct land-use change (e.g. deforestation for farmland), leading to decreasing carbon stocks and causing emissions. The [land-use categories](#user-content-fn-25)[^25] are

* forest land
* crop land, where crop land and [perennial crop](#user-content-fn-26)[^26] land are regarded as one land use
* grassland
* wetlands
* settlements
* other land

Zero direct land use change emissions shall be counted if the use of the land on which biomass was cultivated has not changed since January 2008 or 20 years before the biomass was cultivated, whichever was the later. This shall be proven using relevant sections of the RED-certification of the biomass; signed declaration from the biomass supplier, supported by farm management records evidencing continuous use; historical satellite or aerial imagery showing continuous land-use since January 2008.

If [eligible land-use change](#user-content-fn-27)[^27] happened in January 2008 or after, the annualized emissions from carbon stock changes caused by land-use change shall be calculated by dividing total emissions equally over 20 years.

<details>

<summary><strong>Calculation:</strong> Direct land-use change emissions</summary>

$$\textbf{(Eq.33)} \ E\_{dLUC} = ((CS\_{R} - CS\_{A}) \times 3{.}664\times \frac{1}{20} \times \frac{1}{P} - e\_{B})\times Q\_{biomass,total}\times LHV\_{biomass}$$

* $$E\_{dLUC}$$ represents the annualized emissions from carbon stock change due to land-use change, in tCO<sub>2</sub>eq.
* $$CS\_R$$ represents the carbon stock per unit area (including soil and vegetation) associated with the **reference land use**. The reference land use shall be the land use in January 2008 or 20 years before the biomass was obtained, whichever was the later. Calculated following the [guidelines for the calculation of land carbon stocks](#user-content-fn-6)[^6].
* $$CS\_A$$ represents the carbon stock per unit area (including soil and vegetation) associated with the **actual land use**. In cases where the carbon stock accumulated over more than one year, the value attributed shall be the estimated stock per unit area after 20 years or when the crop reaches maturity, whichever is earlier. Calculated following the [guidelines for the calculation of land carbon stocks](#user-content-fn-6)[^6].
* $$P$$ represents the productivity of the biomass crop, in unit biomass energy / unit area and year.
* $$e\_B$$ is a bonus of 29 g CO2 eq / MJ biomass energy, applied for a period of 20 years from the date of conversion of the land, provided biomass is obtained from a restored degraded land under the following conditions:
  * Evidence is provided that the land was not in use for agriculture in January 2008 or any other activity, and
  * is [severely degraded land](#user-content-fn-28)[^28], including land that was formerly in agricultural use.
  * A steady increase in carbon stocks and sizable reduction in erosion phenomena for severely degraded land is ensured
* $$Q\_{biomass, total}$$ is defined in Eq. 25.
* $$LHV\_{biomass,i}$$ represents the lower heating value of the biomass type $$i$$, in MJ/t.

</details>

**Biomass processing**

Emissions associated with the upstream and on-site processing of biomass prior to its conversion (e.g. drying, mixing or shredding of feedstock) shall be accounted for.

Project Developers shall determine the emissions from biomass processing by multiplying the mass of biomass used with an appropriate emission factor.

Emission factors shall be sourced from

* [**RED III**](#user-content-fn-24)[^24] **default values for term&#x20;*****e***<sub>***p***</sub> from Annex V or Annex VI of the Directive, where available. Where Project Developers used RED III default values for the calculation of biomass production emissions, the corresponding default values for processing emissions shall be used.

Where no default value exists, Project Developers shall choose one of the following options

* demonstrate that the processing emissions (upstream and on-site) are included in the biomass production emission factor
* source an emission factor for upstream and on-site processing from reputable databases or peer-reviewed literature
* Calculate the emissions from upstream and on-site processing using the [Processing and energy use](/modules/processing-and-energy-use) module.

**Biomass transport**

Emissions associated with the transport of biomass from the sourcing location to the facility shall be accounted for in the [Transportation](/modules/transportation) module. Municipal solid waste and municipal sludge enter the system boundary when deposited at the BioCCS facility and therefore don't have any associated transport emissions.

**Biomass storage**

Emissions associated with the storage of biomass feedstock ahead of conversion shall be calculated separately for each feedstock that is harvested or collected at the same time and stored in the same way.

Biomass storage emissions are set to zero for each feedstock that Project Developers demonstrate meets at least one of the following conditions:

* the feedstock is coarse woody material that stays naturally well-aerated throughout storage; or
* feedstock is pelleted for storage; or
* feedstocks that do not naturally remain well-aerated, but are either:
  * processed within four weeks of entering storage; or
  * stored at a moisture content of 30% or below;
* Project Developers demonstrate that biomass is stored in a way that avoids significant CH<sub>4</sub> emissions from anaerobic decomposition given the nature of the feedstock and the local conditions

Where none of the above applies, emissions from storage of biomass shall be quantified.

<details>

<summary><strong>Calculation:</strong> Biomass storage emissions</summary>

**Biomass other than manure and slurry**

$$\textbf{(Eq.34)}\ E\_{b\ storage}=\sum\_{i} ( {C\_{to}}CH\_4\times 0.0013\times Q\_{biomass,total, i}\times C\_{biomass, total, i}\times (T\_{storage}-1))\times GWP\_{100,CH4}$$

* $$i$$ represents the share of the total biomass harvested or collected at the same time and stored in the same way.
* $$C\_{to}CH\_4$$ represents the molecular mass ratio of methane to carbon, which is 1.335.
* 0.0013 represents the [monthly fractional loss](#user-content-fn-29)[^29] of biomass carbon from storage.
* $$Q\_{biomass, total,i}$$ represents the amount of share $$i$$ of the total biomass, in tonnes.
* $$C\_{biomass, total, i}$$ represents the carbon content of share $$i$$ of the total biomass, in mass%.
* $$T\_{storage}$$ represents the rounded-up time for which the biomass share is stored, in months.
* $${GWP}\_{100,CH4}$$ represents the global warming potential of CH$$\_4$$ over 100 years.

**Manure and slurry**

Manure and slurry may be stored onsite for several days or weeks if they cannot be utilized immediately upon their delivery to the biomass conversion site. During this storage period, methane and N<sub>2</sub>O are emitted linearly over time. When the feedstock is stored for 180 days (a conventional manure/slurry management scenario), 2% of its nitrogen is emitted as N<sub>2</sub>O, plus some methane expressed as a fraction of its biomethane potential (*BMP*). The ratio of average days manure and slurry are stored at the biomass conversion site, to the average storage duration of 180 days, is [used to adjust the N<sub>2</sub>O and methane emission benchmarks](#user-content-fn-8)[^8] detailed in Table A1 and A2 in the [Appendix](/methodologies/biogenic-carbon-capture-and-storage-bioccs/appendix) (see example in the box below).

{% hint style="info" %}
For example, if manure is stored at a biogas site 18 days on average before being added to the digester, this represents 10% of the average 180 days of conventional manure storage. As shown in Table A1, when manure is stored for 180 days:

* 2% of its nitrogen is emitted as N2O, and
* 1.5% of its BMP is emitted as methane.

When this storage time is shortened to 18 days in the biogas scenario, (10% of the conventional storage duration):

* the nitrogen emission rate is reduced to 0.2% (10% of 2%), and
* the methane emission rate is reduced to 0.15% of BMP (10% of 1.5%).
  {% endhint %}

Eq. 35 shall be used if the project uses **manure** as a feedstock input, to calculate N<sub>2</sub>O emissions from manure storage.

$$\begin{aligned}\textbf{(Eq.35)}\ E\_{ N2O\ manure\ storage} = \sum\_{i} Q\_{manure, i}\times \ % N\times R\_{N\ as\ N2O}\ \times N\_{to \ N2O}\times \frac{Days\ stored}{180}\times \ GWP\_{N2O}\times 10^{-3}\end{aligned}$$

* $$E\_{ N2O\ manure\ storage}$$ represents the sum of GHG emissions from N$$\_2$$O due to the storage of manure type *i* (chicken or cow) in the project scenario, in tCO$$\_2$$eq.
* $$Q\_{manure, i}$$ represents the mass of manure type *i* used as feedstock in the project scenario, in kg.
* $$% N$$ represents the percent of manure mass as nitrogen, reported as fraction.
  * For chicken manure, this is 1.4% of fresh matter as nitrogen, as shown in Table A1 in the [Appendix](/methodologies/biogenic-carbon-capture-and-storage-bioccs/appendix).
  * For cow and all other manure types, this is 0.65% of fresh matter as nitrogen, as shown in Table A1 in the [Appendix](/methodologies/biogenic-carbon-capture-and-storage-bioccs/appendix) (2.7% of dry matter as nitrogen \* 24% dry matter)
* $$R\_{N\ as\ N2O}$$ represents the rate of nitrogen emitted as N$$\_2$$O from conventional manure storage of 180 days. According to Table A1, this equals 2%.
* $$Days\ stored/180$$ represents the number of days manure is kept stored. A default value of 15 days can be assumed if no project data is available. 180 represents the conventional manure storage duration of 180 days.
* $$N\_{to\ N2O}$$ represents the conversion of nitrogen to N$$\_2$$O equivalents by multiplying by the ratio of their molecular mass (1.57).
* $$GWP\_{N2O}$$ represents the global warming potential of N$$\_2$$O over 100 years, which is [273 kgCO<sub>2</sub>eq/kg N<sub>2</sub>O](#user-content-fn-30)[^30].
* It is multiplied with $$10^{-3}$$ to convert from kgCO<sub>2</sub> eq to tCO<sub>2</sub>eq.

Eq. 36 shall be used if the project uses **manure and/or slurry** as a feedstock input, to calculate methane emissions from manure and/or slurry storage.

$$\begin{aligned}\textbf{(Eq.36)}\ E\_{CH4\ storage} = \sum \&Q\_{manure,i}\times {BMP}*{i}\times E*{BMP,\ CH4}\times \ &{\rho CH}*{4}\times {\frac{Days\ stored}{180}\times GWP}*{bio\ CH4}\times 10^{-3}\end{aligned}$$

* $$E\_{\ CH4\ storage}$$ represents the emissions of methane from storage of manure and/or slurry, in tCO$$\_2$$eq.
* $$Q\_{manure, i}$$ is explained in Eq. 35.
* $$BMP\_{i}$$ represents the biomethane potential of feedstock type $${i}$$, in nm$$^3$$ of CH$$\_4$$ per tonne of fresh matter, presented in Table A1 and A2 in the [Appendix](/methodologies/biogenic-carbon-capture-and-storage-bioccs/appendix).
* $$E\_{BMP,\ CH4}$$ represents methane emissions during storage as % of BMP, presented in Table A1 and A2 in the [Appendix](/methodologies/biogenic-carbon-capture-and-storage-bioccs/appendix).
* $${\rho CH}\_{4}$$ represents the methane density, which is[ 0.75](#user-content-fn-31)[^31] kg/m³.
* $$Days\ stored/180$$ was described in Eq. 35.
* $${GWP}\_{bio\ CH4}$$ represents the global warming potential of biogenic CH$$\_4$$ over 100 years, which is 27[^32] kgCO$$\_2$$eq/kg CH$$\_4$$.
* It is multiplied with $$10^{-3}$$ to convert from kgCO<sub>2</sub> eq to tCO<sub>2</sub>eq.

</details>

**Biomass conversion: energy and material use**

Emissions associated with the energy (e.g. fuel, electricity, heat) and material inputs (e.g. chemicals, water) consumed for the conversion of biomass into co-products and any waste disposal processes shall be accounted for in the [Processing and energy use](/modules/processing-and-energy-use) module.

**Biomass conversion: fugitive emissions**

Fugitive emissions associated with the conversion of biomass, e.g. CH<sub>4</sub> and N<sub>2</sub>O shall be accounted for in the [Processing and energy use](/modules/processing-and-energy-use) module. Any CO<sub>2</sub> emitted from the conversion of biomass is biogenic and therefore considered to have zero associated emissions.

**Biomass conversion: embodied emissions**

Embodied emissions from the facility's infrastructure and machinery used for biomass conversion to CO<sub>2</sub> and primary product(s) shall be accounted for in the [Infrastructure and machinery](/modules/infrastructure-and-machinery) module.

For BioCCS projects at **anaerobic digestion sites**, the following simplification for data collection is applied:

* Buildings and main infrastructure at the biogas site have an assumed lifetime of 20 years. Embodied emissions from infrastructure and machinery are modeled and extrapolated from the **main digester exterior volume** (m<sup>3</sup>) to simplify data collection. The ecoinvent process for the anaerobic digestion plant present in the [Appendix](/methodologies/biogenic-carbon-capture-and-storage-bioccs/appendix) is used, considering 1 m<sup>3</sup> of digester volume annually.

### Energy use in capture process

Energy consumption for the CO<sub>2</sub> capture process may be sourced externally, or drawn internally from the facility's own energy output (**parasitic load**).

#### **External energy**

If the energy to power the capture unit is not drawn from the facility's own energy production but sourced externally (e.g. electricity or heat from the grid, on-site diesel generator or solar panels) emissions are calculated by multiplying the amount of energy consumed with the emission factor for the relevant energy source (electricity, heat or fuel combustion). See the [Processing and energy use module](/modules/processing-and-energy-use) for details on the calculations.

If the project's CO<sub>2</sub> capture unit recovers and exports heat or electricity, this **exported energy shall be deducted from the gross external energy consumed** by the project. If more energy is recovered and exported than imported, the net amount of energy consumed is negative and the associated emissions shall be set to zero, provided substantial proof is delivered by the Project Developer. Recover and export of energy does not include:

* Heat or electricity produced and consumed on-site at the capture facility, as it is accounted for elsewhere.
* Heat or electricity produced specifically for export from the facility rather than recovered from a necessary process

#### **Internal energy and parasitic load**

If the energy to power the capture unit is drawn from the facility's own energy production, the emissions associated with the production of that energy, also referred to as **parasitic load**, are attributed to the BioCCS project. The emissions are calculated according to the following steps:

1. **Calculate the parasitic load** (i.e. the amount of energy in kWh or MJ consumed by the capture unit)
2. **Calculate the amount of biomass corresponding to the parasitic load** (i.e. the amount of biomass needed to generate the amount of energy in the parasitic load)
3. **Calculate the life-cycle emissions from supply and conversion of that biomass**, using either
   1. **Simplified approach: Facility energy emission factor** using a verified emissions factor for the facility's energy production, or
   2. **Full approach: Biomass-based calculation** calculating the emissions from all biomass [supply and conversion emission](#user-content-fn-21)[^21]s, $$EF\_{biomass}$$, calculated in Eq. 25.

If the BioCCS project captures CO<sub>2</sub> from a process that converts biomass feedstock including food and feed crops or food and feed crop-based fuels, energy produced from the conversion of that feedstock shall not be used to operate the capture process, except for the case of recovered heat.

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Parasitic load approach</summary>

Project Developers seeking certification under the EU CRCF shall only use the full approach (biomass-based calculation) to determine emissions from parasitic load demand.&#x20;

</details>

<details>

<summary><strong>Calculation:</strong> External energy and parasitic load energy demand</summary>

The parasitic load is calculated by dividing the energy consumed by the capture unit by the energy efficiency of the entire facility.

For facilities producing only electricity or only heat, the term in the equation that corresponds to the absent energy output (i.e. heat or electricity) is set to zero, and the equation simplifies.

$$\textbf{(Eq.37)} \ Q\_{Parasitic\ load, energy} = \frac{C\_{elec} \* Q\_{elec, capture, parasitic} + C\_{heat} *Q\_{heat, capture, parasitic}}{C\_{elec}* \eta\_{elec} + C\_{heat} \* \eta\_{heat}}$$

* $$Q\_{Parasitic\ load, energy}$$ represents the parasitic load, in kWh or MJ.
* $$C\_{elec}$$ represents the exergy fraction of electricity, set to 1.
* $$Q\_{elec, capture, parasitic}$$ represents the electricity consumed by the capture unit as the parasitic load, in kWh or MJ, provided via primary project data.
* $$\eta\_{elec}$$ represents the electrical efficiency of the facility. It is dimensionless.
  * For facilities producing **either electricity or heat**, it shall be calculated according to Eq. 40.
  * For facilities producing **both electricity and heat**, it may be calculated according to Eq. 40 or set for the entire certification period based on technical documentation of the facility.
* $$C\_{heat}$$ represents the Carnot efficiency of the heat, defined as $$(T\_{heat} - T\_0) / T\_{heat}$$, where $$T\_{heat}$$ is the average temperature of the heat in K, and $$T\_0$$ is the ambient temperature, 273.15 K.
* $$Q\_{heat, capture, parasitic}$$ represents the heat consumed by the capture unit as the parasitic load, in kWh or MJ, provided via primary project data.
* $$\eta\_{heat}$$ represents the heat efficiency of the facility. It is dimensionless.
  * For facilities producing **either electricity or heat**, it shall be calculated according to Eq. 40.
  * For facilities producing **both electricity and heat**, it may be calculated according to Eq. 40 or set for the entire certification period based on technical documentation of the facility.

$$\textbf{(Eq.38)} \ Q\_{heat/elec, net,external} = Q\_{heat/elec, gross,external} - Q\_{heat/elec,capture, recovered}$$

* $$Q\_{heat/elec, net,external}$$ represents the net amount of external heat or electricity consumed by the capture process, if it comes from a singular source. If it comes from multiple sources, it shall be calculated using Eq. 39.
* $$Q\_{heat/elec, gross,external}$$ represents the gross amount of heat or electricity imported from outside the facility for direct use by the capture process.
* $$Q\_{heat/elec,capture, recovered}$$ represents the amount of heat or electricity recovered from the capture process and exported. This is zero if the site doesn't recover and export any energy.

If the heat or electricity is imported from more than one source, the net consumption of each source shall be calculated proportionally, based on its share of the gross consumption

$$\textbf{(Eq.39)} \ Q\_{heat/elec, net,external,i} = Q\_{heat/elec, gross,external,i} \* \frac{\sum\_{i} Q\_{heat/elec, net,external,i}}{\sum\_{i} Q\_{heat/elec, gross,external,i}}$$

The electrical or heat efficiency of the facility is calculated by dividing the total energy produced (electricity or heat) by the theoretical energy available in the input biomass feedstock.

$$\textbf{(Eq.40)} \ \eta\_{elec/heat} = \frac{Q\_{elec/heat, total} }{Q\_{biomass, total}\* LHV\_{biomass}}$$

* $$\eta\_{elec/heat}$$ represents the electrical or heat efficiency of the facility. It is dimensionless.
* $$Q\_{elec/heat, total}$$ represents the total electricity or heat production of the facility including the parasitic load (i.e. the electricity or heat consumed by the capture unit) during the monitoring period, in kWh or MJ.
* $$Q\_{biomass, \ total}$$ represents the total biomass input of the facility for the production of electricity or heat during a monitoring period, in tonnes.
* $$LHV\_{biomass}$$ represents lower heating value of the biomass input, in an appropriate energy per mass unit (e.g. MJ/t, kWh/t).

</details>

<details>

<summary><strong>Calculation:</strong> Parasitic load, corresponding biomass</summary>

The amount of biomass corresponding to the parasitic load, the **parasitic load biomass**, is calculated by dividing the parasitic load by the theoretical energy content of the biomass used as input.

$$\textbf{(Eq.41)} \ Q\_{Parasitic\ load, biomass} = \frac {Q\_{Parasitic\ load, energy}}{LHV\_{biomass} }$$

* $$Q\_{Parasitic\ load, biomass}$$ represents the amount of biomass corresponding to the parasitic load, in tonnes.
* $$Q\_{Parasitic\ load, energy}$$ is defined in Eq. 37.
* $$LHV\_{biomass}$$ is defined in Eq. 40.

{% hint style="info" %}
For example, a retrofit BECCS facility produces 10,000 MWh of electricity during the monitoring period, including the electricity used by the capture unit, which amounts to 1,000 MWh. To produce the total electricity, the facility requires 9,000 tonnes of wood pellets with a LHV of 17 MJ/kg.

**Step 1: Calculate parasitic load energy demand**

Substep 1: Calculate electricity efficiency, Eq. 40

$$10,000\ MWh / (9,000 \ t \ \* 17 \frac{MJ}{kg} \ \* 1,000 \frac{kg}{t} \ \* \frac{1 }{3600}\frac{MWh}{ MJ})=0.235 = 23.5%$$

Substep 2: Calculate parasitic load energy demand with electrical efficiency, Eq. 37

$$(1*1,000 \ MWh) / (1*0.235)=4,255 \ MWh$$

**Step 2: Calculate the corresponding amount of biomass, Eq. 41**

$$4,255\ MWh / (17 \frac{MJ}{kg} \ \* 1,000 \frac{kg}{t} \ \* \frac{1 }{3600}\frac{MWh}{ MJ})=900 \ t$$\
\
The parasitic load emissions shall be calculated for the sourcing, processing and conversion of 900 t wood pellets.\
\
For facilities **producing only electricity or only heat**, the share of energy used by the capture unit to the total energy production (including the internally consumed energy) simply corresponds to the share of biomass needed to provide this energy to the total biomass input.

In this example, the capture unit consumes 10% of the total electricity production, so the amount of biomass required to provide this share corresponds to 10% of the total biomass input.

For facilities **producing both electricity and heat**, the relation is not as simple, as the heat efficiency is different to the electricity efficiency and the Carnot efficiency of the heat has to be considered.
{% endhint %}

</details>

<details>

<summary><strong>Calculation:</strong> Emissions associated with the parasitic load biomass</summary>

Project Developers shall choose one of the following approaches to calculate the emissions associated with the parasitic load biomass.

**Simplified approach: Facility energy emission factor**

Where a [verified emission factor](#user-content-fn-33)[^33] for the energy produced by the facility is available, Project Developers may use this value and multiply with the net energy consumed by the capture unit $$Q\_{elec, capture, net}$$ or $$Q\_{heat, capture, net}$$, to determine parasitic load emissions, provided full justification and underlying calculations are submitted. The emission factor shall be calculated for the total energy produced (including energy consumed internally), not for the total energy exported.

$$\textbf{(Eq.42)} E\_{Parasitic \ load} =Q\_{elec, \ capture, net}\*EF\_{electricity \ production }+Q\_{heat, \ capture, net}\*EF\_{heat \ production }$$

* $$E\_{Parasitic \ load}$$ represents the parasitic load emissions, in tCO<sub>2</sub>eq.
* $$Q\_{elec, \ capture, net}$$ is defined in Eq. 38.
* $$Q\_{heat, \ capture, net}$$ is defined in Eq. 38.
* $$EF\_{electricity \ production }$$ represents the verified emission factor of the facility's total electricity production, in tCO<sub>2</sub>eq / kWh or MJ.
* $$EF\_{heat \ production }$$ represents the verified emission factor of the facility's total heat production, in tCO<sub>2</sub>eq / kWh or MJ.

**Full approach: Biomass-based calculation**

$$\textbf{(Eq.43)} E\_{Parasitic \ load} =Q\_{Parasitic\ load, biomass}\times EF\_{biomass}$$

* $$E\_{Parasitic \ load}$$ represents the parasitic load emissions, in tCO<sub>2</sub>eq.
* $$Q\_{Parasitic\ load, biomass}$$ represents the amount of biomass corresponding to the parasitic load, in tonnes, calculated in Eq. 41.
* $$EF\_{biomass}$$ represents the emission factor for all processes related to biomass used at the site from biomass production, in tCO<sub>2</sub>eq/tonne of biomass, calculated in Eq. 25.

</details>

### Material consumption in capture process

Emissions associated with material consumed **solely by the CO**<sub>**2**</sub>**&#x20;capture process**, meaning consumed for capture after the point of CO<sub>2</sub> generation (e.g. solvents, adsorbents, and other process chemicals, material consumed for disposal of chemical waste, water) shall be fully attributed to the project.

See the [Processing and energy use module](/modules/processing-and-energy-use) for details on the calculations

### Embodied emissions in capture process

Embodied emissions from infrastructure and machinery that **are only used for the CO**<sub>**2**</sub>**&#x20;capture process**, and are used for capture after the point of CO<sub>2</sub> generation (e.g. liquefaction, compression equipment) shall be fully attributed to the project.

See the [Infrastructure and machinery module](/modules/infrastructure-and-machinery) for details on the calculation.

### Storage of associated CO<sub>2</sub>

If a BioCCS project captures [associated CO<sub>2</sub>](#user-content-fn-20)[^20] alongside eligible biogenic CO<sub>2</sub> and permanently stores it, the amount of associated CO<sub>2</sub> that ends up in permanent storage shall be excluded from the calculation of the capture stage emissions.

The amount of associated CO<sub>2</sub> stored is the amount of associated CO<sub>2</sub> captured minus any losses attributable to the associated CO<sub>2</sub> prior to entering storage.

<details>

<summary><strong>Calculation</strong>: Associated CO<sub>2</sub> stored</summary>

$$\textbf{(Eq.44)} \ CO\_{2\ stored, assoc} =CO\_{2\ captured,assoc}- CO\_{2\ transport\ losses, assoc }-{CO\_{2\ storage\ losses, assoc}}$$

* $$CO\_{2\ stored, assoc}$$ is defined in Eq. 22.
* $$CO\_{2\ captured,assoc}$$ is defined in Eq. 9.
* $$CO\_{2\ transport\ losses, assoc}$$ represents the amount of associated CO<sub>2</sub> lost during the transport stage, in tCO<sub>2</sub>.
* $$CO\_{2\ storage\ losses, assoc}$$ represents the amount of associated fossil CO<sub>2</sub> lost during the storage stage, in tCO<sub>2</sub>.

**Transport losses** of the associated CO<sub>2</sub> shall be calculated following the rules in the [Calculation of transport losses](#calculation-of-transport-losses) section. In order to calculate the losses attributed to the associated CO<sub>2</sub>, in Eq. 12 ([Overall mass balance approach](#transport-losses-overall-mass-balance-approach)) and 14 ([Individual monitoring approach](#transport-losses-individual-monitoring-approach)), the term $$F\_ {RCC}\* \frac{CO\_{2\ captured, biogenic}}{CO\_{2\ project}}$$ shall be replaced with $$\frac{CO\_{2\ captured, assoc}}{CO\_{2\ project}}$$.

**Storage losses** shall be calculated following the rules in the [Calculation of storage losses](#calculation-of-storage-losses) section, and replacing the term $$F\_ {RCC}\* \frac{CO\_{2\ captured, biogenic}}{CO\_{2\ project}}$$ with $$\frac{CO\_{2\ captured, assoc}}{CO\_{2\ project}}$$ in Eq. 16.

</details>

## Transport stage emissions

Emission sources from the **transport stage** include all operational and embodied emissions related to the transport of the project CO<sub>2</sub> stream, from leaving the capture site to entering the storage site. Transport may happen via pipeline networks, rail, road, shipping or a combination of those.

Transport emission sources include:

* energy use from any transport via rail, road, maritime vessel, or pipeline
* energy use from any stationary processes (e.g. intermediate storage),
* embodied emissions from infrastructure and machinery used in transportation and stationary processes.

Details on the calculation of emissions from the transport stage can be found in the Rainbow [Transportation](/modules/transportation) module.

#### Emission allocation

Only emissions associated with the transport of project CO<sub>2</sub> shall be attributed to the BioCCS project. For each [transport segment](#user-content-fn-34)[^34] $$S$$, emissions are allocated using the allocation fraction $$F\_S$$, as defined in [Calculation: Allocation fraction $$F\_S$$](#calculation-allocation-fraction), regardless of whether the project CO<sub>2</sub> stream is at all times segregated from CO<sub>2</sub> stream from sources or not.

{% hint style="info" %}
Although a segregated stream is never mixed with CO<sub>2</sub> from other sources, the amount of project CO<sub>2</sub> transported does not necessarily correspond to the total amount of CO<sub>2</sub> transported.

For example:

* if the project captures and transports eligible biogenic CO<sub>2</sub> and ineligible CO<sub>2</sub> from a mixed stream, only the emissions associated with the transport of the eligible biogenic fraction are attributed to the project.
* **For CRCF-projects only:** if the project captures eligible biogenic CO<sub>2</sub>, but designates part of the captured CO<sub>2</sub> for storage under an alternative framework other than the CRCF (i.e. $$F\_{CRCF} < 1$$), only emissions associated with the fraction stored under the CRCF are be attributed to the project.

In all other cases, the allocation fraction simplifies to 1.
{% endhint %}

## Storage stage emissions

Emissions sources at the **storage stage** include all operational and embodied emissions from CO<sub>2</sub> storage, from the project CO<sub>2</sub> entering the storage site to going into permanent geological storage.

Storage emission sources include:

* energy use from injection of CO<sub>2</sub> and any associated processes,
* energy use from any intermediate storage or processing operations,
* energy and material use from any storage site monitoring operations, i.e. all necessary activities to ensure the integrity of the CO<sub>2</sub> storage (e.g. water sampling, soil fluids monitoring, plume modeling), including estimated emissions for post-closure monitoring of the storage site scaled per tonne of CO<sub>2</sub> injected.
* embodied emissions from infrastructure and machinery used at storage site (e.g. injection well, transport infrastructure at storage site, monitoring wells).

Emissions from the storage stage shall be accounted using the

* [Processing and energy use](/modules/processing-and-energy-use) module for operational emissions (e.g. electricity and heat consumption, fuel combustion, material consumption)
* [Infrastructure and machinery](/modules/infrastructure-and-machinery) module for embodied emissions

#### Emission allocation

Only emissions associated with the storage of project CO<sub>2</sub> shall be attributed to the BioCCS project. For each storage site $$K$$, emissions are allocated using the allocation fraction $$F\_K$$, as defined in Eq. 16, regardless of whether the project CO<sub>2</sub> stream is at all times segregated from CO<sub>2</sub> stream from sources or not

{% hint style="info" %}
Although a segregated stream is never mixed with CO<sub>2</sub> from other sources, the amount of project CO<sub>2</sub> stored does not necessarily correspond to the total amount of CO<sub>2</sub> stored.

For example:

* if the project captures and stores eligible biogenic CO<sub>2</sub> and ineligible CO<sub>2</sub> from a mixed stream, only the emissions associated with the storage of the eligible biogenic fraction are attributed to the BioCCS project.
* **For CRCF-projects only:** if the project captures eligible biogenic CO<sub>2</sub>, but designates part of the captured CO<sub>2</sub> for storage under an alternative framework other than the CRCF (i.e. $$F\_{CRCF} < 1$$), only emissions associated with the fraction stored under the CRCF are attributed to the project.

In all other cases, the allocation fraction simplifies to 1.
{% endhint %}

#### Capture of fossil CO<sub>2</sub> at the storage site

Fossil CO<sub>2</sub> emitted as a result of fuel combustion at the storage site may be captured and permanently stored at the storage site. In this case, the amount of the fossil CO<sub>2</sub> captured minus any losses prior to entering permanent storage shall be deducted from the storage stage emissions.

## Leakage emissions

Emissions from leakage include biomass-related leakage and bioenergy/material diversion leakage. All leakage types are described in detail in the [Principles & Requirements](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#lc9eewbyvlyk) section, and their quantification approaches are outlined below.

Note that biomass-related leakage emissions (counterfactual carbon storage, diversion of biomass and iLUC) are accounted for in the biomass emission factor in Eq. 25. Biomass-related leakage emissions are considered for the following [biomass fractions](#user-content-fn-9)[^9]:

* Greenfield:
  * Biomass fraction allocated to CO<sub>2</sub> generation
  * Parasitic load biomass fraction
* Retrofit:
  * Baseline biomass fraction (if used for parasitic load)
  * Additional biomass fraction

### Counterfactual carbon storage

The leakage from [counterfactual carbon storage](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#counterfactual-carbon-storage) is defined as the fraction of biomass carbon that would have likely have remained stored in the alternative fate scenario, rather than being decaying and being released. This fraction is not eligible for crediting and shall be **deducted from the project's removals**.

* If all of the carbon stored in the biomass would be released within 15 years, the counterfactual carbon storage is zero, and all biomass carbon is eligible for crediting.
* If the counterfactual emissions of CO<sub>2</sub> and CH<sub>4</sub> within 15 years **do not exceed** the amount of biomass carbon lost through decay after 50 years, then the leakage from counterfactual carbon storage is calculated as the total biomass carbon minus the counterfactual emissions within 15 years.
* If the counterfactual emissions of CO<sub>2</sub> and CH<sub>4</sub> within 15 years exceed the amount of biomass carbon lost through decay after 50 years, the leakage from counterfactual carbon storage corresponds to the carbon storage in the biomass at 50 years. This increases the eligibility of slow-decaying biomass feedstock with comparably large near-term emissions of methane[^35].

The counterfactual emissions within 15 years are the sum of all GHG emissions from decay of the biomass over that period. For each gas, emissions are calculated as the carbon released within 15 years multiplied by the fraction emitted as that gas (CO<sub>2</sub> and CH<sub>4</sub>) and converted to tCO<sub>2</sub>eq using the 100-year Global Warming Potential.

If the project uses **agro-food waste** as feedstock, Project Developers shall include the **soil organic carbon** (SOC) gains from biomass decay in the counterfactual in the quantification of the counterfactual carbon storage. The assessment shall be based on secondary literature or models.

The assessment of the counterfactual emissions shall be based on peer-reviewed literature, recognized national or regional GHG inventory reports, documented industry data or direct measurements, and shall be representative of the biomass type and the specific alternative fate scenario (e.g. relevant geographic or climatic conditions).

{% hint style="info" %}
**Example 1**

A Project Developer of a BioCCS retrofit sources an additional 200t of corn stover to meet the energy demand of the capture unit. The alternative fate of the biomass is demonstrated to be burned on the field. In this case, no counterfactual carbon storage is considered, as 100% the carbon stored in the biomass is proven to be released to the atmosphere in the near term.
{% endhint %}

{% hint style="info" %}
**Example 2**

A Project Developer of a BioCCS retrofit sources an additional 200t of cashew nut shell cake to meet the energy demand of the capture unit. The biomass contains 100t of carbon. The alternative fate of the biomass is to be left in piles to decay. After 15 years, 20% of the carbon remains stored in the biomass, 1% remains after 50 years. 1% of the carbon is released as methane within the first 15 years.

* The counterfactual emissions within 15 years are 290 tCO<sub>2</sub>eq for the carbon emitted as CO<sub>2</sub> (99% of the 80% of total biomass carbon emitted) and 29 tCO<sub>2</sub>eq for carbon emitted as CH<sub>4</sub> (1% or the 80% of total biomass carbon emitted), which sums up to 319 tCO<sub>2</sub>eq.
* The biomass carbon lost in the counterfactual due to decay at 50 years is 363 tCO<sub>2</sub>eq (99% of the total biomass carbon).

The counterfactual emissions after 15 years **do not exceed** the counterfactual carbon loss at 50 years (319 tCO<sub>2</sub>eq emissions < 363 tCO<sub>2</sub>eq storage). The leakage from counterfactual carbon storage equals to the total biomass carbon minus the counterfactual emissions within 15 years, which is 48 tCO<sub>2</sub>eq) (367 tCO<sub>2</sub>eq total biomass carbon - 319 tCO<sub>2</sub>eq emissions).
{% endhint %}

{% hint style="info" %}
**Example 3**

A Project Developer of a BioCCS retrofit sources an additional 200t of sustainably sourced wood chips to meet the energy demand of the capture unit. The biomass contains 100t of carbon. The alternative fate of the biomass is to be left in piles to decay. After 15 years, 20% of the carbon remains stored in the biomass, and after 50 years 5% remain. 2.5% of the biomass carbon lost due to decay is released as methane within the first 15 years.

* The counterfactual emissions within 15 years are 286 tCO<sub>2</sub>eq for the carbon emitted as CO<sub>2</sub> (97.5% of the 80% of total biomass carbon emitted) and 72 tCO<sub>2</sub>eq for carbon emitted as CH<sub>4</sub> (2.5% of the 80% of total biomass carbon emitted), which sums up to 358 tCO<sub>2</sub>eq.
* The biomass carbon lost in the counterfactual due to decay at 50 years is 348 tCO<sub>2</sub>eq (95% of the total biomass carbon).

The counterfactual emissions after 15 years exceed the counterfactual carbon loss at 50 years (358 tCO<sub>2</sub>eq emissions > 348 tCO<sub>2</sub>eq storage). The leakage from counterfactual carbon storage equals to the biomass carbon still stored at 50 years, which is 18 tCO<sub>2</sub>eq (5% of total biomass carbon).
{% endhint %}

### Biomass diversion

Leakage associated with the [diversion of the biomass](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#diversion-of-biomass) from its alternative use shall be quantified for each biomass type and source. To quantify the leakage emissions, Project Developers shall:

1. **Determine the quantity of the biomass** type $$i$$ used by the project, that would have had a valuable alternative use.
2. **Follow** [**Alternative fate**](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#alternative-fate-of-biomass) **section guidelines** to determine the alternative use scenario of the biomass.
3. **Identify the most likely replacement product or process** for the diverted biomass.
4. **Source an appropriate conversion factor** to calculate the quantity needed to replace **the original function** of the biomass based on the business-as-usual (BAU) function.
5. **Source an appropriate emission factor** for the production and use of the replacement product.
6. **Calculate the associated emissions** according to the equation below
7. Repeat for each **biomass** type $$i$$ with a valuable alternative use.

### Indirect land use change emissions

To quantify [iLUC emissions](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#indirect-land-use-change) when required according to the [Principles & requirements](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#indirect-land-use-change), the Project Developer shall classify each **energy crop**, or the feedstock from which the **forestry or agro-food waste** is derived, according to Table 8 below.

For crop types not listed, or for which [direct land use change emissions](#calculation-of-land-use-change-emissions) have been calculated, no iLUC emissions are considered.

Table 8: [iLUC emission factors](#user-content-fn-36)[^36] for different crop types.

| Crop Type                           | iLUC emission factor (gCO2eq/MJ) |
| ----------------------------------- | -------------------------------- |
| Cereals and other starch-rich crops | 12                               |
| Sugar crops                         | 13                               |
| Oil crops                           | 55                               |

### Diversion of bioenergy and biomaterial

For **energy leakage calculations**, if a retrofit project produces and exports less energy than the BAU, and this reduction is directly related to retrofitting the facility, additional emissions associated with the compensation of the reduced output shall be quantified. This includes but is not limited to electricity, heat, biogas, and biomethane export.

**For material leakage calculations,** if a retrofit project produces and exports less material than the BAU, and this reduction is directly related to retrofitting the facility, additional emissions associated with the compensation of the reduced output shall be quantified by identifying the quantity of the marginal material and multiplying it with an appropriate emission factor reflecting its production.

<details>

<summary><strong>Calculation:</strong> Leakage</summary>

$$\textbf{(Eq.45)} \ E\_{leakage} = E\_{energy/material\ diversion}$$

* $$E\_{leakage}$$ represents the leakage emissions term, in tCO<sub>2</sub>eq, used in Eq. 2.
* $$E\_{energy/material \ diversion }$$represents the leakage emissions from the diversion of bioenergy and biomaterials, in tCO<sub>2</sub>eq.

***

**Counterfactual carbon storage**

Calculation of counterfactual emissions within 15 years:

$$\textbf{(Eq.46)} \ E\_{counterfactual\ emissions,15}=C\_{biomass}\times (1-F\_{carbon, stored,15})\times \sum\_{i}F\_{carbon, emitted,15,i}\times C\_{to}i\times GWP\_{100,i}$$

* $$E\_{counterfactual\ emissions,15 }$$ represents the counterfactual emissions from the biomass within 15 years, in tCO<sub>2</sub>eq.
* $$C\_{biomass}$$ represents the total carbon content of the biomass feedstock, in tonnes.
* $$F\_{carbon, stored, 15}$$ represents the estimated fraction of biomass carbon still stored at 15 years. It shall be provided using secondary sources.
* $$F\_{carbon, emitted,15,i}$$ represents the estimated fraction of biomass carbon emitted as greenhouse gas $$i$$ (CO<sub>2</sub> or CH<sub>4</sub>) within 15 years. The fractions across all GHGs $$i$$ shall sum to 1. It shall be provided using secondary sources.
* $$C\_{to}i$$ represents the conversion of carbon to the greenhouse gas $$i$$ by multiplying by the ratio of their molecular mass. This is 3.667 for C to CO<sub>2</sub> and 1.333 for C to CH<sub>4</sub>.
* $$GWP\_{100,i}$$ represents the 100-year Global Warming Potential of greenhouse gas $$i$$, in CO<sub>2</sub> eq / $$i$$. This is 1 for CO<sub>2</sub> and 27 for CH<sub>4</sub>.

Calculation of counterfactual carbon loss at 50 years:

$$\textbf{(Eq.47)} \ C\_{carbon, loss, 50}=(C\_{biomass}\times C\_{to}CO\_2) \times (1-F\_{carbon, stored,50})$$

* $$C\_{carbon, loss, 50}$$ represents the amount of biomass carbon lost due to biomass decay at 50 years in the counterfactual, in tCO<sub>2</sub>eq.
* $$C\_{biomass}$$ is defined in Eq. 46.
* $$C\_{to}CO\_2$$ represents the conversion of carbon to CO<sub>2</sub> equivalents by multiplying by the ratio of their molecular mass (3.667).
* $$F\_{carbon, stored, 50}$$ represents the estimated fraction of biomass carbon still stored after 50 years. It shall be provided using secondary sources.

The leakage from counterfactual carbon storage is calculated

* according to Eq. 48 (Option A) for biomass feedstock whose counterfactual emissions within 15 years **do not exceed** the biomass carbon loss at 50 years as the difference between total biomass carbon and counterfactual emissions within 15 years.
* according to Eq. 49 (Option B) for biomass feedstock whose counterfactual emissions within 15 years **do exceed** the biomass carbon loss at 50 years as the biomass carbon still stored at 50 years.

Option A

$$\textbf{(Eq.48)} \ C\_{counterfactual}=(C\_{biomass}\times C\_{to}CO\_2)-E\_{counterfactual \ emissions,15}$$

* $$C\_{Counterfactual}$$ represents the leakage from counterfactual carbon storage for all biomass used at the site in the monitoring period, in tCO<sub>2</sub>eq.
* $$C\_{biomass}$$ is defined in Eq. 46.
* $$C\_{to}CO\_2$$ is defined in Eq. 47.
* $$E\_{counterfactual\ emissions,15 }$$ is defined in Eq. 46.

Option B

$$\textbf{(Eq.49)} \ C\_{counterfactual}=(C\_{biomass}\times C\_{to}CO\_2) \times F\_{carbon, stored,50}$$

* $$C\_{Counterfactual}$$ is defined in Eq. 48.
* $$C\_{biomass}$$ is defined in Eq. 46.
* $$C\_{to}CO\_2$$ is defined in Eq. 47.
* $$F\_{carbon, stored, 50}$$ is defined in Eq. 57

***

**Biomass diversion**

$$\textbf{(Eq.50)}\ E\_{biomass\ diversion} =\sum\_{i} Q\_{biomass,total, i}\times F\_{conversion, i}\times EF\_{alternative \ use, i}$$

* $$E\_{biomass\ diversion }$$ represents the leakage emissions from the diversion and replacement of all biomass used at the site in the monitoring period, in tCO<sub>2</sub>eq.
* $$Q\_{biomass, total, i}$$ represents the total amount biomass consumed by the underlying facility during the monitoring period, in tonnes.
* $$F\_{conversion,i}$$ represents an appropriate conversion factor for biomass type $$i$$, in appropriate unit/tonnes.
* $$EF\_{alternative \ use,i}$$ represents the appropriate emission factor for the replacement product of biomass type $$i$$, in tCO<sub>2</sub>eq/appropriate unit.

***

**Indirect land use change**

$$\textbf{(Eq.51)}\ E\_{iLUC} =\sum\_{i} Q\_ {biomass, total,i} \times iLUC\_ {i}\times LHV\_ {i}\times 10^{-6}$$

* $$E\_{iLUC}$$ represents the indirect land use change emissions of the project for all biomass used at the site in the monitoring period, in tCO<sub>2</sub>eq.
* $$Q\_{biomass, total,i}$$ represents the total amount biomass consumed by the underlying facility during the monitoring period, in tonnes.
* $$iLUC\_{i}$$ represents the iLUC emission factor for biomass type $$i$$, in gCO<sub>2</sub>eq/MJ, taken from Table 8.
* $$LHV\_{i}$$ represents the lower heating value of the biomass type $$i$$, in MJ/t.
* it is multiplied by $$10^{-6}$$ to convert from gCO<sub>2</sub>eq to tCO<sub>2</sub>eq.

***

**Diversion of bioenergy and biomaterial**

For energy leakage:

$$\textbf{(Eq.52)}\ E\_{energy\ diversion} = \sum\_i(Q\_{energy,i, baseline}-Q\_{energy,i, retrofit})\times EF\_{energy,i}$$

* $$Q\_{energy,i, baseline}$$ represents the energy of type *i* delivered to the grid in the baseline (BAU), in kWh or MJ.
* $$Q\_{energy,i, retrofit}$$ represent the energy of type *i* delivered to the grid by the BioCCS project, in kWh or MJ.
* $$EF\_{energy,i}$$ represents the energy of type *i* grid emissions factor and shall be taken for the national grid (at the maximum granularity) or bidding zone level, and if possible, regional mixes shall be used.

For material leakage:

$$\textbf{(Eq.53)}\ E\_{material\ diversion} = (Q\_{material, baseline}-Q\_{material, retrofit})\times EF\_{material}$$

* $$Q\_{material, baseline}$$ represents the amount of material exported in the baseline (BAU), in an appropriate unit.
* $$Q\_{material, retrofit}$$ represents the amount of material exported by the BioCCS project, in an appropriate unit.
* $$EF\_{material}$$ represents the material production emission factor.

</details>

## Uncertainty assessment <a href="#dk35zb8m2b1p" id="dk35zb8m2b1p"></a>

An uncertainty assessment is presented below for all aspects of GHG quantification set **at the methodology level**. The findings from this assessment are then applied **at the project level**, where project-specific GHG quantification also undergoes an uncertainty assessment.

The **overall project GHG quantification uncertainty** is determined by qualitatively combining both the methodology-level and project-specific uncertainties for each identified source of uncertainty.

The assumptions made at the methodology level are assessed qualitatively.

* The assumption that **no carbon was stored in the absence of the project** has low uncertainty. In the absence of the project, feedstock materials would follow their conventional fate and the CO<sub>2</sub> would not have been captured and stored. Any indirect carbon storage is accounted for within the leakage assessment.
* The assumption made for the calculation of embodied emissions of the underlying biogas production site in a retrofit scenario (buildings and main infrastructure have a lifetime of 20 years, and calculation based on the external volume of the main digester) has low uncertainty. It is based on the assessment of numerous certification projects under the Rainbow [Biogas from anaerobic digestion](/methodologies/biogas-from-anaerobic-digestion) methodology, that showed minor impacts from infrastructure (1-2% of project life cycle GHG emissions).
* The assumptions made for the **storage emissions from manure and slurry** have low uncertainty.

The **qualitative uncertainty** at methodology level is **low**, which translates to a [**discount factor**](/rainbow-standard-documents/rainbow-standard-rules/ghg-quantification#discount-factor) **of 3%**.

At the project level, Project Developers shall quantify the uncertainty in the GHG quantification, using e.g. statistical analysis of project data, calibration records or manufacturer specifications. Where a direct quantification is not possible, uncertainty estimates from reputable sources (e.g. peer-reviewed literature or local/national regulations) may be used, if justified. Common sources of uncertainty are

* measurement uncertainty (e.g. accuracy of the flow meters used to measure CO<sub>2</sub> flow),
* sampling uncertainty (e.g. statistical distribution in the value for the concentration of CO<sub>2</sub> in the stream),
* models (e.g. equation of state to model the density of the stream),
* estimates or secondary data used (e.g. when project data is not available).

To combine quantitative uncertainties, Project Developers shall follow the principles set out in the [*IPCC: Good Practice Guidance and Uncertainty Management in National GHG Inventories*](#user-content-fn-37)[^37] (Chapter 6, Section 3), using either an error propagation approach or Monte Carlo simulation. Uncertainty shall be assessed based on the 95% confidence interval.

The **discount factor** corresponds to the higher of the two uncertainty values, methodology- or project-level, and is deducted from the **net GHG removals**. If the discount factor exceeds **15%**, the project is deemed ineligible for crediting.

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Discount factor</summary>

For CRCF-projects, the discount factor is applied to the **gross GHG removals**, $$R\_{project}$$.&#x20;

</details>

[^1]: ISO 14064-2:2019. Greenhouse gases — Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements.

[^2]: Project's captured CO<sub>2</sub> that is at all times transported and injected separately from other CO<sub>2</sub> streams.

[^3]: Project's captured CO<sub>2</sub> that is mixed with other CO<sub>2</sub> streams for any transport or injection step.

[^4]: The average amount of biomass consumed by the underlying biomass conversion over the past three years prior to retrofitting.

[^5]: The energy demand of the capture unit is covered by energy produced by the underlying biomass conversion facility, see [Internal energy and parasitic load](#internal-energy-and-parasitic-load) section

[^6]: Commission Decision of 10 June 2010 on guidelines for the calculation of land carbon stocks for the purpose of Annex V to Directive 2009/28/EC, [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32010D0335\&qid=1779037741393)

[^7]: Wernet, G., Bauer, C., Steubing, B., Reinhard, J., Moreno-Ruiz, E., Weidema, B., 2016. The ecoinvent database version 3 (part I): overview and methodology. Int J Life Cycle Assess 21, 1218–1230. <https://doi.org/10.1007/s11367-016-1087-8>

[^8]: Esnouf A., Brockmann D., Cresson R. (2021) Analyse du cycle de vie du biométhane issu de ressources agricoles - Rapport d’ACV. INRAE Transfert, 170pp.

[^9]: An accounting construct to delineate which fraction of biomass is used for what purpose:

    * baseline vs additional biomass (retrofit)
    * biomass allocated to CO<sub>2</sub> generation vs allocated to bioenergy generation vs parasitic load (greenfield)

    Further information in the [Biomass fractions](/methodologies/biogenic-carbon-capture-and-storage-bioccs/eligibility-and-scope#biomass-fractions) section.

[^10]: This includes:

    * Capture of fossil CO<sub>2</sub> generated by the capture process, called **associated CO**<sub>**2**</sub>
    * Capture of **CO**<sub>**2**</sub>**&#x20;from a mixed stream**. This is defined as
      * **CO**<sub>**2**</sub>**&#x20;streams generated and captured together:** a stream of mixed fossil and biogenic CO<sub>2</sub>, generated from feedstock that includes a share of fossil-based material, or
      * **CO**<sub>**2**</sub>**&#x20;streams generated separately, and captured together**: the co-capture of the project CO<sub>2</sub> stream and one or more CO<sub>2</sub> streams from project-unrelated sources at the same capture facility. This includes fossil CO<sub>2</sub>, biogenic CO<sub>2</sub> from sustainable (zero-rated) biomass and biogenic CO<sub>2</sub> from unsustainable (non-zero-rated) biomass.

[^11]: e.g. through proof of 100% [eligible](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#biomass-sustainability) feedstock in combination with design documents of the capture facility showing no capture of CO<sub>2</sub> from other sources.

[^12]: i.e. the concentration is averaged across all measurement intervals, weighted by the mass of gas measured at each interval, to reflect its relative contribution to the total flow.

[^13]: Capture of fossil CO<sub>2</sub> generated by the capture process

[^14]: truck, ship, pipeline, train

[^15]: e.g. the operator of the CO2 pipeline network.

[^16]: Validation and verification body.

[^17]: Ineligible CO<sub>2</sub> generated by the capture process and captured alongside the eligible biogenic CO<sub>2</sub>. Not to be confused with CO<sub>2</sub> captured from a mixed stream, which is not included in the project CO<sub>2</sub>.

[^18]: Commission Implementing Regulation (EU) 2018/2066 of 19 December 2018 on the monitoring and reporting of greenhouse gas emissions pursuant to Directive 2003/87/EC of the European Parliament and of the Council and amending Commission Regulation (EU) No 601/2012, [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02018R2066-20250527#anx_IV)

[^19]: Fossil CO2 that is emitted as a result of the capture process and captured alongside the project's biogenic CO2.

[^20]: Ineligible CO<sub>2</sub> generated by the capture process and captured alongside the eligible biogenic CO<sub>2</sub>. Not to be confused with CO<sub>2</sub> captured from a **mixed stream.**

[^21]: This includes

    * biomass production (for non-waste biomass, e.g. on-farm processes, cultivation, harvesting)
    * direct land use change emissions
    * biomass processing (e.g. drying, mixing or shredding of feedstock)
    * transport of biomass to the site
    * biomass storage (direct CH<sub>4</sub> and N<sub>2</sub>O emissions)
    * biomass conversion (i.e. all processes related to bioenergy production or waste treatment)
    * leakage emissions

[^22]: e.g. based on official statistics published, or independent biomass market analysis/research reports.

[^23]: See [Proof of waste status](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#proof-of-waste-status)

[^24]: The EU's Renewable energy directive

[^25]: according to the IPCC Guidelines for national GHG inventories, Chapter 3, consistent representation of lands, [URL](https://www.ipcc-nggip.iges.or.jp/public/2019rf/pdf/4_Volume4/19R_V4_Ch03_Land%20Representation.pdf)

[^26]: multi-annual crops, the stem of which is usually not annually harvested

[^27]: **Eligible land-use change** refers to a conversion of land that, despite occurring in or after January 2008, does not violate the sustainability criteria in the [Biomass sustainability](/methodologies/biogenic-carbon-capture-and-storage-bioccs/principles-and-requirements#biomass-sustainability) section for marginal and primary energy crops.

[^28]: ‘Severely degraded land’ means land that, for a significant period of time, has either been significantly salinated or presented significantly low organic matter content and has been severely eroded

[^29]: This value is extracted from the European Commissions Delegated Act on Permanent Carbon Removals.

[^30]: Intergovernmental Panel on Climate Change 2021. Chapter 7: The Earth’s Energy Budget, Climate Feedbacks, and Climate Sensitivity. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, doi:10.1017/9781009157896.009

[^31]: Teferra, D.M., Wubu, W., Teferra, D.M., Wubu, W., 2018. Biogas for Clean Energy, in: Anaerobic Digestion. IntechOpen.[ https://doi.org/10.5772/intechopen.79534](https://doi.org/10.5772/intechopen.79534)

    \\

[^32]: Intergovernmental Panel on Climate Change 2021. Chapter 7: The Earth’s Energy Budget, Climate Feedbacks, and Climate Sensitivity. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, doi:10.1017/9781009157896.009.

[^33]: e.g. already calculated for RED III auditing purposes

[^34]: A transport segment is a section of the transportation process involving the movement of CO<sub>2</sub> from point A to point B

[^35]: Methane is a greenhouse gas with a large global warming potential of 27 tCO<sub>2</sub>eq per tonne of CH<sub>4</sub> (GWP<sub>100</sub>).

    Value taken from the [IPCC Sixth Assessment Report](https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter07.pdf)

[^36]: The table is adapted from the EU's Renewable Energy Directive (RED III), Annex VIII, Part A. [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02018L2001-20240716)

[^37]: Penman, J., Kruger, D., Galbally, I., Hiraishi, T., Nyenzi, B., Emmanuel, S., Buendia, L., Hoppaus, R.,

    Martinsen, T., Meijer, J., Miwa, K., & Tanabe, K. (Eds.). (2000) *Good Practice Guidance and*

    *Uncertainty Management in National Greenhouse Gas Inventories*, IPCC National Greenhouse Gas

    Inventories Programme, Institute for Global Environmental Strategies ISBN 4-88788-000-6, [URL](https://www.ipcc-nggip.iges.or.jp/public/gp/english/)


# Sampling and measurements

<details>

<summary>🇪🇺 <strong>CRCF requirement</strong>: Measurements of CO<sub>2</sub> stream</summary>

In addition to following the requirements set out in this section, CRCF projects shall ensure measurements of the CO<sub>2</sub> stream are taken in accordance with Articles 40-46 and Article 49 of the [European Commission's Implementing Regulation 2018/2066](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02018R2066-20250527#anx_IV).

</details>

### **Measurement standards**

All measurements of the CO<sub>2</sub> stream shall be carried out using methods based on&#x20;

* EN 14181: stationary source emissions - quality assurance of automated measuring systems
* EN 15259: air quality - measurement for stationary emission sources - requirements for measurement sections and sites and for the measurement objective, plan and report
* other relevant EN standards, in particular EN ISO 16811-2: stationary source emissions - manual and automatic determination of velocity and volume flow rate in ducts

Where none of the above is available, methods shall be based on suitable ISO standards, national standards, industry best practice guidelines or scientifically proven methodologies.&#x20;

Laboratories carrying out measurements, calibration and equipment assessment for the measurement system shall have at least one quality assurance accreditation for the relevant analytical methods or calibration activities, such as:

* ISO/IEC 17025
* CEN/TS 17225-1
* ISO 10694

### **Calibration requirements**

Measurement systems shall be:&#x20;

* **Calibrated, adjusted, and checked at regular intervals**, including prior to entering service, at an accredited calibration facility or laboratory traceable to recognized international or national measurement standards.
* **Installed in accordance** with international or national standards or the manufacturer's specifications.
* **Recalibrated periodically**, at least annually, meeting or exceeding international or national standards (e.g. EN 14181 in the EU) or manufacturer's specifications, including parallel measurements against standard reference methods carried out by competent staff.

Where a component of a measurement system cannot be calibrated, Project Developers shall  identify this in the monitoring plan and propose an alternative control method.

Where equipment is found to be non-compliant with performance requirements, Project Developers shall take corrective action without undue delay.

### **Determination of the amount of CO**<sub>**2**</sub>

The amount of CO<sub>2</sub> at each [measurement point](#user-content-fn-1)[^1] shall be determined using **direct measurements** (i.e. physical measurement equipment) rather than a calculation-based approach. Measurements shall meet a maximum measurement uncertainty of **±2.5%**, meaning the uncertainty across all measured parameters.

The amount of CO<sub>2</sub> shall be calculated by continuously measuring the CO<sub>2</sub> concentration and the mass or volume flow rate, and multiplying them. For each measured parameter listed below, **hourly averages** shall be calculated using all data points available within that hour. Raw measurements data shall be made available upon request by Rainbow or the VVB.

Where equipment is temporarily out of operation during part of an hour, the hourly average may still be calculated from the remaining data points, provided at least **80% of the expected readings** for that hour are available. If fewer than 80% are available, the requirements in the [Handling missing data](#handling-missing-data) section below apply.&#x20;

The following requirements for the measurement of the CO<sub>2</sub> stream parameters apply:

#### **Mass or volumetric flow of the stream,**  $$m\_{stream}$$ **or** $$V\_{stream}$$

The mass or volumetric flow of the CO<sub>2</sub> stream shall be measured

* **continuously**, at least every 15 minutes, and **aggregated over one day.**
* before leaving the capture site, when being transferred to a new transport segment, before entering the storage site, and/or at the last monitoring point before entering permanent storage, depending on whether the [segregated](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#segregated-stream) or the [non-segregated stream](/methodologies/biogenic-carbon-capture-and-storage-bioccs/ghg-quantification#non-segregated-stream) approach applies.&#x20;
* using a mass or volumetric flow meter. Project Developer shall prioritize metering technologies that are [widely used ](#user-content-fn-2)[^2] in CCS measurements, such as differential pressure meters (orifice plate meters), turbine meters and coriolis meter.&#x20;

Flow meters shall be chosen according to the conditions and ranges under which it will operate.&#x20;

#### Density of the stream, $$\rho\_{stream}$$

The amount of CO<sub>2</sub> is reported in tonnes of CO<sub>2</sub>, a mass unit. To convert volume to mass flow, the stream's density is required.&#x20;

The density shall be measured either by using an in-line densitometer[^3] or similar devices, or modeled using an **equation of state (EoS)**. To model density from the EoS, the selection of an appropriate model, knowledge of the stream composition and reference pressure and temperature measurements are crucial. Various approaches for density determination using EoS can be found in the[ literature](#user-content-fn-4)[^4]. &#x20;

Measurements of the density shall be conducted

* **continuously**, and at the same frequency as the flow metering,
* as close to the metering point as possible.

Densitometers shall be calibrated with relevant reference fluids.

#### Pressure and temperature of the stream, $$p,T$$

Volumetric flow and density measurements are recorded at operational pressure and temperature but shall be converted to **standard temperature and pressure conditions, STP.**

Measurements of the operational pressure and temperature shall be conducted&#x20;

* **continuously**, at the same frequency as the flow metering. Raw measurements data shall be made available upon request by Rainbow or the VVB.&#x20;
* as close to the metering point as possible
* using pressure and temperature meters (e.g., pressure transducers, thermocouples, thermistors)

#### Concentration of CO<sub>2</sub> in the stream, $$F\_{mass,\ CO2}$$

​The CO<sub>2</sub> concentration is measured either by direct measurement of the CO<sub>2</sub> concentration in the stream, or by indirect measurement of the chemical composition (i.e. CO<sub>2</sub> and impurities) of the stream. The CO<sub>2</sub> concentration using either of the two methods shall be measured

* **continuously**, at the same frequency as the flow metering. (raw measurements data shall be made available upon request by Rainbow or the VVB), and
* as close to the metering point as possible and prior to mixing with another stream, and
* using in-line or on-line analyzer.

Typical analytical technologies are based on gas chromatography, non-dispersive infrared spectroscopy (NDIR), and ultraviolet-visible (UV-Vis) spectroscopy. Concentration measurement systems shall be

* chosen according to the expected and actual composition of the stream, covering the detection range required by local/national standards or operational requirements, and
* **on-site calibration at commissioning** shall be performed against traceable calibration gases

### **Determination of biogenic fraction of CO**<sub>**2**</sub>

Project Developers shall determine $$F\_B$$ according to Article 39 of the[ EU ETS monitoring and reporting](#user-content-fn-5)[^5], using either

* a mass balance approach of material inputs by type for every monitoring period, or
* continuous C14 testing over a representative period of time, following ISO 13833 or ASTM D6866 standard test methods, or
* other standards and analytical methods, subject to approval by Rainbow and the VVB.

### **Handling missing data**

Where a valid hourly reading cannot be obtained because equipment is **out of control, out of range, or out of operation**, a substitute value shall be determined for each missing hour:

* **For missing concentration data:** the substitute value shall be calculated as the average concentration over the monitoring period **plus twice the standard deviation.**
* **For data other than concentration:** the substitute value shall be derived from a mass balance or energy balance model of the process, and validated against the remaining measured parameters for a period of the same length as the data gap.

If measurement equipment is down for more than **5 consecutive days**, the Project Developer shall notify Rainbow without delay and propose corrective measures. Where the Project Developer is not the operator of the transport or storage infrastructure, a formal agreement shall be in place ensuring that all relevant measurement data and gap-filling records are communicated to the Project Developer in a timely manner.

[^1]: Depending on the type of stream (segregated or non-segregated) this can be the amount of CO<sub>2</sub>&#x20;

    * leaving the capture facility and  entering the first transport segment
    * entering a transport segment&#x20;
    * leaving a transport segment
    * entering the storage site
    * injected into geological storage

[^2]: Chinello, G.; Arellano, Y.; Span, R.; van Putten, D.; Abdulrahman, A.; Joonaki, E.; Arrhenius, K.; Murugan, A.; Toward standardized measurement of CO<sub>2</sub> transfer in the CCS chain, Nexus, *1,* 100013, **2024**. [DOI](https://www.sciencedirect.com/science/article/pii/S2950160124000111#sec3)\
    \
    Mills, C.; Flow Measurement in support of Carbon Capture, Utilisation and Storage (CCUS), 2021. [DOI](https://www.researchgate.net/profile/Chris-Mills-6/publication/368881913_Flow_Measurement_in_support_of_Carbon_Capture_utilisation_and_Storage_CCUS/links/63ff432d0cf1030a5660c413/Flow-Measurement-in-support-of-Carbon-Capture-utilisation-and-Storage-CCUS.pdf)

[^3]: Common densitometer are nucleonic meter (using gamma-rays) meter or torsional resonators. Coriolis meter can also measure density of the stream.

[^4]: McKay, C; Nazeri, M.; Haghighi, H.; Erickson, D.; Recommendations for the selection of equation of state during design and operation of impure CO2 transport and storage,  Proceedings of the 16th Greenhouse Gas Control Technologies Conference, **2022**. [DOI](https://doi.org/10.1016/j.ijggc.2023.103877)\
    \
    \
    Vitali, M.; Leporini, M.; Masi, O.; Speranza, A.; Corvaro, F.; Marchetti, B.; Net zero Flow Assurance - Validation of various equations of state for the prediction of VLE and density of CO<sub>2</sub>-rich mixtures for CCUS applications, International Journal of Greenhouse Gas Control, *125,* 103877, **2023.** [DOI](https://doi.org/10.1016/j.ijggc.2023.103877)<br>

[^5]: Commission Implementing Regulation (EU) 2018/2066 of 19 December 2018 on the monitoring and reporting of greenhouse gas emissions pursuant to Directive 2003/87/EC of the European Parliament and of the Council and amending Commission Regulation (EU) No 601/2012. [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02018R2066-20240701).


# Risk assessment template

:point\_right: Download the template [here](https://docs.google.com/spreadsheets/d/1F2ewKDxHiK5gBljo6pHxW6Tb1MV6y-uC72HHqhqfaeU/edit?gid=1985359524#gid=1985359524)&#x20;

{% embed url="<https://docs.google.com/spreadsheets/d/1F2ewKDxHiK5gBljo6pHxW6Tb1MV6y-uC72HHqhqfaeU/edit?gid=1985359524#gid=1985359524>" %}


# CRCF requirements

This page lists all the additional requirements mentioned in the methodology, that apply for projects seeking certification under the European Commission's CRCF.&#x20;

Project Developers shall also follow all requirements in the [Rainbow Procedures Manual on CRCF](https://docs.rainbowstandard.io//rainbow-standard-documents/procedures-manual/crcf-requirements).

### Eligibility and scope

<details>

<summary>🇪🇺<strong>CRCF requirement:</strong> Confirmation of the origin of the CO<sub>2</sub> stream</summary>

If the facility at which the CRCF-project captures CO<sub>2</sub> is not subject to monitoring of the biogenic CO<sub>2</sub> amount under the EU Emission Trading System (EU-ETS), Project Developers shall provide access, immediately at request, to representatives of the VVB, Rainbow or relevant national authorities to allow unannounced C14 testing of the CO<sub>2</sub> stream leaving the facility, and if relevant, prior to being mixed with any separately captured fossil CO<sub>2</sub> stream. If the biogenic origin cannot be confirmed, then no credits shall be issued for the corresponding monitoring period.

</details>

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Eligible storage</summary>

For CRCF-projects, the capture facility shall be located in the European Union and the storage site(s) shall be permitted under the ​[Directive (EU) 2009/31/EC](https://eur-lex.europa.eu/eli/dir/2009/31/oj/eng) on the geological storage of carbon dioxide.

</details>

### Principles & requirements

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Biomass sustainability</summary>

In addition to meeting all requirements outlined above, Projects seeking certification under the CRCF shall also comply with the following:&#x20;

#### **RED-certified biomass**

Project shall use biomass that is compliant with the EU's [Renewable Energy Directive](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32023L2413\&qid=1699364355105) (RED) III. Specifically, this means that &#x20;

* biomass shall be compliant with the sustainability requirements set out in Article 29 of the RED for the purposes referred to in Article 29, Paragraph 1 (a), (b) and (c), even if the project does not generate renewable energy that is taken into account under the RED.
* the requirements on GHG savings set out in Article 29, Paragraph 10 shall only be met if the CO<sub>2</sub> is captured at a facility producing heat, electricity or a biofuel, bioliquid or biogas. The GHG savings criteria apply to the product of the facility.&#x20;
* biomass from waste or residues from agricultural, aquaculture, fisheries and forestry residues are subject to the sustainability requirements set out in Article 29, Paragraphs 2 to 7. Other biomass types are not subject to the requirements in these paragraphs.

Compliance shall be demonstrated by certification of the biomass from&#x20;

* [voluntary schemes](https://energy.ec.europa.eu/topics/renewable-energy/bioenergy/voluntary-schemes_en) approved by the Commission in accordance with Article 30, Paragraph 4 of RED, or
* national schemes recognized by the Commission in accordance with Article 30, Paragraph 6 of RED, or
* schemes recognized by the competent national authority in the state where the BioCCS capture facility is located.

#### **Additional biomass sustainability requirements**

Project Developers shall also demonstrate that

* biomass is not identified as being produced from a high indirect land use change risk feedstock, as defined in the [Delegated Regulation 2019/807](https://eur-lex.europa.eu/eli/reg_del/2019/807/oj/eng) to the RED.
* if biomass is sourced from areas designated by the national competent authority for

  conservation, including areas covered by the national restoration plan established under

  [Regulation (EU) 2024/1991](https://eur-lex.europa.eu/eli/reg/2024/1991/oj/eng), or in habitats that are protected, the sourcing shall be in

  accordance with the conservation and restoration objectives for those areas.

#### **CO**<sub>**2**</sub>**&#x20;captured from energy production covered under RED**

If CO<sub>2</sub> is captured from an energy production process covered by the RED, Project Developers shall demonstrate that

* the national implementation of that directive applies to the operator of the energy production process and that the operator complies with this national implementation.
* the operator complies with any measures in that national implementation that ensure that woody biomass is used according to the [list of priorities](#user-content-fn-1)[^1] established in Article 3, Paragraph 3 of the RED, including any derogations introduced by Member States under Article 3, Paragraph 3 (a), if the operator benefits from a relevant support scheme for energy production.
* the operator does not receive direct financial support from Member States for the use of saw logs, veneer logs, industrial grade roundwood, stumps and roots to produce energy, in line with Article 3, Paragraph 3 (c)&#x20;

Facilities regulated under the RED undergo periodic assessment of compliance with the sustainability requirements by Member State competent authorities. This periodic assessment shall not prevent the compliance assessment conducted by the VVB for approval of credit issuance. In practice, this means that the VVB does not need to wait for the completion of an ongoing RED assessment of compliance before assessing the BioCCS project and approving credit issuance. However, if the Member State assessment results in any non-conformity with Article 29 of the RED, Project Developers shall notify Rainbow and the VVB immediately.&#x20;

#### **Voluntary compensation of biomass**

To support the regeneration of natural carbon stocks used for the generation of permanent carbon removals, Project Developers may purchase [carbon farming sequestration units](#user-content-fn-2)[^2] and report the amount in the monitoring report.&#x20;

</details>

<details>

<summary>🇪🇺 <strong>CRCF requirement</strong>: Risk assessment </summary>

Project Developers seeking compliance with the EU's CRCF shall additionally evaluate and address the following risks.

#### **Climate change adaptation**

To comply with the *do-no-significant-harm to climate change adaptation* criteria, Project Developers shall identify the physical climate risks that are material to the project from those listed in Section II of Appendix A to Annex 1 of the [Commission Delegated Regulation (EU) 2021/2139](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02021R2139-20260101#app_A) and perform a robust climate risk and vulnerability assessment following the steps outlined in Section I of that same appendix.

#### **Sustainable use and protection of water and marine resources**

Any potential risks due to the project to the good status or the good ecological potential of bodies of water, including surface water and groundwater, or to the good environmental status of marine waters. In the case that pollutants that are scrubbed from flue gases in order to reduce air pollution may be released to a body of water, the air pollution benefit and the availability of alternative discharge strategies shall be taken into consideration when evaluating the impact on water quality.&#x20;

Addressing the following [Minimum environmental and social risks](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment) defined in the Rainbow Standard Rules is equivalent to addressing this risk:

* Minimize pollutant discharges to water, noise and vibration&#x20;
* Avoid and/or minimize negative impacts on terrestrial and marine biodiversity and ecosystems
* Minimize water consumption and stress in the project&#x20;

#### **Circular economy, efficient use of sustainably sourced bio-based materials**

Any potential risks to the circular economy objectives from the projects, considering&#x20;

* the project leads to significant inefficiencies in the use of materials or in the direct or indirect use of natural resources such as non-renewable energy sources, raw materials, water and land at one or more stages of the life cycle of products, including in terms of durability, reparability, upgradability, reusability or recyclability of products
* the project leads to a significant increase in the generation, incineration or disposal of waste, with the exception of the incineration of non-recyclable hazardous waste
* the long-term disposal of waste may cause significant and long-term harm to the environment

#### **Pollution prevention and control**

Any potential risks to generate a significant increase in the emissions of pollutants to air, water or land from the project. Where facilities are within the scope of [Directive 2010/75/EU](#user-content-fn-3)[^3] they shall comply with all requirements arising from that Directive.&#x20;

Where facilities are not in the scope of that Directive, addressing the following [Minimum environmental and social risks](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment) defined in the Rainbow Standard Rules is equivalent to addressing this risk.

* Minimize pollutant emissions to air
* Minimize pollutant discharges to water, noise and vibration&#x20;
* Minimize generation of waste and release of hazardous materials, chemical pesticides and fertilizers

#### **Protection and restoration of biodiversity and ecosystems**

Any potential risks from the project to the good condition or resilience of ecosystems or to the conservation status of habitats and species, including those of Union interest or to the achievement of targets or obligations set out in national restoration plans established under [Regulation (EU) 2024/1991](https://eur-lex.europa.eu/eli/reg/2024/1991/oj/eng).

Addressing the following [Minimum environmental and social risks](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment) defined in the Rainbow Standard Rules is equivalent to addressing this risk. Note that any potential risk to targets or obligations in national restoration plans shall be addressed separately.&#x20;

* &#x20;Avoid and/or minimize negative impacts on terrestrial and marine biodiversity and ecosystems
* Protect the habitats of rare, threatened, and endangered species, including areas needed for habitat connectivity
* Do not convert natural forests, grasslands, wetlands, or high conservation value habitats
* Minimize soil degradation and soil erosion
* Minimize water consumption and stress in the project

</details>

### GHG Quantification

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Data sources</summary>

In addition to the data listed in the table above, Project Developers of CRCF-projects shall additionally monitor and update the fraction of injected CO<sub>2</sub> dedicated for carbon removals under the CRCF, $$F\_{CRCF}$$.

</details>

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Recognition under different schemes</summary>

Project Developers can choose to credit part of net carbon removal under a scheme other than the CRCF. In this case, the fraction credited under the CRCF, $$F\_{CRCF}$$ shall be applied to the net removal calculation in Eq. 1 .

</details>

<details>

<summary>🇪🇺 <strong>CRCF requirement</strong>: Emission factors biomass production</summary>

For CRCF-compliant projects, Project Developers shall follow the hierarchical list below for selecting biomass production emission factors:

1. RED III disaggregated default values for term *e*<sub>*ec,*</sub>
2. Default values at regional level (NUTS2),
3. Calculate averages based on local farming practices based on e.g. data of a group of farms, as an alternative to using a single actual value

Note that the use of representative emissions factors from other databases or literature is not allowed under the CRCF.

</details>

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Discount factor</summary>

For CRCF-projects, the discount factor is applied to the **gross GHG removals**, $$R\_{project}$$.&#x20;

</details>

<details>

<summary>🇪🇺 <strong>CRCF requirement:</strong> Parasitic load approach</summary>

Project Developers seeking certification under the EU CRCF shall only use the full approach (biomass-based calculation) to determine emissions from parasitic load demand.&#x20;

</details>

### Sampling and measurements

<details>

<summary>🇪🇺 <strong>CRCF requirement</strong>: Measurements of CO<sub>2</sub> stream</summary>

In addition to following the requirements set out in this section, CRCF projects shall ensure measurements of the CO<sub>2</sub> stream are taken in accordance with Articles 40-46 and Article 49 of the [European Commission's Implementing Regulation 2018/2066](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02018R2066-20250527#anx_IV).

</details>

[^1]: (a)  wood-based products;

    (b)  extending the service life of wood-based products;

    (c)  re-use;

    (d)  recycling;

    (e)  bioenergy;

    (f)  disposal.

[^2]: Temporary carbon credits issued under the carbon farming branch of the CRCF that certify the removal and storage of CO2 through land-based activities such as soil carbon sequestration, agroforestry, and peatland rewetting.

[^3]: Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial and livestock rearing emissions (integrated pollution prevention and control), [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02010L0075-20240804)


# Appendix

### Secondary data: Biomass storage emissions

The table below specifies secondary data for the calculation of biomass storage emissions. Biomass storage emissions are calculated as part of the emissions from [CO<sub>2</sub> generation](#generation-of-co2) and/or [Internal energy use (parasitic load)](#internal-energy-and-parasitic-load).&#x20;

*Table A1 Summary of cow and chicken manure characteristics (from* [*Esnouf et al., 2021* ](#user-content-fn-1)[^1]*unless otherwise stated).*

<table><thead><tr><th>Parameter</th><th width="174">Value for Chicken</th><th>Value for Cow</th></tr></thead><tbody><tr><td>Fresh matter as nitrogen (%)</td><td><a data-footnote-ref href="#user-content-fn-2">1.4</a></td><td>-</td></tr><tr><td>Dry matter in manure (%)</td><td>-</td><td>24</td></tr><tr><td>Dry matter as nitrogen (%)</td><td>-</td><td>2.7</td></tr><tr><td>Nitrogen lost as N<sub>2</sub>O per 180 days of storage (%)</td><td>2</td><td>2</td></tr><tr><td>Rate of N<sub>2</sub>O released from manure spreading (kgN<sub>2</sub>O/t of manure spread)</td><td>0.177</td><td>0.177</td></tr><tr><td><a data-footnote-ref href="#user-content-fn-3">Biochemical methane potential (BMP) (m<sup>3</sup> CH<sub>4</sub>/tonne fresh manure)</a></td><td>86</td><td>51</td></tr><tr><td>Methane emissions during storage (as % of BMP)</td><td>1.5</td><td>1.5</td></tr></tbody></table>

*Table A2 Summary of slurry characteristics (from* [*Esnouf et al., 2021* ](#user-content-fn-1)[^1]*unless otherwise stated).*

<table><thead><tr><th width="443">Parameter</th><th>Value</th></tr></thead><tbody><tr><td>Dry matter in slurry (%)</td><td>4.27</td></tr><tr><td>Dry matter as nitrogen (%)</td><td>7.11</td></tr><tr><td>Nitrogen lost as N<sub>2</sub>O per 180 days of storage (%)</td><td>0.08</td></tr><tr><td>Rate of N<sub>2O</sub> released from slurry spreading (kgN<sub>2</sub>O/t of manure spread)</td><td>0.057</td></tr><tr><td><a data-footnote-ref href="#user-content-fn-3">Biochemical methane potential (BMP) (m<sup>3</sup> CH<sub>4</sub>/tonne fresh slurry)</a></td><td>19</td></tr><tr><td>Methane emissions during storage (as % of BMP)</td><td>36</td></tr></tbody></table>

### Ecoinvent activities

The table below presents a non-exhaustive selection of Ecoinvent activities that may be used in the GHG reduction calculations for this methodology. Additional activities may be used for any project, if the following selection does not cover all relevant activities.

*Table A3 List of ecoinvent 3.12 processes used in the GHG reduction quantification model, all processes are from the cutoff database.*

<table data-full-width="false"><thead><tr><th width="223">Input</th><th>Ecoinvent activity name</th></tr></thead><tbody><tr><td>grid electricity</td><td><ul><li>market for electricity, low voltage</li><li>market for electricity, medium voltage</li></ul></td></tr><tr><td>onsite solar electricity</td><td>electricity production, photovoltaic, 570kWp open ground installation, multi-Si</td></tr><tr><td>diesel fuel material</td><td><ul><li>market for diesel, low-sulfur</li><li>market for diesel</li></ul></td></tr><tr><td>diesel burning</td><td><ul><li>diesel, burned in agricultural machinery</li><li>diesel, burned in diesel-electric generating set, 18.5kW</li></ul></td></tr><tr><td>natural gas burning</td><td>natural gas, burned in gas turbine</td></tr><tr><td>heat, from steam</td><td>market for heat, from steam, in chemical industry</td></tr><tr><td>heat, from municipal incineration</td><td>heat, from municipal waste incineration to generic market for heat district or industrial, other than natural gas</td></tr><tr><td>heat, from biomethane burning</td><td>market for heat, central or small-scale, biomethane</td></tr><tr><td>heat, from straw burning in a furnace</td><td>heat production, straw, at furnace 300kW</td></tr><tr><td>heat, from natural gas</td><td><ul><li>market for heat, district or industrial, natural gas</li><li>market for heat, central or small-scale, natural gas</li></ul></td></tr><tr><td>water</td><td><ul><li>market for tap water</li><li>market for water, decarbonised</li><li>market for water, deionised</li></ul></td></tr><tr><td>non-hazardous landfill</td><td><ul><li>market for process-specific burdens, slag landfill</li><li>market for process-specific burdens, sanitary landfill</li><li>market for process-specific burdens, inert material landfill</li></ul></td></tr><tr><td>hazardous waste treatment</td><td><ul><li>market for hazardous waste, for incineration</li><li>market for hazardous waste, for underground deposit</li></ul></td></tr><tr><td>Energy crop: maize silage</td><td>maize silage production | maize silage | Cutoff, U, RoW</td></tr><tr><td>Energy crop: sunflower</td><td>market for sunflower silage | sunflower silage | Cutoff, U, GLO</td></tr><tr><td>Energy crop: rye grass</td><td>market for ryegrass silage | ryegrass silage | Cutoff, U, GLO</td></tr><tr><td>Energy crop: other grass silage</td><td>grass silage production, Swiss integrated production, intensive | grass silage, Swiss integrated production | Cutoff, U, CH</td></tr><tr><td>Energy crop: alfalfa, and triticale</td><td>alfalfa-grass mixture production, Swiss integrated production | alfalfa-grass mixture, Swiss integrated production | Cutoff, U, CH</td></tr><tr><td>Energy crop: whole corn</td><td>sweet corn production | sweet corn | Cutoff, U, RoW</td></tr><tr><td>Straw</td><td>wheat grain production | straw | Cutoff, U, RoW</td></tr><tr><td>Biogas plant construction</td><td>anaerobic digestion plant construction, agriculture, with methane recovery | anaerobic digestion plant, agriculture, with methane recovery | Cutoff, U, RoW</td></tr></tbody></table>

[^1]: Esnouf A., Brockmann D., Cresson R. (2021) Analyse du cycle de vie du biométhane issu de ressources agricoles - Rapport d’ACV. INRAE Transfert, 170pp.

[^2]: Gangagni Rao Anupoju, Ahuja, S., Bharath Gandu, Sandhya K, Kranti Kuruti and Venkata Swamy Yerramsetti (2015). Biogas from Poultry Litter: A Review on Recent Technological Advancements. Springer eBooks, pp.133–147. doi:<https://doi.org/10.1007/978-3-319-17915-5\\_8>.

[^3]: Methasim project data 2021 <https://ifip.asso.fr/base-de-donnees-methasim/>


# Version history

This page describes the changes in the BioCCS methodology.

| Description of the change | Justification | Date            | Version changed |
| ------------------------- | ------------- | --------------- | --------------- |
| Release of methodology    | --            | June 29th, 2026 | V1.0            |


# Distributed open-kiln biochar

| **Methodology name** | Distributed open-kiln biochar |
| -------------------- | ----------------------------- |
| **Version**          | 1.0                           |
| **Methodology ID**   | RBW-BCR-DOB-V1.0              |
| **Release date**     | April 24th, 2026              |
| **Status**           | In use                        |

This methodology document outlines the requirements for distributed biochar projects certified under the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules). These projects produce biochar at smaller scales and with more low-tech methods than for industrial biochar production.

<details>

<summary><strong>Acknowledgements</strong> <span data-gb-custom-inline data-tag="emoji" data-code="1f91d">🤝</span></summary>

*This methodology was developed by Rainbow with valuable input and support from the Rainbow Distributed biochar Working Group members and other expert contributors.*

*We would like to thank Marc Hernandez Folguera (Planboo), Lorenz Buser (Cotierra), Adrien Humbert (Circonomy), Nando Knodel (Carbon Connect), Daniel Guarin (Carboneers), Isabel Messori (Atmosfair), Abhishek Sharma, Jiwesh Garg, Kaushal Bisht (Varaha), and Gerard Cornelissen (Norwegian Geotechnical Institute) for their insights and contributions throughout the development process.*

</details>

Note that the [Distributed open-kiln biochar ](/methodologies/distributed-open-kiln-biochar)methodology and the [Distributed closed-kiln biochar](/methodologies/distributed-closed-kiln-biochar) methodology have large overlaps with one another. For reference, here are the points of divergence:

<table><thead><tr><th width="170.44451904296875">Criteria</th><th>Open kiln requirement</th><th>Closed kiln requirement</th></tr></thead><tbody><tr><td>Kiln design</td><td>Must be cone-shaped with a flame-curtain design to reliably combust pyrolysis gases at the rim.</td><td>Must trap and concentrate pyrolysis gases in a dedicated chimney or chamber, exposing them to oxygen and high temperatures to combust them before emission.</td></tr><tr><td>Biochar pollutants</td><td>Not required to provide PAH content of biochar.</td><td>Must provide PAH content of biochar.</td></tr><tr><td>Methane measurement techniques</td><td>Must use the carbon mass balance method only.</td><td>May use either carbon mass balance or volumetric flow × concentration to measure methane emissions.</td></tr><tr><td>Eligible biomass</td><td>Must also justify that the specific biomass type, preparation, and particle size are appropriate for flame-curtain operation.</td><td>May use any eligible biomass provided it meets the requirements.</td></tr><tr><td>Photo proof in dMRV</td><td>Must provide photos of the clean pyrolysis process, flame curtain, quenching.</td><td>No photos required of the clean pyrolysis process and flame curtain.</td></tr><tr><td>Inputs</td><td>No energy inputs expected during pyrolysis, no additional data requirements.</td><td>Must provide energy inputs for any syngas combustion.</td></tr></tbody></table>

## Glossary

<table data-header-hidden><thead><tr><th width="216"></th><th></th></tr></thead><tbody><tr><td><strong>Kiln</strong></td><td>An individual pyrolysis unit that produced biochar. A kiln may be mobile or stationary, used individually or collectively, and open or closed.</td></tr><tr><td><strong>Site</strong></td><td>A distinct location where a kiln or kilns are operated.</td></tr><tr><td><strong>Kiln operator</strong></td><td>The individual performing pyrolysis and producing biochar. This includes preparing biomass, loading it into the kiln, surveilling pyrolysis, storing biochar, taking biochar samples, and ensuring durable biochar end use.</td></tr><tr><td><strong>Kiln supervisor</strong></td><td>Hired by the Project Developer to be the party responsible for ensuring quality of the operations by on-the-ground presence and random visits to kiln operators.</td></tr><tr><td><strong>dMRV</strong></td><td>A digital platform (application or website) provided by a third-party dMRV provider other than Rainbow, to allow kiln operators to record and document their operations, ensuring compliance with methodology requirements.</td></tr><tr><td><strong>Kiln run</strong></td><td>One full pyrolysis process, the operation of one kiln, one batch of biochar produced.</td></tr><tr><td><strong>Production Batch</strong></td><td>Biochar produced under the same conditions regarding kiln type, biomass feedstock, and temperature curve. A production batch has a maximum validity of 6 months or 200 tonnes of biochar, whichever comes first. Key measurements like carbon content and H/C ratio are done once per production batch.</td></tr><tr><td><strong>Biochar</strong></td><td>Material that is rich in stable carbon, produced through the thermal conversion of biomass in a low-oxygen environment.</td></tr><tr><td><strong>Bone-dry biochar</strong></td><td>Biochar with a moisture content of 0%, typically measured immediately after exiting the kiln before any water is added during quenching.</td></tr><tr><td><strong>End use application</strong></td><td>The way biochar will be used, such as direct application to soil, mixing with compost and application of the mix to soil, mixing with cement for use in concrete.</td></tr><tr><td><strong>End use point</strong></td><td>The step in the production chain where biochar leaves the direct control of biochar producers, where it is assumed to be incorporated into its final end use application.</td></tr><tr><td><strong>Feedstock</strong></td><td>The organic material used as the raw input for biochar production, such as wood, agricultural residues, or manure.</td></tr><tr><td><strong>Molar H/C</strong><sub><strong>org</strong></sub><strong> ratio</strong></td><td>The ratio of hydrogen to organic carbon atoms in biochar, used to assess the stability and quality of biochar; lower ratios indicate higher stability.</td></tr><tr><td><strong>Production batch ID</strong></td><td>A unique identifier for each production batch.</td></tr><tr><td><strong>Pyrolysis</strong></td><td>Thermal decomposition process that occurs in the absence of oxygen</td></tr><tr><td><strong>Quenching</strong></td><td>The process of rapidly cooling biochar immediately after pyrolysis to stop combustion and minimize methane emissions.</td></tr><tr><td><strong>Site Composite Pile</strong></td><td>A growing pile of biochar subsamples accumulated by the Kiln Operator over the course of a Production Batch. After each kiln run, a defined quantity of biochar is set aside and added to this pile. One Site Composite Pile is maintained per site per Production Batch.</td></tr><tr><td><strong>Site Composite Sample</strong></td><td>A representative sample of biochar taken from the thoroughly mixed Site Composite Pile once the Production Batch is complete. Site Composite Samples from all sites within the same Production Batch are combined to form the Production Batch Composite Pile.</td></tr><tr><td><strong>Production Batch Composite Pile</strong></td><td>A combined pile of Site Composite Samples collected from all sites contributing to the same Production Batch. The pile is thoroughly mixed by the Kiln Supervisor before a representative sample is taken for laboratory analysis.</td></tr><tr><td><strong>Production Batch Representative Sample</strong></td><td>The final representative sample taken from the mixed Production Batch Composite Pile and sent to an accredited laboratory for measurement of organic carbon content, permanence indicators (H/Corg ratio and/or inertinite content), and, once per year, environmental pollutants.</td></tr></tbody></table>


# Eligibility and scope

## Eligible Project Developers <a href="#id-7d9f62an42y" id="id-7d9f62an42y"></a>

Distributed biochar projects uniquely operate with a network of many actors. All recognized actors and their roles are outlined below. Upon validation, Project Developers shall provide a **detailed description of all actors in the project and their responsibilities**.

See the Appendix for the Operating Procedure and responsibilities for [Kiln Operators](/methodologies/distributed-open-kiln-biochar/appendix#appendix-3-operating-procedure-for-kiln-operator), [Kiln Supervisors](/methodologies/distributed-open-kiln-biochar/appendix#appendix-4-operating-procedure-for-kiln-supervisor) and [Project Developers](/methodologies/distributed-open-kiln-biochar/appendix#appendix-5-operating-procedure-for-project-developer).

<table><thead><tr><th width="127.0396728515625">Type of actor</th><th width="316.7440185546875">Operational role</th><th width="311.2335205078125">Carbon project role</th></tr></thead><tbody><tr><td><strong>Kiln Operator</strong></td><td>The individual performing pyrolysis and producing biochar. This includes preparing biomass, loading it into the kiln, surveilling pyrolysis, storing biochar, taking biochar samples, and ensuring durable biochar end use.</td><td>Executes the carbon removal activity and records raw data and proof. Receives carbon finance from credit sales, distributed by the Kiln Supervisor or Project Developer.</td></tr><tr><td><strong>Kiln Supervisor</strong></td><td>Hired by the Project Developer to be the party responsible for ensuring quality of the operations by on-the-ground presence and random visits to Kiln Operators.</td><td>Visits each Kiln Operator at least once per year, and coordinates biochar bulk density measurements onsite. May provide trainings to Kiln Operators.<br>The Kiln Supervisor shall not receive payments or other incentives related to number of carbon credits issued.</td></tr><tr><td><strong>Project Developer</strong></td><td>Coordinates with Kiln Supervisors to ensure high quality biochar production, sampling and measurements; manage data and proof for submission to Rainbow and VVB (i.e. check anomalies).<br>May also train, provide dMRV, provide kilns, and operate kilns.</td><td>An intermediary between Rainbow and on-the-ground operations, including Kiln Operators and Supervisors.<br>Responsible for centralized project data management, registration, VVB interactions, and ensuring carbon finance is distributed to Kiln Operators.</td></tr><tr><td><strong>dMRV provider</strong></td><td>Provides a third-party dMRV platform (digital monitoring, reporting and verification) apart from Rainbow, in the form of an application or website, to allow Kiln Operators to record operations.</td><td>The dMRV tool must have all features needed to for kiln operators to prove compliance with methodology requirements. Full requirements <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#dmrv-requirements">here</a>.<br>Can also be a Project Developer.</td></tr><tr><td><strong>Technology provider</strong></td><td>Provides the physical kiln used to perform pyrolysis and produce biochar.</td><td>Must provide kilns that meet methodology requirements, and help define which kilns are the same type, for defining the Production Batch. Full requirements <a href="#eligible-kilns">here</a>.<br>Can also be a Project Developer.</td></tr></tbody></table>

## Eligible technologies

### Eligible kilns

Only open kilns are eligible under this methodology. Eligible kilns must:

* maintain pyrolysis temperatures of at least 350°C, for the entire pyrolysis duration (excluding ramp up period)
* employ a conical flame-curtain design to reliably combust pyrolysis gases at the rim (this includes but is not limited to steel Kon-Tiki cones and steel-shielded soil pits, and excludes unmodified soil pits)
* be equipped with fixed, continuously-logging thermocouples, placed in the same spot on all kilns. See the [temperature curve requirements](/methodologies/distributed-open-kiln-biochar/principles-and-requirements#temperature-curves) for further instructions
* come with safety protocols and instructions for operators
* have a unique identifier permanently affixed to the kiln structure that cannot be removed, altered, or transferred to another unit (e.g. a QR code, engraved serial number, or equivalent)

Project Developers shall submit the design specifications of kilns for validation by the Rainbow team and a VVB, including the form, function, size and dimensions of the kiln. After a kiln design is validated and approved as eligible by Rainbow and a VVB, the design will be added to Rainbow’s published list of eligible kilns. For any future projects using the same kiln design, the kiln shall be considered **automatically eligible**. Project Developers only need to demonstrate that their kiln matches a design already listed.

### Eligible biomass feedstock

Eligible biomasses are those that:

* could not have been used for valuable products (e.g. low quality wood), and
* were not grown for the purpose of CDR[^1] or bioenergy production.

For simplification, all feedstocks that meet the above requirements will be referred to hereafter as waste. Biomass feedstocks are categorized accordingly:

<table><thead><tr><th width="170.7734375">Biomass type</th><th width="557.83984375">Description</th></tr></thead><tbody><tr><td>Forest waste</td><td><ul><li><strong>Secondary forest:</strong> Natural but not primary old-growth forest, may still be managed for timber</li><li><strong>Managed forest:</strong> Managed mixed-use forests that may include agroforestry, plantations or rotational logging</li><li><strong>Necessary tree removal from any forest:</strong> Damaged trees, or trees removed for planned forest management such as preventing disease spread or fires</li></ul><p>Subject to <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#waste-status">Proof of waste status</a>, <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#forestry-certification">Forestry certification</a>, and <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#leakage">Leakage </a>requirements.</p></td></tr><tr><td>Agro-food waste</td><td><ul><li><strong>Residues otherwise left on soil</strong> or reapplied to soils for nutrient recycling, through mulching, composting, or spreading</li><li><strong>Residues otherwise burnt in the field</strong>, with no substantial return of nutrients or organic carbon to soil</li><li><strong>Food processing facility</strong> waste</li></ul><p>Subject to <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#waste-status">Proof of waste status</a> and <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#leakage">Leakage </a>requirements.</p></td></tr><tr><td>Invasive species</td><td>Woody or herbaceous plants proven to be locally or regionally invasive (non-native and causing environmental or human harm).<br>Subject to <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#invasive-species-status">Proof of invasive species</a> requirements.</td></tr></tbody></table>

Project Developers shall justify that the chosen **biomass type, preparation method and particle size is appropriate for use in open kilns** and will not lead to smothering, uneven gas release, or poor heat transfer, which risk disrupting the flame curtain and emitting methane. Coarse, rigid, woody or semi-woody biomass are recommended, and include but are not limited to pruning wood, branches, crop stalks (maize, sorghum, sesame), bamboo, and moderately-sized wood chips.

Biomass must be explicitly **subject to** [**stakeholder consultation**](/methodologies/distributed-open-kiln-biochar/principles-and-requirements#biomass-stakeholder-consultation), attesting to its status as waste or invasive species, and the Project Developer's right to use it. See the [Environmental and social safeguards](/methodologies/distributed-open-kiln-biochar/principles-and-requirements#biomass-stakeholder-consultation) section for more details.

### Feedstock Composition and Consistency

Each [Production Batch](#user-content-fn-2)[^2] shall use either a **single feedstock type** or a **consistent feedstock mix**, subject to the following requirements.

<table><thead><tr><th width="105.09716796875">Type</th><th width="174.3876953125">Definition</th><th>Requirements</th></tr></thead><tbody><tr><td><strong>Single feedstock</strong></td><td>Each kiln run in the Production Batch uses one biomass feedstock type</td><td><ul><li>Biochar produced from different feedstock types shall be kept physically separate during production, storage, and sampling.</li><li>Biochar produced from different feedstock types shall be tracked and reported separately in the dMRV system for all measurements and end-use applications.</li></ul></td></tr><tr><td><strong>Mixed feedstock</strong></td><td>Each kiln run in the Production Batch uses the same feedstock mix</td><td><ul><li>The mass of each feedstock component is weighed individually and documented prior to each run.</li><li>The composition of the blend remains consistent within a tolerance of ±10% by mass of each feedstock type across runs.</li></ul></td></tr></tbody></table>

Woody pruning from different tree or shrub species may be treated as a single feedstock type if:

* Project Developers justify that carbon content and other physicochemical characteristics are the same across species, from reputable secondary sources, and
* Kiln Operators document via photograph of each kiln run that
  * all leaves are removed prior to use, and
  * bulk density, moisture content and particle size are the same for all biomass species.

A project may use multiple single-feedstock types **across different kiln runs**, and group the biochar from the same single-feedstock runs into Production Batches. Production Batches may be non-contiguous.

{% hint style="info" %}
For example, if Feedstock #1 if used on Day 1, a different Feedstock #2 on Day 2, and Feedstock #1 is used again on Day 3, the resulting biochar from Day 3 could be part of the same Production Batch as the biochar produced on Day 1.
{% endhint %}

### Eligible biochar product and end use

Credits shall be issued based on the **end use of biochar** (as opposed to production of biochar), specifically when it is mixed into a permanent matrix. A permanent matrix is defined as a medium that ensures the biochar cannot be physically separated or used for energy (e.g., as fuel).

Eligible end uses include:

* **Direct application to soil**
* **Mixing into soil-related products** with expected sale or distribution to professional users, such as compost, manure, or fertilizer mixes. To be considered sufficiently mixed, biochar must make up less than 50% by volume of the total mixture.
* Addition to **concrete or asphalt**

All biochar must have a molar $$H/C\_{org}$$​ below [**0.7**](#user-content-fn-3)[^3].

### Project design

The distributed network of actors results in several project scopes and designs. A typology is provided below for informational purposes only and for clear labeling of project types. All designs listed below are eligible under this methodology, and other designs may be approved on a case by cases.

<table><thead><tr><th width="131.51171875"></th><th width="308">Collective</th><th>Self-sufficient</th></tr></thead><tbody><tr><td><strong>Mobile</strong></td><td><p><strong>Portable Community Kilns</strong></p><ul><li>Kiln is moved from site to site.</li><li>Central operator provides pyrolysis as a service to multiple farmers.</li><li>Kiln travels to centralized biomass sources, and biochar is left with farmers or distributed locally.</li></ul></td><td><p><strong>Portable Farmer Units</strong></p><ul><li>Kiln is moved from site to site.</li><li>Farmers pyrolyze their own biomass on-site or nearby, and use biochar on the same farm</li></ul></td></tr><tr><td><strong>Stationary</strong></td><td><p><strong>Shared Pyrolysis Hubs</strong></p><ul><li>Kiln at a fixed and shared location.</li><li>Central operator manages the kiln.</li><li>Biomass comes from several sources, biochar distributed to users who may or may not have provided the biomass.</li></ul></td><td><p><strong>On-Farm Producers</strong></p><ul><li>Kiln at a fixed location, at an individual's farm.</li><li>Farmers pyrolyze their own biomass and use the biochar on their own land.</li></ul></td></tr></tbody></table>

## Certification requirements

#### **Crediting period duration**

The maximum duration of the crediting period for projects certified under this methodology is 5 years. Upon reaching the maximum duration, a project's crediting period may be renewed, according to the [Crediting Period Renewal](/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal) procedure.

#### **Monitoring period duration**

The default monitoring period duration is one year, but may be shorter at the Project Developer's request. Project Developers shall submit a Monitoring Report at least once per 24 months. Failure to do so shall result in the project being [deregistered](/rainbow-standard-documents/procedures-manual/project-certification-procedure#deregistration).

#### **Site audits**

Site audits for projects under this methodology **must be done in-person and must be conducted at least once per year** by a Rainbow-accredited Validation and Verification Body (VVB, the auditor)**.** The site audit shall include the direct observation of one kiln run at each site, in addition to the general site audit requirements in the [Rainbow Procedures Manual](/rainbow-standard-documents/procedures-manual/project-certification-procedure#site-audit).

The required number of sites to audit per project per year vary according to the project size, and shall adhere to the following framework:

<table><thead><tr><th width="144.18182373046875">Project Size</th><th width="184.72723388671875">Annual audit rate</th><th width="154.8018798828125">Annual audit minimum number of sites</th><th>Indicative 5-Year Cumulative Coverage</th></tr></thead><tbody><tr><td><strong>&#x3C;10 sites</strong></td><td>2 sites per year</td><td>2</td><td>100% of all sites visited at least once</td></tr><tr><td><strong>11–200 sites</strong></td><td>10% of sites per year</td><td>2</td><td>~50% of all sites visited at least once</td></tr><tr><td><strong>201–500 sites</strong></td><td>5% of sites per year</td><td>15</td><td>~25–50% of all sites visited at least once</td></tr><tr><td><strong>500+ sites</strong></td><td>5% of sites per year</td><td>10, maximum 40 per year</td><td>~25% of all sites, maximum 200 unique sites over 5 years</td></tr></tbody></table>

Project Developers shall justify how the audited sites were selected each year, adhering to the following principles:

* **Rotation**: The audited sites shall rotate each year so that over the 5-year crediting period, a large sample size of sites are audited. No site shall be selected for audit in two consecutive years unless it received a non-conformity finding in its most recent audit or makes up an exceptionally large proportion of biochar production in the project.
* **Random**: Random site selection is the ideal approach to ensure that site audits cover realistic day-to-day operations. Project Developers shall outline their efforts to randomly select sites and ensure that visits represent real conditions.
* **Prioritize large sites**: Sites with higher biochar production volumes shall be given priority, and should be visited more frequently and earlier in the crediting period than low-producing sites.

The points above **remain principles rather than strict requirements** because Rainbow recognizes the on-the-ground challenges with coordinating site audits, and that announcing audit visits in advance is often a practical necessity due to travel distances, access arrangements, and the need for the Kiln Operator to be ready to run pyrolysis.

If the project is tracking the amount of biochar produced using volume based measurements, and is drying the biochar for bulk density measurements using the oven drying method, then the annual site audit shall also include a moisture content cross-check under oversight of the VVB, as described in the [Sampling and Measurements](/methodologies/distributed-open-kiln-biochar/sampling-and-measurements#biochar-volume) section

#### **Versioning and project compliance**

When this methodology is revised, projects are required to comply with the latest version for subsequent verifications of RCCs.

## Project scope

One project is defined as:

* the operation of one or more kilns, across one or more sites,
* within a single country,
* using the same kiln technology,
* using the same dMRV approach, and
* operated at sites that are under the oversight or data access of a single Project Developer.

The **project scope is cradle-to-grave** and includes all processes that result from biochar production and application. This includes but is not limited to the following:

* carbon removals from biochar production
* induced emissions from
  * biomass sourcing
  * leakage
  * upstream and downstream transport
  * embodied emissions from infrastructure and machinery
  * onsite process emissions from biomass preparation, biochar processing and energy use.

Any processes that would have occurred regardless of the biochar production and application activities may be excluded from the project scope.

## Baseline scope

A **standardized baseline of 0** **removals** is set, because it is assumed that no biochar production or other dedicated carbon removal activity would have occurred under business-as-usual conditions. There is no share of the project activity in the baseline scenario.

Any permanent carbon storage from the alternate fate of the biomass feedstock used by the project is addressed in the [Leakage](/methodologies/distributed-open-kiln-biochar/principles-and-requirements#counterfactual-biomass-carbon-storage) section.

[^1]: Carbon dioxide removal

[^2]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for **a maximum of 6 months operating time or 200 tonnes of biochar**, whichever comes first.

[^3]: Leng, L., Huang, H., Li, H., Li, J., Zhou, W., 2019. Biochar stability assessment methods: A review. Science of The Total Environment 647, 210–222. <https://doi.org/10.1016/j.scitotenv.2018.07.402>


# Principles & requirements

Project Developers shall demonstrate that they comply with all principles and requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements), and described below with a specific focus on distributed biochar production.

{% content-ref url="/pages/CRADNrj4mfS258PN3x7N" %}
[Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules)
{% endcontent-ref %}

## Additionality <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

Project Developers shall demonstrate additionality using the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template) and following the requirements of the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#additionality).

{% tabs %}
{% tab title="Regulatory surplus analysis" %}
**Regulatory surplus analysis** shall demonstrate that there are no regulations that require or mandate project activities (for removal and avoidance activities). It is acceptable if regulations promote or set targets for these activities, because the resulting increase in activities shall be accounted for in the [baseline scenario](/methodologies/distributed-open-kiln-biochar/eligibility-and-scope#baseline-scope).

At the European Union level, projects automatically pass the regulatory surplus analysis, which has been conducted by the Rainbow Science Team. Project Developers are only required to provide a country-level regulatory surplus analysis.
{% endtab %}

{% tab title="Investment analysis" %}
**Investment analysis** may be used to prove that revenue from carbon finance is necessary to make the project investment a financially viable and interesting option. The investment may cover:

* The creation and launching of new sites
* Expansion of capacity of existing activities
* Expansion by installing new processes

Business plans shall be provided as initial proof for investment analysis. During verification, **audited financial statements** **must be provided as proof** that the initial estimates from the business plan were reasonable, and that carbon finance was used as initially described for the expected investment.

Note that for investments in expansion, **only the additional carbon removals enabled by the expansion shall be eligible for Rainbow Carbon Credits.**
{% endtab %}

{% tab title="Barrier analysis" %}
**Barrier analysis** may be used to prove that the project faces financial, institutional, or technological barriers to ongoing operations that can only be overcome using carbon finance. Examples include but are not limited to:

* Financial barrier: financial analysis demonstrating that the project is not financially viable, evidenced by net cash being lower than the working capital requirements, or proof that the project is not meeting the projected financial targets in the business plans and loan documents, and that carbon finance would make it financially viable.
* Institutional barrier: description of new regulation that the project must make costly changes to comply with, financial analysis showing that the project cannot fund the changes on their own, and carbon finance is necessary to make it viable.

For any type of barrier analysis, **audited financial statements must be provided** as proof. These documents should either demonstrate the financial status to prove financial barriers, or show that the project could not independently fund solutions to overcome institutional or technological barriers.
{% endtab %}
{% endtabs %}

## Durability <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

#### Durability threshold

All projects certified under this methodology shall prove **durable carbon removals for at least 100 years**. Project Developers may claim an extended durability threshold of 1000 years if they choose the 1000-year pathway for [GHG quantification](/methodologies/distributed-open-kiln-biochar/ghg-quantification#biochar-carbon-storage) and measurements.

#### Reversal risk assessment

The major carbon reversal risks from biochar carbon storage are:

1. **Insufficient biochar stability**, where biochar carbon is not sufficiently carbonized and is decomposed by microbes and soil organisms, resulting in re-emission of CO<sub>2</sub>.
2. **Failure to durably incorporate into a permanent matrix** (e.g. soil or soil-like material), where biochar is instead burned or destroyed, intentionally or unintentionally (e.g. as fuel, in storage fires, or via waste incineration).

This methodology establishes the following mandatory project design requirements to mitigate these risks, detailed in the following sections:

* measuring the durable carbon fraction
* verification of biochar end use

Upon meeting these requirements for each verification and credit issuance, the risk of reversal is considered **negligible** for biochar application to soils. There are no further project requirements to assess reversal risks or conduct post-crediting monitoring for reversals.

All projects certified under this methodology shall contribute the default minimum 2% of their verified removal RCCs to the Rainbow Buffer Pool, as defined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#durability).

#### Risk mitigation: Measuring permanent carbon fraction <a href="#kmzukpswu89" id="kmzukpswu89"></a>

Not all biomass carbon that is converted to biochar is expected to remain durably stored. The durability of biochar carbon depends on the its physicochemical stability, which is influenced by factors such as carbonization temperature and biomass feedstock.

Project Developers shall measure one of the following well-known [proxy indicators](#user-content-fn-1)[^1] of biochar durability for each [Production Batch](#user-content-fn-2)[^2]. These indicators serve both as **eligibility thresholds**, and as inputs to **quantify the permanent fraction of carbon** ($$F\_{perm}$$) expected to remain durably stored beyond the applicable durability threshold.

The fraction of permanently stored carbon shall be quantified using the models and equations specified in the [GHG quantification](/methodologies/distributed-open-kiln-biochar/ghg-quantification#biochar-carbon-storage) section. Only this fraction shall be issued as removal RCCs.

<table><thead><tr><th width="136">Pathway</th><th width="213">Indicator</th><th>Threshold requirement</th></tr></thead><tbody><tr><td>100-year pathway</td><td>Hydrogen-to-organic-carbon atomic ratio (<span class="math">H/C_{\text{org}}</span>)</td><td><span class="math">H/C_{\text{org}}</span> must be less than 0.7</td></tr><tr><td>1000-year pathway</td><td>Random reflectance distribution</td><td><ul><li>The fraction of the biochar residual organic carbon that has a random reflectance of 2% or higher can be considered <a data-footnote-ref href="#user-content-fn-3">inertinite</a>, which is an extremely stable, permanent storage of mineral-like organic carbon.</li><li>Must also have <span class="math">H/C_{\text{org}}</span> less than 0.7</li></ul></td></tr></tbody></table>

The distinction between the 100-year and 1,000-year durability pathways provides supplementary qualitative information and does not affect the inherent attributes of the removal RCC.

These indicators are **suitable proof that a substantial fraction** of the carbon present in biochar is permanently stable. The **specific amount** of permanently stored carbon is determined using the models and equations detailed in the [GHG quantification](/methodologies/distributed-open-kiln-biochar/ghg-quantification#biochar-carbon-storage) section.

These durability indicators shall be monitored for each Production Batch according to this methodology's [Sampling Requirements](#sampling-and-measurements).

Issuing removal RCCs only for the verified, highly stable fraction of biochar carbon mitigates the risk of biological decomposition and re-emission after soil application.

#### Risk mitigation: Proof of biochar end use <a href="#id-5a8ye61po9ri" id="id-5a8ye61po9ri"></a>

Project Developers shall prove that all biochar has been used in the intended durable storage application and [eligible biochar end use](/methodologies/distributed-open-kiln-biochar/eligibility-and-scope#eligible-biochar-product-and-end-use) (e.g. incorporated into soils, added to fertilizer mixes, mixed in concrete). This shall be done by documenting all of the following information in dMRV:

* Proof of **delivery and use** of the biochar to its point of end use, specifying the date, GPS coordinates, address, amount of biochar, name of the user/buyer, and Production Batch ID.
* **Photo diary of biochar application and/or mixing**, including time-stamped and geo-located photos of the process.

## No double counting <a href="#id-8f3i2uvmiuhl" id="id-8f3i2uvmiuhl"></a>

Project Developers shall sign the [Rainbow MRV & Registry Terms & Conditions](/other/terms-and-contracts/terms-and-conditions-for-project-developers-mrv-+-registry), committing to follow the requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules), including not double using or double issuing carbon credits.

Project Developers shall demonstrate that they hold the sole right to issue carbon credits for all biochar produced under the project, and that no third party will seek to issue credits for the same biochar.

* If biochar is applied to soils by participants within the project network (e.g., farmers who also provide biomass or operate kilns), this is considered to remain within the project scope through to end use, and no additional double counting documentation is required.
* If biochar is transferred to third parties, such as farmers outside the project network or companies incorporating it into construction materials, then Project Developers shall obtain recognition that the Project Developer holds the sole right to issue credits for that biochar, and that the recipient will not seek to issue credits for its use.

## Co-benefits <a href="#id-8f3i2uvmiuhl" id="id-8f3i2uvmiuhl"></a>

Projects should support at least two **quantifiable and verifiable** environmental or social co-benefits, aligned with the [UN Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDGs) framework. Any co-benefits claimed by the Project Developer shall be **quantified, monitored, and audited** for each verification and credit issuance.

Common co-benefits under this methodology are detailed in the table below. Project Developers may suggest and prove other co-benefits not mentioned here.

SDG 13 on Climate Action by default is not considered a co-benefit here, since it is implicitly accounted for in the issuance of carbon credits. If the project delivers climate benefits that are not accounted for in the GHG reduction quantifications, then they may be considered as co-benefits.

*Table 1 Common co-benefits that projects under this methodology may provide are detailed, including types of proof that can be used to justify each co-benefit.*

<table><thead><tr><th width="233.75">UN SDG</th><th width="345">Example</th><th>Proof</th></tr></thead><tbody><tr><td><strong>SDG 1.5:</strong> Build the resilience of the poor and those in vulnerable situations, ensure significant mobilization of resources from a variety of sources</td><td>Kiln Operators, who are often smallholder farmers, receive direct payments from carbon finance generated (<em>mandatory, see</em> <a href="#benefit-sharing"><em>Benefit sharing</em></a> <em>requirements)</em>.</td><td>Payment slips, bank transaction records, contracts.</td></tr><tr><td><strong>SDG 2.4:</strong> Ensure sustainable food production systems, increase productivity, help maintain resilient ecosystems, improve land and soil quality.</td><td>Biochar application to agricultural soils can <a data-footnote-ref href="#user-content-fn-4">increase crop yields</a>.</td><td>Proof of biochar sales to farmers for agricultural use, invoices, receipts of sale of biochar to farmers.</td></tr><tr><td><strong>SDG 3.9:</strong> reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination</td><td>Agricultural residues (feedstock) are pyrolyzed instead of open-field burning, improving air quality.</td><td>Biomass type records, local data on traditional burning practices.</td></tr><tr><td><strong>SDG 12.2:</strong> Sustainable management and efficient use of natural resources</td><td>Biomass waste is converted into valuable biochar instead of being burned or discarded.</td><td>Biomass type records, local statistics on traditional biomass disposal methods.</td></tr></tbody></table>

## Environmental and social safeguards

Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.**

Projects must follow all national, local, and European (if located in Europe) environmental regulations related to, for example, pyrolysis, gasification, waste feedstock management, and biochar spreading on soils.

### Biomass requirements

#### Waste status

Project Developers shall **provide proof of waste status** for any biomass feedstock categorized as waste. This can be done via any one of the following three methods:

* **Price**: if Project Developers did not pay for the biomass, or if they were paid to handle it, the biomass can be considered waste. Acceptable proof includes invoices, receipts, or contracts.
* **Contextual analysis**: Project Developers may submit an analysis supported by reputable sources that the biomass 1) could not be used as main material products, and 2) was not grown for the purpose of CDR[^5].
* **Positive list of wastes**: if the biomass is included in the following list, it can be considered waste. Acceptable proof includes invoices, receipts, contracts, or photographic evidence and is required for validation:

{% columns %}
{% column %}

* sawmill residues
* shavings
* bark
* forestry tops and branches
* wildfire management residues
* sugar beet pulp
  {% endcolumn %}

{% column %}

* straw
* corn cobs
* wood from horticulture (trimmings or whole plants)
* nut shells
* bagasse
  {% endcolumn %}
  {% endcolumns %}

#### Invasive species status

Project Developers shall **provide proof of invasive species status** for any biomass feedstock categorized as invasive species. This may include but is not limited to peer-reviewed scientific literature documenting the species as invasive in the specific region, national or regional government invasive species lists or registers, regional intergovernmental lists (e.g. IUCN Invasive Species Specialist Group database), or local official weed management orders.

Project Developers shall provide an **Ecosystem Restoration Plan**, outlining all of the following:

* the extent of invasive species harvesting, and how much biomass is left in the field after harvesting
* procedures to ensure only targeted invasive species are harvested
* impacts on biodiversity and habitat loss
* impacts on ecosystem carbon loss

#### Forestry certification

Biomass feedstock originating from forests shall provide at least one of the following forestry sustainability certificates (or similar, with a sufficient justification):

* FSC (Forest Stewardship Council)⁠
* PEFC (Program for the Endorsement of Forest Certification)⁠
* RSB (Roundtable on Sustainable Biomaterials)⁠
* SFI (Sustainable Forestry Initiative)⁠
* SBP (Sustainable Biomass Program)⁠

These certifications are used to prove:

* Legal and transparent chain of custody
* Proper forest regeneration
* Safeguarding biodiversity and soil health
* Historically stable or increasing forest carbon stocks
* Sound socio-environmental practices in forestry operations⁠

#### Biomass stakeholder consultation

In addition to the general Rainbow [stakeholder consultation](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#stakeholder-consultation) requirements, Project Developers shall **explicitly consult stakeholders on the project's use of biomass.** This shall cover the Project Developer's right to use the biomass, the biomass status as waste or invasive species, and the alternative fate of the biomass.

### Kiln operation requirements

Distributed biochar production may pose health and safety risks to Kiln Operators, including but not limited to risk of burns and inhalation of smoke and pollutants. Project Developers shall prove all of the following:

* Kiln Operators and Supervisors follow required [safety training](#trainings)
* Kiln Operators are equipped with and use burn protection equipment such as fire resistant gloves or appropriate footwear
* Kiln Operators are equipped with and use smoke protection equipment such as eyewear and masks
* pyrolysis occurs in ventilated outdoor spaces

### Biochar requirements

Biochar applied to soils must be below the pollutant concentration thresholds outlined in Table 2, defined by the [World Biochar Certificate Guidelines](#user-content-fn-6)[^6] (for WBC-Agro). This shall be measured on a representative composite sample of biochar **anytime biomass feedstock changes, or annually**, if biomass feedstock does not change.

PAH measurement is not required for open kilns under this methodology because open flame curtain kilns using clean agricultural residue feedstocks have been shown in the [scientific literature](#user-content-fn-7)[^7] to produce biochar with sufficiently low PAH concentrations.

*Table 2 The thresholds for pollutant concentrations allowed in biochar, as detailed in the* [*World Biochar Certificate Guidelines*](#user-content-fn-6)[^6]*.*

<table><thead><tr><th width="353.44439697265625">Substance</th><th>Limit amount (g/tonne dry matter)</th></tr></thead><tbody><tr><td>Pb</td><td>300</td></tr><tr><td>Cd</td><td>5</td></tr><tr><td>Cu</td><td>200</td></tr><tr><td>Ni</td><td>100</td></tr><tr><td>Hg</td><td>2</td></tr><tr><td>Zn</td><td>1000</td></tr><tr><td>Cr</td><td>200</td></tr><tr><td>As</td><td>20</td></tr></tbody></table>

{% hint style="info" %}
*Disclaimer: The European Biochar Certificate (EBC) and the World Biochar Certificate (WBC) are independent certification programs designed to ensure the quality of biochar products. These certifications are administered and trademarked by Carbon Standards International (CSI) and are distinct from the Rainbow certification and the issuance of carbon credits.*

*The threshold values provided here are based on the voluntary guidelines of the World Biochar Certificate (WBC), reproduced with permission. While these values have been adopted by the Rainbow standard as pollutant thresholds, they are only indicative. Meeting these thresholds for Rainbow certification does not imply eligibility for or any association with the EBC or WBC programs. Project Developers certified under the Rainbow standard shall not make claims or use any trademarked materials from CSI, unless explicitly allowed by CSI.*

*Voluntary certification under the WBC and EBC schemes is overseen by CSI and includes additional requirements beyond pollutant thresholds.*
{% endhint %}

### Environmental and social risk assessment

Project Developers shall fill in the [Rainbow Distributed biochar risk assessment](/methodologies/distributed-open-kiln-biochar/risk-evaluation-template), to evaluate the identified environmental and social risks of projects. The identified risks include:

* Heavy metal or other pollutants in biochar applied to agricultural soils
* Disruption of soil health when collecting and exporting organic matter
* Presence of heavy metals, toxins or other chemical pollutants in the biomass⁠
* Spread of diseases or invasive species
* Cultivation of feedstock
* Deforestation from use of forestry products as feedstock
* Distant transport of feedstock inputs (>100 km)
* Timely and fair payments to smallholder farmers
* Safe kiln operation and training events to prevents burns
* Use of large amounts of water, if water is scarce, for quenching

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

Project Developers shall follow the requirements in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-safeguards) for conducting stakeholder consultation, and where [IPLCs ](#user-content-fn-8)[^8]are involved, obtaining free prior and informed consent (FPIC). Although the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-safeguards) requires benefit sharing only if IPLCs are involved, this methodology requires it in all cases, as detailed in the following section.

#### Benefit sharing

Project Developers shall demonstrate that Kiln Operators are fairly compensated for their contribution to the project. This includes **timely payments** that are not deferred until credits are issued and sold, and **allocation of a fair share** of carbon finance revenues.

The committed timing and amount of benefit sharing shall be defined by Project Developers and **disclosed transparently in project documentation** on the Rainbow registry.

Project Developers shall demonstrate adherence to this commitment annually by providing payment slips, bank transaction records, or other ex-post evidence of payments having occurred.

## Leakage

Project Developers shall source biomass in a way that reduces leakage. Project Developers shall **assess** and, if identified to be material, **quantify** the leakage caused by the distributed biochar project and **deduct** the associated emissions from the project removals. This shall be done by first identifying the alternative use of biomass, and then assessing the leakage risks from the following identified leakage sources:

* Biomass diversion and replacement
* Counterfactual biomass carbon storage

Where leakage risks are identified, Project Developers shall **mitigate** the risk, and document such efforts to do so. Where leakage cannot be fully mitigated, leakage emissions shall be counted towards the project induced GHG emissions and therefore **deducted from project removals**.

#### Alternative use

Project Developers shall evaluate the most likely alternative use/s of each type of biomass used, in order to assess leakage risks associated with **the baseline carbon storage and the diversion of biomass**. The assessment shall be transparent and conservative.

The alternative use shall address questions such as:

* was the biomass used for a product or service, that now needs to be replaced (e.g. bioenergy production)?
* was the biomass going to store carbon anyway (in the biomass itself and/or in the soil)?

Proof shall be provided and may include signed statements from the biomass provider, historical records from the biomass provider, regional statistics or reputable reporting.

A short list of likely alternative uses may be provided for descriptive purposes, but for the purpose of further analysis, one single alternative use per biomass shall be proposed.

#### Biomass diversion and replacement

Using waste biomass helps mitigate activity shifting leakage. However, waste biomass or invasive species may still have valuable alternative uses.

If the [Alternative use of biomass](#alternative-use) assessment concludes that the biomass has a **valuable existing use**, Project Developers shall assess the impacts of diverting it for biochar production. This assessment must address, at a minimum:

* The availability of **substitute materials** (either the same material, if locally abundant, or alternative materials that fulfill the same function).
* The risk of **indirect land use change or deforestation**, particularly if diverting the biomass creates demand for new materials to replace its original function,

Specifically, Project Developers shall identify the **most likely replacement product or process** for the diverted biomass. Project Developers shall justify the amount of replacement product needed to replace the original function of the biomass based on the business-as-usual (BAU) function, using an appropriate conversion factor.

Proof shall be provided and may include signed statements from the biomass provider, historical records from the biomass provider, regional statistics or reputable reporting.

#### Counterfactual biomass carbon storage

Projects shall only be credited for carbon storage that is genuinely additional. **If the alternative use of biomass was to be left on the soil or reapplied to soils** for nutrient recycling, then any permanent carbon storage that would have occurred anyway in the absence of the project shall be **deducted from the project's carbon removal capacity**.

* Any carbon that is demonstrated to remain stored in the feedstock for up to **50 years** shall be considered as baseline carbon storage.
* A **minimum of 0.5%** of the feedstock carbon content is assumed to remain stored and deducted from the project removals.

[Details](/methodologies/distributed-open-kiln-biochar/ghg-quantification#biomass-leakage) are outlined in the GHG quantification section.

#### Upstream and downstream emissions

Upstream and downstream emissions are accounted for in the life-cycle based GHG quantifications in companion [modules](/modules/processing-and-energy-use).

## Monitoring

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information:

<table><thead><tr><th width="229">Measurement frequency</th><th>Parameters</th></tr></thead><tbody><tr><td><strong>Each</strong> <a data-footnote-ref href="#user-content-fn-9"><strong>Production Batch</strong></a><strong>, on a single representative sample of biochar</strong></td><td><ul><li><span class="math">H/C_{\text{org}}</span> and organic carbon content (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li><li>Inertinite content (fraction of the distribution sample that has a random reflectance of 2% or higher) and residual carbon (<em>if calculating 1000-year removals</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li><li>Biochar moisture content, on at least 3 biochar samples (<em>if measuring biochar amount via mass</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-mass">here</a>)</li></ul></td></tr><tr><td><strong>Once per year, or anytime biomass feedstock changes</strong></td><td><ul><li>Methane emissions, on three runs representative of all other kilns in the same Production Batch (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#methane-emissions">here</a>)</li><li>Environmental pollutants of biochar, on one composite sample mixing biochar from each kiln run (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#biochar-requirements">here</a>)</li><li>Dry bulk density of biochar, on at least one sample from each kiln (i.e. 20 different kilns, 20 bulk density measurements) (<em>if measuring biochar amount via volume</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-volume">here</a>)</li><li>Biomass to biochar conversion factor (<em>if <strong>not</strong> weighing the biomass input of each kiln run)</em> (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biomass-amount-used">here</a>)</li><li>Updated biomass leakage assessment (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#leakage">here</a>)</li></ul></td></tr><tr><td><strong>Each kiln run</strong></td><td><ul><li>Moisture content of biomass input (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#moisture-content-of-biomass">here</a>)</li><li>Type of biomass input (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biomass-used">here</a>)</li><li>Amount of biomass input, via precise mass measurements if using a feedstock mix, or estimates if using a singular biomass (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biomass-amount-used">here</a>)</li><li>Mass or volume of fresh biochar produced (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biochar-produced">here</a>)</li><li>Temperature curve measured in each kiln using real-time sensors, proving pyrolysis has occurred (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#temperature-curves">here</a>)</li><li>Photographs of the pyrolysis process, showing for example a lack of white smoke and ash, and the duration of the kiln run (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#quality-and-oversight">here</a>)</li><li>Sampling records (proof of setting aside a small sub-sample of biochar, to be combined with sub-samples from all other kiln runs in the same Production Batch) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li></ul></td></tr><tr><td><strong>All biochar used</strong></td><td><ul><li>Proof of eligible, durable biochar end use, with names and GPS coordinates of spreading locations, among other information (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#id-5a8ye61po9ri">here</a>)</li></ul></td></tr><tr><td><strong>Once per year</strong></td><td><ul><li>Kiln Operator training (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#trainings">here</a>)</li><li>Proof and findings from the visits of Kiln Supervisor to each Kiln Operator (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#kiln-supervisor-site-visits">here</a>)</li><li>Proof of calibration and accuracy of onsite scales for weighing biochar to determine biochar amount (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biochar-produced">here</a>)</li></ul></td></tr><tr><td><strong>Once per verification and credit issuance</strong></td><td><ul><li>Quality oversight report from the Project Developer (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#quality-oversight-report">here</a>)</li><li>Environmental sustainability and Leakage compliance of biomass feedstock (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#biomass-requirements">here </a>and <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#leakage">here</a>)</li></ul></td></tr></tbody></table>

The Project Developer is the party responsible for adhering to the Monitoring Plan.

## dMRV requirements

Distributed biochar uniquely heavily relies on third-party [**dMRV**](#user-content-fn-10)[^10] **platforms** to allow for detailed tracking of operations across a network of Kiln Operators.

Project Developers shall select the dMRV to be used by Kiln Operators and Supervisors to document the operating procedures. The chosen dMRV shall provide step by step procedures to Kiln Operators and be able to track the following:

<table><thead><tr><th width="275.953125">Item to track</th><th>Further requirements</th></tr></thead><tbody><tr><td>Eligible kiln use</td><td>Scanned QR codes of individual kilns and photos of the kiln displaying the required technical features</td></tr><tr><td>Biomass moisture content</td><td>Photos of sensor readings</td></tr><tr><td>Biomass preparation and amount</td><td><ul><li>Photos of the biomass to be pyrolyzed before each kiln run and</li><li>The mass or volume of biomass used</li></ul></td></tr><tr><td>Pyrolysis temperature and duration</td><td>Continuous thermocouple readings</td></tr><tr><td>Pyrolysis process quality</td><td>Photos taken throughout the pyrolysis process, including at least one after the last addition of biomass to the kiln, showing the intact and clean flame curtain</td></tr><tr><td>Rapid quenching</td><td>Through time-stamped photos or short videos showing the start and end time of quenching</td></tr><tr><td>Amount of biochar produced</td><td><ul><li>Volume of biochar produced from each kiln run, and bulk density measurements conducted by the Kiln Supervisor, or</li><li>Mass of biochar produced from each kiln run, and moisture content measurements</li></ul></td></tr><tr><td>Biochar sampling records</td><td>Scanned QR codes of the original biochar bags from which the sample is taken, and photos of the sample</td></tr><tr><td>Biochar delivery and application</td><td>Scanned QR codes of biochar bags for delivery and photos</td></tr><tr><td>Aggregated measurements and data</td><td>For GHG quantification</td></tr></tbody></table>

Methane emissions testing, including results and photos of the process, may be handled in the dMRV platform or in a separate report shared with Rainbow and the VVB.

All photographs must include a timestamp and GPS coordinates. All temperature curves must include a timestamp.

Any data tracked directly in the dMRV platform and uploaded with a delay must:

* include a timestamp of when the upload occurred, and
* be uploaded as a batch with all relevant data upon connectivity, as opposed to manually uploading individual chosen files from chosen kiln runs, to prevent selective submission of preferred data.

The dMRV platform must prevent Kiln Operators from modifying data once it has been uploaded. Data from dMRV shall be made available and verifiable by Rainbow, the Project Developer and the VVB, through an oversight-only view, and [exportable files](#user-content-fn-11)[^11].

All project records must be retained for a minimum of five years following the end of the project's final monitoring period.

At project validation, Rainbow will review the proposed dMRV platform to ensure it is capable of providing the above-mentioned data and proof. After a dMRV platform design is validated and approved as eligible, the platform will be added to Rainbow’s published list of eligible platform. For any future projects using the same dMRV platform, the platform shall be considered **automatically eligible**.

{% hint style="info" %}
The use of an approved dMRV platform is not sufficient to ensure project compliance with the present methodology. All listed data points and proof shall be uploaded to the dMRV platform in order to issue credits.

If any piece of operational proof or documentation is missing in dMRV, the entire kiln run is ineligible.
{% endhint %}

<table><thead><tr><th width="183.73828125">Role</th><th>Use of dMRV platform</th></tr></thead><tbody><tr><td><strong>Kiln Operators</strong></td><td><ul><li>Directly upload the required information to the dMRV platform, and flag any known anomalies.</li></ul></td></tr><tr><td><strong>Kiln Supervisors</strong></td><td><ul><li>Directly upload any biochar bulk density and/or moisture content measurements to the dMRV platform (depending on the measurement method for the <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biochar-produced">amount of biochar produced</a>), and flag any known anomalies.</li></ul></td></tr><tr><td><strong>Project Developer</strong></td><td><ul><li>Check the information and proof for every kiln run recorded on the dMRV platform, ensuring its accuracy and data preparation (unless outsourcing this task to the dMRV provider, see the <a href="#raw-data-checking">Raw data checking</a> section)</li><li>Provide a <a href="#quality-oversight-report">report on oversight</a> findings, listing non-conformities, adjusted data, and kiln runs excluded from certification.</li></ul></td></tr><tr><td><strong>VVB</strong></td><td><ul><li>Check the complete raw records in dMRV of a random sample of kiln runs, to cover at least 20% of all events.</li><li>Check all records related to biochar bulk density and/or moisture content measurements conducted by Kiln Supervisors, as detailed in the <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-amount-produced">biochar amount produced</a> section.</li><li>Findings shall follow the non-conformity procedure outlined in the <a href="/pages/LqYMOAq4owP6jpiFyN5K#non-conformities">Rainbow Procedures Manual</a>. Major non-conformities shall trigger a more thorough audit of a larger sample of events.</li></ul></td></tr></tbody></table>

## Quality and oversight

### Raw data checking

The Project Developer is ultimately responsible for the quality and accuracy of raw records submitted to the VVBs for audit, and identifying and flagging runs that do not meet the quality threshold. All **records from each kiln run shall be individually checked**, ensuring at a minimum all of the following components:

* the duration of the kiln run is consistent with the amount of biochar produced
* the amount of biomass feedstock used is broadly consistent with the amount of biochar produced, based on photographic evidence of the feedstock pile prior to the run
* the amount of biochar produced is [broadly consistent](#user-content-fn-12)[^12] with the amount of biochar reported as applied in an eligible end use
* flame curtain photos show a clean burn
* pyrolysis temperature is consistently high throughout the duration of the kiln run. Project Developers shall suggest their own definition for acceptable temperature curves upon validation. Full details are in the [temperature curve](#temperature-curves) section
* quenching was rapid enough to mitigate methane emissions

Any kiln run with incomplete data, or that demonstrates unsatisfactory practices, is rendered ineligible for crediting (except for the tolerance threshold of [temperature curve](#temperature-curves) failures).

Raw data checking may be completed by the Project Developer, or may be delegated to the Rainbow-approved dMRV provider. Data checking may be completed manually, or via a dMRV-enabled system for automatically scanning for and flagging anomalies. Criteria and anomalies shall be either defined at the dMRV level and applied across all projects, or according to project-specific criteria, and shall be approved by Rainbow. If opting for an automatic flagging approach, the dMRV provider must demonstrate via trial runs that it is capable of flagging deviations from the criteria, and define a protocol for random manual checks.

The VVB shall also manually review the complete raw dMRV records for a random sample of kiln runs, covering at least 20% of all events.

### Kiln Supervisor site visits

The Kiln Supervisor shall **visit each Kiln Operator annually and observe one kiln run**, ensuring:

* feedstock is properly added to the kiln
* biomass moisture content measurements are taken appropriately
* storage conditions for biomass and biochar are appropriate
* biochar sampling procedures are followed

The Kiln Supervisor shall also collect the **Site Composite Sample** during this site visit, which is mixed with other Site Composite Samples to generate the **Production Batch Representative Sample**. Biochar durability indicators and bulk density measurements (if using the biochar volume approach) are done on this biochar sample. See the [Biochar sampling procedure](/methodologies/distributed-open-kiln-biochar/sampling-and-measurements#biochar-sampling-procedure) section for more details.

Proof of the site visits shall be included in the Monitoring Plan and submitted at least once per year, including the name of the Kiln Supervisor, date of visit, and the findings and follow up actions of each Kiln Operator.

{% hint style="info" %}
Note that the Kiln Supervisor site visits are in addition to the annual VVB site audits, described in the [Certification Requirements](/methodologies/distributed-open-kiln-biochar/eligibility-and-scope#certification-requirements) section.
{% endhint %}

### Quality oversight report

Project Developers shall prepare a report, **upon each verification and credit issuance**, summarizing the findings of dMRV oversight via raw data checking and site visits, as described above. This report shall detail:

* the cumulative biomass used, biochar produced, and biochar applied in an eligible end use, noting any discrepancies and justification,
* any kiln runs that were excluded from certification and the reason for exclusion
* any non-conformities in data uploaded to dMRV and their remediation
* any non-conformities or failure to adhere to best practices in onsite visits, and their remediation

### Temperature curves

All kilns shall be equipped with fixed, continuously-logging thermocouples, producing a documented temperature curve over time for each kiln run. The purpose is twofold: to ensure pyrolysis actually occurred, and to assess the quality of the pyrolysis run.

To **ensure pyrolysis actually occurred**, the temperature curve must show that the temperature of the pyrolysis zone remained above 350°C for the entire process, excluding the ramp up and quenching phases.

To **assess pyrolysis quality**, Project Developers shall submit project-specific criteria for evaluating temperature curves during project validation. These criteria shall be used to flag and exclude ineligible kiln runs, and shall be approved by Rainbow and the VVB. Criteria shall be designed to flag:

* Incomplete biomass drying prior to pyrolysis, and
* Improper feedstock loading rates, such as overloading events that cause a drop in pyrolysis temperature or extinguish the flame curtain.

Criteria definitions shall address target temperatures, durations, and allowable variance, and ramp-up period, quenching, and main pyrolysis time.

**Placement**: Thermocouples should be placed inside the kiln at an appropriate number and spacing to meet the above-mentioned performance requirements. For kilns where it is not technically feasible to place thermocouples inside, they may be placed on the outside of kilns and heat-transfer or energy-balance models shall be used to demonstrate that pyrolysis zone remained above 350°C for the entire process.

**Checking temperature curves**: Temperature curve results from all kiln runs shall be individually checked, according to the [Raw data checking](#raw-data-checking-open-kiln) requirements.

**Tolerance for thermocouple failures**: some kiln runs are expected to experience thermocouple failures. Biochar from kiln runs that experience a thermocouple failure may still be credited if all other required proof is still available for the kiln run, if the reason for the failure can be explained and justified, and if a kiln does not experience consecutive failures. This is applicable to kiln runs that make up a cumulative maximum of 5% of the biochar in the [Production Batch](#user-content-fn-2)[^2]. Beyond this 5%, any kiln runs with thermocouple failures shall be discarded and not credited. The biochar in such excluded kiln runs does not count towards the size-limit of the Production Batch.

**Calibration**: All thermocouples shall undergo regular calibration.

{% hint style="info" %}
**Integrated temperature sensors** are a promising and relatively new pathway to **verify pyrolysis quality and consistency** for certification of distributed biochar production, ensuring low methane emissions and proper biochar production. Strict methodology-level requirements are not set because:

* Thermocouple setups (number, placement, spacing) vary by kiln design.
* Different biomass feedstocks produce distinct temperature curves due to varied energy content.
* Universal temperature thresholds are not yet established.

Ideally temperature sensors will be used to prove that pyrolysis remains **above 500-550°C**, which is a more robust sign of high-quality pyrolysis than 350°C. However, due to the novelty and expected difficulties in this technology's early deployment, this requirement remains flexible for the time being.
{% endhint %}

### Trainings

Upon validation, Project Developers shall submit their Training Protocol, describing how they ensure:

* frequency of trainings for Kiln Operators and Kiln Supervisors
* testing or proof of adequate completion of training
* ongoing training and support

#### Kiln Operator training

Project Developers are responsible for ensuring regular trainings are provided to Kiln Operators involved in their project. The Kiln Supervisor or the Project Developer may be the party providing training. Training shall cover at least the following aspects of kiln operation:

* safety provisions for operating the kiln
* biomass preparation (drying, eligible biomass size, appropriate size of biomass)
* taking biomass moisture content measurements
* feeding biomass into the kiln to ensure consistent pyrolysis
* rapid quenching
* managing the [biochar sampling procedure](/methodologies/distributed-open-kiln-biochar/sampling-and-measurements#biochar-sampling-procedure)
* use of dMRV

#### Kiln Supervisor training

Project Developers shall justify the expertise and qualifications of Kiln Supervisors. This may be through dedicated training or previous relevant experience. This shall cover at a minimum:

* all points listed above, to be transmitted to Kiln Operators
* biochar amount measurements, including bulk density and moisture content

[^1]: - Rodrigues, L., Budai, A., Elsgaard, L., Hardy, B., Keel, S.G., Mondini, C., Plaza, C., Leifeld, J., 2023. The importance of biochar quality and pyrolysis yield for soil carbon sequestration in practice. European Journal of Soil Science 74, e13396. [https://doi.org/10.1111/ejss.1339](https://doi.org/10.1111/ejss.13396)
    - Rudra, A., Petersen, H.I., Sanei, H., 2024. Molecular characterization of biochar and the relation to carbon permanence. International Journal of Coal Geology 291, 104565. <https://doi.org/10.1016/j.coal.2024.104565>
    - Wang, J., Xiong, Z., Kuzyakov, Y., 2016. Biochar stability in soil: meta-analysis of decomposition and priming effects. GCB Bioenergy 8, 512–523. <https://doi.org/10.1111/gcbb.12266>
    - Sanei, H., Rudra, A., Przyswitt, Z.M.M., Kousted, S., Sindlev, M.B., Zheng, X., Nielsen, S.B., Petersen, H.I., 2024. Assessing biochar’s permanence: An inertinite benchmark. International Journal of Coal Geology 281, 104409. <https://doi.org/10.1016/j.coal.2023.104409>

[^2]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for **a maximum of 6 months operating time or 200 tonnes of biochar**, whichever comes first.

[^3]: Inertinite is a type of maceral. Macerals are the organic compounds in materials like coal and shale, and are extremely permanent. They are analogous to mineral carbon in rocks.

[^4]: * Schmidt, H.-P., Kammann, C., Hagemann, N., Leifeld, J., Bucheli, T.D., Sánchez Monedero, M.A., Cayuela, M.L., 2021. Biochar in agriculture – A systematic review of 26 global meta-analyses. GCB Bioenergy 13, 1708–1730.[ https://doi.org/10.1111/gcbb.12889](https://doi.org/10.1111/gcbb.12889)
    * Joseph, S., Cowie, A.L., Van Zwieten, L., Bolan, N., Budai, A., Buss, W., Cayuela, M.L., Graber, E.R., Ippolito, J.A., Kuzyakov, Y., Luo, Y., Ok, Y.S., Palansooriya, K.N., Shepherd, J., Stephens, S., Weng, Z. (Han), Lehmann, J., 2021. How biochar works, and when it doesn’t: A review of mechanisms controlling soil and plant responses to biochar. GCB Bioenergy 13, 1731–1764.[ https://doi.org/10.1111/gcbb.12885](https://doi.org/10.1111/gcbb.12885)

[^5]: Carbon dioxide removal

[^6]: WBC (2023): World Biochar Certificate – Guidelines for a Sustainable Production of Biochar and its Certification.' Carbon Standards International, Frick, Switzerland, (<http://www.european-biochar.org>), version 1.1 from 20th December 2024. [URL](https://www.carbon-standards.com/en/standards/service-514~production-of-biochar.html).

[^7]: Cornelissen, Gerard, et al. “Emissions and Char Quality of Flame-Curtain “Kon Tiki” Kilns for Farmer-Scale Charcoal/Biochar Production.” *PLOS ONE*, vol. 11, no. 5, 18 May 2016, p. e0154617, [www.ncbi.nlm.nih.gov/pmc/articles/PMC4871524/](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4871524/), <https://doi.org/10.1371/journal.pone.0154617>.

[^8]: Indigenous peoples are defined in the [Glossary](https://docs.rainbowstandard.io/~/changes/180/glossary#general) as people that self-identify as Indigenous and are recognized by others as Indigenous, with historical continuity with pre-colonial societies; distinct languages, customs, and institutions; a strong connection to ancestral lands or territories; and are often governed by customary laws or traditional authorities.

    Local communities are defined in the [Glossary](https://docs.rainbowstandard.io/~/changes/180/glossary#general) as non-Indigenous people with a long-standing connection to a particular rural or semi-rural geographic area; reliance on local natural resources for livelihood; social cohesion or shared cultural traits, though not necessarily Indigenous; living in geographic proximity to a part of the project area, including but not limited to sourcing, production, and/or end use locations.

[^9]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for a maximum of 6 months operating time or 100 tonnes of biochar, whichever comes first.

[^10]: digital monitoring, reporting and verification

[^11]: There is no specific format or template to follow. Exported data must be in a widely usable and accessible format and file type, to ensure that data remain accessible outside of the dMRV platform.

[^12]: Amount of biochar produced **does not need to match exactly** the amount reported as applied within the same monitoring period, as biochar may be stored and applied in a later monitoring period. Cumulative biochar production records must remain consistent with cumulative end-use application records across monitoring periods


# GHG quantification

Calculations of GHG emissions for the baseline and project scenarios shall follow a robust, recognized method and good practice guidance. The overall methodological approach is a comparative life cycle assessment (LCA) at the project-scale, based on [ISO 14064-2:2019](#user-content-fn-1)[^1].

This methodology shall be used in conjunction with the Rainbow modules listed below. **Modules are like mini-methodologies** that only cover a part of the project life-cycle. Combining the relevant modules for a project results in a complete picture of the required data, calculations, monitoring plans, and other information needed for a full GHG quantification.

<table data-view="cards"><thead><tr><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="image">Cover image</th></tr></thead><tbody><tr><td>Processing and energy use</td><td><a href="/pages/BTxxPIM3a4Nai1Wkwu2Y">/pages/BTxxPIM3a4Nai1Wkwu2Y</a></td><td><a href="/files/xqDoBuMbX7fcBqJ8AanC">/files/xqDoBuMbX7fcBqJ8AanC</a></td></tr><tr><td>Transportation</td><td><a href="/pages/VTWdCc7guKu1x0azAizi">/pages/VTWdCc7guKu1x0azAizi</a></td><td><a href="/files/XAxrYlLSh0qtvbDkKkqp">/files/XAxrYlLSh0qtvbDkKkqp</a></td></tr><tr><td>Infrastructure and machinery</td><td><a href="/pages/IwqpSqlee22qTIPti3Sl">/pages/IwqpSqlee22qTIPti3Sl</a></td><td><a href="/files/gE6Zo8o6awA0p9LnSTnF">/files/gE6Zo8o6awA0p9LnSTnF</a></td></tr></tbody></table>

**GHG quantification shall be done separately for each biochar** [**Production Batch**](#user-content-fn-2)[^2], since each batch by definition has distinctly measured biochar carbon characteristics. The GHG quantification results of multiple Production Batches may be combined for one monitoring period.

## System boundary

The system boundary of this quantification section starts at the procurement of biomass feedstock, and ends at the biochar end of life, after accounting for decay and re-emission in its end use application. Biomass feedstock production impacts are excluded because biomass is required to be waste or invasive species, and therefore not allocated any production or cultivation emissions. The system boundary includes the following key steps, also displayed in Figure 1:

* biomass collection
* biomass transport to the kiln
* biomass processing (including but not limited to drying and chipping)
* embodied emissions from manufacturing the kilns, including their shipping to the pyrolysis site and end of life waste treatment
* methane emissions from the pyrolysis process
* biochar transport to the site of use

<figure><img src="/files/979n54WOQXHpbifSoWtu" alt=""><figcaption><p>Figure 1 The system boundary of the distributed biochar quantification is summarized. Processes are grouped and color-coded according to the section below where they are described in detail.</p></figcaption></figure>

Any steps that are fully manual do not incur any GHG emissions. Any steps that would have occurred anyway in the baseline scenario shall be excluded from the system boundary.

The following high-level equations shall be used to calculate carbon removals from distributed biochar projects.

<details>

<summary><strong>Calculations:</strong> Removals</summary>

$$\textbf{(Eq.1)}\ Net\ Removal = R\_{baseline}-R\_{project}-E\_{project}$$

where,

* $$Net\ Removal$$ represents the net removals from the project during the monitoring period, in tonnes of CO$$\_2$$eq. Its sign is positive.
* $$R\_{baseline}$$ represents any baseline GHG removals, representing permanent storage that would have occurred in the absence of the project, in tonnes of CO$$\_2$$eq. Its sign is negative. Its value is zero, as outlined in the [baseline scope](/methodologies/distributed-open-kiln-biochar/eligibility-and-scope#baseline-scope) section.
* $$R\_{project}$$ represents the project's gross GHG removals, in tonnes of CO$$\_2$$eq. Its sign is negative.
* $$E\_{project}$$ represents the project's total induced GHG emissions across the project life cycle, in tonnes of CO$$\_2$$eq. Its sign is positive.

$$\textbf{(Eq.2)}\ E\_{project} = {E}*{project,\ leakage} + E*{project,\ methane}+ {E}*{Transport,\ total}+ E*{infra,\ machinery} + E\_{project,\ processing}$$

where,

* $$E\_{project}$$ was described in Eq. 1.
* $$E\_{project,\ leakage}$$ represents the project's GHG emissions from leakage from use of biomass.
* $$E\_{project,\ methane}$$ represents the total methane emissions from pyrolysis, in tCO$$\_2$$eq, calculated in the [Pyrolysis process](#pyrolysis-process) section below.
* $${E}\_{Transport,\ total}$$ represents the project's GHG emissions from the [Transportation](/modules/transportation) module, including the energy use and embodied emissions involved in transporting all input and output materials.
* $$E\_{infra,\ machinery}$$ represents the total emissions from the [Infrastructure and machinery](/modules/infrastructure-and-machinery) module allocated to the project for the monitoring period.
* $$E\_{project,\ processing}$$ represents the total emissions from other inputs and outputs calculated in the [Processing and energy use](/modules/processing-and-energy-use) module.

***

GHG quantification is performed for each Production Batch, based on the amount of biochar produced, but removal Rainbow Carbon Credits (RCCs) are issued on the basis of biochar delivery and application in an eligible end use. The following equation is used to determine the number of RCCs to issue per monitoring period, accounting for **a potential delay in biochar use after production**. See the [Functional unit](#kpxsamb8logm) section for more details.

$$\textbf{(Eq.3)}\ Removal\ RCCs= \frac{Net\ removal}{tonne\ or\ m^3\ biochar\ produced} \times tonne\ or\ m^3\ biochar\ delivered$$

Where

* $$Removal\ RCCs$$ represents the number of removal credits to be issued at the end of the monitoring period.
* $$Net\ removal$$ was calculated in Eq. 1.
* $$tonne\ or\ m^3\ biochar\ produced$$ represents the amount of **biochar produced** in the entire Production Batch. Project Developers may choose whether to report it by mass or volume, in tonnes or in m<sup>3</sup> of biochar.
* $$tonne\ or\ m^3\ biochar\ delivered$$ represents the amount of **biochar delivered in an eligible end use** in the monitoring period, for the given Production Batch. It must be reported in the same units as for the $$tonne\ or\ m^3\ biochar\ produced$$ variable.

</details>

## Functional unit <a href="#kpxsamb8logm" id="kpxsamb8logm"></a>

The functional unit shall be **1 tonne of biochar produced** or **1 m**<sup>**3**</sup>**&#x20;of biochar produced**, depending on the project's chosen measurement method for the [Biochar amount produced](/methodologies/distributed-open-kiln-biochar/sampling-and-measurements#biochar-amount-produced).

Input data shall be provided for all processes related to biochar production in the given Production Batch, and net project removals are first calculated for **all processes across the entire duration of the Production Batch**.

This is normalized to net removals per functional unit by **dividing by the amount of biochar produced** in the Production Batch.

The number of credits to issue in the given monitoring period is calculated by multiplying the amount of biochar delivered and applied in an eligible end use, by the net removals per tonne or m<sup>3</sup> of biochar produced.

This approach is detailed in Eq. 3 above.

## Data sources <a href="#kpxsamb8logm" id="kpxsamb8logm"></a>

The required **primary data for GHG calculations** from projects are presented in Table 1. These data shall be **aggregated for all kiln runs within a** [**Production Batch**](#user-content-fn-2)[^2], after being measured and reported in dMRV at the frequencies summarized in the [Monitoring](/methodologies/distributed-open-kiln-biochar/principles-and-requirements#monitoring) section, and made publicly available.

Note that the table **does not include all information needed for project monitoring and verification: only the data inputs for ongoing GHG quantification**. The full list of information is provided in the minimum requirements for a [Monitoring Plan](/methodologies/distributed-open-kiln-biochar/principles-and-requirements#monitoring).

*Table 1 Summary of primary data needed from projects and their source for GHG quantification. All primary data sources listed here are required to be monitored and updated during verification. \*Note that only one approach is required for reporting transport data. See the* [*Transportation module*](/modules/transportation) *for more details. \*\*See the* [*Infrastructure and machinery*](/modules/infrastructure-and-machinery#ghg-quantification) *module for more details.*

<table><thead><tr><th width="160.6605224609375">Category</th><th width="209.40625">Parameter</th><th width="159.3359375">Unit</th><th>Source</th></tr></thead><tbody><tr><td>General, credit issuance</td><td>Volume or mass of biochar delivered in permanent end use</td><td>m<sup>3</sup> or tonnes of biochar</td><td>Measured onsite, dMRV</td></tr><tr><td>Carbon storage</td><td>Volume or mass of biochar produced</td><td>m<sup>3</sup> or tonnes of biochar</td><td>Measured onsite, dMRV</td></tr><tr><td>Carbon storage</td><td>Bulk density of biochar (<em>only if using volume</em>)</td><td>tonne of biochar/m<sup>3</sup></td><td>Measured onsite, dMRV</td></tr><tr><td>Carbon storage</td><td>Biochar moisture content (<span class="math">M_{\text{%}}</span>) (<em>only if using mass</em>)</td><td>Percent</td><td>Elemental analysis by accredited laboratory</td></tr><tr><td>Carbon storage</td><td>Biochar <span class="math">H/C_{\text{org}}</span></td><td>Ratio</td><td>Elemental analysis by accredited laboratory</td></tr><tr><td>Carbon storage</td><td>Biochar organic carbon content</td><td>Percent</td><td>Elemental analysis by accredited laboratory</td></tr><tr><td>Carbon storage</td><td>Fraction of <span class="math">R_{O}</span><br>distribution measurements above 2% (<em>only if using 1000-year approach</em>)</td><td>Fraction</td><td>Analysis by accredited laboratory</td></tr><tr><td>Carbon storage</td><td>Residual organic carbon (<span class="math">C_{org,\ f\ residual}</span>) (<em>only if using 1000-year approach</em>)</td><td>Fraction</td><td>Analysis by accredited laboratory</td></tr><tr><td>Carbon storage</td><td><a data-footnote-ref href="#user-content-fn-3">GPS coordinates </a>of biochar spreading sites (for determining soil temperature)</td><td>coordinates</td><td>dMRV</td></tr><tr><td>Biomass leakage</td><td>Carbon sequestration rate (<em>or use default 0.5%)</em></td><td>Percent</td><td>Secondary literature, models</td></tr><tr><td>Pyrolysis process</td><td>Methane emissions rate</td><td>g CH<sub>4</sub>/kg dry biochar</td><td>Analyses from accredited independent provider</td></tr><tr><td>Pyrolysis machinery</td><td><p>Item and material type, material amount,</p><p>item lifetime**</p></td><td><ul><li>kg, tonne, m<sup>3</sup></li><li>years</li><li>e.g. kiln made of 80 kg steel for 5 years</li></ul></td><td>Technical specifications, bill of materials, invoices</td></tr><tr><td>Transport of biomass</td><td>Distance biomass transported by motorized vehicle*</td><td>km</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biomass</td><td>Weight of biomass transported*</td><td>tonne</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biomass</td><td>Vehicle type for biomass transport*</td><td>category</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biomass</td><td>Fuel quantity consumed for biomass transport*</td><td>liters fuel</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biochar</td><td>Distance biochar transported by motorized vehicle*</td><td>km</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biochar</td><td>Weight of biochar transported*</td><td>tonne</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biochar</td><td>Vehicle type for biochar transport*</td><td>category</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biochar</td><td>Fuel quantity consumed for biochar transport*</td><td>liters fuel</td><td>Operational records, conservative justified estimates</td></tr></tbody></table>

The [ecoinvent database](#user-content-fn-4)[^4] version 3.12 (hereafter referred to as ecoinvent) shall be the main source of emission factors unless otherwise specified. Ecoinvent is preferred because it is traceable, reliable, and well-recognized. The ecoinvent processes selected are detailed in [Appendix 1](#appendix).

No other secondary data sources are used in this methodology.

## Assumptions

1. All biochar from the same Production Batch has the same characteristics (e.g. $$M\_{\text{%}}$$, $$H/C\_{\text{org}}$$...).
2. All biochar made from the same feedstock has the same methane emission rate from pyrolysis.
3. The permanent carbon sequestration rate from biomass leakage, where the alternate fate is being left on the field to decompose, is at least 0.5%.

## Baseline scenario <a href="#ly65klblzpa9" id="ly65klblzpa9"></a>

There is no baseline because it is assumed that there is no significant share of the project activity already occurring in business-as-usual. Therefore, the baseline for removal credits is zero and is omitted from calculations.

According to the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/project-and-baseline-scope#updating-the-baseline), this assumption shall be re-assessed at a minimum every 5 years, and any changes to this assumption would be [applied to existing projects](/rainbow-standard-documents/procedures-manual/project-certification-procedure#compliance-and-project-updates).

## Project scenario <a href="#i4figd8ytjua" id="i4figd8ytjua"></a>

### Biomass leakage

#### Counterfactual carbon storage

{% hint style="info" %}
This section is only required if the feedstock's alternative use was to be **left on the soil or reapplied to soils for nutrient recycling**. This includes but is not limited to:

* mulching
* composting
* spreading fast-decaying cellulose-based residues (e.g. decay within 5 years)
  {% endhint %}

Project leakage shall account for permanent carbon storage that would have occurred anyway in the absence of the project.

Although most biomass carbon would be released before the project's permanence horizon, a small fraction may be stabilized permanently as soil carbon. This portion is counted as leakage and deducted from the project's carbon removal capacity.

The uncertainty around biomass carbon being 1) naturally incorporated into the soil and 2) converted to a stable carbon form is high, influenced by factors such as climate, soil type, soil health, and land use, making it hard to estimate for individual projects. Thus, it is assumed that a default **0.5% of the carbon in the biomass feedstock** left on the soil, or reapplied to soil, will be permanently stored in soils.

Project Developers may conduct a project-specific assessment and provide a different carbon sequestration rate, but the final rate used in calculations shall be 0.5% or higher.

#### Biomass diversion and replacement

Leakage associated with the diversion and replacement of the biomass from its alternative use shall be quantified for each biomass used.

Project Developers shall follow the [Alternative use](/methodologies/distributed-open-kiln-biochar/principles-and-requirements#alternative-use) and [Biomass diversion and replacement](/methodologies/distributed-open-kiln-biochar/principles-and-requirements#biomass-diversion-and-replacement) guidelines in the Leakage section to determine the type and amount of replacement/substitute product or process.

Project Developers shall provide a conservative and representative emission factor for the production and use of the replacement product.

<details>

<summary><strong>Calculations:</strong> Biomass leakage, biomass amount, biochar amount</summary>

$$\textbf{(Eq.4)}\ {E}*{project\ leakage}= E*{CF\ carbon\ storage}+ E\_{replacement}$$

Where,

* $$E\_{CF\ carbon\ storage}$$ represents the biomass leakage from the monitoring period, in tCO$$\_2$$eq. This value shall be applied to Equation 2.
* $$E\_{CF\ carbon\ storage}$$ represents the permanent carbon removal in the baseline scenario in the monitoring period, in tCO$$\_2$$eq.
* $$E\_{replacement}$$ represents the leakage emissions from the diversion of biomass and replacement of its substitute, in tCO<sub>2</sub>eq.

$$\textbf{(Eq.5)}\ E\_{CF\ carbon\ storage}= A\_{biomass}\times C\_{biomass} \times S\_{biomass} \times C\ to\ {CO}\_{2}$$

Where,

* $$E\_{CF\ carbon\ storage}$$ was described in Equation 4.
* $$A\_{biomass}$$ represents the amount of biomass feedstock used in the monitoring period, in tonnes of dry matter. It may be **weighed directly** and converted to dry mass using biomass moisture content measurement&#x73;**, or calculated** using Eq. 6 below
* $$C\_{biomass}$$ represents the concentration of carbon in the biomass feedstock, in tonnes of carbon per tonne of dry matter. This value may come from secondary sources.
* $$S\_{biomass}$$ represents the permanent sequestration rate of carbon applied to soils, which may be provided by the Project Developer from secondary sources, but shall be at least 0.5%, as described in the [Assumptions ](#id-4l7lx2ihb6hj)section.
* $$C\ to\ {CO}\_{2}$$ is 44/12 = 3.67, and represents the molar masses of CO$$\_2$$ and carbon respectively, and is used to convert tonnes of carbon to tonnes of CO$$\_2$$eq.

$$\textbf{(Eq.6)}\ A\_{biomass} = A\_{biochar} \div CF\_{biomass\ to\ biochar}$$

Where,

* $$A\_{biomass}$$ was described in Eq. 5.
* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar. It shall be calculated using either Equation 7, 8, or 9, depending on the project's chosen [biochar amount measurement method](/methodologies/distributed-open-kiln-biochar/sampling-and-measurements#amount-of-biochar-produced).
* $$CF\_{biomass\ to\ biochar}$$ represents the biomass to biochar conversion factor, as tonnes fresh biomass input $$\div$$ tonnes dry biochar output. It may be taken from secondary sources or measured for each project, as detailed in the [Sampling and measurements](/methodologies/distributed-open-kiln-biochar/sampling-and-measurements#amount-of-biomass-used) section.

$$\textbf{(Eq.7)}\ A\_{biochar} = V \* BD\_{fresh}\*(1-M\_{fresh%})$$

where,

* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar.
* $$V$$ represents the volume of biochar produced in m<sup>3</sup>.
* $$BD\_{fresh}$$ represents the bulk density of fresh biochar (as opposed to dry biochar), considering the mass of fresh biochar, in tonnes biochar/m<sup>3</sup>.
* $$M\_{fresh%}$$ represents the moisture content of fresh biochar, on a weight basis (%w/w), so $$1-M\_{fresh%}$$ converts to dry mass of biochar.

$$\textbf{(Eq.8)}\ A\_{biochar} = mass\_{fresh}\*(1-M\_{fresh%})$$

where,

* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar.
* $$mass\_{fresh}$$ represents the mass of fresh or quenched biochar directly measured with scales at each kiln, in tonnes.
* $$M\_{fresh%}$$ represents the moisture content of fresh biochar, on a weight basis (%w/w), so $$1-M\_{fresh%}$$ converts to dry mass of biochar.

$$\textbf{(Eq.9)}\ A\_{biochar} = mass\_{bone\ dry}$$

where,

* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar.
* $$mass\_{bone\ dry}$$ represents the mass of dry biochar directly measured with scales at each kiln, in tonnes. Since it is measured on biochar immediately after exiting the kiln, it is assumed to be bone dry (i.e. 0% moisture content).

$$\textbf{(Eq.10)}\ E\_{replacement}=A\_{biomass}*F\_{conversion}* EF\_{alternative \ use}$$

where,

* $$E\_{replacement}$$ was described in Equation 4.
* $$A\_{biomass}$$ was calculated in Eq. 5.
* $$F\_{conversion}$$ represents a conversion factor for biomass replacement of its substitute.
* $$EF\_{alternative \ use}$$ represents the conservative and representative emission factor for the replacement product of the biomass, in tCO<sub>2</sub>eq/appropriate unit.

</details>

### Biomass processing

The Rainbow [Processing and energy use](/modules/processing-and-energy-use) module shall be used to quantify the emissions from energy or material use for preparing biomass for pyrolysis. This includes but is not limited to drying and chipping biomass.

### Transport of biomass and biochar

If biomass is transported to a pyrolysis site, or biochar is transported to its end-use point, using **a vehicle that is not manually powered**, transport emissions shall be accounted for using the [Transportation module](/modules/transportation) to calculate $${E}\_{Transport,\ total}$$ used in Eq. 2.

For this distributed small-scale technology type, it is expected that direct proof of transport will be unavailable (e.g., distance transported or fuel use during delivery). Therefore, Project Developers may provide **justified and conservative estimates** of transport distance, fuel consumed, and transport method.

### Pyrolysis process

Methane emissions from pyrolysis shall be accounted for using direct methane measurements on a subset of representative kiln runs, following the [Sampling and measurements](/methodologies/distributed-open-kiln-biochar/sampling-and-measurements#methane-emissions) requirements, and using the following equations.

<details>

<summary><strong>Calculations</strong>: Pyrolysis methane emissions</summary>

$$\textbf{(Eq.11)}\ {E}*{project,\ methane}= A*{biochar}\* E\_{bioCH\_4}\div 1000\*GWP\_{bioCH\_4}$$

Where,

* $$E\_{project,\ methane}$$ represents the total methane emissions from pyrolysis, in tCO$$\_2$$eq. It shall be used in Equation 2.
* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar. It shall be calculated using either Equation 7, 8, or 9, depending on the project's chosen [biochar amount measurement method](/methodologies/distributed-open-kiln-biochar/sampling-and-measurements#biochar-amount-produced).
* $$E\_{bioCH\_4}$$ represents the emission rate of biogenic methane from the pyrolysis process, in gCH<sub>4</sub>/kg dry biochar, measured according to the [Sampling and Measurement ](/methodologies/distributed-open-kiln-biochar/sampling-and-measurements#methane-emissions)requirements.
* $${GWP}\_{bio\ CH4}$$ represents the global warming potential of biogenic CH$$\_4$$ over 100 years, which is 27[^5] tCO$$\_2$$eq/t CH$$\_4$$.
* Divided by 1000 to convert from gCH<sub>4</sub>/kg dry biochar to tonne CH<sub>4</sub>/tonne dry biochar.

</details>

### Infrastructure and machinery

The Rainbow [Infrastructure and machinery module](/modules/infrastructure-and-machinery) shall be used to quantify the embodied emissions of kilns.

### Biochar carbon storage

Project Developers shall choose between one of two approaches to quantify the gross carbon removals from their biochar product, as described in the [Durability](/methodologies/distributed-open-kiln-biochar/principles-and-requirements#lc9eewbyvlyk-1) section. A single approach must be used consistently throughout each monitoring period, though a different approach may be chosen for subsequent monitoring periods.

1. Modeling 100-year removals using bulk measurements of $$H/C\_{\text{org}}$$, or
2. Estimating 1000-year removals using random reflectance measurements as proxies for inertinite.

#### Approach 1: Modeling 100-year removals using bulk measurements of $$H/C\_{\text{org}}$$ <a href="#id-2rhx2av7of74" id="id-2rhx2av7of74"></a>

Project Developers shall quantify the gross carbon removals from their biochar project by modeling 100-year removals using bulk measurements of $$H/C\_{\text{org}}$$. These measurements shall be done once per [Production Batch](#user-content-fn-2)[^2]. The measurements shall be done on the **Production Batch Representative Sample**, mixing biochar from each kiln run. See [Sampling and measurements](/methodologies/distributed-open-kiln-biochar/sampling-and-measurements) for more details.

This approach is based on research from [Woolf et al., 2021](#user-content-fn-6)[^6], and the [IPCC modeling method](#user-content-fn-7)[^7]. It is rooted in soil ecology and soil biochemistry disciplines. The **permanent fraction** of biochar carbon remaining after 100 years ($$F\_{\text{perm 100}}$$) is modeled according to the local average annual temperature.

Temperature shall be obtained in the following ways:

* Biochar application to soil or mixing into horticultural products: Soil temperature shall be obtained for the end use location of each biochar spreading or mixing event, using the GPS coordinates provided in the Verification of end use report and the global soil temperature dataset from [Lembrechts et al., 2021](#user-content-fn-8)[^8]. The Rainbow Certification Team can provide soil temperature values for Project Developers based on the provided GPS coordinates.
* Biochar mixing into concrete: Average annual air temperature at the location where biochar is mixed into concrete shall be used. It shall be taken from reputable public databases.

*Table 2 Soil temperature ranges are categorized and their corresponding c and m regression coefficients are presented, which are used in Eq. 10 below to calculate* $$F\_{perm}$$. *Values are taken from* [*Woolf et al., 2021*](#user-content-fn-6)[^6]*.*

| Soil temperature (°C) | c    | m    |
| --------------------- | ---- | ---- |
| <7.49                 | 1.13 | 0.46 |
| 7.5-12.49             | 1.10 | 0.59 |
| 12.5-17.49            | 1.04 | 0.64 |
| 17.5-22.49            | 1.01 | 0.65 |
| >22.5                 | 0.98 | 0.66 |

<details>

<summary><strong>Calculations:</strong> Biochar carbon storage</summary>

$$\textbf{(Eq.12)}\ F\_{perm\ 100} = c - m\*H/C\_{org}$$

where,

* $$F\_{perm\ 100}$$ represents the fraction of biochar carbon remaining after 100 years
* $$c$$ and $$m$$ represent regression coefficients, taken from [Woolf et al., 2021](#user-content-fn-6)[^6], and summarized in Table 2 for the corresponding project location's soil or air temperature.
* $$H/C\_{org}$$ represents the ratio of molar hydrogen to organic carbon in biochar, measured via elemental analysis by an accredited laboratory for each production batch.

$$\textbf{(Eq.13)}\ R\_{project}= F\_{perm\ 100}\*{C\_{org}*A}*{biochar}\*C\ to\ {CO}*{2}*-1$$

where,

* $$R\_{project}$$ represents the total carbon removals from biochar during the monitoring period, in tonnes of CO$$\_2$$eq. This value shall be applied to Equation 1 to calculate total project removals.
* $$F\_{perm\ 100}$$ is calculated in Equation 12.
* $$C\_{org}$$ represents the concentration of organic carbon in biochar, on a dry weight basis.
* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar. It is obtained using Equation 7, 8, or 9, depending on the project's chosen measurement method.
* $$C\ to\ {CO}\_{2}$$ is 44/12 = 3.67, and represents the molar masses of CO$$\_2$$ and C respectively, and is used to convert tonnes C to tonnes of CO$$\_2$$eq.
* It is multiplied by -1 to obtain a negative sign. Removals are reported as a negative value.

</details>

#### Approach 2: Estimating 1000-year removals based on inertinite fraction <a href="#id-2rhx2av7of74" id="id-2rhx2av7of74"></a>

This approach is based on the research from [Sanei et al., 2024](#user-content-fn-9)[^9], and is rooted in the organic petrology and geochemistry disciplines. This approach is built upon research showing that fractions of inertinite in biochar samples are:

* [inert and permanent](#user-content-fn-10)[^10] and will not re-release their carbon for at least 1000 years.
* represented by the fraction of residual (i.e. not reactive, not labile) organic carbon in the sample with a Random Reflectance ($$R\_o$$) of [2% or higher](#user-content-fn-9)[^9].

Project Developers shall provide $$R\_o$$ distribution, [labile organic carbon content](#user-content-fn-11)[^11], and moisture content for biochar from each [Production Batch](#user-content-fn-2)[^2], following the [Sampling requirements](/methodologies/distributed-open-kiln-biochar/sampling-and-measurements#biochar-sampling-procedure).

To determine the inertinite fraction of the biochar's organic carbon, first the labile carbon fraction is measured and subtracted from total organic carbon content, and only the residual organic carbon content is considered.

Next, random reflectance measurements are used to determine the fraction of residual organic carbon that is classified as inertinite:

* The fraction of the distribution with an $$R\_o$$ **above 2%** represents the fraction of the biochar carbon that is stored permanently for 1000 years.
* The fraction of the distribution with an $$R\_o$$ **below 2%** represents the fraction of biochar carbon that is not permanently stored, and for which no removal RCCs are issued.

$$R\_o$$ distribution shall be based on at least 500 measurements, yielding a frequency distribution diagram similar to the examples in Figure 2a and 2b.

![Figure 2a An example of a random reflectance frequency distribution diagram, with an analysis described below.](/files/RvDwkJem5UkBnsnCmFSv)

{% hint style="info" %}
Example 1: This biochar sample has heterogenous quality and a wide distribution of $$R\_o$$ measurements. The biochar sample has:

* labile organic carbon content of 5%,
* residual organic carbon content of 95%,
* mean $$R\_o$$ of 2.12, and
* 72% of the $$R\_o$$ measurements are above the 2% inertinite threshold.

Therefore, this biochar sample has an $$F\_{\text{perm\ 1000}}$$ of $$0.72 \times 0.95=0.684$$ , so 68.4% of the organic carbon in the sample will be converted to CO$$\_2$$eq and considered as 1000-year carbon removals. The remaining 31.6% of carbon is assumed to decompose within the 1000-year permanence horizon, and is not considered for any removal RCCs.
{% endhint %}

![Figure 2b An example of a random reflectance frequency distribution diagram, with an analysis described below.](/files/zys8iUA26XGiah6RpKoc)

{% hint style="info" %}
Example 2: This biochar sample has more homogenous quality and a narrow distribution of $$R\_o$$ measurements. The biochar sample has:

* labile organic carbon content of 1%
* residual organic carbon content of 99%
* mean $$R\_o$$ of 2.32, and
* 95% of the $$R\_o$$ measurements are above the 2% inertinite threshold.

Therefore, this biochar sample has an $$F\_{\text{perm\ 1000}}$$ of $$0.99\*0.95=0.94$$, so 94% of the organic carbon in the sample will be converted to CO$$\_2$$eq and considered as 1000-year carbon removals. The remaining 6% of carbon is assumed to decompose within the 1000-year permanence horizon, and is not considered for any removal RCCs.
{% endhint %}

<details>

<summary><strong>Calculations: 1000-year removal credits with random reflectance</strong></summary>

$$\textbf{(Eq.14)}\ F\_{perm\ 1000} = {Sample\ fraction}*{> 2%\ Ro} \times C*{org,\ f\ residual}$$

where,

* $$F\_{perm\ 1000}$$ represents the fraction of biochar carbon remaining after 1000 years.
* $${Sample\ fraction}\_{> 2%\ Ro}$$ represents the fraction of the distribution sample that has a random reflectance ($$R\_O$$) of 2% or higher.
* $$C\_{org,\ f\ residual}$$ represents the fraction of the biochar organic carbon that is residual carbon, as opposed to reactive/labile organic carbon. It may be measured and reported directly, or obtained by subtracting measured *reactive* carbon from 100.

$$\textbf{(Eq.15)}\ R\_{project,\ 1000}=F\_{perm\ 1000}\*{C\_{org}*A}*{biochar}\*C\ to\ {CO}*{2}*-1$$

where,

* $$R\_{project,\ 1000}$$ represents the total carbon removals from biochar during the monitoring period, in tonnes of CO$$\_2$$eq. This value shall be applied to Equation 1 to calculate overall project removals.
* $$F\_{perm\ 1000}$$ is calculated in Equation 14.
* $$C\_{org}$$, $$A\_{biochar}$$ and $$C\ to\ {CO}\_{2}$$ are described in Equation 13.
* It is multiplied by -1 to obtain a negative sign. Removals are reported as a negative value.

</details>

## Uncertainty assessment <a href="#dk35zb8m2b1p" id="dk35zb8m2b1p"></a>

An uncertainty assessment is presented below for all aspects of GHG quantification set **at the methodology level**. The findings from this assessment are then applied **at the project level**, where project-specific GHG quantification also undergoes an uncertainty assessment.

The **overall project GHG quantification uncertainty** is determined by qualitatively combining both the methodology-level and project-specific uncertainties for each identified source of uncertainty.

The uncertainty of [assumptions](#assumptions) are assessed below:

| Assumption                                                                                                                                   | Uncertainty                                                                                                                                                                                |
| -------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| All biochar from the same Production Batch has the same characteristics (e.g. $$M\_{\text{%}}$$, $$H/C\_{\text{org}}$$, inertinite content). | In principle this assumption has low uncertainty, but the ability of Kiln Operators to maintain consistent pyrolysis conditions across sites and across kiln runs is moderately uncertain. |
| All biochar made from the same feedstock has the same methane emission rate from pyrolysis.                                                  | In principle this assumption has low uncertainty, but the ability of Kiln Operators to maintain consistent pyrolysis conditions across sites and across kiln runs is moderately uncertain. |
| The permanent carbon sequestration rate from biomass leakage, where the alternate fate is being left on the field to decompose, is 0.5%.     | High uncertainty, but the total net project removals is not sensitive to this assumption, so a low overall impact.                                                                         |

The equations and models have moderate uncertainty. The model for 100-year permanence from [Woolf et al., 2021](#user-content-fn-6)[^6] has high uncertainty because it is a model fitted to experimental data, which always introduces variability. The equations for 1000-year permanence from [Sanei et al., 2024](#user-content-fn-12)[^12] have low uncertainty because they are basic conversion equations.

Estimates may be used for the amount of processing and energy use inputs and the transport steps, rather than providing direct proof of each step. This is expected to introduce negligible to moderate uncertainty, depending on the level of justification provided for each project. For example, it may be negligible if the process is entirely manual/not motorized, requiring no transport or energy inputs. The uncertainty of these estimates and specific input data shall be assessed at the project level.

The uncertainty at the methodology level of the above-mentioned points are estimated to be moderate. This translates to a **minimum discount factor of at least 6%** for projects under this methodology.

[^1]: ISO 14064-2:2019. Greenhouse gases — Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements.

[^2]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for **a maximum of 6 months operating time or 200 tonnes of biochar**, whichever comes first.

[^3]: The coordinates are used by Rainbow Certification Team to obtain the average soil temperature (°C) where the biochar is spread.

[^4]: Wernet, G., Bauer, C., Steubing, B., Reinhard, J., Moreno-Ruiz, E., Weidema, B., 2016. The ecoinvent database version 3 (part I): overview and methodology. Int J Life Cycle Assess 21, 1218–1230. <https://doi.org/10.1007/s11367-016-1087-8>

[^5]: Intergovernmental Panel on Climate Change 2021. Chapter 7: The Earth’s Energy Budget, Climate Feedbacks, and Climate Sensitivity. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, doi:10.1017/9781009157896.009.

[^6]: Woolf, D., Lehmann, J., Ogle, S., Kishimoto-Mo, A.W., McConkey, B., Baldock, J., 2021. Greenhouse Gas Inventory Model for Biochar Additions to Soil. Environmental Science & Technology 55, 14795–14805.[ https://doi.org/10.1021/acs.est.1c02425](https://doi.org/10.1021/acs.est.1c02425)

[^7]: IPCC 2019. Appendix 4 Method for Estimating the Change in Mineral Soil Organic Carbon Stocks from Biochar Amendments: Basis for Future Methodological Development. 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 4 Agriculture, Forestry and Other Land Use. [URL](https://www.ipcc-nggip.iges.or.jp/public/2019rf/pdf/4_Volume4/19R_V4_Ch02_Ap4_Biochar.pdf).

[^8]: Lembrechts et al., Global maps of soil temperature (2021). Global Change Biology. DOI: [10.1111/gcb.16060](https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16060). [URL](https://zenodo.org/records/7134169).

[^9]: Sanei, H., Rudra, A., Przyswitt, Z.M.M., Kousted, S., Sindlev, M.B., Zheng, X., Nielsen, S.B., Petersen, H.I., 2024. Assessing biochar’s permanence: An inertinite benchmark. International Journal of Coal Geology 281, 104409[ https://doi.org/10.1016/j.coal.2023.104409](https://doi.org/10.1016/j.coal.2023.104409)

[^10]: International Committee for Coal and Organic Petrology (ICCP), 2001. The new inertinite classification (ICCP System 1994). Fuel 80, 459–471.[ https://doi.org/10.1016/S0016-2361(00)00102-2](https://doi.org/10.1016/S0016-2361\(00\)00102-2)

[^11]: determined by e.g. thermogravimetric analysis (TGA) or Rock-Eval 6

[^12]: Sanei, H., Rudra, A., Przyswitt, Z.M.M., Kousted, S., Sindlev, M.B., Zheng, X., Nielsen, S.B., Petersen, H.I., 2024. Assessing biochar’s permanence: An inertinite benchmark. International Journal of Coal Geology 281, 104409 <https://doi.org/10.1016/j.coal.2023.104409>


# Sampling and measurements

A summary of measurements and their frequency is outlined in the table below. See each corresponding section for more details.

<table><thead><tr><th width="229">Measurement frequency</th><th>Parameters</th></tr></thead><tbody><tr><td><strong>Each</strong> <a data-footnote-ref href="#user-content-fn-1"><strong>Production Batch</strong></a><strong>, on a single representative sample of biochar</strong></td><td><ul><li><span class="math">H/C_{\text{org}}</span> and organic carbon content (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li><li>Inertinite content (fraction of the distribution sample that has a random reflectance of 2% or higher) and residual carbon (<em>if calculating 1000-year removals</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li><li>Biochar moisture content, on at least 3 biochar samples (<em>if measuring biochar amount via mass</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-mass">here</a>)</li></ul></td></tr><tr><td><strong>Once per year, or anytime biomass feedstock changes</strong></td><td><ul><li>Methane emissions, on three runs representative of all other kilns in the same Production Batch (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#methane-emissions">here</a>)</li><li>Environmental pollutants of biochar, on one composite sample mixing biochar from each kiln run (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#biochar-requirements">here</a>)</li><li>Dry bulk density of biochar, on at least one sample from each kiln (i.e. 20 different kilns, 20 bulk density measurements) (<em>if measuring biochar amount via volume</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-volume">here</a>)</li><li>Biomass to biochar conversion factor (<em>if <strong>not</strong> weighing the biomass input of each kiln run)</em> (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biomass-amount-used">here</a>)</li><li>Updated biomass leakage assessment (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#leakage">here</a>)</li></ul></td></tr><tr><td><strong>Each kiln run</strong></td><td><ul><li>Moisture content of biomass input (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#moisture-content-of-biomass">here</a>)</li><li>Type of biomass input (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biomass-used">here</a>)</li><li>Amount of biomass input, via precise mass measurements if using a feedstock mix, or estimates if using a singular biomass (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biomass-amount-used">here</a>)</li><li>Mass or volume of fresh biochar produced (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biochar-produced">here</a>)</li><li>Temperature curve measured in each kiln using real-time sensors, proving pyrolysis has occurred (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#temperature-curves">here</a>)</li><li>Photographs of the pyrolysis process, showing for example a lack of white smoke and ash, and the duration of the kiln run (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#quality-and-oversight">here</a>)</li><li>Sampling records (proof of setting aside a small sub-sample of biochar, to be combined with sub-samples from all other kiln runs in the same Production Batch) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li></ul></td></tr><tr><td><strong>All biochar used</strong></td><td><ul><li>Proof of eligible, durable biochar end use, with names and GPS coordinates of spreading locations, among other information (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#id-5a8ye61po9ri">here</a>)</li></ul></td></tr><tr><td><strong>Once per year</strong></td><td><ul><li>Kiln Operator training (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#trainings">here</a>)</li><li>Proof and findings from the visits of Kiln Supervisor to each Kiln Operator (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#kiln-supervisor-site-visits">here</a>)</li><li>Proof of calibration and accuracy of onsite scales for weighing biochar to determine biochar amount (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biochar-produced">here</a>)</li></ul></td></tr><tr><td><strong>Once per verification and credit issuance</strong></td><td><ul><li>Quality oversight report from the Project Developer (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#quality-oversight-report">here</a>)</li><li>Environmental sustainability and Leakage compliance of biomass feedstock (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#biomass-requirements">here </a>and <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#leakage">here</a>)</li></ul></td></tr></tbody></table>

## Production Batch definition <a href="#id-2xck12gc2auz" id="id-2xck12gc2auz"></a>

A Production Batch is defined as the **biochar produced across multiple sites and kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve**. See the [Eligible biomass feedstock](/methodologies/distributed-open-kiln-biochar/eligibility-and-scope#eligible-biomass-feedstock-open) section for requirements on single and mixed feedstock definitions.

It is assumed that all biochar from the same Production Batch has the same characteristics. The definition of **production batch is used to group the following measurements:** $$H/C\_{\text{org}}$$, organic carbon content, inertinite content (optional), and methane emissions.

{% hint style="info" icon="lightbulb-gear" %}
A Production Batch is **an accounting construct** used to group and track biochar produced under consistent conditions, rather than a discrete operational event. It represents a defined set of kiln runs sharing the same feedstock type, kiln type, and pyrolysis parameters, allowing that biochar to be characterized, sampled, and credited collectively.
{% endhint %}

**GHG quantification shall be done separately for each biochar** [**Production Batch**](#user-content-fn-2)[^2], since each batch by definition has distinctly measured biochar carbon characteristics. The GHG quantification results of multiple Production Batches may be combined for one monitoring period and credit issuance.

A Production Batch is valid for **a maximum of 6 months operating time or 200 tonnes of biochar**, whichever comes first. After this period or mass threshold, the biochar is considered part of a new Production Batch, even if conditions remain unchanged. This means that after 6 months of operating time, the Production Batch ID resets, a new batch is created, and new monitoring requirements apply, regardless of whether 200 tonnes have been produced or if feedstock or pyrolysis conditions have changed.

Where a project operates many kilns, Project Developers may choose how to designate subgroups of kilns that each contribute to their own distinct Production Batches. This allows projects to manage Production Batch validity periods more effectively, avoiding a situation where all kilns in a large project are tied to a single batch that reaches its validity limits quickly.

Note that the 6-month validity clock runs on operating time. Production pauses during the rainy season do not count toward the 6-month limit, provided the 200-tonne threshold has not been reached.

A 5-tonne tolerance buffer is allowed, permitting a Production Batch to reach up to 205 tonnes. This accounts for the on-the-ground challenges of predicting precise biochar output across multiple kilns over an extended period.

{% hint style="info" %}
For example,

* A small project may only produce 200 tonnes of biochar evenly throughout the year. A new Production Batch would start at the 6-month mark, and biochar would start being added to a new Site Composite Biochar Pile.
* A larger project may produce a total of 1200 tonnes of biochar per year, with a total of 100 tonnes/month across all 10 kilns in the project, and 10 tonnes/month/kiln, operating year-round. The Project Developer could either:
  * keep all 10 kilns grouped together, and reach the 200 tonne mark within 2 months. This would result in 6 Production Batches in the year. Or,
  * split the kilns into two groups of 5 kilns each, and reach the 200 tonne mark for each group within 4 months. Two distinct production batches would be produced in parallel. They reset after 4 months, 3 times per year, for a total of 6 Production Batches.
* A different project may produce 50 tonnes of biochar in January and February, then stop production for 5 months, and produce another 50 tonnes in August. The biochar produced in August may be grouped with the biochar produced at the beginning of the year in the same Production Batch, since the delineation is 6-months of operating time, not 6 calendar months.
  {% endhint %}

Production Batches **may be non-contiguous**.

{% hint style="info" %}
For example, if Feedstock #1 if used on Day 1, a different Feedstock #2 on Day 2, and Feedstock #1 is used again on Day 3, the resulting biochar from Day 3 could be part of the same Production Batch as the biochar produced on Day 1.
{% endhint %}

## Methane emissions

Methane emissions shall be measured **anytime the biomass feedstock or feedstock mix changes, or annually if the biomass feedstock does not change**. See the [Feedstock composition and consistency](/methodologies/distributed-open-kiln-biochar/eligibility-and-scope#feedstock-composition-and-consistency) section for the definition of a feedstock change.

Measurements shall be conducted on three runs across three separate kilns of the same technology type and using the same feedstock, operated by different kiln operators where more than three operators are active in the project.

Methane emissions testing, including results and photos of the process, may be handled in the dMRV app or in a separate report shared with Rainbow and the VVB.

Methane emissions shall be reported in kg CH<sub>4</sub>/kg biochar. The **mean of all measurements plus one standard deviation** shall be used for [GHG quantification](/methodologies/distributed-open-kiln-biochar/ghg-quantification#pyrolysis-process) of all biochar produced in that year using the same biomass feedstock, and shall remain representative of all kiln runs provided that:

* the kiln type is the same,
* the biomass feedstock type remains the same, and
* biomass moisture content requirements are met for the methane-testing kiln runs, and are representative of expected moisture content during ongoing kiln runs (mean <20% for woody biomass; <15% for all other biomass; no individual measurement above 25%).

#### Measurement timing

Methane emission measurements shall be conducted once per 12-month period. Measurements must be completed before credits can be issued for any biochar produced within that period, but **may be conducted at any point during the 12-month period** to which they apply.

If the representativeness conditions listed above are met, **measurement results may be applied both retroactively and prospectively** to kiln runs within the same 12-month period.

{% hint style="info" %}
For example, if biochar is produced from January through March, production then pauses, and resumes in November using the same biomass feedstock, kiln type, and operators, methane measurements from November may be applied to biochar produced in March of the same period.

Credits for the January-March biochar cannot be issued in March because methane emission measurements would not be available at that time, but may be issued after the November measurement campaign, if adequate production records have been maintained demonstrating all representativeness conditions are satisfied.
{% endhint %}

#### **Measurement approaches**

Methane measurements for open kilns shall be done using the **carbon mass balance approach**, as described in [scientific publications](#user-content-fn-3)[^3] and summarized below.

The difference in the mass of known carbon input (via biomass) and output (in the form of biochar) is assumed[^4] to be emitted as gas. The concentrations of CH<sub>4</sub>, CO, CO<sub>2</sub>, and other carbon-containing species are measured continuously throughout the kiln run, using instruments including but not limited to non-dispersive infrared (NDIR) sensors. The total amount of each gas species is calculated by multiplying the relative fraction of each species by the total mass of carbon-containing gas emitted.

This approach does not require measurement of gas flow rate and is therefore the only feasible method for open kilns, where gas emissions are diffuse and not contained in a defined duct or stack.

Gas concentration measurements shall

* be taken across the entire kiln run, from start up through the end of quenching (if applicable),
* be conducted by an independent measurement provider with demonstrated technical competence in field emissions measurement, and
* use instruments calibrated in accordance with manufacturer specifications and [relevant ISO standards](#user-content-fn-5)[^5] for the gas species being measured.

Proof of calibration and a measurement report signed by the independent provider must be provided.

## Biomass

### Biomass moisture content

Kiln operators shall demonstrate that for each kiln run, the average moisture content of biomass is:

* <20% (w/w) for woody biomass, or
* <15% (w/w) for any other biomass, including any mixture with non-woody biomass.

These thresholds serve two purposes:

* ensuring that pyrolysis **methane emissions remain consistently low**, and
* ensuring that annual methane emission measurements (conducted under the same moisture conditions) **remain representative** of all credited kiln runs.

These thresholds are based on research[^6] demonstrating that below 15% moisture content, all biomass types produce reliably low methane emissions, and that for woody biomass specifically, methane emissions remain consistently low at moisture contents up to 20%.

Moisture content shall be measured using a calibrated handheld moisture meter immediately prior to pyrolysis. A photograph of each sensor reading must be uploaded to the dMRV platform as evidence.

Measurements shall be taken at a rate of one measurement per 100 kg of dried, ready-to-pyrolyze feedstock, with a minimum of 10 measurements per kiln run. Measurement points shall be evenly distributed across the biomass pile, covering both its surface area and depth. The mean of all measurements must not exceed the applicable threshold above, and no individual measurement shall exceed 25%.

### Biomass amount used

The amount of biomass used serves two purposes:

* quantifying counterfactual biomass carbon storage, where applicable, and
* providing a rough validation check on the photographed biomass quantity against the reported biochar output.

It shall be determined for each kiln run using one of the following approaches:

* **Direct weighing** of biomass inputs for each kiln run, with moisture content subtracted using the biomass moisture content measurements.
* **Calculation** by dividing the dry mass of biochar produced by a feedstock-specific biochar yield conversion ratio.

Where the calculation approach is used:

* **Amount of biochar produced** may be provided by weighing directly as dry mass, or derived from volume or quenched mass measurements using Equation 6 or 7 in the [GHG quantification](/methodologies/distributed-open-kiln-biochar/ghg-quantification#calculations-biomass-leakage) section.
* The **yield conversion ratio** may be drawn from reputable and transparent secondary sources, and must correspond to the project's specific configuration of kiln type, feedstock type, pyrolysis temperature, and duration. Where no suitable secondary values exist, the ratio shall be measured across at least three representative kiln runs.

## Biochar

### Biochar sampling procedure

Kiln Operators and Kiln Supervisors shall follow the general biochar sampling procedure outlined below:

{% stepper %}
{% step %}
**Each kiln run**

After each kiln run at a given site, a defined quantity of biochar is set aside from that run, and added to the **Site Composite Pile**. The Kiln Operator continuously adds biochar subsamples to this single site-level pile throughout the entire Production Batch duration. The Site Composite Pile is stored in a protected and dry space.
{% endstep %}

{% step %}
**Mixing the site's biochar, once per Production Batch**

The Site Composite Pile shall be thoroughly mixed by the Kiln Operator to ensure homogeneity. Once per Production Batch, a representative sample of biochar is then taken from this mixed site-level pile by the Kiln Operator or the Kiln Supervisor. This is called the **Site Composite Sample**.
{% endstep %}

{% step %}
**Combining all sites' biochar, once per Production Batch**

The Site Composite Samples are combined from each site into a **Production Batch Composite Pile** representing biochar production across all sites for the Production Batch.
{% endstep %}

{% step %}
**Taking a representative sample**

The Production Batch Composite Biochar Pile is thoroughly mixed by the kiln supervisor, and a representative sample— the **Production Batch Representative Sample**— is taken and sent to an accredited laboratory for measurement of organic carbon content, permanence indicators (i.e. H/C ratio and/or inertinite content), and, once per year, environmental pollutants.
{% endstep %}
{% endstepper %}

Biochar from all kiln runs throughout the entire Production Batch duration must be added to the Site Composite Pile before the composite sample is taken and sent for laboratory analysis. The Site Composite Sample may only be taken once the Production Batch is complete, either at the end of the 6-month validity period or upon reaching the 200-tonne threshold. Taking the sample earlier, while kiln runs are still ongoing, would mean the sample is not representative of all biochar in the batch.

Specific protocols within this approach may vary depending on the project type and the kiln size. The [**suggested detailed approach**](#user-content-fn-7)[^7] is provided below, but Project Developers may propose their own approach if it:

* is detailed in the PDD;
* ensures one homogenized and representative composite sample per Production Batch;
* describes the amount and frequency of subsamples and composite samples.

The VVB and the Rainbow Certification team must validate the rigor and representativeness of the proposed sampling approach.

Records shall be uploaded to dMRV at each step, and track the date and time, location, the kiln ID/QR code, the Production Batch ID/QR code, and visual proof of the steps taken.

#### Suggested detailed biochar sampling approach

* **Sampling each kiln run for Site Composite Pile:** Set aside a biochar sub-sample from each kiln run, by taking a small amount from 3 different spots in the biochar from the most recent kiln run. Continuously add these small samples to the Site Composite Pile throughout the Production Batch.
* **Mixing for Site Composite Sample:** Grind the biochar to a size of approximately <3 mm. Mix the ground sample by shoveling the pile three times from one pile to another. A sub-sample is taken from 10 spots in the mixed pile. The 10 sub-samples are re-combined, and then mixed by shoveling the pile three times from one pile to another. From the mixed pile of the combined sub-samples, 10 subsamples should be taken at 10 different spots in the pile and combined. The remaining biochar in the Site Composite Pile may be used in an eligible permanent end use and credited.
* **Mixing for Production Batch Composite Biochar Pile:** Collect all Site Composite Samples from different sites grouping their biochar into the same Production Batch. Combine all Site Composite Samples into one pile. Shovel the pile three times from one pile to another. Take a sub-sample of from 15 spots in the mixed pile. The 15 sub-samples are re-combined, and then mixed by shoveling the pile three times from one pile to another.
* **Taking a representative sample:** From the mixed pile of the combined sub-samples, 10 subsamples should be taken at 10 different spots in the pile and combined. This final sample is the Production Batch Representative Sample, and shall be sent to an accredited laboratory for measurement of organic carbon content, permanence indicators (i.e. H/C ratio and/or inertinite content) and environmental pollutants.
* **Maintain a Retention sample**: Keep the remaining biochar in the Production Batch Composite Pile in a protected area, separate from all other Production Batch Composite Piles, to be used as the retention sample. Retention samples must be stored for a minimum of two years.

### Biochar amount produced

Project Developers shall choose one of the two following approaches for measuring the amount of biochar produced: **volume or mass**. The same measurement approach shall be used for all biochar, across all kilns for a given Production Batch. The options are outlined in the figure below, and detailed in the following sections.

<figure><img src="/files/q1QedRtEgoGVDARkNx43" alt=""><figcaption></figcaption></figure>

#### Biochar volume

Volume of biochar must be converted to mass of biochar, because laboratory measurements of organic carbon content and are provided on a dry w/w% basis (i.e. in g organic carbon/kg dry biochar). Biochar volume is **converted to dry mass using dry bulk density measurements**, which require **a critical biochar drying step**. All components are detailed below.

* **Volume:** Project Developers shall establish a standardized container type (e.g. box or bag, rigid or loose material) for use across all project sites. All container volumes shall be predefined and tracked in dMRV. Kiln Operators must record the number of containers filled with biochar and applied to permanent end uses. Biochar volume must be measured for each kiln run.
* **Dry bulk density**: Onsite measurements are required for bulk density and shall be conducted by the Kiln Supervisor. As part of their annual site visit, they shall collect a representative sample from the [Site Composite Pile](#user-content-fn-8)[^8] at each site. One biochar bulk density measurement must be established for each site per year, unless the feedstock changes. The dry mass of the sample for the bulk density measurement shall be obtained using one of the following methods:
  * Directly weigh bone-dry biochar upon exit from the kiln. Since this does not involve mixing a composite and representative sample, it must be done on at least 3 separate runs per kiln.
  * Weigh fresh biochar mass, and adjust by the measured moisture content, described below.
* **Biochar drying and moisture content:** Biochar must be sufficiently dried to 0% moisture content to obtain accurate dry bulk density measurements. It shall be dried using one of the following methods:
  * Moisture analyzer: use a laboratory-grade [moisture analyzer](#user-content-fn-9)[^9].
  * Oven drying: dry the biochar in a ventilated oven at at least 110°C for a minimum duration of 48 hours. Subtract the final mass from the initial to determine moisture content and confirm complete drying.
    * Where oven drying is used, the VVB shall conduct or oversee cross-check measurements of moisture content using a laboratory-grade moisture analyzer during the annual [site audit](/methodologies/distributed-open-kiln-biochar/eligibility-and-scope#site-audits), covering biochar samples from at least 3 different production sites. These cross-checks serve to verify that oven drying achieved complete moisture removal.
    * Where the VVB's measurements differ materially from the kiln supervisor's records in a direction that would result in fewer credits being issued, the VVB's measurements shall supersede the Kiln Supervisor's records for crediting purposes, and the Project Developer shall investigate and document the discrepancy.
    * Where the VVB's measurements would result in the same or greater number of credits, the Kiln Supervisor's records may continue to be used.

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><p>Kiln Supervisors shall <strong>take and prepare the biochar sample</strong> following these steps:</p><ul><li>Take a mixture of biochar sampled from the bottom, middle, and top of the <a data-footnote-ref href="#user-content-fn-8">Site Composite Pile</a>, already set aside by the Kiln Operator for sampling.</li><li>Transport the biochar from the Kiln Operator’s site to the location with measurement equipment, taking measures to protect the biochar from breaking during transport (if applicable, depending on project design)</li><li>Keep biochar samples from each site separate.</li><li><p>If using fresh biomass, dry the sample using</p><ul><li>a ventilated oven at at least 110°C for a minimum duration of 48 hours, or</li><li>a laboratory-grade <a data-footnote-ref href="#user-content-fn-9">moisture analyzer</a>, described above.</li></ul></li></ul></td></tr><tr><td><p>Kiln Supervisors shall <strong>conduct and report bulk density measurements</strong> as follows:</p><ul><li>Use containers of a standard material and predefined volume size.</li><li>Use scales with proven calibration and high accuracy (e.g., digital readings; if non-digital, values rounded down).</li><li>Conduct measurements separately for each site (samples from different sites shall not be mixed, and measurements shall not be taken on composite samples).</li><li>Outliers may be excluded from the bulk density dataset (defined as any individual measurement that is 3 standard deviations above or below the mean of the dataset).</li><li>The final bulk density value used for GHG quantification of each Production Batch shall be the <strong>mean minus one standard deviation of all measurements</strong> within that batch.</li></ul></td></tr></tbody></table>

Photos shall be uploaded to dMRV at each step. Project Developers shall prove that all measurement instruments used, such as scales and/or moisture analyzers are calibrated at least once per year.

The VVB shall review **all records** related to biochar drying and bulk density measurements to ensure that:

* **Drying:** biochar was fully dried to 0% moisture content prior to measurement.
* **Transport and handling:** the biochar sample used for bulk density measurement is similar to, and representative of, the biochar initially sampled, and has not been excessively damaged during transport or handling.
* **Representative subsample:** the biochar sample used for bulk density measurement has a bulk density consistent with the larger biochar retention sample pile from which it was taken.

#### Biochar mass

If biochar mass is used as the main indicator of biochar production and use, Project Developers shall provide Kiln Operators with accurate and calibrated measurement scales. The biochar output of all kiln runs shall be weighed upon completion of pyrolysis. Biochar mass may be measured either before quenching (bone dry) or after quenching.

If biochar is **weighed before quenching**, the recorded mass already reflects the dry mass of biochar produced and may be used directly to calculate carbon removals (see Eq. 9 in the [GHG quantification](/methodologies/distributed-open-kiln-biochar/ghg-quantification#calculations-biomass-leakage-biomass-amount-biochar-amount) section).

If biochar is **weighed after quenching**, the moisture content of the biochar must be measured and accounted for. Moisture content must be measured on at least 3 separate samples for every biochar Production Batch (see Eq. 8 in the [GHG quantification](/methodologies/distributed-open-kiln-biochar/ghg-quantification#calculations-biomass-leakage-biomass-amount-biochar-amount) section).

Moisture measurements shall be conducted using one of the following methods:

* By the Kiln Supervisor, following the oven drying or [moisture analyzer](#user-content-fn-9)[^9] approach described above for biochar drying. Measurements must begin on the same day the biochar is produced and weighed (i.e. within 24 hours). Time-stamped photos shall be uploaded to dMRV at each step.
* By sending biochar samples to an accredited independent laboratory for moisture content measurement. Samples shall be sent on the same day the biochar is produced and weighed, and must be protected to minimize moisture loss, including at a minimum wrapping the biochar in three layers of sealed plastic bags. Photos shall be uploaded to dMRV at each step, including time stamps showing that biochar is produced, weighed and sent on the same day (i.e. within 24 hours), and including photographic evidence of sealing the biochar sample.

Project Developers shall prove that all measurement instruments used, such as scales and/or moisture analyzers are calibrated at least once per year.

The VVB shall review all records related to biochar drying and moisture content measurements, if taken.

## Accredited labs

Proximate and elemental analysis of biochar shall be performed by laboratories with at least one quality assurance accreditation, such as:

* ISO/IEC 17025
* CEN/TS 17225-1
* ISO 10694

Unaccredited laboratories from academic settings shall be evaluated on a case by case basis by the VVB and the Rainbow Certification Team.

[^1]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for a maximum of 6 months operating time or 100 tonnes of biochar, whichever comes first.

[^2]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for **a maximum of 6 months operating time or 200 tonnes of biochar**, whichever comes first.

[^3]: * Lotz, S., N.Hagemann, D.Hölscher, and H.-P.Schmidt. 2026. “Methane Emissions From Flame Curtain Pyrolysis (Kon-Tiki).” GCB Bioenergy18, no. 4: e70108. <https://doi.org/10.1111/gcbb.70108>.
    * Cornelissen, Gerard, et al. “Flame Curtain Kilns Produce Biochar from Dry Biomass with Minimal Methane Emissions.” *Science of the Total Environment*, vol. 903, 1 Dec. 2023, pp. 166547–166547, <https://doi.org/10.1016/j.scitotenv.2023.166547>.

[^4]: Some of this difference in carbon mass is actually lost as aerosols and particulate matter rather than gas, but treating it entirely as gaseous carbon would slightly overestimate total gas-phase emissions, making this a conservative assumption.

[^5]: * ISO 12039:2019: Stationary Source Emissions — Determination of the Mass Concentration of Carbon Monoxide, Carbon Dioxide and Oxygen in Flue Gas — Performance Characteristics of Automated Measuring Systems
    * ISO 25140:2010: Stationary Source Emissions — Automatic Method for the Determination of the Methane Concentration Using Flame Ionisation Detection (FID).
    * ISO 25139:2011: Stationary Source Emissions — Manual Method for the Determination of the Methane Concentration Using Gas Chromatography.

[^6]: * Cornelissen, Gerard, et al. “Flame Curtain Kilns Produce Biochar from Dry Biomass with Minimal Methane Emissions.” *Science of the Total Environment*, vol. 903, 1 Dec. 2023, pp. 166547–166547, <https://doi.org/10.1016/j.scitotenv.2023.166547>. [URL](https://www.sciencedirect.com/science/article/pii/S0048969723051720).
    * Lotz, Simon, et al. “Methane Emissions from Flame Curtain Pyrolysis (Kon‐Tiki).” *GCB Bioenergy*, vol. 18, no. 4, 13 Mar. 2026, <https://doi.org/10.1111/gcbb.70108>. [URL](https://onlinelibrary.wiley.com/doi/10.1111/gcbb.70108).

[^7]: The recommended approach sampling requirements are based on the following sources:

    * [EU Fertilising Products Regulation (EU) 2019/1009](#user-content-fn-9)\[^9]
    * [European Biochar Certificate Guidelines Annex 4 Representative Sampling](#user-content-fn-10)\[^10]

[^8]: After each kiln run at a given site, a defined quantity of biochar is set aside from that run, and added to the **Site Composite Pile**. Biochar subsamples are continuously added to this single site-level pile throughout the production batch duration.

[^9]: Specifically a thermogravimetric moisture analyzer using the loss-on-drying (LOD) method. As opposed to a handheld moisture sensor.


# Version history

This page describes the changes in the Distributed open-kiln biochar methodology.

| Description of the change | Justification | Date             | Version changed |
| ------------------------- | ------------- | ---------------- | --------------- |
| Release of methodology    | --            | April 24th, 2026 | V1.0            |


# Appendix

## Appendix 1: Ecoinvent inputs

See the appendices of the associated GHG quantification modules for lists of ecoinvent processes used. This methodology does not introduce the use of any additional ecoinvent processes.

<table data-view="cards"><thead><tr><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="image">Cover image</th></tr></thead><tbody><tr><td>Processing and energy use ecoinvent inputs</td><td><a href="/pages/BTxxPIM3a4Nai1Wkwu2Y#appendix">/pages/BTxxPIM3a4Nai1Wkwu2Y#appendix</a></td><td><a href="/files/xqDoBuMbX7fcBqJ8AanC">/files/xqDoBuMbX7fcBqJ8AanC</a></td></tr><tr><td>Infrastructure and machinery ecoinvent inputs</td><td><a href="/pages/IwqpSqlee22qTIPti3Sl#appendix">/pages/IwqpSqlee22qTIPti3Sl#appendix</a></td><td><a href="/files/gE6Zo8o6awA0p9LnSTnF">/files/gE6Zo8o6awA0p9LnSTnF</a></td></tr><tr><td>Transportation ecoinvent inputs</td><td><a href="/pages/VTWdCc7guKu1x0azAizi#appendix">/pages/VTWdCc7guKu1x0azAizi#appendix</a></td><td><a href="/files/XAxrYlLSh0qtvbDkKkqp">/files/XAxrYlLSh0qtvbDkKkqp</a></td></tr></tbody></table>

## Appendix 2: Operating procedure for Kiln Operator

<details>

<summary>Preparation of biomass</summary>

* **Select Eligible Feedstock:**
  * Use only approved biomass types (e.g., forest waste, agricultural residues, invasive species).
  * Ensure biomass is classified as waste (not grown for CDR/bioenergy, not usable for valuable products).
  * Use only coarse, rigid, woody or semi-woody biomass appropriate for open kilns (e.g., pruning wood, branches, crop stalks, bamboo, moderately-sized wood chips). Do not use biomass types that may smother the flame curtain or cause uneven gas release.
  * Keep records of biomass type and source (e.g., photos, invoices, or contracts).
* **Dry Biomass:**
  * Measure moisture content using a calibrated handheld moisture meter immediately prior to pyrolysis.
  * Take at least one measurement per 100 kg of feedstock, with a minimum of 10 measurements per kiln run, distributed evenly across the biomass pile covering both its surface area and depth.
  * Ensure mean moisture content is below the applicable threshold: ≤20% for woody biomass, or ≤15% for any other biomass or any mixture containing non-woody biomass. No individual measurement may exceed 25%.
  * Upload photos of each sensor reading to dMRV as proof.
* **Prepare Biomass for Kiln:**
  * Chop or chip biomass to the appropriate size for the kiln, as specified in the project's training protocol.
  * If using woody prunings from multiple tree or shrub species treated as a single feedstock: remove all leaves prior to loading, and document via photo that bulk density, moisture content and particle size are consistent across species.
  * Document biomass preparation with photos and upload to dMRV.

</details>

<details>

<summary>Conducting pyrolysis</summary>

* **Identify the Kiln**
  * Scan the kiln's QR code or take a photo of its unique serial number, and upload a photo of the kiln displaying its required technical features (e.g., thermocouple placement, flame-curtain design) to dMRV before starting each kiln run.
* **Load Biomass:**
  * Load dried biomass into the kiln following training guidelines for proper feeding rates.
  * Before loading, photograph the full biomass pile staged for the kiln run.
  * Avoid overloading, which can cause a drop in pyrolysis temperature or disrupt secondary combustion.
  * For kilns capable of continuous production, adhere to the project-defined maximum operating duration or biochar mass per kiln run.
* **Record Biomass Amount:**
  * Record the amount of biomass used per kiln run using one of the following approaches:
    * Directly weigh biomass inputs and subtract moisture using moisture content measurements; or
    * Use a validated feedstock-specific biomass-to-biochar conversion ratio applied to the dry biochar output.
* **Monitor Pyrolysis:**
  * Start the kiln and confirm that temperature sensors are functioning before loading biomass.
  * Maintain pyrolysis temperature ≥350°C throughout the entire process, excluding the ramp-up and quenching phases.
  * Document the process with time-stamped, GPS-tagged photos or videos of kiln operation, including biomass feeding.
  * Temperature sensor readings are continuously and automatically recorded by the thermocouple.
* **Quench Biochar:**
  * Rapidly quench biochar immediately after pyrolysis is complete to minimise methane emissions.
  * Document quenching with time-stamped photos or short videos showing the start and end time of the quenching process.

</details>

<details>

<summary>Measure and prepare biochar samples</summary>

**Measure Biochar Quantity:**

* Choose either the volume approach or the mass approach, consistently across all kilns for the Production Batch.
  * Volume approac&#x68;*:* Fill standardized containers of predefined volume and record the number of containers produced per kiln run in dMRV.
  * Mass approach, bone dr&#x79;*:* Weigh biochar before quenching using calibrated scales. Record the mass directly in dMRV.
  * Mass approach, post-quenc&#x68;*:* Weigh biochar after quenching using calibrated scales. Record the fresh mass in dMRV. Moisture content must then be measured on at least 3 separate samples per Production Batch to convert to dry mass.

**Set Aside Biochar Subsamples for the Site Composite Pile:**

* After each kiln run, follow the project's predefined Sampling Plan. Take several biochar samples from different spots in the pile, and add them to the Site Composite Pile.
* Continue adding subsamples to this pile from every kiln run throughout the entire Production Batch duration.
* Upload photos of subsamples being set aside to dMRV, including the kiln ID/QR code, Production Batch ID/QR code, date, time, and GPS location.

**Take the Site Composite Sample**

* This may be done by the Kiln Operator or the Kiln Supervisor
* Once per Production Batch, after all kiln runs are complete, thoroughly mix the Site Composite Pile. Take subsamples and combine into the Site Composite Sample.
* The remaining biochar in the Site Composite Pile may be used in an eligible permanent end use and credited.

</details>

<details>

<summary>Uploading proof to dMRV</summary>

**Upload Required Data for Each Kiln Run:**

* Kiln run proof:
  * Continuous temperature curves from the thermocouple sensor (automatically measured)
  * Photos/videos of pyrolysis, including biomass feeding and quenching.
  * Biomass moisture content sensor readings (photos).
  * Biomass type and amount used.
  * Biochar volume or mass produced.
  * Unique identification of the kiln (QR code, serial number...).
* Sampling proof:
  * Photos of the subsample being set aside and added to the Site Composite Pile.
  * QR codes of biochar bags (if applicable).
* End-use proof (for all biochar delivered):
  * Date, GPS coordinates, and address of biochar delivery and application.
  * Name of user/buyer and Production Batch ID.
  * Time-stamped, geo-located photos of biochar application or mixing.

**Flag Anomalies:**

* Report any known issues to the Project Developer or Kiln Supervisor, including incomplete data, unsatisfactory pyrolysis, or thermocouple failures.

</details>

## Appendix 3: Operating procedure for Kiln Supervisor

<details>

<summary>Annual site visits</summary>

**Schedule Visits:**

* Visit each kiln operator at least once per year.
* Observe at least one kiln run per site during the visit.

**Verify Compliance:**

* Confirm that biomass type and moisture content are appropriate and that moisture measurements are taken correctly.
* Confirm that biomass is loaded at appropriate rates without overloading the kiln.
* Confirm that temperature sensors are functioning and recording continuously.
* Confirm that the flame curtain appears intact and indicates low rates of incomplete pyrolysis and methane emissions.
* Confirm that quenching begins promptly after pyrolysis and is documented with time-stamped photos or video.
* Check that storage conditions for biomass and biochar are appropriate (dry, protected from contamination).
* Confirm that the Kiln Operator is correctly building the Site Composite Pile with subsamples from each kiln run throughout the Production Batch.

</details>

<details>

<summary>Production Batch Composite and Representative Samples</summary>

**Prepare Production Batch Composite Sample:**

* Collect a representative sample from the Site Composite Pile at each site from the bottom, middle, and top of the pile.
* Transport the sample carefully to avoid breakage.
* Keep samples from different sites separate at all times if conducting bulk density measurements (see below).

**Prepare Production Batch Representative Sample:**

* Combine all Site Composite Samples into one pile.
* Mix and recombine subsamples from different spots in the pile.
* Take the final Production Batch Representative Sample.

**Send for Laboratory Analysis:**

* Set aside part of the Production Batch Representative Sample for bulk density measurements if using the volume approach to measure the amount of biochar produced.
* Send the Production Batch Representative Sample to an accredited laboratory for measurement of:
  * Organic carbon content (each Production Batch)
  * H/C<sub>org</sub> ratio (and inertinite content and residual organic carbon, if using the 1000-year pathway) (each Production Batch)
  * Environmental pollutants (once per year, or anytime biomass feedstock changes).
* Store Retention Sample:
  * Keep the remaining biochar in the Production Batch Composite Pile in a protected area as a retention sample for 2 years.
* Upload Records:
  * Upload photos, dates, times, and QR codes to dMRV.

</details>

<details>

<summary>Bulk density measurements (volume approach)</summary>

Measure bulk density for projects using the volume-based approach.

**Prepare the sample**

* Dry the Site Composite Pile described in the section above to 0% moisture content using one of the following methods:
  * Moisture analyser: use a laboratory-grade moisture analyser.
  * Oven drying: dry in a ventilated oven at ≥110°C for a minimum of 48 hours. Subtract the final mass from the initial mass to determine moisture content and confirm complete drying.

**Measure Bulk Density:**

* Use containers of a standard material and predefined volume.
* Use calibrated scales (digital preferred; if analog, round down values).
* Measure each site’s biochar separately (no mixing).
* Exclude outliers (3 standard deviations from the mean).
* Calculate the final bulk density of biochar in the Production Batch as the mean of all measurements minus one standard deviation.

**Upload Proof:**

* Upload photos of each step to dMRV.

</details>

<details>

<summary>Training and oversight</summary>

**Conduct Training:**

* Train Kiln Operators on:
  * Safety protocols for kiln operation.
  * Biomass preparation (drying, sizing) and moisture content measurement.
  * Correct biomass loading rates to maintain the flame curtain.
  * Rapid quenching.
  * Biochar sampling procedures.
  * Use of dMRV, including photo requirements, GPS tagging, and batch upload requirements.
  * This may be done by the Kiln Supervisor or the Project Developer.

**Site Visits:**

* During and after site visits, or at any other time, flag any non-compliant kiln runs (e.g., secondary combustion failure, missing energy input records, missing data, improper sampling).
* Report findings and required follow-up actions to the Project Developer. Provide findings to be included in the Project Developer's Quality Oversight Report.

</details>

## Appendix 4: Operating procedure for Project Developer

<details>

<summary>Project setup and kiln technology management</summary>

**Define Project Scope**

* Register the project as a single entity operating one or more kilns across one or more sites, within a single country, using the same kiln technology and dMRV approach.
* Ensure all sites and kilns are under the oversight or data access of the Project Developer.

**Select and Deploy Kiln Technology**

* Use pre-approved kiln designs from Rainbow’s published list. For new designs, submit for Rainbow and VVB approval.
* Verify that all kilns employ a conical flame-curtain design and are equipped with fixed, continuously-logging thermocouples placed in the same position on all kilns.
* Assign a unique, permanently affixed identifier (e.g., QR code or engraved serial number) to each kiln.
* Document kiln technical features (e.g., chimney design, sensor placement) in dMRV.

**Define Project-Specific Criteria at Validation**

* Biomass feedstock types, justification of suitability for open kiln operation, and proof of waste or invasive species status.
* Sampling and measurement protocols (e.g., H/C ratio, bulk density, methane emissions).
* Training Protocol for Kiln Operators and Kiln Supervisors.
* Project-specific criteria for evaluating temperature curves, including acceptable temperature ranges and durations, ramp-up period, and definition of the main pyrolysis phase. Criteria shall be designed to flag incomplete biomass drying and improper feedstock loading rates.

**Select and Validate dMRV Platform**

* Use pre-approved kiln designs from Rainbow’s published list. For new designs, ensure the platform meets Rainbow’s requirements and can track all of the required data points.
* Submit the platform for Rainbow validation before use.

</details>

<details>

<summary>Oversight of all kiln runs</summary>

**Review dMRV Data**

* Check every kiln run for:
  * Temperature curves: pyrolysis zone maintained ≥350°C throughout (excluding ramp-up and quenching), and project-specific quality criteria met.
  * Biomass moisture content: mean at or below the applicable threshold (≤20% for woody biomass, ≤15% for all other biomass or mixed biomass), and no individual measurement above 25%.
  * Flame curtain photos show a clean, intact burn throughout pyrolysis.
  * Biomass and biochar amounts are broadly consistent with photographic evidence.
  * Quenching was performed promptly and documented with time-stamped photos or video.
  * Biochar volume or mass is recorded.
  * Sampling records confirm a subsample was set aside and added to the Site Composite Pile.
* Alternatively, outsource the checking step to a dMRV provider.

**Coordinate Biochar Sampling**

* Ensure Kiln Supervisors combine Site Composite Samples into the Production Batch Composite Pile and send the Production Batch Representative Sample to an accredited laboratory for:
  * Organic carbon content (each Production Batch)
  * H/C<sub>org</sub> ratio (and inertinite content and residual organic carbon, if using the 1000-year pathway) (each Production Batch)
  * Environmental pollutants (once per year, or anytime biomass feedstock changes).

**Flag Non-Conformities**

* Exclude ineligible kiln runs (e.g., incomplete data, improper pyrolysis).
* Document reasons for exclusion in the Oversight Report. Note that excluded kiln runs do not count towards the Production Batch size limit.

**Coordinate Methane Emission Testing**

* Schedule Testing:
  * Conduct testing annually or whenever biomass feedstock changes.
  * Test three representative kiln runs (same kiln type and feedstock).
* Use Accredited Providers:
  * Ensure testing is done by organizations accredited with ASTM D7036, ISO 17025, or approved by state/regional authorities.
* Document Results:
  * Upload methane emission measurements, proof of calibration, and a signed measurement report to dMRV or share as a separate report with Rainbow and the VVB.

</details>

<details>

<summary>Training and support</summary>

**Train Kiln Operators on:**

* Safety protocols for kiln operation.
* Biomass preparation (drying, sizing) and moisture content measurement.
* Correct biomass loading rates to maintain the flame curtain.
* Rapid quenching.
* Biochar sampling procedures.
* Use of dMRV, including photo requirements, GPS tagging, and batch upload requirements.
* This may be done by the Kiln Supervisor or the Project Developer.

**Train Kiln Supervisors on:**

* All topics covered in Kiln Operator training, so that Supervisors can effectively assess and support Kiln Operators during site visits.
* Biochar amount measurements, including bulk density measurement procedures and moisture content measurement using oven drying or a laboratory-grade moisture analyser.
* How to adhere to the biochar sampling plan.

**Upload training records to dMRV, including:**

* Attendance logs.
* Photos/videos of training sessions.
* Test results or proof of completion.

**Offer Ongoing Support:**

* Provide refresher training and troubleshooting support (e.g., temperature curve analysis, flame curtain quality, moisture measurement).

</details>

<details>

<summary>Quality Oversight Report</summary>

To be completed for each Production Batch.

**Compile Data**

* List all kiln runs and their status (eligible/ineligible).
* Document the cumulative biomass used, biochar produced, and biochar applied in an eligible end use, noting any discrepancies and providing justification.
* Document non-conformities (e.g., missing data, improper sampling) and remediation steps.

**Include any site visit findings**

* Summarize Kiln Supervisor observations from any annual site visits that took place during the time period in question, including findings on biomass handling, kiln operation, flame curtain quality, and sampling compliance.
* List any non-conformities or failures to adhere to best practices identified during visits, and their remediation.

**Submit to VVB**

* Provide the report to the Validation and Verification Body (VVB) for audit.
* Address any VVB recommendations (e.g., additional site visits, data corrections).

</details>


# Risk assessment template

This methodology uses the risk assessment template version 1.0

:point\_right: Download the template [here](https://docs.google.com/spreadsheets/d/1wY6p8B2SyqHMY8QTjpk2pl9RTekFI1bHlbvE9ZGPueE/edit?usp=drive_link)

{% embed url="<https://docs.google.com/spreadsheets/d/1wY6p8B2SyqHMY8QTjpk2pl9RTekFI1bHlbvE9ZGPueE/edit?usp=sharing>" %}


# Distributed closed-kiln biochar

| **Methodology name** | Distributed closed-kiln biochar |
| -------------------- | ------------------------------- |
| **Version**          | 1.0                             |
| **Methodology ID**   | RBW-BCR-DCB-V1.0                |
| **Release date**     | April 24th, 2026                |
| **Status**           | In use                          |

This methodology document outlines the requirements for distributed biochar projects certified under the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules). These projects produce biochar at smaller scales per kiln run, and with more low-tech and mid-tech methods, than for industrial biochar production.

<details>

<summary><strong>Acknowledgements</strong> <span data-gb-custom-inline data-tag="emoji" data-code="1f91d">🤝</span></summary>

*This methodology was developed by Rainbow with valuable input and support from the Rainbow Distributed biochar Working Group members and other expert contributors.*

*We would like to thank Marc Hernandez Folguera (Planboo), Lorenz Buser (Cotierra), Adrien Humbert (Circonomy), Nando Knodel (Carbon Connect), Daniel Guarin (Carboneers), Isabel Messori (Atmosfair), Abhishek Sharma, Jiwesh Garg, Kaushal Bisht (Varaha), and Gerard Cornelissen (Norwegian Geotechnical Institute) for their insights and contributions throughout the development process.*

</details>

Note that the [Distributed open-kiln biochar ](/methodologies/distributed-open-kiln-biochar)methodology and the [Distributed closed-kiln biochar](/methodologies/distributed-closed-kiln-biochar) methodology have large overlaps with one another. For reference, here are the points of divergence:

<table><thead><tr><th width="170.44451904296875">Criteria</th><th>Open kiln requirement</th><th>Closed kiln requirement</th></tr></thead><tbody><tr><td>Kiln design</td><td>Must be cone-shaped with a flame-curtain design to reliably combust pyrolysis gases at the rim.</td><td>Must trap and concentrate pyrolysis gases in a dedicated chimney or chamber, exposing them to oxygen and high temperatures to combust them before emission.</td></tr><tr><td>Biochar pollutants</td><td>Not required to provide PAH content of biochar.</td><td>Must provide PAH content of biochar.</td></tr><tr><td>Methane measurement techniques</td><td>Must use the carbon mass balance method only.</td><td>May use either carbon mass balance or volumetric flow × concentration to measure methane emissions.</td></tr><tr><td>Eligible biomass</td><td>Must also justify that the specific biomass type, preparation, and particle size are appropriate for flame-curtain operation.</td><td>May use any eligible biomass provided it meets the requirements.</td></tr><tr><td>Photo proof in dMRV</td><td>Must provide photos of the clean pyrolysis process, flame curtain, quenching.</td><td>No photos required of the clean pyrolysis process and flame curtain.</td></tr><tr><td>Inputs</td><td>No energy inputs expected during pyrolysis, no additional data requirements.</td><td>Must provide energy inputs for any syngas combustion.</td></tr></tbody></table>

## Glossary

<table data-header-hidden><thead><tr><th width="216"></th><th></th></tr></thead><tbody><tr><td><strong>Kiln</strong></td><td>An individual pyrolysis unit that produced biochar. A kiln may be mobile or stationary, used individually or collectively, and open or closed.</td></tr><tr><td><strong>Site</strong></td><td>A distinct location where a kiln or kilns are operated.</td></tr><tr><td><strong>Kiln operator</strong></td><td>The individual performing pyrolysis and producing biochar. This includes preparing biomass, loading it into the kiln, surveilling pyrolysis, storing biochar, taking biochar samples, and ensuring durable biochar end use.</td></tr><tr><td><strong>Kiln supervisor</strong></td><td>Hired by the Project Developer to be the party responsible for ensuring quality of the operations by on-the-ground presence and random visits to kiln operators.</td></tr><tr><td><strong>dMRV</strong></td><td>A digital platform (application or website) provided by a third-party dMRV provider other than Rainbow, to allow kiln operators to record and document their operations, ensuring compliance with methodology requirements.</td></tr><tr><td><strong>Kiln run</strong></td><td>One full pyrolysis process, the operation of one kiln, one batch of biochar produced.</td></tr><tr><td><strong>Production Batch</strong></td><td>Biochar produced under the same conditions regarding kiln type, biomass feedstock, and temperature curve. A production batch has a maximum validity of 6 months or 200 tonnes of biochar, whichever comes first. Key measurements like carbon content and H/C ratio are done once per production batch.</td></tr><tr><td><strong>Biochar</strong></td><td>Material that is rich in stable carbon, produced through the thermal conversion of biomass in a low-oxygen environment.</td></tr><tr><td><strong>Bone-dry biochar</strong></td><td>Biochar with a moisture content of 0%, typically measured immediately after exiting the kiln before any water is added during quenching.</td></tr><tr><td><strong>End use application</strong></td><td>The way biochar will be used, such as direct application to soil, mixing with compost and application of the mix to soil, mixing with cement for use in concrete.</td></tr><tr><td><strong>End use point</strong></td><td>The step in the production chain where biochar leaves the direct control of biochar producers, where it is assumed to be incorporated into its final end use application.</td></tr><tr><td><strong>Feedstock</strong></td><td>The organic material used as the raw input for biochar production, such as wood, agricultural residues, or manure.</td></tr><tr><td><strong>Molar H/C</strong><sub><strong>org</strong></sub><strong> ratio</strong></td><td>The ratio of hydrogen to organic carbon atoms in biochar, used to assess the stability and quality of biochar; lower ratios indicate higher stability.</td></tr><tr><td><strong>Production batch ID</strong></td><td>A unique identifier for each production batch.</td></tr><tr><td><strong>Pyrolysis</strong></td><td>Thermal decomposition process that occurs in the absence of oxygen</td></tr><tr><td><strong>Quenching</strong></td><td>The process of rapidly cooling biochar immediately after pyrolysis to stop combustion and minimize methane emissions.</td></tr><tr><td><strong>Site Composite Pile</strong></td><td>A growing pile of biochar subsamples accumulated by the Kiln Operator over the course of a Production Batch. After each kiln run, a defined quantity of biochar is set aside and added to this pile. One Site Composite Pile is maintained per site per Production Batch.</td></tr><tr><td><strong>Site Composite Sample</strong></td><td>A representative sample of biochar taken from the thoroughly mixed Site Composite Pile once the Production Batch is complete. Site Composite Samples from all sites within the same Production Batch are combined to form the Production Batch Composite Pile.</td></tr><tr><td><strong>Production Batch Composite Pile</strong></td><td>A combined pile of Site Composite Samples collected from all sites contributing to the same Production Batch. The pile is thoroughly mixed by the Kiln Supervisor before a representative sample is taken for laboratory analysis.</td></tr><tr><td><strong>Production Batch Representative Sample</strong></td><td>The final representative sample taken from the mixed Production Batch Composite Pile and sent to an accredited laboratory for measurement of organic carbon content, permanence indicators (H/Corg ratio and/or inertinite content), and, once per year, environmental pollutants.</td></tr></tbody></table>


# Eligibility and scope

## Eligible Project Developers <a href="#id-7d9f62an42y" id="id-7d9f62an42y"></a>

Distributed biochar projects uniquely operate with a network of many actors. All recognized actors and their roles are outlined below. Upon validation, Project Developers shall provide a **detailed description of all actors in the project and their responsibilities**.

See the Appendix for the Operating Procedure and responsibilities for [Kiln Operators](/methodologies/distributed-closed-kiln-biochar/appendix#appendix-3-operating-procedure-for-kiln-operator), [Kiln Supervisors](/methodologies/distributed-closed-kiln-biochar/appendix#appendix-4-operating-procedure-for-kiln-supervisor) and [Project Developers](/methodologies/distributed-closed-kiln-biochar/appendix#appendix-5-operating-procedure-for-project-developer).

<table><thead><tr><th width="127.0396728515625">Type of actor</th><th width="316.7440185546875">Operational role</th><th width="311.2335205078125">Carbon project role</th></tr></thead><tbody><tr><td><strong>Kiln Operator</strong></td><td>The individual performing pyrolysis and producing biochar. This includes preparing biomass, loading it into the kiln, surveilling pyrolysis, storing biochar, taking biochar samples, and ensuring durable biochar end use.</td><td>Executes the carbon removal activity and records raw data and proof. Receives carbon finance from credit sales, distributed by the Kiln Supervisor or Project Developer.</td></tr><tr><td><strong>Kiln Supervisor</strong></td><td>Hired by the Project Developer to be the party responsible for ensuring quality of the operations by on-the-ground presence and random visits to Kiln Operators.</td><td>Visits each Kiln Operator at least once per year, and coordinates biochar bulk density measurements onsite. May provide trainings to Kiln Operators.<br>The Kiln Supervisor shall not receive payments or other incentives related to number of carbon credits issued.</td></tr><tr><td><strong>Project Developer</strong></td><td>Coordinates with Kiln Supervisors to ensure high quality biochar production, sampling and measurements; manage data and proof for submission to Rainbow and VVB (i.e. check anomalies).<br>May also train, provide dMRV, provide kilns, and operate kilns.</td><td>An intermediary between Rainbow and on-the-ground operations, including Kiln Operators and Supervisors.<br>Responsible for centralized project data management, registration, VVB interactions, and ensuring carbon finance is distributed to Kiln Operators.</td></tr><tr><td><strong>dMRV provider</strong></td><td>Provides a third-party dMRV platform (digital monitoring, reporting and verification) apart from Rainbow, in the form of an application or website, to allow Kiln Operators to record operations.</td><td>The dMRV tool must have all features needed to for kiln operators to prove compliance with methodology requirements. Full requirements <a href="/pages/E9DuvMhIvPOLnyBYPnkG#dmrv-requirements">here</a>.<br>Can also be a Project Developer.</td></tr><tr><td><strong>Technology provider</strong></td><td>Provides the physical kiln used to perform pyrolysis and produce biochar.</td><td>Must provide kilns that meet methodology requirements, and help define which kilns are the same type, for defining the Production Batch. Full requirements <a href="#eligible-kilns">here</a>.<br>Can also be a Project Developer.</td></tr></tbody></table>

## Eligible technologies

### Eligible kilns

Only closed kilns are eligible under this methodology. Eligible kilns must:

* maintain pyrolysis temperatures of at least 350°C, for the entire pyrolysis duration (excluding ramp up period)
* be equipped with fixed, continuously-logging thermocouples, placed in the same spot on all kilns. See the [temperature curve requirements](/methodologies/distributed-closed-kiln-biochar/principles-and-requirements#temperature-curves) for further instructions.
* demonstrate a reactor design with secondary combustion that traps and concentrates pyrolysis gasses in a dedicated chimney or chamber, and exposes them to oxygen and high temperatures and combusts them, before being emitted to the atmosphere
* come with safety protocols and instructions for operators
* have a unique identifier permanently affixed to the kiln structure that cannot be removed, altered, or transferred to another unit (e.g., a QR code, engraved serial number, or equivalent)
* for kilns capable of continuous production, define a kiln run as a maximum operating duration or biochar mass produced, to serve as the reference unit for all per-kiln-run monitoring requirements

Project Developers shall submit the design specifications of kilns for validation by the Rainbow team and a VVB, including the form, function, size and dimensions of the kiln. After a kiln design is validated and approved as eligible by Rainbow and a VVB, it will be added to Rainbow’s published list of eligible kilns. For any future projects using the same kiln design, the kiln shall be considered **automatically eligible**. Project Developers only need demonstrate that their kiln matches a design already listed.

### Eligible biomass feedstock

Eligible biomasses are those that:

* could not have been used for valuable products (e.g. low quality wood), and
* were not grown for the purpose of CDR[^1] or bioenergy production.

For simplification, all feedstocks that meet the above requirements will be referred to hereafter as waste. Biomass feedstocks are categorized accordingly:

<table><thead><tr><th width="170.7734375">Biomass type</th><th width="557.83984375">Description</th></tr></thead><tbody><tr><td>Forest waste</td><td><ul><li><strong>Secondary forest:</strong> Natural but not primary old-growth forest, may still be managed for timber</li><li><strong>Managed forest:</strong> Managed mixed-use forests that may include agroforestry, plantations or rotational logging</li><li><strong>Necessary tree removal from any forest:</strong> Damaged trees, or trees removed for planned forest management such as preventing disease spread or fires</li></ul><p>Subject to <a href="/pages/E9DuvMhIvPOLnyBYPnkG#waste-status">Proof of waste status</a>, <a href="/pages/E9DuvMhIvPOLnyBYPnkG#forestry-certification">Forestry certification</a>, and <a href="/pages/E9DuvMhIvPOLnyBYPnkG#leakage">Leakage </a>requirements.</p></td></tr><tr><td>Agro-food waste</td><td><ul><li><strong>Residues otherwise left on soil</strong> or reapplied to soils for nutrient recycling, through mulching, composting, or spreading</li><li><strong>Residues otherwise burnt in the field</strong>, with no substantial return of nutrients or organic carbon to soil</li><li><strong>Food processing facility</strong> waste</li></ul><p>Subject to <a href="/pages/E9DuvMhIvPOLnyBYPnkG#waste-status">Proof of waste status</a> and <a href="/pages/E9DuvMhIvPOLnyBYPnkG#leakage">Leakage </a>requirements.</p></td></tr><tr><td>Invasive species</td><td>Woody or herbaceous plants proven to be locally or regionally invasive (non-native and causing environmental or human harm).<br>Subject to <a href="/pages/E9DuvMhIvPOLnyBYPnkG#invasive-species-status">Proof of invasive species</a> requirements.</td></tr></tbody></table>

Biomass must be explicitly **subject to** [**stakeholder consultation**](/methodologies/distributed-closed-kiln-biochar/principles-and-requirements#biomass-stakeholder-consultation), attesting to its status as waste or invasive species, and the Project Developer's right to use it. See the [Environmental and social safeguards](/methodologies/distributed-closed-kiln-biochar/principles-and-requirements#biomass-stakeholder-consultation) section for more details.

### Feedstock Composition and Consistency

Each [Production Batch](#user-content-fn-2)[^2] shall use either a **single feedstock type** or a **consistent feedstock mix**, subject to the following requirements.

<table><thead><tr><th width="105.09716796875">Type</th><th width="174.3876953125">Definition</th><th>Requirements</th></tr></thead><tbody><tr><td><strong>Single feedstock</strong></td><td>Each kiln run in the Production Batch uses one biomass feedstock type</td><td><ul><li>Biochar produced from different feedstock types shall be kept physically separate during production, storage, and sampling.</li><li>Biochar produced from different feedstock types shall be tracked and reported separately in the dMRV system for all measurements and end-use applications.</li></ul></td></tr><tr><td><strong>Mixed feedstock</strong></td><td>Each kiln run in the Production Batch uses the same feedstock mix</td><td><ul><li>The mass of each feedstock component is weighed individually and documented prior to each run.</li><li>The composition of the blend remains consistent within a tolerance of ±10% by mass of each feedstock type across runs.</li></ul></td></tr></tbody></table>

Woody pruning from different tree or shrub species may be treated as a single feedstock type if:

* Project Developers justify that carbon content and other physicochemical characteristics are the same across species, from reputable secondary sources, and
* Kiln Operators document via photograph of each kiln run that
  * all leaves are removed prior to use, and
  * bulk density, moisture content and particle size are the same for all biomass species.

A project may use multiple single-feedstock types **across different kiln runs**, and group the biochar from the same single-feedstock runs into Production Batches. Production Batches may be non-contiguous.

{% hint style="info" %}
For example, if Feedstock #1 if used on Day 1, a different Feedstock #2 on Day 2, and Feedstock #1 is used again on Day 3, the resulting biochar from Day 3 could be part of the same Production Batch as the biochar produced on Day 1.
{% endhint %}

### Eligible biochar product and end use

Credits shall be issued based on the **end use of biochar** (as opposed to production of biochar), specifically when it is mixed into a permanent matrix. A permanent matrix is defined as a medium that ensures the biochar cannot be physically separated or used for energy (e.g., as fuel).

Eligible end uses include:

* **Direct application to soil**
* **Mixing into soil-related products** with expected sale or distribution to professional users, such as compost, manure, or fertilizer mixes. To be considered sufficiently mixed, biochar must make up less than 50% by volume of the total mixture.
* Addition to **concrete or asphalt**

All biochar must have a molar $$H/C\_{org}$$​ below [**0.7**](#user-content-fn-3)[^3].

### Project design

The distributed network of actors results in several project scopes and designs. A typology is provided below for informational purposes only and for clear labeling of project types. All designs listed below are eligible under this methodology, and other designs may be approved on a case by cases.

<table><thead><tr><th width="131.51171875"></th><th width="308">Collective</th><th>Self-sufficient</th></tr></thead><tbody><tr><td><strong>Mobile</strong></td><td><p><strong>Portable Community Kilns</strong></p><ul><li>Kiln is moved from site to site.</li><li>Central operator provides pyrolysis as a service to multiple farmers.</li><li>Kiln travels to centralized biomass sources, and biochar is left with farmers or distributed locally.</li></ul></td><td><p><strong>Portable Farmer Units</strong></p><ul><li>Kiln is moved from site to site.</li><li>Farmers pyrolyze their own biomass on-site or nearby, and use biochar on the same farm</li></ul></td></tr><tr><td><strong>Stationary</strong></td><td><p><strong>Shared Pyrolysis Hubs</strong></p><ul><li>Kiln at a fixed and shared location.</li><li>Central operator manages the kiln.</li><li>Biomass comes from several sources, biochar distributed to users who may or may not have provided the biomass.</li></ul></td><td><p><strong>On-Farm Producers</strong></p><ul><li>Kiln at a fixed location, at an individual's farm.</li><li>Farmers pyrolyze their own biomass and use the biochar on their own land.</li></ul></td></tr></tbody></table>

## Certification requirements

#### **Crediting period duration**

The maximum duration of the crediting period for projects certified under this methodology is 5 years. Upon reaching the maximum duration, a project's crediting period may be renewed, according to the [Crediting Period Renewal](/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal) procedure.

#### **Monitoring period duration**

The default monitoring period duration is one year, but may be shorter at the Project Developer's request. Project Developers shall submit a Monitoring Report at least once per 24 months. Failure to do so shall result in the project being [deregistered](/rainbow-standard-documents/procedures-manual/project-certification-procedure#deregistration).

#### **Site audits**

Site audits for projects under this methodology **must be done in-person and must be conducted at least once per year** by a Rainbow-accredited Validation and Verification Body (VVB, the auditor)**.** The site audit shall include the direct observation of one kiln run at each site, in addition to the general site audit requirements in the [Rainbow Procedures Manual](/rainbow-standard-documents/procedures-manual/project-certification-procedure#site-audit).

The required number of sites to audit per project per year vary according to the project size, and shall adhere to the following framework:

<table><thead><tr><th width="144.18182373046875">Project Size</th><th width="184.72723388671875">Annual audit rate</th><th width="154.8018798828125">Annual audit minimum number of sites</th><th>Indicative 5-Year Cumulative Coverage</th></tr></thead><tbody><tr><td><strong>&#x3C;10 sites</strong></td><td>2 sites per year</td><td>2</td><td>100% of all sites visited at least once</td></tr><tr><td><strong>11–200 sites</strong></td><td>10% of sites per year</td><td>2</td><td>~50% of all sites visited at least once</td></tr><tr><td><strong>201–500 sites</strong></td><td>5% of sites per year</td><td>15</td><td>~25–50% of all sites visited at least once</td></tr><tr><td><strong>500+ sites</strong></td><td>5% of sites per year</td><td>10, maximum 40 per year</td><td>~25% of all sites, maximum 200 unique sites over 5 years</td></tr></tbody></table>

Project Developers shall justify how the audited sites were selected each year, adhering to the following principles:

* **Rotation**: The audited sites shall rotate each year so that over the 5-year crediting period, a large sample size of sites are audited. No site shall be selected for audit in two consecutive years unless it received a non-conformity finding in its most recent audit or makes up an exceptionally large proportion of biochar production in the project.
* **Random**: Random site selection is the ideal approach to ensure that site audits cover realistic day-to-day operations. Project Developers shall outline their efforts to randomly select sites and ensure that visits represent real conditions.
* **Prioritize large sites**: Sites with higher biochar production volumes shall be given priority, and should be visited more frequently and earlier in the crediting period than low-producing sites.

The points above **remain principles rather than strict requirements** because Rainbow recognizes the on-the-ground challenges with coordinating site audits, and that announcing audit visits in advance is often a practical necessity due to travel distances, access arrangements, and the need for the Kiln Operator to be ready to run pyrolysis.

If the project is tracking the amount of biochar produced using volume based measurements, and is drying the biochar for bulk density measurements using the oven drying method, then the annual site audit shall also include a moisture content cross-check under oversight of the VVB, as described in the [Sampling and Measurements](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements#biochar-volume) section

#### **Versioning and project compliance**

When this methodology is revised, projects are required to comply with the latest version for subsequent verifications of RCCs.

## Project scope

One project is defined as:

* the operation of one or more kilns, across one or more sites,
* within a single country,
* using the same kiln technology,
* using the same dMRV approach, and
* operated at sites that are under the oversight or data access of a single Project Developer.

The **project scope is cradle-to-grave** and includes all processes that result from biochar production and application. This includes but is not limited to the following:

* carbon removals from biochar production
* induced emissions from
  * biomass sourcing
  * leakage
  * upstream and downstream transport
  * embodied emissions from infrastructure and machinery
  * onsite process emissions from biomass preparation, biochar processing and energy use.

Any processes that would have occurred regardless of the biochar production and application activities may be excluded from the project scope.

## Baseline scope

A **standardized baseline of 0** **removals** is set, because it is assumed that no biochar production or other dedicated carbon removal activity would have occurred under business-as-usual conditions. There is no share of the project activity in the baseline scenario.

Any permanent carbon storage from the alternate fate of the biomass feedstock used by the project is addressed in the [Leakage](/methodologies/distributed-closed-kiln-biochar/principles-and-requirements#counterfactual-biomass-carbon-storage) section.

[^1]: Carbon dioxide removal

[^2]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for **a maximum of 6 months operating time or 200 tonnes of biochar**, whichever comes first.

[^3]: Leng, L., Huang, H., Li, H., Li, J., Zhou, W., 2019. Biochar stability assessment methods: A review. Science of The Total Environment 647, 210–222. <https://doi.org/10.1016/j.scitotenv.2018.07.402>


# Principles & requirements

Project Developers shall demonstrate that they comply with all principles and requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements), and described below with a specific focus on distributed biochar production.

{% content-ref url="/pages/CRADNrj4mfS258PN3x7N" %}
[Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules)
{% endcontent-ref %}

## Additionality <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

Project Developers shall demonstrate additionality using the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template) and following the requirements of the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#additionality).

{% tabs %}
{% tab title="Regulatory surplus analysis" %}
**Regulatory surplus analysis** shall demonstrate that there are no regulations that require or mandate project activities (for removal and avoidance activities). It is acceptable if regulations promote or set targets for these activities, because the resulting increase in activities shall be accounted for in the [baseline scenario](/methodologies/distributed-closed-kiln-biochar/eligibility-and-scope#baseline-scope).

At the European Union level, projects automatically pass the regulatory surplus analysis, which has been conducted by the Rainbow Science Team. Project Developers are only required to provide a country-level regulatory surplus analysis.
{% endtab %}

{% tab title="Investment analysis" %}
**Investment analysis** may be used to prove that revenue from carbon finance is necessary to make the project investment a financially viable and interesting option. The investment may cover:

* The creation and launching of new sites
* Expansion of capacity of existing activities
* Expansion by installing new processes

Business plans shall be provided as initial proof for investment analysis. During verification, **audited financial statements** **must be provided as proof** that the initial estimates from the business plan were reasonable, and that carbon finance was used as initially described for the expected investment.

Note that for investments in expansion, **only the additional carbon removals enabled by the expansion shall be eligible for Rainbow Carbon Credits.**
{% endtab %}

{% tab title="Barrier analysis" %}
**Barrier analysis** may be used to prove that the project faces financial, institutional, or technological barriers to ongoing operations that can only be overcome using carbon finance. Examples include but are not limited to:

* Financial barrier: financial analysis demonstrating that the project is not financially viable, evidenced by net cash being lower than the working capital requirements, or proof that the project is not meeting the projected financial targets in the business plans and loan documents, and that carbon finance would make it financially viable.
* Institutional barrier: description of new regulation that the project must make costly changes to comply with, financial analysis showing that the project cannot fund the changes on their own, and carbon finance is necessary to make it viable.

For any type of barrier analysis, **audited financial statements must be provided** as proof. These documents should either demonstrate the financial status to prove financial barriers, or show that the project could not independently fund solutions to overcome institutional or technological barriers.
{% endtab %}
{% endtabs %}

## Durability <a href="#lc9eewbyvlyk" id="lc9eewbyvlyk"></a>

#### Durability threshold

All projects certified under this methodology shall prove **durable carbon removals for at least 100 years**. Project Developers may claim an extended durability threshold of 1000 years if they choose the 1000-year pathway for [GHG quantification](/methodologies/distributed-closed-kiln-biochar/ghg-quantification#biochar-carbon-storage) and measurements.

#### Reversal risk assessment

The major carbon reversal risks from biochar carbon storage are:

1. **Insufficient biochar stability**, where biochar carbon is not sufficiently carbonized and is decomposed by microbes and soil organisms, resulting in re-emission of CO<sub>2</sub>.
2. **Failure to durably incorporate into a permanent matrix** (e.g. soil or soil-like material), where biochar is instead burned or destroyed, intentionally or unintentionally (e.g. as fuel, in storage fires, or via waste incineration).

This methodology establishes the following mandatory project design requirements to mitigate these risks, detailed in the following sections:

* measuring the durable carbon fraction
* verification of biochar end use

Upon meeting these requirements for each verification and credit issuance, the risk of reversal is considered **negligible** for biochar application to soils. There are no further project requirements to assess reversal risks or conduct post-crediting monitoring for reversals.

All projects certified under this methodology shall contribute the default minimum 2% of their verified removal RCCs to the Rainbow Buffer Pool, as defined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#durability).

#### Risk mitigation: Measuring permanent carbon fraction <a href="#kmzukpswu89" id="kmzukpswu89"></a>

Not all biomass carbon that is converted to biochar is expected to remain durably stored. The durability of biochar carbon depends on the its physicochemical stability, which is influenced by factors such as carbonization temperature and biomass feedstock.

Project Developers shall measure one of the following well-known [proxy indicators](#user-content-fn-1)[^1] of biochar durability for each [Production Batch](#user-content-fn-2)[^2]. These indicators serve both as **eligibility thresholds**, and as inputs to **quantify the permanent fraction of carbon** ($$F\_{perm}$$) expected to remain durably stored beyond the applicable durability threshold.

The fraction of permanently stored carbon shall be quantified using the models and equations specified in the [GHG quantification](/methodologies/distributed-closed-kiln-biochar/ghg-quantification#biochar-carbon-storage) section. Only this fraction shall be issued as removal RCCs.

<table><thead><tr><th width="136">Pathway</th><th width="213">Indicator</th><th>Threshold requirement</th></tr></thead><tbody><tr><td>100-year pathway</td><td>Hydrogen-to-organic-carbon atomic ratio (<span class="math">H/C_{\text{org}}</span>)</td><td><span class="math">H/C_{\text{org}}</span> must be less than 0.7</td></tr><tr><td>1000-year pathway</td><td>Random reflectance distribution</td><td><ul><li>The fraction of the biochar residual organic carbon that has a random reflectance of 2% or higher can be considered <a data-footnote-ref href="#user-content-fn-3">inertinite</a>, which is an extremely stable, permanent storage of mineral-like organic carbon.</li><li>Must also have <span class="math">H/C_{\text{org}}</span> less than 0.7</li></ul></td></tr></tbody></table>

The distinction between the 100-year and 1,000-year durability pathways provides supplementary qualitative information and does not affect the inherent attributes of the removal RCC.

These indicators are **suitable proof that a substantial fraction** of the carbon present in biochar is permanently stable. The **specific amount** of permanently stored carbon is determined using the models and equations detailed in the [GHG quantification](/methodologies/distributed-closed-kiln-biochar/ghg-quantification#biochar-carbon-storage) section.

These durability indicators shall be monitored for each Production Batch according to this methodology's [Sampling Requirements](#sampling-and-measurements).

Issuing removal RCCs only for the verified, highly stable fraction of biochar carbon mitigates the risk of biological decomposition and re-emission after soil application.

#### Risk mitigation: Proof of biochar end use <a href="#id-5a8ye61po9ri" id="id-5a8ye61po9ri"></a>

Project Developers shall prove that all biochar has been used in the intended durable storage application and [eligible biochar end use](/methodologies/distributed-closed-kiln-biochar/eligibility-and-scope#eligible-biochar-product-and-end-use) (e.g. incorporated into soils, added to fertilizer mixes, mixed in concrete). This shall be done by documenting all of the following information in dMRV:

* Proof of **delivery and use** of the biochar to its point of end use, specifying the date, GPS coordinates, address, amount of biochar, name of the user/buyer, and Production Batch ID.
* **Photo diary of biochar application and/or mixing**, including time-stamped and geo-located photos of the process.

## No double counting <a href="#id-8f3i2uvmiuhl" id="id-8f3i2uvmiuhl"></a>

Project Developers shall sign the [Rainbow MRV & Registry Terms & Conditions](/other/terms-and-contracts/terms-and-conditions-for-project-developers-mrv-+-registry), committing to follow the requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules), including not double using or double issuing carbon credits.

Project Developers shall demonstrate that they hold the sole right to issue carbon credits for all biochar produced under the project, and that no third party will seek to issue credits for the same biochar.

* If biochar is applied to soils by participants within the project network (e.g., farmers who also provide biomass or operate kilns), this is considered to remain within the project scope through to end use, and no additional double counting documentation is required.
* If biochar is transferred to third parties, such as farmers outside the project network or companies incorporating it into construction materials, then Project Developers shall obtain recognition that the Project Developer holds the sole right to issue credits for that biochar, and that the recipient will not seek to issue credits for its use.

## Co-benefits <a href="#id-8f3i2uvmiuhl" id="id-8f3i2uvmiuhl"></a>

Projects should support at least two **quantifiable and verifiable** environmental or social co-benefits, aligned with the [UN Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDGs) framework. Any co-benefits claimed by the Project Developer shall be **quantified, monitored, and audited** for each verification and credit issuance.

Common co-benefits under this methodology are detailed in the table below. Project Developers may suggest and prove other co-benefits not mentioned here.

SDG 13 on Climate Action by default is not considered a co-benefit here, since it is implicitly accounted for in the issuance of carbon credits. If the project delivers climate benefits that are not accounted for in the GHG reduction quantifications, then they may be considered as co-benefits.

*Table 1 Common co-benefits that projects under this methodology may provide are detailed, including types of proof that can be used to justify each co-benefit.*

<table><thead><tr><th width="233.75">UN SDG</th><th width="345">Example</th><th>Proof</th></tr></thead><tbody><tr><td><strong>SDG 1.5:</strong> Build the resilience of the poor and those in vulnerable situations, ensure significant mobilization of resources from a variety of sources</td><td>Kiln Operators, who are often smallholder farmers, receive direct payments from carbon finance generated (<em>mandatory, see</em> <a href="#benefit-sharing"><em>Benefit sharing</em></a> <em>requirements)</em>.</td><td>Payment slips, bank transaction records, contracts.</td></tr><tr><td><strong>SDG 2.4:</strong> Ensure sustainable food production systems, increase productivity, help maintain resilient ecosystems, improve land and soil quality.</td><td>Biochar application to agricultural soils can <a data-footnote-ref href="#user-content-fn-4">increase crop yields</a>.</td><td>Proof of biochar sales to farmers for agricultural use, invoices, receipts of sale of biochar to farmers.</td></tr><tr><td><strong>SDG 3.9:</strong> reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination</td><td>Agricultural residues (feedstock) are pyrolyzed instead of open-field burning, improving air quality.</td><td>Biomass type records, local data on traditional burning practices.</td></tr><tr><td><strong>SDG 12.2:</strong> Sustainable management and efficient use of natural resources</td><td>Biomass waste is converted into valuable biochar instead of being burned or discarded.</td><td>Biomass type records, local statistics on traditional biomass disposal methods.</td></tr></tbody></table>

## Environmental and social safeguards

Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.**

Projects must follow all national, local, and European (if located in Europe) environmental regulations related to, for example, pyrolysis, gasification, waste feedstock management, and biochar spreading on soils.

### Biomass requirements

#### Waste status

Project Developers shall **provide proof of waste status** for any biomass feedstock categorized as waste. This can be done via any one of the following three methods:

* **Price**: if Project Developers did not pay for the biomass, or if they were paid to handle it, the biomass can be considered waste. Acceptable proof includes invoices, receipts, or contracts.
* **Contextual analysis**: Project Developers may submit an analysis supported by reputable sources that the biomass 1) could not be used as main material products, and 2) was not grown for the purpose of CDR[^5].
* **Positive list of wastes**: if the biomass is included in the following list, it can be considered waste. Acceptable proof includes invoices, receipts, contracts, or photographic evidence and is required for validation:

{% columns %}
{% column %}

* sawmill residues
* shavings
* bark
* forestry tops and branches
* wildfire management residues
* sugar beet pulp
  {% endcolumn %}

{% column %}

* straw
* corn cobs
* wood from horticulture (trimmings or whole plants)
* nut shells
* bagasse
  {% endcolumn %}
  {% endcolumns %}

#### Invasive species status

Project Developers shall **provide proof of invasive species status** for any biomass feedstock categorized as invasive species. This may include but is not limited to peer-reviewed scientific literature documenting the species as invasive in the specific region, national or regional government invasive species lists or registers, regional intergovernmental lists (e.g. IUCN Invasive Species Specialist Group database), or local official weed management orders.

Project Developers shall provide an **Ecosystem Restoration Plan**, outlining all of the following:

* the extent of invasive species harvesting, and how much biomass is left in the field after harvesting
* procedures to ensure only targeted invasive species are harvested
* impacts on biodiversity and habitat loss
* impacts on ecosystem carbon loss

#### Forestry certification

Biomass feedstock originating from forests shall provide at least one of the following forestry sustainability certificates (or similar, with a sufficient justification):

* FSC (Forest Stewardship Council)⁠
* PEFC (Program for the Endorsement of Forest Certification)⁠
* RSB (Roundtable on Sustainable Biomaterials)⁠
* SFI (Sustainable Forestry Initiative)⁠
* SBP (Sustainable Biomass Program)⁠

These certifications are used to prove:

* Legal and transparent chain of custody
* Proper forest regeneration
* Safeguarding biodiversity and soil health
* Historically stable or increasing forest carbon stocks
* Sound socio-environmental practices in forestry operations⁠

#### Biomass stakeholder consultation

In addition to the general Rainbow [stakeholder consultation](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#stakeholder-consultation) requirements, Project Developers shall **explicitly consult stakeholders on the project's use of biomass.** This shall cover the Project Developer's right to use the biomass, the biomass status as waste or invasive species, and the alternative fate of the biomass.

### Kiln operation requirements

Distributed biochar production may pose health and safety risks to Kiln Operators, including but not limited to risk of burns and inhalation of smoke and pollutants. Project Developers shall prove all of the following:

* Kiln Operators and Supervisors follow required [safety training](#trainings)
* Kiln Operators are equipped with and use burn protection equipment such as fire resistant gloves or appropriate footwear
* Kiln Operators are equipped with and use smoke protection equipment such as eyewear and masks
* pyrolysis occurs in ventilated outdoor spaces

### Biochar requirements

Biochar applied to soils must be below the pollutant concentration thresholds outlined in Table 2, defined by the [World Biochar Certificate Guidelines](#user-content-fn-6)[^6] (for WBC-Agro). This shall be measured on a representative composite sample of biochar **anytime biomass feedstock changes, or annually**, if biomass feedstock does not change.

*Table 2 The thresholds for pollutant concentrations allowed in biochar, as detailed in the* [*World Biochar Certificate Guidelines*](#user-content-fn-6)[^6]*.*

<table><thead><tr><th width="353.44439697265625">Substance</th><th>Limit amount (g/tonne dry matter)</th></tr></thead><tbody><tr><td>Pb</td><td>300</td></tr><tr><td>Cd</td><td>5</td></tr><tr><td>Cu</td><td>200</td></tr><tr><td>Ni</td><td>100</td></tr><tr><td>Hg</td><td>2</td></tr><tr><td>Zn</td><td>1000</td></tr><tr><td>Cr</td><td>200</td></tr><tr><td>As</td><td>20</td></tr><tr><td>8 EFSA PAH</td><td>1</td></tr></tbody></table>

{% hint style="info" %}
*Disclaimer: The European Biochar Certificate (EBC) and the World Biochar Certificate (WBC) are independent certification programs designed to ensure the quality of biochar products. These certifications are administered and trademarked by Carbon Standards International (CSI) and are distinct from the Rainbow certification and the issuance of carbon credits.*

*The threshold values provided here are based on the voluntary guidelines of the World Biochar Certificate (WBC), reproduced with permission. While these values have been adopted by the Rainbow standard as pollutant thresholds, they are only indicative. Meeting these thresholds for Rainbow certification does not imply eligibility for or any association with the EBC or WBC programs. Project Developers certified under the Rainbow standard shall not make claims or use any trademarked materials from CSI, unless explicitly allowed by CSI.*

*Voluntary certification under the WBC and EBC schemes is overseen by CSI and includes additional requirements beyond pollutant thresholds.*
{% endhint %}

### Environmental and social risk assessment

Project Developers shall fill in the [Rainbow Distributed biochar risk assessment](/methodologies/distributed-closed-kiln-biochar/risk-assessment-template), to evaluate the identified environmental and social risks of projects. The identified risks include:

* Heavy metal or other pollutants in biochar applied to agricultural soils
* Disruption of soil health when collecting and exporting organic matter
* Presence of heavy metals, toxins or other chemical pollutants in the biomass⁠
* Spread of diseases or invasive species
* Cultivation of feedstock
* Deforestation from use of forestry products as feedstock
* Distant transport of feedstock inputs (>100 km)
* Timely and fair payments to smallholder farmers
* Safe kiln operation and training events to prevents burns
* Use of large amounts of water, if water is scarce, for quenching

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

Project Developers shall follow the requirements in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-safeguards) for conducting stakeholder consultation, and where [IPLCs ](#user-content-fn-7)[^7]are involved, obtaining free prior and informed consent (FPIC). Although the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-safeguards) requires benefit sharing only if IPLCs are involved, this methodology requires it in all cases, as detailed in the following section.

#### Benefit sharing

Project Developers shall demonstrate that Kiln Operators are fairly compensated for their contribution to the project. This includes **timely payments** that are not deferred until credits are issued and sold, and **allocation of a fair share** of carbon finance revenues.

The committed timing and amount of benefit sharing shall be defined by Project Developers and **disclosed transparently in project documentation** on the Rainbow registry.

Project Developers shall demonstrate adherence to this commitment annually by providing payment slips, bank transaction records, or other ex-post evidence of payments having occurred.

## Leakage

Project Developers shall source biomass in a way that reduces leakage. Project Developers shall **assess** and, if identified to be material, **quantify** the leakage caused by the distributed biochar project and **deduct** the associated emissions from the project removals. This shall be done by first identifying the alternative use of biomass, and then assessing the leakage risks from the following identified leakage sources:

* Biomass diversion and replacement
* Counterfactual biomass carbon storage

Where leakage risks are identified, Project Developers shall **mitigate** the risk, and document such efforts to do so. Where leakage cannot be fully mitigated, leakage emissions shall be counted towards the project induced GHG emissions and therefore **deducted from project removals**.

#### Alternative use

Project Developers shall evaluate the most likely alternative use/s of each type of biomass used, in order to assess leakage risks associated with **the baseline carbon storage and the diversion of biomass**. The assessment shall be transparent and conservative.

The alternative use shall address questions such as:

* was the biomass used for a product or service, that now needs to be replaced (e.g. bioenergy production)?
* was the biomass going to store carbon anyway (in the biomass itself and/or in the soil)?

Proof shall be provided and may include signed statements from the biomass provider, historical records from the biomass provider, regional statistics or reputable reporting.

A short list of likely alternative uses may be provided for descriptive purposes, but for the purpose of further analysis, one single alternative use per biomass shall be proposed.

#### Biomass diversion and replacement

Using waste biomass helps mitigate activity shifting leakage. However, waste biomass or invasive species may still have valuable alternative uses.

If the [Alternative use of biomass](#alternative-use) assessment concludes that the biomass has a **valuable existing use**, Project Developers shall assess the impacts of diverting it for biochar production. This assessment must address, at a minimum:

* The availability of **substitute materials** (either the same material, if locally abundant, or alternative materials that fulfill the same function).
* The risk of **indirect land use change or deforestation**, particularly if diverting the biomass creates demand for new materials to replace its original function.

Specifically, Project Developers shall identify the **most likely replacement product or process** for the diverted biomass. Project Developers shall justify the amount of replacement product needed to replace the original function of the biomass based on the business-as-usual (BAU) function, using an appropriate conversion factor.

Proof shall be provided and may include signed statements from the biomass provider, historical records from the biomass provider, regional statistics or reputable reporting.

#### Counterfactual biomass carbon storage

Projects shall only be credited for carbon storage that is genuinely additional. **If the alternative use of biomass was to be left on the soil or reapplied to soils** for nutrient recycling, then any permanent carbon storage that would have occurred anyway in the absence of the project shall be **deducted from the project's carbon removal capacity**.

* Any carbon that is demonstrated to remain stored in the feedstock for up to **50 years** shall be considered as baseline carbon storage.
* A **minimum of 0.5%** of the feedstock carbon content is assumed to remain stored and deducted from the project removals.

[Details](/methodologies/distributed-closed-kiln-biochar/ghg-quantification#biomass-leakage) are outlined in the GHG quantification section.

#### Upstream and downstream emissions

Upstream and downstream emissions are accounted for in the life-cycle based GHG quantifications in companion [modules](/modules/processing-and-energy-use).

## Monitoring

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information:

<table><thead><tr><th width="213.005615234375">Measurement frequency</th><th>Parameters</th></tr></thead><tbody><tr><td><strong>Each</strong> <a data-footnote-ref href="#user-content-fn-8"><strong>Production Batch</strong></a><strong>, on a single representative sample of biochar</strong></td><td><ul><li><span class="math">H/C_{\text{org}}</span> and organic carbon content (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li><li>Inertinite content (fraction of the distribution sample that has a random reflectance of 2% or higher) and residual carbon (<em>if calculating 1000-year removals</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li><li>Biochar moisture content, on at least 3 biochar samples (<em>if measuring biochar amount via mass</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-mass">here</a>)</li></ul></td></tr><tr><td><strong>Once per year, or anytime biomass feedstock changes</strong></td><td><ul><li>Methane emissions, on three runs representative of all other kilns in the same Production Batch (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#methane-emissions">here</a>)</li><li>Environmental pollutants of biochar, on one composite sample mixing biochar from each kiln run (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#biochar-requirements">here</a>)</li><li>Dry bulk density of biochar, on at least one sample from each kiln (i.e. 20 different kilns, 20 bulk density measurements) (<em>if measuring biochar amount via volume</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-volume">here</a>)</li><li>Biomass to biochar conversion factor (<em>if <strong>not</strong> weighing the biomass input of each kiln run)</em> (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biomass-amount-used">here</a>)</li><li>Updated biomass leakage assessment (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#leakage">here</a>)</li></ul></td></tr><tr><td><strong>Each kiln run</strong></td><td><ul><li>Moisture content of biomass input (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#moisture-content-of-biomass">here</a>)</li><li>Type of biomass input (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biomass-used">here</a>)</li><li>Amount of biomass input, via precise mass measurements if using a feedstock mix, or estimates if using a singular biomass (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biomass-amount-used">here</a>)</li><li>Amount of any energy inputs used, for example for process ignition.</li><li>Mass or volume of fresh biochar produced (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biochar-produced">here</a>)</li><li>Temperature curve measured in each kiln using real-time sensors, proving pyrolysis has occurred (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#temperature-curves">here</a>)</li><li>Sampling records (proof of setting aside a small sub-sample of biochar, to be combined with sub-samples from all other kiln runs in the same Production Batch) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li></ul></td></tr><tr><td><strong>All biochar used</strong></td><td><ul><li>Proof of eligible, durable biochar end use, with names and GPS coordinates of spreading locations, among other information (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#id-5a8ye61po9ri">here</a>)</li></ul></td></tr><tr><td><strong>Once per year</strong></td><td><ul><li>Kiln Operator training (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#trainings">here</a>)</li><li>Proof and findings from the visits of Kiln Supervisor to each Kiln Operator (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#kiln-supervisor-site-visits">here</a>)</li><li>Proof of calibration and accuracy of onsite scales for weighing biochar to determine biochar amount (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biochar-produced">here</a>)</li></ul></td></tr><tr><td><strong>Once per verification and credit issuance</strong></td><td><ul><li>Quality oversight report from the Project Developer (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#quality-oversight-report">here</a>)</li><li>Environmental sustainability and Leakage compliance of biomass feedstock (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#biomass-requirements">here </a>and <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#leakage">here</a>)</li></ul></td></tr></tbody></table>

The Project Developer is the party responsible for adhering to the Monitoring Plan.

## dMRV requirements

Distributed biochar uniquely heavily relies on third-party [**dMRV**](#user-content-fn-9)[^9] **platforms** to allow for detailed tracking of operations across a network of Kiln Operators.

Project Developers shall select the dMRV to be used by Kiln Operators and Supervisors to document the operating procedures. The chosen dMRV shall provide step by step procedures to Kiln Operators and be able to track the following:

<table><thead><tr><th width="275.953125">Item to track</th><th>Further requirements</th></tr></thead><tbody><tr><td>Eligible kiln use</td><td>Scanned QR codes of individual kilns and photos of the kiln displaying the required technical features</td></tr><tr><td>Biomass moisture content</td><td>Photos of sensor readings</td></tr><tr><td>Biomass preparation and amount</td><td><ul><li>Photos of the biomass to be pyrolyzed before each kiln run and</li><li>The mass or volume of biomass used</li></ul></td></tr><tr><td>Pyrolysis temperature and duration</td><td>Continuous thermocouple readings</td></tr><tr><td>Pyrolysis process quality</td><td>Photos taken throughout the pyrolysis process, including at least one after the last addition of biomass to the kiln, showing the intact and clean flame curtain</td></tr><tr><td>Rapid quenching</td><td>Through time-stamped photos or short videos showing the start and end time of quenching</td></tr><tr><td>Amount of biochar produced</td><td><ul><li>Volume of biochar produced from each kiln run, and bulk density measurements conducted by the Kiln Supervisor, or</li><li>Mass of biochar produced from each kiln run, and moisture content measurements</li></ul></td></tr><tr><td>Biochar sampling records</td><td>Scanned QR codes of the original biochar bags from which the sample is taken, and photos of the sample</td></tr><tr><td>Biochar delivery and application</td><td>Scanned QR codes of biochar bags for delivery and photos</td></tr><tr><td>Aggregated measurements and data</td><td>For GHG quantification</td></tr></tbody></table>

The amount of energy inputs used, for example for process ignition, may be tracked or calculated outside of the dMRV platform.

Methane emissions testing, including results and photos of the process, may be handled in the dMRV platform or in a separate report shared with Rainbow and the VVB.

All photographs must include a timestamp and GPS coordinates. All temperature curves must include a timestamp.

Any data tracked directly in the dMRV platform and uploaded with a delay must:

* include a timestamp of when the upload occurred, and
* be uploaded as a batch with all relevant data upon connectivity, as opposed to manually uploading individual chosen files from chosen kiln runs, to prevent selective submission of preferred data.

The dMRV platform must prevent Kiln Operators from modifying data once it has been uploaded. Data from dMRV shall be made available and verifiable by Rainbow, the Project Developer and the VVB, through an oversight-only view, and [exportable files](#user-content-fn-10)[^10].

All project records must be retained for a minimum of five years following the end of the project's final monitoring period.

At project validation, Rainbow will review the proposed dMRV platform to ensure it is capable of providing the above-mentioned data and proof. After a dMRV platform design is validated and approved as eligible, the platform will be added to Rainbow’s published list of eligible platform. For any future projects using the same dMRV platform, the platform shall be considered **automatically eligible**.

{% hint style="info" %}
The use of an approved dMRV platform is not sufficient to ensure project compliance with the present methodology. All listed data points and proof shall be uploaded to the dMRV platform in order to issue credits.

If any piece of operational proof or documentation is missing in dMRV, the entire kiln run is ineligible.
{% endhint %}

<table><thead><tr><th width="183.73828125">Role</th><th>Use of dMRV platform</th></tr></thead><tbody><tr><td><strong>Kiln Operators</strong></td><td><ul><li>Directly upload the required information to the dMRV platform, and flag any known anomalies.</li></ul></td></tr><tr><td><strong>Kiln Supervisors</strong></td><td><ul><li>Directly upload any biochar bulk density and/or moisture content measurements to the dMRV platform (depending on the measurement method for the <a href="/pages/2JToRbMjCtnlIBxzi8vN#amount-of-biochar-produced">amount of biochar produced</a>), and flag any known anomalies.</li></ul></td></tr><tr><td><strong>Project Developer</strong></td><td><ul><li>Check the information and proof for every kiln run recorded on the dMRV platform, ensuring its accuracy and data preparation (unless outsourcing this task to the dMRV provider, see the <a href="#raw-data-checking">Raw data checking</a> section)</li><li>Provide a <a href="#quality-oversight-report">report on oversight</a> findings, listing non-conformities, adjusted data, and kiln runs excluded from certification.</li></ul></td></tr><tr><td><strong>VVB</strong></td><td><ul><li>Check the complete raw records in dMRV of a random sample of kiln runs, to cover at least 20% of all events.</li><li>Check all records related to biochar bulk density and/or moisture content measurements conducted by Kiln Supervisors, as detailed in the <a href="/pages/2JToRbMjCtnlIBxzi8vN#biochar-amount-produced">biochar amount produced</a> section.</li><li>Findings shall follow the non-conformity procedure outlined in the <a href="/pages/LqYMOAq4owP6jpiFyN5K#non-conformities">Rainbow Procedures Manual</a>. Major non-conformities shall trigger a more thorough audit of a larger sample of events.</li></ul></td></tr></tbody></table>

## Quality and oversight

### Raw data checking

The Project Developer is ultimately responsible for the quality and accuracy of raw records submitted to the VVBs for audit, and identifying and flagging runs that do not meet the quality threshold. All **records from each kiln run shall be individually checked**, ensuring at a minimum all of the following components:

* the duration of the kiln run is consistent with the amount of biochar produced
* the amount of biomass feedstock used is broadly consistent with the amount of biochar produced, based on photographic evidence of the feedstock pile prior to the run
* the amount of biochar produced is [broadly consistent](#user-content-fn-11)[^11] with the amount of biochar reported as applied in an eligible end use
* pyrolysis temperature is consistently high throughout the duration of the kiln run. Project Developers shall suggest their own definition for acceptable temperature curves upon validation. Full details are in the [temperature curve](#temperature-curves) section
* quenching was rapid enough to mitigate methane emissions

Any kiln run with incomplete data, or that demonstrates unsatisfactory practices, is rendered ineligible for crediting (except for the tolerance threshold of [temperature curve](#temperature-curves) failures).

Raw data checking may be completed by the Project Developer, or may be delegated to the Rainbow-approved dMRV provider. Data checking may be completed manually, or via a dMRV-enabled system for automatically scanning for and flagging anomalies. Criteria and anomalies shall be either defined at the dMRV level and applied across all projects, or according to project-specific criteria, and shall be approved by Rainbow. If opting for an automatic flagging approach, the dMRV provider must demonstrate via trial runs that it is capable of flagging deviations from the criteria, and define a protocol for random manual checks.

The VVB shall also manually review the complete raw dMRV records for a random sample of kiln runs, covering at least 20% of all events.

### Kiln Supervisor site visits

The Kiln Supervisor shall **visit each Kiln Operator annually and observe one kiln run**, ensuring:

* feedstock is properly added to the kiln
* biomass moisture content measurements are taken appropriately
* storage conditions for biomass and biochar are appropriate
* biochar sampling procedures are followed

The Kiln Supervisor shall also collect the **Site Composite Sample** during this site visit, which is mixed with other Site Composite Samples to generate the **Production Batch Representative Sample**. Biochar durability indicators and bulk density measurements (if using the biochar volume approach) are done on this biochar sample. See the [Biochar sampling procedure](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements#biochar-sampling-procedure) section for more details.

Proof of the site visits shall be included in the Monitoring Plan and submitted at least once per year, including the name of the Kiln Supervisor, date of visit, and the findings and follow up actions of each Kiln Operator.

{% hint style="info" %}
Note that the Kiln Supervisor site visits are in addition to the annual VVB site audits, described in the [Certification Requirements](/methodologies/distributed-closed-kiln-biochar/eligibility-and-scope#certification-requirements) section.
{% endhint %}

### Quality oversight report

Project Developers shall prepare a report, **upon each verification and credit issuance**, summarizing the findings of dMRV oversight via raw data checking and site visits, as described above. This report shall detail:

* the cumulative biomass used, biochar produced, and biochar applied in an eligible end use, noting any discrepancies and justification,
* any kiln runs that were excluded from certification and the reason for exclusion
* any non-conformities in data uploaded to dMRV and their remediation
* any non-conformities or failure to adhere to best practices in onsite visits, and their remediation

### Temperature curves

All kilns shall be equipped with fixed, continuously-logging thermocouples, producing a documented temperature curve over time for each kiln run. The purpose is twofold: to ensure pyrolysis actually occurred, and to assess the quality of the pyrolysis run.

To **ensure pyrolysis actually occurred**, the temperature curve must show that the temperature of the pyrolysis zone remained above 350°C for the entire process, excluding the ramp up and quenching phases.

To **assess pyrolysis quality**, Project Developers shall submit project-specific criteria for evaluating temperature curves during project validation. These criteria shall be used to flag and exclude ineligible kiln runs, and shall be approved by Rainbow and the VVB. Criteria shall be designed to flag:

* Incomplete biomass drying prior to pyrolysis, and
* Improper feedstock loading rates, such as overloading events that cause a drop in pyrolysis temperature or extinguish the flame curtain.

Criteria definitions shall address target temperatures, durations, and allowable variance, and ramp-up period, quenching, and main pyrolysis time.

**Placement**: Thermocouples should be placed inside the kiln at an appropriate number and spacing to meet the above-mentioned performance requirements. For kilns where it is not technically feasible to place thermocouples inside, they may be placed on the outside of kilns and heat-transfer or energy-balance models shall be used to demonstrate that pyrolysis zone remained above 350°C for the entire process.

**Checking temperature curves**: Temperature curve results from all kiln runs shall be individually checked, according to the [Raw data checking](#raw-data-checking-closed-kiln) requirements.

**Tolerance for thermocouple failures**: some kiln runs are expected to experience thermocouple failures. Biochar from kiln runs that experience a thermocouple failure may still be credited if all other required proof is still available for the kiln run, if the reason for the failure can be explained and justified, and if a kiln does not experience consecutive failures. This is applicable to kiln runs that make up a cumulative maximum of 5% of the biochar in the [Production Batch](#user-content-fn-2)[^2]. Beyond this 5%, any kiln runs with thermocouple failures shall be discarded and not credited. The biochar in such excluded kiln runs does not count towards the size-limit of the Production Batch.

**Calibration**: All thermocouples shall undergo regular calibration.

{% hint style="info" %}
**Integrated temperature sensors** are a promising and relatively new pathway to **verify pyrolysis quality and consistency** for certification of distributed biochar production, ensuring low methane emissions and proper biochar production. Strict methodology-level requirements are not set because:

* Thermocouple setups (number, placement, spacing) vary by kiln design.
* Different biomass feedstocks produce distinct temperature curves due to varied energy content.
* Universal temperature thresholds are not yet established.

Ideally temperature sensors will be used to prove that pyrolysis remains **above 500-550°C**, which is a more robust sign of high-quality pyrolysis than 350°C. However, due to the novelty and expected difficulties in this technology's early deployment, this requirement remains flexible for the time being.
{% endhint %}

### Trainings

Upon validation, Project Developers shall submit their Training Protocol, describing how they ensure:

* frequency of trainings for Kiln Operators and Kiln Supervisors
* testing or proof of adequate completion of training
* ongoing training and support

#### Kiln Operator training

Project Developers are responsible for ensuring regular trainings are provided to Kiln Operators involved in their project. The Kiln Supervisor or the Project Developer may be the party providing training. Training shall cover at least the following aspects of kiln operation:

* safety provisions for operating the kiln
* biomass preparation (drying, eligible biomass size, appropriate size of biomass)
* taking biomass moisture content measurements
* feeding biomass into the kiln to ensure consistent pyrolysis
* rapid quenching
* managing the [biochar sampling procedure](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements#biochar-sampling-procedure)
* use of dMRV

#### Kiln Supervisor training

Project Developers shall justify the expertise and qualifications of Kiln Supervisors. This may be through dedicated training or previous relevant experience. This shall cover at a minimum:

* all points listed above, to be transmitted to Kiln Operators
* biochar amount measurements, including bulk density and moisture content

[^1]: - Rodrigues, L., Budai, A., Elsgaard, L., Hardy, B., Keel, S.G., Mondini, C., Plaza, C., Leifeld, J., 2023. The importance of biochar quality and pyrolysis yield for soil carbon sequestration in practice. European Journal of Soil Science 74, e13396. [https://doi.org/10.1111/ejss.1339](https://doi.org/10.1111/ejss.13396)
    - Rudra, A., Petersen, H.I., Sanei, H., 2024. Molecular characterization of biochar and the relation to carbon permanence. International Journal of Coal Geology 291, 104565. <https://doi.org/10.1016/j.coal.2024.104565>
    - Wang, J., Xiong, Z., Kuzyakov, Y., 2016. Biochar stability in soil: meta-analysis of decomposition and priming effects. GCB Bioenergy 8, 512–523. <https://doi.org/10.1111/gcbb.12266>
    - Sanei, H., Rudra, A., Przyswitt, Z.M.M., Kousted, S., Sindlev, M.B., Zheng, X., Nielsen, S.B., Petersen, H.I., 2024. Assessing biochar’s permanence: An inertinite benchmark. International Journal of Coal Geology 281, 104409. <https://doi.org/10.1016/j.coal.2023.104409>

[^2]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for **a maximum of 6 months operating time or 200 tonnes of biochar**, whichever comes first.

[^3]: Inertinite is a type of maceral. Macerals are the organic compounds in materials like coal and shale, and are extremely permanent. They are analogous to mineral carbon in rocks.

[^4]: * Schmidt, H.-P., Kammann, C., Hagemann, N., Leifeld, J., Bucheli, T.D., Sánchez Monedero, M.A., Cayuela, M.L., 2021. Biochar in agriculture – A systematic review of 26 global meta-analyses. GCB Bioenergy 13, 1708–1730.[ https://doi.org/10.1111/gcbb.12889](https://doi.org/10.1111/gcbb.12889)
    * Joseph, S., Cowie, A.L., Van Zwieten, L., Bolan, N., Budai, A., Buss, W., Cayuela, M.L., Graber, E.R., Ippolito, J.A., Kuzyakov, Y., Luo, Y., Ok, Y.S., Palansooriya, K.N., Shepherd, J., Stephens, S., Weng, Z. (Han), Lehmann, J., 2021. How biochar works, and when it doesn’t: A review of mechanisms controlling soil and plant responses to biochar. GCB Bioenergy 13, 1731–1764.[ https://doi.org/10.1111/gcbb.12885](https://doi.org/10.1111/gcbb.12885)

[^5]: Carbon dioxide removal

[^6]: WBC (2023): World Biochar Certificate – Guidelines for a Sustainable Production of Biochar and its Certification.' Carbon Standards International, Frick, Switzerland, (<http://www.european-biochar.org>), version 1.1 from 20th December 2024. [URL](https://www.carbon-standards.com/en/standards/service-514~production-of-biochar.html).

[^7]: Indigenous peoples are defined in the [Glossary](https://docs.rainbowstandard.io/glossary#general) as people that self-identify as Indigenous and are recognized by others as Indigenous, with historical continuity with pre-colonial societies; distinct languages, customs, and institutions; a strong connection to ancestral lands or territories; and are often governed by customary laws or traditional authorities.

    Local communities are defined in the [Glossary](https://docs.rainbowstandard.io/~/changes/180/glossary#general) as non-Indigenous people with a long-standing connection to a particular rural or semi-rural geographic area; reliance on local natural resources for livelihood; social cohesion or shared cultural traits, though not necessarily Indigenous; living in geographic proximity to a part of the project area, including but not limited to sourcing, production, and/or end use locations.

[^8]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for a maximum of 6 months operating time or 100 tonnes of biochar, whichever comes first.

[^9]: digital monitoring, reporting and verification

[^10]: There is no specific format or template to follow. Exported data must be in a widely usable and accessible format and file type, to ensure that data remain accessible outside of the dMRV platform.

[^11]: Amount of biochar produced **does not need to match exactly** the amount reported as applied within the same monitoring period, as biochar may be stored and applied in a later monitoring period. Cumulative biochar production records must remain consistent with cumulative end-use application records across monitoring periods


# GHG quantification

Calculations of GHG emissions for the baseline and project scenarios shall follow a robust, recognized method and good practice guidance. The overall methodological approach is a comparative life cycle assessment (LCA) at the project-scale, based on [ISO 14064-2:2019](#user-content-fn-1)[^1].

This methodology shall be used in conjunction with the Rainbow modules listed below. **Modules are like mini-methodologies** that only cover a part of the project life-cycle. Combining the relevant modules for a project results in a complete picture of the required data, calculations, monitoring plans, and other information needed for a full GHG quantification.

<table data-view="cards"><thead><tr><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="image">Cover image</th></tr></thead><tbody><tr><td>Processing and energy use</td><td><a href="/pages/BTxxPIM3a4Nai1Wkwu2Y">/pages/BTxxPIM3a4Nai1Wkwu2Y</a></td><td><a href="/files/xqDoBuMbX7fcBqJ8AanC">/files/xqDoBuMbX7fcBqJ8AanC</a></td></tr><tr><td>Transportation</td><td><a href="/pages/VTWdCc7guKu1x0azAizi">/pages/VTWdCc7guKu1x0azAizi</a></td><td><a href="/files/XAxrYlLSh0qtvbDkKkqp">/files/XAxrYlLSh0qtvbDkKkqp</a></td></tr><tr><td>Infrastructure and machinery</td><td><a href="/pages/IwqpSqlee22qTIPti3Sl">/pages/IwqpSqlee22qTIPti3Sl</a></td><td><a href="/files/gE6Zo8o6awA0p9LnSTnF">/files/gE6Zo8o6awA0p9LnSTnF</a></td></tr></tbody></table>

**GHG quantification shall be done separately for each biochar** [**Production Batch**](#user-content-fn-2)[^2], since each batch by definition has distinctly measured biochar carbon characteristics. The GHG quantification results of multiple Production Batches may be combined for one monitoring period.

## System boundary

The system boundary of this quantification section starts at the procurement of biomass feedstock, and ends at the biochar end of life, after accounting for decay and re-emission in its end use application. Biomass feedstock production impacts are excluded because biomass is required to be waste or invasive species, and therefore not allocated any production or cultivation emissions. The system boundary includes the following key steps, also displayed in Figure 1:

* biomass collection
* biomass transport to the kiln
* biomass processing (including but not limited to drying and chipping)
* energy used to start the kiln (including high-quality wood, and any associated leakage emissions)
* energy used to combust methane emissions within the reactor
* embodied emissions from manufacturing the kilns, including their shipping to the pyrolysis site and end of life waste treatment
* methane emissions from the pyrolysis process
* biochar transport to the site of use

<figure><img src="/files/rOSKGxO5AUAL4Li8oReq" alt=""><figcaption><p>Figure 1 The system boundary of the distributed biochar quantification is summarized. Processes are grouped and color-coded according to the section below where they are described in detail.</p></figcaption></figure>

Any steps that are fully manual do not incur any GHG emissions. Any steps that would have occurred anyway in the baseline scenario shall be excluded from the system boundary.

The following high-level equations shall be used to calculate carbon removals from distributed biochar projects.

<details>

<summary><strong>Calculations:</strong> Removals</summary>

$$\textbf{(Eq.1)}\ Net\ Removal = R\_{baseline}-R\_{project}-E\_{project}$$

where,

* $$Net\ Removal$$ represents the net removals from the project during the monitoring period, in tonnes of CO$$\_2$$eq. Its sign is positive.
* $$R\_{baseline}$$ represents any baseline GHG removals, representing permanent storage that would have occurred in the absence of the project, in tonnes of CO$$\_2$$eq. Its sign is negative. Its value is zero, as outlined in the [baseline scope](/methodologies/distributed-closed-kiln-biochar/eligibility-and-scope#baseline-scope) section.
* $$R\_{project}$$ represents the project's gross GHG removals, in tonnes of CO$$\_2$$eq. Its sign is negative.
* $$E\_{project}$$ represents the project's total induced GHG emissions across the project life cycle, in tonnes of CO$$\_2$$eq. Its sign is positive.

$$\textbf{(Eq.2)}\ E\_{project} = {E}*{project,\ leakage} + E*{project,\ methane}+ {E}*{Transport,\ total}+ E*{infra,\ machinery} + E\_{project,\ processing}$$

where,

* $$E\_{project}$$ was described in Eq. 1.
* $$E\_{project,\ leakage}$$ represents the project's GHG emissions from leakage from use of biomass.
* $$E\_{project,\ methane}$$ represents the total methane emissions from pyrolysis, in tCO$$\_2$$eq, calculated in the [Pyrolysis process](#pyrolysis-process) section below.
* $${E}\_{Transport,\ total}$$ represents the project's GHG emissions from the [Transportation](/modules/transportation) module, including the energy use and embodied emissions involved in transporting all input and output materials.
* $$E\_{infra,\ machinery}$$ represents the total emissions from the [Infrastructure and machinery](/modules/infrastructure-and-machinery) module allocated to the project for the monitoring period.
* $$E\_{project,\ processing}$$ represents the total emissions from other inputs and outputs calculated in the [Processing and energy use](/modules/processing-and-energy-use) module.

***

GHG quantification is performed for each Production Batch, based on the amount of biochar produced, but removal Rainbow Carbon Credits (RCCs) are issued on the basis of biochar delivery and application in an eligible end use. The following equation is used to determine the number of RCCs to issue per monitoring period, accounting for **a potential delay in biochar use after production**. See the [Functional unit](#kpxsamb8logm) section for more details.

$$\textbf{(Eq.3)}\ Removal\ RCCs= \frac{Net\ removal}{tonne\ or\ m^3\ biochar\ produced} \times tonne\ or\ m^3\ biochar\ delivered$$

Where

* $$Removal\ RCCs$$ represents the number of removal credits to be issued at the end of the monitoring period.
* $$Net\ removal$$ was calculated in Eq. 1.
* $$tonne\ or\ m^3\ biochar\ produced$$ represents the amount of **biochar produced** in the entire Production Batch. Project Developers may choose whether to report it by mass or volume, in tonnes or in m<sup>3</sup> of biochar.
* $$tonne\ or\ m^3\ biochar\ delivered$$ represents the amount of **biochar delivered in an eligible end use** in the monitoring period, for the given Production Batch. It must be reported in the same units as for the $$tonne\ or\ m^3\ biochar\ produced$$ variable.

</details>

## Functional unit <a href="#kpxsamb8logm" id="kpxsamb8logm"></a>

The functional unit shall be **1 tonne of biochar produced** or **1 m**<sup>**3**</sup>**&#x20;of biochar produced**, depending on the project's chosen measurement method for the [Biochar amount produced](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements#biochar-amount-produced).

Input data shall be provided for all processes related to biochar production in the given Production Batch, and net project removals are first calculated for **all processes across the entire duration of the Production Batch**.

This is normalized to net removals per functional unit by **dividing by the amount of biochar produced** in the Production Batch.

The number of credits to issue in the given monitoring period is calculated by multiplying the amount of biochar delivered applied in an eligible end use, by the net removals per tonne or m<sup>3</sup> of biochar produced.

This approach is detailed in Eq. 3 above.

## Data sources <a href="#kpxsamb8logm" id="kpxsamb8logm"></a>

The required **primary data for GHG calculations** from projects are presented in Table 1. These data shall be **aggregated for all kiln runs within a** **Production Batch**, after being measured and reported in dMRV at the frequencies summarized in the [Monitoring](/methodologies/distributed-closed-kiln-biochar/principles-and-requirements#monitoring) section, and made publicly available.

Note that the table **does not include all information needed for project monitoring and verification: only the data inputs for ongoing GHG quantification**. The full list of information is provided in the minimum requirements for a [Monitoring Plan](broken://pages/kRkqwDGuCJMBhsZ0VuaV#monitoring).

*Table 1 Summary of primary data needed from projects and their source for GHG quantification. All primary data sources listed here are required to be monitored and updated during verification. \*Note that only one approach is required for reporting transport data. See the* [*Transportation module*](/modules/transportation) *for more details. \*\*See the* [*Infrastructure and machinery*](/modules/infrastructure-and-machinery#ghg-quantification) *module for more details.*

<table><thead><tr><th width="160.6605224609375">Category</th><th width="209.40625">Parameter</th><th width="159.3359375">Unit</th><th>Source</th></tr></thead><tbody><tr><td>General, credit issuance</td><td>Volume or mass of biochar delivered in permanent end use</td><td>m<sup>3</sup> or tonnes of biochar</td><td>Measured onsite, dMRV</td></tr><tr><td>Carbon storage</td><td>Volume or mass of biochar produced</td><td>m<sup>3</sup> or tonnes of biochar</td><td>Measured onsite, dMRV</td></tr><tr><td>Carbon storage</td><td>Bulk density of biochar (<em>only if using volume</em>)</td><td>tonne of biochar/m<sup>3</sup></td><td>Measured onsite, dMRV</td></tr><tr><td>Carbon storage</td><td>Biochar moisture content (<span class="math">M_{\text{%}}</span>) (<em>only if using mass</em>)</td><td>Percent</td><td>Elemental analysis by accredited laboratory</td></tr><tr><td>Carbon storage</td><td>Biochar <span class="math">H/C_{\text{org}}</span></td><td>Ratio</td><td>Elemental analysis by accredited laboratory</td></tr><tr><td>Carbon storage</td><td>Biochar organic carbon content</td><td>Percent</td><td>Elemental analysis by accredited laboratory</td></tr><tr><td>Carbon storage</td><td>Fraction of <span class="math">R_{O}</span><br>distribution measurements above 2% (<em>only if using 1000-year approach</em>)</td><td>Fraction</td><td>Analysis by accredited laboratory</td></tr><tr><td>Carbon storage</td><td>Residual organic carbon (<span class="math">C_{org,\ f\ residual}</span>) (<em>only if using 1000-year approach</em>)</td><td>Fraction</td><td>Analysis by accredited laboratory</td></tr><tr><td>Carbon storage</td><td><a data-footnote-ref href="#user-content-fn-3">GPS coordinates </a>of biochar spreading sites (for determining soil temperature)</td><td>coordinates</td><td>dMRV</td></tr><tr><td>Biomass leakage</td><td>Carbon sequestration rate (<em>or use default 0.5%)</em></td><td>Percent</td><td>Secondary literature, models</td></tr><tr><td>Pyrolysis process</td><td>Methane emissions rate</td><td>g CH<sub>4</sub>/kg dry biochar</td><td>Analyses from accredited independent provider</td></tr><tr><td>Pyrolysis process</td><td>Energy or wood for starting pyrolysis (amount and type)</td><td>MJ, kWh, liters fuel, kg wood</td><td>Measured onsite, dMRV</td></tr><tr><td>Pyrolysis machinery</td><td><p>Item and material type, material amount,</p><p>item lifetime**</p></td><td><ul><li>kg, tonne, m<sup>3</sup></li><li>years</li><li>e.g. kiln made of 80 kg steel for 5 years</li></ul></td><td>Technical specifications, bill of materials, invoices</td></tr><tr><td>Transport of biomass</td><td>Distance biomass transported by motorized vehicle*</td><td>km</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biomass</td><td>Weight of biomass transported*</td><td>tonne</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biomass</td><td>Vehicle type for biomass transport*</td><td>category</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biomass</td><td>Fuel quantity consumed for biomass transport*</td><td>liters fuel</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biochar</td><td>Distance biochar transported by motorized vehicle*</td><td>km</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biochar</td><td>Weight of biochar transported*</td><td>tonne</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biochar</td><td>Vehicle type for biochar transport*</td><td>category</td><td>Operational records, conservative justified estimates</td></tr><tr><td>Transport of biochar</td><td>Fuel quantity consumed for biochar transport*</td><td>liters fuel</td><td>Operational records, conservative justified estimates</td></tr></tbody></table>

The [ecoinvent database](#user-content-fn-4)[^4] version 3.12 (hereafter referred to as ecoinvent) shall be the main source of emission factors unless otherwise specified. Ecoinvent is preferred because it is traceable, reliable, and well-recognized. The ecoinvent processes selected are detailed in [Appendix 1](#appendix).

No other secondary data sources are used in this methodology.

## Assumptions

1. All biochar from the same Production Batch has the same characteristics (e.g. $$M\_{\text{%}}$$, $$H/C\_{\text{org}}$$...).
2. All biochar made from the same feedstock has the same methane emission rate from pyrolysis.
3. The permanent carbon sequestration rate from biomass leakage, where the alternate fate is being left on the field to decompose, is at least 0.5%.

## Baseline scenario <a href="#ly65klblzpa9" id="ly65klblzpa9"></a>

There is no baseline because it is assumed that there is no significant share of the project activity already occurring in business-as-usual. Therefore, the baseline for removal credits is zero and is omitted from calculations.

According to the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/project-and-baseline-scope#updating-the-baseline), this assumption shall be re-assessed at a minimum every 5 years, and any changes to this assumption would be [applied to existing projects](/rainbow-standard-documents/procedures-manual/project-certification-procedure#compliance-and-project-updates).

## Project scenario <a href="#i4figd8ytjua" id="i4figd8ytjua"></a>

### Biomass leakage

{% hint style="info" %}
This section is only required if the feedstock's alternative use was to be **left on the soil or reapplied to soils for nutrient recycling**. This includes but is not limited to:

* mulching
* composting
* spreading fast-decaying cellulose-based residues (e.g. decay within 5 years)
  {% endhint %}

Project leakage shall account for permanent carbon storage that would have occurred anyway in the absence of the project.

Although most biomass carbon would be released before the project's permanence horizon, a small fraction may be stabilized permanently as soil carbon. This portion is counted as leakage and deducted from the project's carbon removal capacity.

The uncertainty around biomass carbon being 1) naturally incorporated into the soil and 2) converted to a stable carbon form is high, influenced by factors such as climate, soil type, soil health, and land use, making it hard to estimate for individual projects. Thus, it is assumed that a default **0.5% of the carbon in the biomass feedstock** left on the soil, or reapplied to soil, will be permanently stored in soils.

Project Developers may conduct a project-specific assessment and provide a different carbon sequestration rate, but the final rate used in calculations shall be 0.5% or higher.

#### Biomass diversion and replacement

Leakage associated with the diversion and replacement of the biomass from its alternative use shall be quantified for each biomass used.

Project Developers shall follow the [Alternative use](/methodologies/distributed-closed-kiln-biochar/principles-and-requirements#alternative-use) and [Biomass diversion and replacement](/methodologies/distributed-closed-kiln-biochar/principles-and-requirements#biomass-diversion-and-replacement) guidelines in the Leakage section to determine the type and amount of replacement/substitute product or process.

Project Developers shall provide a conservative and representative emission factor for the production and use of the replacement product.

<details>

<summary><strong>Calculations:</strong> Biomass leakage, biomass amount, biochar amount</summary>

$$\textbf{(Eq.4)}\ {E}*{project\ leakage}= E*{CF\ carbon\ storage}+ E\_{replacement}$$

Where,

* $$E\_{CF\ carbon\ storage}$$ represents the biomass leakage from the monitoring period, in tCO$$\_2$$eq. This value shall be applied to Equation 2.
* $$E\_{CF\ carbon\ storage}$$ represents the permanent carbon removal in the baseline scenario in the monitoring period, in tCO$$\_2$$eq.
* $$E\_{replacement}$$ represents the leakage emissions from the diversion of biomass and replacement of its substitute, in tCO<sub>2</sub>eq.

$$\textbf{(Eq.5)}\ E\_{CF\ carbon\ storage}= A\_{biomass}\times C\_{biomass} \times S\_{biomass} \times C\ to\ {CO}\_{2}$$

Where,

* $$E\_{CF\ carbon\ storage}$$ was described in Equation 4.
* $$A\_{biomass}$$ represents the amount of biomass feedstock used in the monitoring period, in tonnes of dry matter. It may be **weighed directly** and converted to dry mass using biomass moisture content measurement&#x73;**, or calculated** using Eq. 6 below
* $$C\_{biomass}$$ represents the concentration of carbon in the biomass feedstock, in tonnes of carbon per tonne of dry matter. This value may come from secondary sources.
* $$S\_{biomass}$$ represents the permanent sequestration rate of carbon applied to soils, which may be provided by the Project Developer from secondary sources, but shall be at least 0.5%, as described in the [Assumptions ](#id-4l7lx2ihb6hj)section.
* $$C\ to\ {CO}\_{2}$$ is 44/12 = 3.67, and represents the molar masses of CO$$\_2$$ and carbon respectively, and is used to convert tonnes of carbon to tonnes of CO$$\_2$$eq.

$$\textbf{(Eq.6)}\ A\_{biomass} = A\_{biochar} \div CF\_{biomass\ to\ biochar}$$

Where,

* $$A\_{biomass}$$ was described in Eq. 5.
* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar. It shall be calculated using either Equation 7, 8, or 9, depending on the project's chosen [biochar amount measurement method](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements#amount-of-biochar-produced).
* $$CF\_{biomass\ to\ biochar}$$ represents the biomass to biochar conversion factor, as tonnes fresh biomass input $$\div$$ tonnes dry biochar output. It may be taken from secondary sources or measured for each project, as detailed in the [Sampling and measurements](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements#amount-of-biomass-used) section.

$$\textbf{(Eq.7)}\ A\_{biochar} = V \* BD\_{fresh}\*(1-M\_{fresh%})$$

where,

* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar.
* $$V$$ represents the volume of biochar produced in m<sup>3</sup>.
* $$BD\_{fresh}$$ represents the bulk density of fresh biochar (as opposed to dry biochar), considering the mass of fresh biochar, in tonnes biochar/m<sup>3</sup>.
* $$M\_{fresh%}$$ represents the moisture content of fresh biochar, on a weight basis (%w/w), so $$1-M\_{fresh%}$$ converts to dry mass of biochar.

$$\textbf{(Eq.8)}\ A\_{biochar} = mass\_{fresh}\*(1-M\_{fresh%})$$

where,

* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar.
* $$mass\_{fresh}$$ represents the mass of fresh or quenched biochar directly measured with scales at each kiln, in tonnes.
* $$M\_{fresh%}$$ represents the moisture content of fresh biochar, on a weight basis (%w/w), so $$1-M\_{fresh%}$$ converts to dry mass of biochar.

$$\textbf{(Eq.9)}\ A\_{biochar} = mass\_{bone\ dry}$$

where,

* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar.
* $$mass\_{bone\ dry}$$ represents the mass of dry biochar directly measured with scales at each kiln, in tonnes. Since it is measured on biochar immediately after exiting the kiln, it is assumed to be bone dry (i.e. 0% moisture content).

$$\textbf{(Eq.10)}\ E\_{replacement}=A\_{biomass}*F\_{conversion}* EF\_{alternative \ use}$$

where,

* $$E\_{replacement}$$ was described in Equation 4.
* $$A\_{biomass}$$ was calculated in Eq. 5.
* $$F\_{conversion}$$ represents a conversion factor for biomass replacement of its substitute.
* $$EF\_{alternative \ use}$$ represents the conservative and representative emission factor for the replacement product of the biomass, in tCO<sub>2</sub>eq/appropriate unit.

</details>

### Biomass processing

The Rainbow [Processing and energy use](/modules/processing-and-energy-use) module shall be used to quantify the emissions from energy or material use for preparing biomass for pyrolysis. This includes but is not limited to drying and chipping biomass.

### Transport of biomass and biochar

If biomass is transported to a pyrolysis site, or biochar is transported to its end-use point, using **a vehicle that is not manually powered**, transport emissions shall be accounted for using the [Transportation module](/modules/transportation) to calculate $${E}\_{Transport,\ total}$$ used in Eq. 2.

For this distributed small-scale technology type, it is expected that direct proof of transport will be unavailable (e.g., distance transported or fuel use during delivery). Therefore, Project Developers may provide **justified and conservative estimates** of transport distance, fuel consumed, and transport method.

### Pyrolysis process

Any energy used to start the kiln (including high-quality wood and any associated leakage emissions), as well as energy used to combust methane emissions within the reactor, shall be included in the project’s total induced GHG emissions quantification. These emissions shall be calculated using the [Processing and energy use module](/modules/processing-and-energy-use).

Methane emissions from pyrolysis shall be accounted for using direct methane measurements on a subset of representative kiln runs, following the [Sampling and measurements](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements#methane-emissions) requirements, and using the following equations.

<details>

<summary><strong>Calculations</strong>: Pyrolysis methane emissions</summary>

$$\textbf{(Eq.11)}\ {E}*{project,\ methane}= A*{biochar}\* E\_{bioCH\_4}\div 1000\*GWP\_{bioCH\_4}$$

Where,

* $$E\_{project,\ methane}$$ represents the total methane emissions from pyrolysis, in tCO$$\_2$$eq. It shall be used in Equation 2.
* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar. It shall be calculated using either Equation 7, 8 or 9, depending on the project's chosen [biochar amount measurement method](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements#biochar-amount-produced).
* $$E\_{bioCH\_4}$$ represents the emission rate of biogenic methane from the pyrolysis process, in gCH<sub>4</sub>/kg dry biochar, measured according to the [Sampling and Measurement ](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements#methane-emissions)requirements.
* $${GWP}\_{bio\ CH4}$$ represents the global warming potential of biogenic CH$$\_4$$ over 100 years, which is 27[^5] tCO$$\_2$$eq/t CH$$\_4$$.
* Divided by 1000 to convert from gCH<sub>4</sub>/kg dry biochar to tonne CH<sub>4</sub>/tonne dry biochar.

</details>

### Infrastructure and machinery

The Rainbow [Infrastructure and machinery module](/modules/infrastructure-and-machinery) shall be used to quantify the embodied emissions of kilns.

### Biochar carbon storage

Project Developers shall choose between one of two approaches to quantify the gross carbon removals from their biochar product, as described in the [Durability](/methodologies/distributed-closed-kiln-biochar/principles-and-requirements#lc9eewbyvlyk-1) section. A single approach must be used consistently throughout each monitoring period, though a different approach may be chosen for subsequent monitoring periods.

1. Modeling 100-year removals using bulk measurements of $$H/C\_{\text{org}}$$, or
2. Estimating 1000-year removals using random reflectance measurements as proxies for inertinite.

#### Approach 1: Modeling 100-year removals using bulk measurements of $$H/C\_{\text{org}}$$ <a href="#id-2rhx2av7of74" id="id-2rhx2av7of74"></a>

Project Developers shall quantify the gross carbon removals from their biochar project by modeling 100-year removals using bulk measurements of $$H/C\_{\text{org}}$$. These measurements shall be done once per [Production Batch](#user-content-fn-2)[^2]. The measurements shall be done on the **Production Batch Representative Sample**, mixing biochar from each kiln run. See [Sampling and measurements](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements) for more details.

This approach is based on research from [Woolf et al., 2021](#user-content-fn-6)[^6], and the [IPCC modeling method](#user-content-fn-7)[^7]. It is rooted in soil ecology and soil biochemistry disciplines. The **permanent fraction** of biochar carbon remaining after 100 years ($$F\_{\text{perm 100}}$$) is modeled according to the local average annual temperature.

Temperature shall be obtained in the following ways:

* Biochar application to soil or mixing into horticultural products: Soil temperature shall be obtained for the end use location of each biochar spreading or mixing event, using the GPS coordinates provided in the Verification of end use report and the global soil temperature dataset from [Lembrechts et al., 2021](#user-content-fn-8)[^8]. The Rainbow Certification Team can provide soil temperature values for Project Developers based on the provided GPS coordinates.
* Biochar mixing into concrete: Average annual air temperature at the location where biochar is mixed into concrete shall be used. It shall be taken from reputable public databases.

*Table 2 Soil temperature ranges are categorized and their corresponding c and m regression coefficients are presented, which are used in Eq. 10 below to calculate* $$F\_{perm}$$. *Values are taken from* [*Woolf et al., 2021*](#user-content-fn-6)[^6]*.*

| Soil temperature (°C) | c    | m    |
| --------------------- | ---- | ---- |
| <7.49                 | 1.13 | 0.46 |
| 7.5-12.49             | 1.10 | 0.59 |
| 12.5-17.49            | 1.04 | 0.64 |
| 17.5-22.49            | 1.01 | 0.65 |
| >22.5                 | 0.98 | 0.66 |

<details>

<summary><strong>Calculations:</strong> Biochar carbon storage</summary>

$$\textbf{(Eq.12)}\ F\_{perm\ 100} = c - m\*H/C\_{org}$$

where,

* $$F\_{perm\ 100}$$ represents the fraction of biochar carbon remaining after 100 years
* $$c$$ and $$m$$ represent regression coefficients, taken from [Woolf et al., 2021](#user-content-fn-6)[^6], and summarized in Table 2 for the corresponding project location's soil or air temperature.
* $$H/C\_{org}$$ represents the ratio of molar hydrogen to organic carbon in biochar, measured via elemental analysis by an accredited laboratory for each production batch.

$$\textbf{(Eq.13)}\ R\_{project}= F\_{perm\ 100}\*{C\_{org}*A}*{biochar}\*C\ to\ {CO}*{2}*-1$$

where,

* $$R\_{project}$$ represents the total carbon removals from biochar during the monitoring period, in tonnes of CO$$\_2$$eq. This value shall be applied to Equation 1 to calculate total project removals.
* $$F\_{perm\ 100}$$ is calculated in Equation 12.
* $$C\_{org}$$ represents the concentration of organic carbon in biochar, on a dry weight basis.
* $$A\_{biochar}$$ represents the amount of biochar produced during the monitoring period, in tonnes of dry biochar. It is obtained using Equation 7, 8 or 9 depending on the project's chosen measurement method.
* $$C\ to\ {CO}\_{2}$$ is 44/12 = 3.67, and represents the molar masses of CO$$\_2$$ and C respectively, and is used to convert tonnes C to tonnes of CO$$\_2$$eq.
* It is multiplied by -1 to obtain a negative sign. Removals are reported as a negative value.

</details>

#### Approach 2: Estimating 1000-year removals based on inertinite fraction <a href="#id-2rhx2av7of74" id="id-2rhx2av7of74"></a>

This approach is based on the research from [Sanei et al., 2024](#user-content-fn-9)[^9], and is rooted in the organic petrology and geochemistry disciplines. This approach is built upon research showing that fractions of inertinite in biochar samples are:

* [inert and permanent](#user-content-fn-10)[^10] and will not re-release their carbon for at least 1000 years.
* represented by the fraction of residual (i.e. not reactive, not labile) organic carbon in the sample with a Random Reflectance ($$R\_o$$) of [2% or higher](#user-content-fn-9)[^9].

Project Developers shall provide $$R\_o$$ distribution, [labile organic carbon content](#user-content-fn-11)[^11], and moisture content for biochar from each [Production Batch](#user-content-fn-2)[^2], following the [Sampling requirements](/methodologies/distributed-closed-kiln-biochar/sampling-and-measurements#biochar-sampling-procedure).

To determine the inertinite fraction of the biochar's organic carbon, first the labile carbon fraction is measured and subtracted from total organic carbon content, and only the residual organic carbon content is considered.

Next, random reflectance measurements are used to determine the fraction of residual organic carbon that is classified as inertinite:

* The fraction of the distribution with an $$R\_o$$ **above 2%** represents the fraction of the biochar carbon that is stored permanently for 1000 years.
* The fraction of the distribution with an $$R\_o$$ **below 2%** represents the fraction of biochar carbon that is not permanently stored, and for which no removal RCCs are issued.

$$R\_o$$ distribution shall be based on at least 500 measurements, yielding a frequency distribution diagram similar to the examples in Figure 2a and 2b.

![Figure 2a An example of a random reflectance frequency distribution diagram, with an analysis described below.](/files/RvDwkJem5UkBnsnCmFSv)

{% hint style="info" %}
Example 1: This biochar sample has heterogenous quality and a wide distribution of $$R\_o$$ measurements. The biochar sample has:

* labile organic carbon content of 5%,
* residual organic carbon content of 95%,
* mean $$R\_o$$ of 2.12, and
* 72% of the $$R\_o$$ measurements are above the 2% inertinite threshold.

Therefore, this biochar sample has an $$F\_{\text{perm\ 1000}}$$ of $$0.72 \times 0.95=0.684$$ , so 68.4% of the organic carbon in the sample will be converted to CO$$\_2$$eq and considered as 1000-year carbon removals. The remaining 31.6% of carbon is assumed to decompose within the 1000-year permanence horizon, and is not considered for any removal RCCs.
{% endhint %}

![Figure 2b An example of a random reflectance frequency distribution diagram, with an analysis described below.](/files/zys8iUA26XGiah6RpKoc)

{% hint style="info" %}
Example 2: This biochar sample has more homogenous quality and a narrow distribution of $$R\_o$$ measurements. The biochar sample has:

* labile organic carbon content of 1%
* residual organic carbon content of 99%
* mean $$R\_o$$ of 2.32, and
* 95% of the $$R\_o$$ measurements are above the 2% inertinite threshold.

Therefore, this biochar sample has an $$F\_{\text{perm\ 1000}}$$ of $$0.99\*0.95=0.94$$, so 94% of the organic carbon in the sample will be converted to CO$$\_2$$eq and considered as 1000-year carbon removals. The remaining 6% of carbon is assumed to decompose within the 1000-year permanence horizon, and is not considered for any removal RCCs.
{% endhint %}

<details>

<summary><strong>Calculations: 1000-year removal credits with random reflectance</strong></summary>

$$\textbf{(Eq.14)}\ F\_{perm\ 1000} = {Sample\ fraction}*{> 2%\ Ro} \times C*{org,\ f\ residual}$$

where,

* $$F\_{perm\ 1000}$$ represents the fraction of biochar carbon remaining after 1000 years.
* $${Sample\ fraction}\_{> 2%\ Ro}$$ represents the fraction of the distribution sample that has a random reflectance ($$R\_O$$) of 2% or higher.
* $$C\_{org,\ f\ residual}$$ represents the fraction of the biochar organic carbon that is residual carbon, as opposed to reactive/labile organic carbon. It may be measured and reported directly, or obtained by subtracting measured *reactive* carbon from 100.

$$\textbf{(Eq.15)}\ R\_{project,\ 1000}=F\_{perm\ 1000}\*{C\_{org}*A}*{biochar}\*C\ to\ {CO}*{2}*-1$$

where,

* $$R\_{project,\ 1000}$$ represents the total carbon removals from biochar during the monitoring period, in tonnes of CO$$\_2$$eq. This value shall be applied to Equation 1 to calculate overall project removals.
* $$F\_{perm\ 1000}$$ is calculated in Equation 14.
* $$C\_{org}$$, $$A\_{biochar}$$ and $$C\ to\ {CO}\_{2}$$ are described in Equation 13.
* It is multiplied by -1 to obtain a negative sign. Removals are reported as a negative value.

</details>

## Uncertainty assessment <a href="#dk35zb8m2b1p" id="dk35zb8m2b1p"></a>

An uncertainty assessment is presented below for all aspects of GHG quantification set **at the methodology level**. The findings from this assessment are then applied **at the project level**, where project-specific GHG quantification also undergoes an uncertainty assessment.

The **overall project GHG quantification uncertainty** is determined by qualitatively combining both the methodology-level and project-specific uncertainties for each identified source of uncertainty.

The uncertainty of [assumptions](#assumptions) are assessed below:

| Assumption                                                                                                                                   | Uncertainty                                                                                                                                                                                |
| -------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| All biochar from the same Production Batch has the same characteristics (e.g. $$M\_{\text{%}}$$, $$H/C\_{\text{org}}$$, inertinite content). | In principle this assumption has low uncertainty, but the ability of Kiln Operators to maintain consistent pyrolysis conditions across sites and across kiln runs is moderately uncertain. |
| All biochar made from the same feedstock has the same methane emission rate from pyrolysis.                                                  | In principle this assumption has low uncertainty, but the ability of Kiln Operators to maintain consistent pyrolysis conditions across sites and across kiln runs is moderately uncertain. |
| The permanent carbon sequestration rate from biomass leakage, where the alternate fate is being left on the field to decompose, is 0.5%.     | High uncertainty, but the total net project removals is not sensitive to this assumption, so a low overall impact.                                                                         |

The equations and models have moderate uncertainty. The model for 100-year permanence from [Woolf et al., 2021](#user-content-fn-6)[^6] has high uncertainty because it is a model fitted to experimental data, which always introduces variability. The equations for 1000-year permanence from [Sanei et al., 2024](#user-content-fn-12)[^12] have low uncertainty because they are basic conversion equations.

Estimates may be used for the amount of processing and energy use inputs and the transport steps, rather than providing direct proof of each step. This is expected to introduce negligible to moderate uncertainty, depending on the level of justification provided for each project. For example, it may be negligible if the process is entirely manual/not motorized, requiring no transport or energy inputs. The uncertainty of these estimates and specific input data shall be assessed at the project level.

The uncertainty at the methodology level of the above-mentioned points are estimated to be moderate. This translates to a **minimum discount factor of at least 6%** for projects under this methodology.

[^1]: ISO 14064-2:2019. Greenhouse gases — Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements.

[^2]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for **a maximum of 6 months operating time or 200 tonnes of biochar**, whichever comes first.

[^3]: The coordinates are used by Rainbow Certification Team to obtain the average soil temperature (°C) where the biochar is spread.

[^4]: Wernet, G., Bauer, C., Steubing, B., Reinhard, J., Moreno-Ruiz, E., Weidema, B., 2016. The ecoinvent database version 3 (part I): overview and methodology. Int J Life Cycle Assess 21, 1218–1230. <https://doi.org/10.1007/s11367-016-1087-8>

[^5]: Intergovernmental Panel on Climate Change 2021. Chapter 7: The Earth’s Energy Budget, Climate Feedbacks, and Climate Sensitivity. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, doi:10.1017/9781009157896.009.

[^6]: Woolf, D., Lehmann, J., Ogle, S., Kishimoto-Mo, A.W., McConkey, B., Baldock, J., 2021. Greenhouse Gas Inventory Model for Biochar Additions to Soil. Environmental Science & Technology 55, 14795–14805.[ https://doi.org/10.1021/acs.est.1c02425](https://doi.org/10.1021/acs.est.1c02425)

[^7]: IPCC 2019. Appendix 4 Method for Estimating the Change in Mineral Soil Organic Carbon Stocks from Biochar Amendments: Basis for Future Methodological Development. 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 4 Agriculture, Forestry and Other Land Use. [URL](https://www.ipcc-nggip.iges.or.jp/public/2019rf/pdf/4_Volume4/19R_V4_Ch02_Ap4_Biochar.pdf).

[^8]: Lembrechts et al., Global maps of soil temperature (2021). Global Change Biology. DOI: [10.1111/gcb.16060](https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.16060). [URL](https://zenodo.org/records/7134169).

[^9]: Sanei, H., Rudra, A., Przyswitt, Z.M.M., Kousted, S., Sindlev, M.B., Zheng, X., Nielsen, S.B., Petersen, H.I., 2024. Assessing biochar’s permanence: An inertinite benchmark. International Journal of Coal Geology 281, 104409[ https://doi.org/10.1016/j.coal.2023.104409](https://doi.org/10.1016/j.coal.2023.104409)

[^10]: International Committee for Coal and Organic Petrology (ICCP), 2001. The new inertinite classification (ICCP System 1994). Fuel 80, 459–471.[ https://doi.org/10.1016/S0016-2361(00)00102-2](https://doi.org/10.1016/S0016-2361\(00\)00102-2)

[^11]: determined by e.g. thermogravimetric analysis (TGA) or Rock-Eval 6

[^12]: Sanei, H., Rudra, A., Przyswitt, Z.M.M., Kousted, S., Sindlev, M.B., Zheng, X., Nielsen, S.B., Petersen, H.I., 2024. Assessing biochar’s permanence: An inertinite benchmark. International Journal of Coal Geology 281, 104409 <https://doi.org/10.1016/j.coal.2023.104409>


# Sampling and measurements

A summary of measurements and their frequency is outlined in the table below. See each corresponding section for more details.

<table><thead><tr><th width="213.005615234375">Measurement frequency</th><th>Parameters</th></tr></thead><tbody><tr><td><strong>Each</strong> <a data-footnote-ref href="#user-content-fn-1"><strong>Production Batch</strong></a><strong>, on a single representative sample of biochar</strong></td><td><ul><li><span class="math">H/C_{\text{org}}</span> and organic carbon content (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li><li>Inertinite content (fraction of the distribution sample that has a random reflectance of 2% or higher) and residual carbon (<em>if calculating 1000-year removals</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li><li>Biochar moisture content, on at least 3 biochar samples (<em>if measuring biochar amount via mass</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-mass">here</a>)</li></ul></td></tr><tr><td><strong>Once per year, or anytime biomass feedstock changes</strong></td><td><ul><li>Methane emissions, on three runs representative of all other kilns in the same Production Batch (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#methane-emissions">here</a>)</li><li>Environmental pollutants of biochar, on one composite sample mixing biochar from each kiln run (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#biochar-requirements">here</a>)</li><li>Dry bulk density of biochar, on at least one sample from each kiln (i.e. 20 different kilns, 20 bulk density measurements) (<em>if measuring biochar amount via volume</em>) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-volume">here</a>)</li><li>Biomass to biochar conversion factor (<em>if <strong>not</strong> weighing the biomass input of each kiln run)</em> (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biomass-amount-used">here</a>)</li><li>Updated biomass leakage assessment (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#leakage">here</a>)</li></ul></td></tr><tr><td><strong>Each kiln run</strong></td><td><ul><li>Moisture content of biomass input (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#moisture-content-of-biomass">here</a>)</li><li>Type of biomass input (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biomass-used">here</a>)</li><li>Amount of biomass input, via precise mass measurements if using a feedstock mix, or estimates if using a singular biomass (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biomass-amount-used">here</a>)</li><li>Amount of any energy inputs used, for example for process ignition.</li><li>Mass or volume of fresh biochar produced (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biochar-produced">here</a>)</li><li>Temperature curve measured in each kiln using real-time sensors, proving pyrolysis has occurred (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#temperature-curves">here</a>)</li><li>Sampling records (proof of setting aside a small sub-sample of biochar, to be combined with sub-samples from all other kiln runs in the same Production Batch) (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#biochar-sampling-procedure">here</a>)</li></ul></td></tr><tr><td><strong>All biochar used</strong></td><td><ul><li>Proof of eligible, durable biochar end use, with names and GPS coordinates of spreading locations, among other information (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#id-5a8ye61po9ri">here</a>)</li></ul></td></tr><tr><td><strong>Once per year</strong></td><td><ul><li>Kiln Operator training (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#trainings">here</a>)</li><li>Proof and findings from the visits of Kiln Supervisor to each Kiln Operator (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#kiln-supervisor-site-visits">here</a>)</li><li>Proof of calibration and accuracy of onsite scales for weighing biochar to determine biochar amount (full description <a href="/pages/dT3jmfAYG6RzvZ2YYgZi#amount-of-biochar-produced">here</a>)</li></ul></td></tr><tr><td><strong>Once per verification and credit issuance</strong></td><td><ul><li>Quality oversight report from the Project Developer (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#quality-oversight-report">here</a>)</li><li>Environmental sustainability and Leakage compliance of biomass feedstock (full description <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#biomass-requirements">here </a>and <a href="/pages/JQ2u8UrsuqFeXrwbSdR7#leakage">here</a>)</li></ul></td></tr></tbody></table>

## Production Batch definition <a href="#id-2xck12gc2auz" id="id-2xck12gc2auz"></a>

A Production Batch is defined as the **biochar produced across multiple sites and kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve**. See the [Eligible biomass feedstock](/methodologies/distributed-closed-kiln-biochar/eligibility-and-scope#eligible-biomass-feedstock-open) section for requirements on single and mixed feedstock definitions.

It is assumed that all biochar from the same Production Batch has the same characteristics. The definition of **production batch is used to group the following measurements:** $$H/C\_{\text{org}}$$, organic carbon content, inertinite content (optional), and methane emissions.

{% hint style="info" icon="lightbulb-gear" %}
A Production Batch is **an accounting construct** used to group and track biochar produced under consistent conditions, rather than a discrete operational event. It represents a defined set of kiln runs sharing the same feedstock type, kiln type, and pyrolysis parameters, allowing that biochar to be characterized, sampled, and credited collectively.
{% endhint %}

**GHG quantification shall be done separately for each biochar** [**Production Batch**](#user-content-fn-2)[^2], since each batch by definition has distinctly measured biochar carbon characteristics. The GHG quantification results of multiple Production Batches may be combined for one monitoring period and credit issuance.

A Production Batch is valid for **a maximum of 6 months operating time or 200 tonnes of biochar**, whichever comes first. After this period or mass threshold, the biochar is considered part of a new Production Batch, even if conditions remain unchanged. This means that after 6 months of operating time, the Production Batch ID resets, a new batch is created, and new monitoring requirements apply, regardless of whether 200 tonnes have been produced or if feedstock or pyrolysis conditions have changed.

Where a project operates many kilns, Project Developers may choose how to designate subgroups of kilns that each contribute to their own distinct Production Batches. This allows projects to manage Production Batch validity periods more effectively, avoiding a situation where all kilns in a large project are tied to a single batch that reaches its validity limits quickly.

Note that the 6-month validity clock runs on operating time. Production pauses during the rainy season do not count toward the 6-month limit, provided the 200-tonne threshold has not been reached.

A 5-tonne tolerance buffer is allowed, permitting a Production Batch to reach up to 205 tonnes. This accounts for the on-the-ground challenges of predicting precise biochar output across multiple kilns over an extended period.

{% hint style="info" %}
For example,

* A small project may only produce s of biochar evenly throughout the year. A new Production Batch would start at the 6-month mark, and biochar would start being added to a new Site Composite Biochar Pile.
* A larger project may produce a total of 600 tonnes of biochar per year, with a total of 50 tonnes/month across all 10 kilns in the project, and 5 tonnes/month/kiln, operating year-round. The Project Developer could either:
  * keep all 10 kilns grouped together, and reach the 200 tonne mark within 2 months. This would result in 6 Production Batches in the year. Or,
  * split the kilns into two groups of 5 kilns each, and reach the 200 tonne mark for each group within 4 months. Two distinct production batches would be produced in parallel. They reset after 4 months, 3 times per year, for a total of 6 Production Batches.
* A different project may produce 50 tonnes of biochar in January and February, then stop production for 5 months, and produce another 50 tonnes in August. The biochar produced in August may be grouped with the biochar produced at the beginning of the year in the same Production Batch, since the delineation is 6-months of operating time, not 6 calendar months.
  {% endhint %}

Production Batches **may be non-contiguous**.

{% hint style="info" %}
For example, if Feedstock #1 if used on Day 1, a different Feedstock #2 on Day 2, and Feedstock #1 is used again on Day 3, the resulting biochar from Day 3 could be part of the same Production Batch as the biochar produced on Day 1.
{% endhint %}

## Methane emissions

Methane emissions shall be measured **anytime the biomass feedstock or feedstock mix changes, or annually if the biomass feedstock does not change**. See the [Feedstock composition and consistency](/methodologies/distributed-closed-kiln-biochar/eligibility-and-scope#feedstock-composition-and-consistency) section for the definition of a feedstock change.

Measurements shall be conducted on three runs across three separate kilns of the same technology type and using the same feedstock, operated by different kiln operators where more than three operators are active in the project.

Methane emissions testing, including results and photos of the process, may be handled in the dMRV app or in a separate report shared with Rainbow and the VVB.

Methane emissions shall be reported in kg CH<sub>4</sub>/kg biochar. The **mean of all measurements plus one standard deviation** shall be used for [GHG quantification](/methodologies/distributed-closed-kiln-biochar/ghg-quantification#pyrolysis-process) of all biochar produced in that year using the same biomass feedstock, and shall remain representative of all kiln runs provided that:

* the kiln type is the same,
* the biomass feedstock type remains the same, and
* biomass moisture content requirements are met for the methane-testing kiln runs, and are representative of expected moisture content during ongoing kiln runs (mean <20% for woody biomass; <15% for all other biomass; no individual measurement above 25%).

#### Measurement timing

Methane emission measurements shall be conducted once per 12-month period. Measurements must be completed before credits can be issued for any biochar produced within that period, but **may be conducted at any point during the 12-month period** to which they apply.

If the representativeness conditions listed above are met, **measurement results may be applied both retroactively and prospectively** to kiln runs within the same 12-month period.

{% hint style="info" %}
For example, if biochar is produced from January through March, production then pauses, and resumes in November using the same biomass feedstock, kiln type, and operators, methane measurements from November may be applied to biochar produced in March of the same period.

Credits for the January-March biochar cannot be issued in March because methane emission measurements would not be available at that time, but may be issued after the November measurement campaign, if adequate production records have been maintained demonstrating all representativeness conditions are satisfied.
{% endhint %}

#### **Measurement approaches**

Methane measurements for closed kilns shall follow either the **carbon mass balance approach** or the **volumetric flow × gas concentration approach**, as described below. Proof of calibration and a measurement report signed by the independent provider must be submitted regardless of which approach is used.

<table data-full-width="true"><thead><tr><th width="136.0880126953125">Name</th><th width="312.844970703125">Description</th><th width="299.0675048828125">Instructions</th></tr></thead><tbody><tr><td><strong>Carbon mass balance</strong></td><td><p>Follow the approach outlined in relevant <a data-footnote-ref href="#user-content-fn-3">scientific publications</a>.</p><p>The difference in the mass of known carbon input (via biomass) and output (in the form of biochar) is <a data-footnote-ref href="#user-content-fn-5">assumed</a> to be emitted as gas. The concentrations of CH<sub>4</sub>, CO, CO<sub>2</sub>, and other carbon-containing species are measured continuously throughout the kiln run, using instruments including but not limited to non-dispersive infrared (NDIR) sensors. The total amount of each gas species is calculated by multiplying the relative fraction of each species by the total mass of carbon-containing gas emitted.</p></td><td><p>Gas concentration measurements shall</p><ul><li>be taken across the entire kiln run, from start up through the end of quenching (if applicable), and</li><li>use instruments calibrated in accordance with manufacturer specifications and <a data-footnote-ref href="#user-content-fn-4">relevant ISO standards</a> for the gas species being measured, and</li><li>be conducted by an independent measurement provider with demonstrated technical competence in field emissions measurement.</li></ul></td></tr><tr><td><strong>Volumetric flow × gas concentration</strong></td><td>Gas flow rate is measured at a defined point in a chimney or flue stack, and gas concentration is measured simultaneously. Methane mass emissions are calculated as the product of the two.<br>Gas flow rate may be measured using portable instruments inserted into or clamped onto the stack, such as a thermal mass flow meter or pitot tube manometer, or using fixed laboratory-grade instrumentation installed by an accredited testing body.<br>This approach is only allowed if there is one sole exit point of flue gas from the closed system (i.e. a single chimney).</td><td><p>Gas concentration measurements shall</p><ul><li>be taken across the entire kiln run, from start up through the end of quenching, and</li><li>be measured simultaneously at the same point in the stack, and</li><li><p>use instruments calibrated in accordance with manufacturer specifications and relevant ISO standards <a data-footnote-ref href="#user-content-fn-6">for volumetric flow</a> and for <a data-footnote-ref href="#user-content-fn-4">gas species concentration</a>, and</p><ul><li>be taken by a measurement organization accredited with either ASTM D7036, ISO 17025, or approved by state or regional authority, or</li><li>for the use of portable equipment, be taken by a reputable independent instrument provider</li></ul></li></ul></td></tr></tbody></table>

## Biomass

### Biomass moisture content

Kiln operators shall demonstrate that for each kiln run, the average moisture content of biomass is:

* <20% (w/w) for woody biomass, or
* <15% (w/w) for any other biomass, including any mixture with non-woody biomass.

These thresholds serve two purposes:

* ensuring that pyrolysis **methane emissions remain consistently low**, and
* ensuring that annual methane emission measurements (conducted under the same moisture conditions) **remain representative** of all credited kiln runs.

These thresholds are based on research[^7] demonstrating that below 15% moisture content, all biomass types produce reliably low methane emissions, and that for woody biomass specifically, methane emissions remain consistently low at moisture contents up to 20%.

Moisture content shall be measured using a calibrated handheld moisture meter immediately prior to pyrolysis. A photograph of each sensor reading must be uploaded to the dMRV platform as evidence.

Measurements shall be taken at a rate of one measurement per 100 kg of dried, ready-to-pyrolyze feedstock, with a minimum of 10 measurements per kiln run. Measurement points shall be evenly distributed across the biomass pile, covering both its surface area and depth. The mean of all measurements must not exceed the applicable threshold above, and no individual measurement shall exceed 25%.

### Biomass amount used

The amount of biomass used serves two purposes:

* quantifying counterfactual biomass carbon storage, where applicable, and
* providing a rough validation check on the photographed biomass quantity against the reported biochar output.

It shall be determined for each kiln run using one of the following approaches:

* **Direct weighing** of biomass inputs for each kiln run, with moisture content subtracted using the biomass moisture content measurements.
* **Calculation** by dividing the dry mass of biochar produced by a feedstock-specific biochar yield conversion ratio.

Where the calculation approach is used:

* **Amount of biochar produced** may be provided by weighing directly as dry mass, or derived from volume or quenched mass measurements using Equation 6 or 7 in the [GHG quantification](/methodologies/distributed-closed-kiln-biochar/ghg-quantification#calculations-biomass-leakage) section.
* The **yield conversion ratio** may be drawn from reputable and transparent secondary sources, and must correspond to the project's specific configuration of kiln type, feedstock type, pyrolysis temperature, and duration. Where no suitable secondary values exist, the ratio shall be measured across at least three representative kiln runs.

## Biochar

### Biochar sampling procedure

Kiln Operators and Kiln Supervisors shall follow the general biochar sampling procedure outlined below:

{% stepper %}
{% step %}
**Each kiln run**

After each kiln run at a given site, a defined quantity of biochar is set aside from that run, and added to the **Site Composite Pile**. The Kiln Operator continuously adds biochar subsamples to this single site-level pile throughout the entire Production Batch duration. The Site Composite Pile is stored in a protected and dry space.
{% endstep %}

{% step %}
**Mixing the site's biochar, once per Production Batch**

The Site Composite Pile shall be thoroughly mixed by the Kiln Operator to ensure homogeneity. Once per Production Batch, a representative sample of biochar is then taken from this mixed site-level pile by the Kiln Operator or the Kiln Supervisor. This is called the **Site Composite Sample**.
{% endstep %}

{% step %}
**Combining all sites' biochar, once per Production Batch**

The Site Composite Samples are combined from each site into a **Production Batch Composite Pile** representing biochar production across all sites for the Production Batch.
{% endstep %}

{% step %}
**Taking a representative sample**

The Production Batch Composite Biochar Pile is thoroughly mixed by the kiln supervisor, and a representative sample— the **Production Batch Representative Sample**— is taken and sent to an accredited laboratory for measurement of organic carbon content, permanence indicators (i.e. H/C ratio and/or inertinite content), and, once per year, environmental pollutants.
{% endstep %}
{% endstepper %}

Biochar from all kiln runs throughout the entire Production Batch duration must be added to the Site Composite Pile before the composite sample is taken and sent for laboratory analysis. The Site Composite Sample may only be taken once the Production Batch is complete, either at the end of the 6-month validity period or upon reaching the 200-tonne threshold. Taking the sample earlier, while kiln runs are still ongoing, would mean the sample is not representative of all biochar in the batch.

Specific protocols within this approach may vary depending on the project type and the kiln size. The [**suggested detailed approach**](#user-content-fn-8)[^8] is provided below, but Project Developers may propose their own approach if it:

* is detailed in the PDD;
* ensures one homogenized and representative composite sample per Production Batch;
* describes the amount and frequency of subsamples and composite samples.

The VVB and the Rainbow Certification team must validate the rigor and representativeness of the proposed sampling approach.

Records shall be uploaded to dMRV at each step, and track the date and time, location, the kiln ID/QR code, the Production Batch ID/QR code, and visual proof of the steps taken.

#### Suggested detailed biochar sampling approach

* **Sampling each kiln run for Site Composite Pile:** Set aside a biochar sub-sample from each kiln run, by taking a small amount from 3 different spots in the biochar from the most recent kiln run. Continuously add these small samples to the Site Composite Pile throughout the Production Batch.
* **Mixing for Site Composite Sample:** Grind the biochar to a size of approximately <3 mm. Mix the ground sample by shoveling the pile three times from one pile to another. A sub-sample is taken from 10 spots in the mixed pile. The 10 sub-samples are re-combined, and then mixed by shoveling the pile three times from one pile to another. From the mixed pile of the combined sub-samples, 10 subsamples should be taken at 10 different spots in the pile and combined. The remaining biochar in the Site Composite Pile may be used in an eligible permanent end use and credited.
* **Mixing for Production Batch Composite Biochar Pile:** Collect all Site Composite Samples from different sites grouping their biochar into the same Production Batch. Combine all Site Composite Samples into one pile. Shovel the pile three times from one pile to another. Take a sub-sample of from 15 spots in the mixed pile. The 15 sub-samples are re-combined, and then mixed by shoveling the pile three times from one pile to another.
* **Taking a representative sample:** From the mixed pile of the combined sub-samples, 10 subsamples should be taken at 10 different spots in the pile and combined. This final sample is the Production Batch Representative Sample, and shall be sent to an accredited laboratory for measurement of organic carbon content, permanence indicators (i.e. H/C ratio and/or inertinite content) and environmental pollutants.
* **Maintain a Retention sample**: Keep the remaining biochar in the Production Batch Composite Pile in a protected area, separate from all other Production Batch Composite Piles, to be used as the retention sample. Retention samples must be stored for a minimum of two years.

### Biochar amount produced

Project Developers shall choose one of the two following approaches for measuring the amount of biochar produced: **volume or mass**. The same measurement approach shall be used for all biochar, across all kilns for a given Production Batch. The options are outlined in the figure below, and detailed in the following sections.

<figure><img src="/files/q1QedRtEgoGVDARkNx43" alt=""><figcaption></figcaption></figure>

#### Biochar volume

Volume of biochar must be converted to mass of biochar, because laboratory measurements of organic carbon content and are provided on a dry w/w% basis (i.e. in g organic carbon/kg dry biochar). Biochar volume is **converted to dry mass using dry bulk density measurements**, which require **a critical biochar drying step**. All components are detailed below.

* **Volume:** Project Developers shall establish a standardized container type (e.g. box or bag, rigid or loose material) for use across all project sites. All container volumes shall be predefined and tracked in dMRV. Kiln Operators must record the number of containers filled with biochar and applied to permanent end uses. Biochar volume must be measured for each kiln run.
* **Dry bulk density**: Onsite measurements are required for bulk density and shall be conducted by the Kiln Supervisor. As part of their annual site visit, they shall collect a representative sample from the [Site Composite Pile](#user-content-fn-9)[^9] at each site. One biochar bulk density measurement must be established for each site per year, unless the feedstock changes. The dry mass of the sample for the bulk density measurement shall be obtained using one of the following methods:
  * Directly weigh bone-dry biochar upon exit from the kiln. Since this does not involve mixing a composite and representative sample, it must be done on at least 3 separate runs per kiln.
  * Weigh fresh biochar mass, and adjust by the measured moisture content, described below.
* **Biochar drying and moisture content:** Biochar must be sufficiently dried to 0% moisture content to obtain accurate dry bulk density measurements. It shall be dried using one of the following methods:
  * Moisture analyzer: use a laboratory-grade [moisture analyzer](#user-content-fn-10)[^10].
  * Oven drying: dry the biochar in a ventilated oven at at least 110°C for a minimum duration of 48 hours. Subtract the final mass from the initial to determine moisture content and confirm complete drying.
    * Where oven drying is used, the VVB shall conduct or oversee cross-check measurements of moisture content using a laboratory-grade moisture analyzer during the annual [site audit](/methodologies/distributed-closed-kiln-biochar/eligibility-and-scope#site-audits), covering biochar samples from at least 3 different production sites. These cross-checks serve to verify that oven drying achieved complete moisture removal.
    * Where the VVB's measurements differ materially from the kiln supervisor's records in a direction that would result in fewer credits being issued, the VVB's measurements shall supersede the Kiln Supervisor's records for crediting purposes, and the Project Developer shall investigate and document the discrepancy.
    * Where the VVB's measurements would result in the same or greater number of credits, the Kiln Supervisor's records may continue to be used.

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><p>Kiln Supervisors shall <strong>take and prepare the biochar sample</strong> following these steps:</p><ul><li>Take a mixture of biochar sampled from the bottom, middle, and top of the <a data-footnote-ref href="#user-content-fn-9">Site Composite Pile</a>, already set aside by the Kiln Operator for sampling.</li><li>Transport the biochar from the Kiln Operator’s site to the location with measurement equipment, taking measures to protect the biochar from breaking during transport (if applicable, depending on project design)</li><li>Keep biochar samples from each site separate.</li><li><p>If using fresh biomass, dry the sample using</p><ul><li>a ventilated oven at at least 110°C for a minimum duration of 48 hours, or</li><li>a laboratory-grade <a data-footnote-ref href="#user-content-fn-10">moisture analyzer</a>, described above.</li></ul></li></ul></td></tr><tr><td><p>Kiln Supervisors shall <strong>conduct and report bulk density measurements</strong> as follows:</p><ul><li>Use containers of a standard material and predefined volume size.</li><li>Use scales with proven calibration and high accuracy (e.g., digital readings; if non-digital, values rounded down).</li><li>Conduct measurements separately for each site (samples from different sites shall not be mixed, and measurements shall not be taken on composite samples).</li><li>Outliers may be excluded from the bulk density dataset (defined as any individual measurement that is 3 standard deviations above or below the mean of the dataset).</li><li>The final bulk density value used for GHG quantification of each Production Batch shall be the <strong>mean minus one standard deviation of all measurements</strong> within that batch.</li></ul></td></tr></tbody></table>

Photos shall be uploaded to dMRV at each step. Project Developers shall prove that all measurement instruments used, such as scales and/or moisture analyzers are calibrated at least once per year.

The VVB shall review **all records** related to biochar drying and bulk density measurements to ensure that:

* **Drying:** biochar was fully dried to 0% moisture content prior to measurement.
* **Transport and handling:** the biochar sample used for bulk density measurement is similar to, and representative of, the biochar initially sampled, and has not been excessively damaged during transport or handling.
* **Representative subsample:** the biochar sample used for bulk density measurement has a bulk density consistent with the larger biochar retention sample pile from which it was taken.

#### Biochar mass

If biochar mass is used as the main indicator of biochar production and use, Project Developers shall provide Kiln Operators with accurate and calibrated measurement scales. The biochar output of all kiln runs shall be weighed upon completion of pyrolysis. Biochar mass may be measured either before quenching (bone dry) or after quenching.

If biochar is **weighed before quenching**, the recorded mass already reflects the dry mass of biochar produced and may be used directly to calculate carbon removals (see Eq. 9 in the [GHG quantification](/methodologies/distributed-closed-kiln-biochar/ghg-quantification#calculations-biomass-leakage-biomass-amount-biochar-amount) section).

If biochar is **weighed after quenching**, the moisture content of the biochar must be measured and accounted for. Moisture content must be measured on at least 3 separate samples for every biochar Production Batch (see Eq. 8 in the [GHG quantification](/methodologies/distributed-closed-kiln-biochar/ghg-quantification#calculations-biomass-leakage-biomass-amount-biochar-amount) section).

Moisture measurements shall be conducted using one of the following methods:

* By the Kiln Supervisor, following the oven drying or [moisture analyzer](#user-content-fn-10)[^10] approach described above for biochar drying. Measurements must begin on the same day the biochar is produced and weighed (i.e. within 24 hours). Time-stamped photos shall be uploaded to dMRV at each step.
* By sending biochar samples to an accredited independent laboratory for moisture content measurement. Samples shall be sent on the same day the biochar is produced and weighed, and must be protected to minimize moisture loss, including at a minimum wrapping the biochar in three layers of sealed plastic bags. Photos shall be uploaded to dMRV at each step, including time stamps showing that biochar is produced, weighed and sent on the same day (i.e. within 24 hours), and including photographic evidence of sealing the biochar sample.

Project Developers shall prove that all measurement instruments used, such as scales and/or moisture analyzers are calibrated at least once per year.

The VVB shall review all records related to biochar drying and moisture content measurements, if taken.

## Accredited labs

Proximate and elemental analysis of biochar shall be performed by laboratories with at least one quality assurance accreditation, such as:

* ISO/IEC 17025
* CEN/TS 17225-1
* ISO 10694

Unaccredited laboratories from academic settings shall be evaluated on a case by case basis by the VVB and the Rainbow Certification Team.

[^1]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for a maximum of 6 months operating time or 100 tonnes of biochar, whichever comes first.

[^2]: A production batch is defined as the biochar produced across multiple kilns of the same technology type, with the same biomass feedstock type or mixture, quenching approach, and pyrolysis temperature curve.<br>

    A production batch is valid for **a maximum of 6 months operating time or 200 tonnes of biochar**, whichever comes first.

[^3]: * Lotz, S., N.Hagemann, D.Hölscher, and H.-P.Schmidt. 2026. “Methane Emissions From Flame Curtain Pyrolysis (Kon-Tiki).” GCB Bioenergy18, no. 4: e70108. <https://doi.org/10.1111/gcbb.70108>.
    * Cornelissen, Gerard, et al. “Flame Curtain Kilns Produce Biochar from Dry Biomass with Minimal Methane Emissions.” *Science of the Total Environment*, vol. 903, 1 Dec. 2023, pp. 166547–166547, <https://doi.org/10.1016/j.scitotenv.2023.166547>.

[^4]: * ISO 12039:2019: Stationary Source Emissions — Determination of the Mass Concentration of Carbon Monoxide, Carbon Dioxide and Oxygen in Flue Gas — Performance Characteristics of Automated Measuring Systems
    * ISO 25140:2010: Stationary Source Emissions — Automatic Method for the Determination of the Methane Concentration Using Flame Ionisation Detection (FID).
    * ISO 25139:2011: Stationary Source Emissions — Manual Method for the Determination of the Methane Concentration Using Gas Chromatography.

[^5]: Some of this difference in carbon mass is actually lost as aerosols and particulate matter rather than gas, but treating it entirely as gaseous carbon may slightly overestimate total gas-phase emissions, making this a conservative assumption.

[^6]: * ISO 16911-1:2013: Stationary Source Emissions — Manual and Automatic Determination of Velocity and Volume Flow Rate in Ducts — Part 1: Manual Reference Method.
    * ISO 16911-2:2013: Stationary Source Emissions — Manual and Automatic Determination of Velocity and Volume Flow Rate in Ducts — Part 2: Automated Measuring Systems.
    * EN 15259:2007: Air Quality — Measurement of Stationary Source Emissions — Requirements for Measurement Sections and Sites and for the Measurement Objective, Plan and Report.

[^7]: * Cornelissen, Gerard, et al. “Flame Curtain Kilns Produce Biochar from Dry Biomass with Minimal Methane Emissions.” *Science of the Total Environment*, vol. 903, 1 Dec. 2023, pp. 166547–166547, <https://doi.org/10.1016/j.scitotenv.2023.166547>. [URL](https://www.sciencedirect.com/science/article/pii/S0048969723051720).
    * Lotz, Simon, et al. “Methane Emissions from Flame Curtain Pyrolysis (Kon‐Tiki).” *GCB Bioenergy*, vol. 18, no. 4, 13 Mar. 2026, <https://doi.org/10.1111/gcbb.70108>. [URL](https://onlinelibrary.wiley.com/doi/10.1111/gcbb.70108).

[^8]: The recommended approach sampling requirements are based on the following sources:

    * [EU Fertilising Products Regulation (EU) 2019/1009](#user-content-fn-10)\[^10]
    * [European Biochar Certificate Guidelines Annex 4 Representative Sampling](#user-content-fn-11)\[^11]

[^9]: After each kiln run at a given site, a defined quantity of biochar is set aside from that run, and added to the **Site Composite Pile**. Biochar subsamples are continuously added to this single site-level pile throughout the production batch duration.

[^10]: Specifically a thermogravimetric moisture analyzer using the loss-on-drying (LOD) method. As opposed to a handheld moisture sensor.


# Version history

This page describes the changes in the Distributed closed-kiln biochar methodology.

| Description of the change | Justification | Date             | Version changed |
| ------------------------- | ------------- | ---------------- | --------------- |
| Release of methodology    | --            | April 24th, 2026 | V1.0            |


# Appendix

## Appendix 1: Ecoinvent inputs

See the appendices of the associated GHG quantification modules for lists of ecoinvent processes used. This methodology does not introduce the use of any additional ecoinvent processes.

<table data-view="cards"><thead><tr><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="image">Cover image</th></tr></thead><tbody><tr><td>Processing and energy use ecoinvent inputs</td><td><a href="/pages/BTxxPIM3a4Nai1Wkwu2Y#appendix">/pages/BTxxPIM3a4Nai1Wkwu2Y#appendix</a></td><td><a href="/files/xqDoBuMbX7fcBqJ8AanC">/files/xqDoBuMbX7fcBqJ8AanC</a></td></tr><tr><td>Infrastructure and machinery ecoinvent inputs</td><td><a href="/pages/IwqpSqlee22qTIPti3Sl#appendix">/pages/IwqpSqlee22qTIPti3Sl#appendix</a></td><td><a href="/files/gE6Zo8o6awA0p9LnSTnF">/files/gE6Zo8o6awA0p9LnSTnF</a></td></tr><tr><td>Transportation ecoinvent inputs</td><td><a href="/pages/VTWdCc7guKu1x0azAizi#appendix">/pages/VTWdCc7guKu1x0azAizi#appendix</a></td><td><a href="/files/XAxrYlLSh0qtvbDkKkqp">/files/XAxrYlLSh0qtvbDkKkqp</a></td></tr></tbody></table>

## Appendix 2: Operating procedure for Kiln Operator

<details>

<summary>Preparation of biomass</summary>

* **Select Eligible Feedstock:**
  * Use only approved biomass types (e.g., forest waste, agricultural residues, invasive species).
  * Ensure biomass is classified as waste (not grown for CDR/bioenergy, not usable for valuable products).
  * Keep records of biomass type and source (e.g., photos, invoices, or contracts).
* **Dry Biomass:**
  * Measure moisture content using a calibrated handheld moisture meter immediately prior to pyrolysis.
  * Take at least one measurement per 100 kg of feedstock, with a minimum of 10 measurements per kiln run, distributed evenly across the biomass pile covering both its surface area and depth.
  * Ensure mean moisture content is below the applicable threshold: ≤20% for woody biomass, or ≤15% for any other biomass or any mixture containing non-woody biomass. No individual measurement may exceed 25%.
  * Upload photos of each sensor reading to dMRV as proof.
* **Prepare Biomass for Kiln:**
  * Chop or chip biomass to the appropriate size for the kiln, as specified in the project's training protocol.
  * If using woody prunings from multiple tree or shrub species treated as a single feedstock: remove all leaves prior to loading, and document via photo that bulk density, moisture content and particle size are consistent across species.
  * Document biomass preparation with photos and upload to dMRV.

</details>

<details>

<summary>Conducting pyrolysis</summary>

* **Identify the Kiln**
  * Scan the kiln's QR code or take a photo of its unique serial number, and upload a photo of the kiln displaying its required technical features (e.g., thermocouple placement, flame-curtain design) to dMRV before starting each kiln run.
* **Load Biomass:**
  * Load dried biomass into the kiln following training guidelines for proper feeding rates.
  * Before loading, photograph the full biomass pile staged for the kiln run.
  * Avoid overloading, which can cause a drop in pyrolysis temperature or disrupt secondary combustion.
  * For kilns capable of continuous production, adhere to the project-defined maximum operating duration or biochar mass per kiln run.
* **Record Biomass Amount:**
  * Record the amount of biomass used per kiln run using one of the following approaches:
    * Directly weigh biomass inputs and subtract moisture using moisture content measurements; or
    * Use a validated feedstock-specific biomass-to-biochar conversion ratio applied to the dry biochar output.
* **Monitor Pyrolysis:**
  * Start the kiln and confirm that temperature sensors are functioning before loading biomass.
  * Maintain pyrolysis temperature ≥350°C throughout the entire process, excluding the ramp-up and quenching phases.
  * Document the process with time-stamped, GPS-tagged photos or videos of kiln operation, including biomass feeding.
  * Temperature sensor readings are continuously and automatically recorded by the thermocouple.
  * Track and record all energy or fuel used for ignition and syngas combustion within the reactor.
* **Quench Biochar:**
  * Rapidly quench biochar immediately after pyrolysis is complete to minimise methane emissions.
  * Document quenching with time-stamped photos or short videos showing the start and end time of the quenching process.

</details>

<details>

<summary>Measure and prepare biochar samples</summary>

**Measure Biochar Quantity:**

* Choose either the volume approach or the mass approach, consistently across all kilns for the Production Batch.
  * Volume approac&#x68;*:* Fill standardized containers of predefined volume and record the number of containers produced per kiln run in dMRV.
  * Mass approach, bone dr&#x79;*:* Weigh biochar before quenching using calibrated scales. Record the mass directly in dMRV.
  * Mass approach, post-quenc&#x68;*:* Weigh biochar after quenching using calibrated scales. Record the fresh mass in dMRV. Moisture content must then be measured on at least 3 separate samples per Production Batch to convert to dry mass.

**Set Aside Biochar Subsamples for the Site Composite Pile:**

* After each kiln run, follow the project's predefined Sampling Plan. Take several biochar samples from different spots in the pile, and add them to the Site Composite Pile.
* Continue adding subsamples to this pile from every kiln run throughout the entire Production Batch duration.
* Upload photos of subsamples being set aside to dMRV, including the kiln ID/QR code, Production Batch ID/QR code, date, time, and GPS location.

**Take the Site Composite Sample**

* This may be done by the Kiln Operator or the Kiln Supervisor
* Once per Production Batch, after all kiln runs are complete, thoroughly mix the Site Composite Pile. Take subsamples and combine into the Site Composite Sample.
* The remaining biochar in the Site Composite Pile may be used in an eligible permanent end use and credited.

</details>

<details>

<summary>Uploading proof to dMRV</summary>

**Upload Required Data for Each Kiln Run:**

* Kiln run proof:
  * Continuous temperature curves from the thermocouple sensor (automatically measured)
  * Photos/videos of pyrolysis, including biomass feeding and quenching.
  * Biomass moisture content sensor readings (photos).
  * Biomass type and amount used.
  * Biochar volume or mass produced.
  * Unique identification of the kiln (QR code, serial number...).
* Sampling proof:
  * Photos of the subsample being set aside and added to the Site Composite Pile.
  * QR codes of biochar bags (if applicable).
* End-use proof (for all biochar delivered):
  * Date, GPS coordinates, and address of biochar delivery and application.
  * Name of user/buyer and Production Batch ID.
  * Time-stamped, geo-located photos of biochar application or mixing.

**Flag Anomalies:**

* Report any known issues to the Project Developer or Kiln Supervisor, including incomplete data, unsatisfactory pyrolysis, or thermocouple failures.

</details>

## Appendix 3: Operating procedure for Kiln Supervisor

<details>

<summary>Annual site visits</summary>

**Schedule Visits:**

* Visit each kiln operator at least once per year.
* Observe at least one kiln run per site during the visit.

**Verify Compliance:**

* Confirm that biomass type and moisture content are appropriate and that moisture measurements are taken correctly.
* Confirm that biomass is loaded at appropriate rates without overloading the kiln.
* Confirm that temperature sensors are functioning and recording continuously.
* Confirm that the combustion chamber is functioning properly and mitigating methane emissions.
* Confirm that quenching begins promptly after pyrolysis and is documented with time-stamped photos or video.
* Check that storage conditions for biomass and biochar are appropriate (dry, protected from contamination).
* Confirm that the Kiln Operator is correctly building the Site Composite Pile with subsamples from each kiln run throughout the Production Batch.

</details>

<details>

<summary>Production Batch Composite and Representative Samples</summary>

**Prepare Production Batch Composite Sample:**

* Collect a representative sample from the Site Composite Pile at each site from the bottom, middle, and top of the pile.
* Transport the sample carefully to avoid breakage.
* Keep samples from different sites separate at all times if conducting bulk density measurements (see below).

**Prepare Production Batch Representative Sample:**

* Combine all Site Composite Samples into one pile.
* Mix and recombine subsamples from different spots in the pile.
* Take the final Production Batch Representative Sample.

**Send for Laboratory Analysis:**

* Set aside part of the Production Batch Representative Sample for bulk density measurements if using the volume approach to measure the amount of biochar produced.
* Send the Production Batch Representative Sample to an accredited laboratory for measurement of:
  * Organic carbon content (each Production Batch)
  * H/C<sub>org</sub> ratio (and inertinite content and residual organic carbon, if using the 1000-year pathway) (each Production Batch)
  * Environmental pollutants (once per year, or anytime biomass feedstock changes).
* Store Retention Sample:
  * Keep the remaining biochar in the Production Batch Composite Pile in a protected area as a retention sample for 2 years.
* Upload Records:
  * Upload photos, dates, times, and QR codes to dMRV.

</details>

<details>

<summary>Bulk density measurements (volume approach)</summary>

Measure bulk density for projects using the volume-based approach.

**Prepare the sample**

* Dry the Site Composite Pile described in the section above to 0% moisture content using one of the following methods:
  * Moisture analyser: use a laboratory-grade moisture analyser.
  * Oven drying: dry in a ventilated oven at ≥110°C for a minimum of 48 hours. Subtract the final mass from the initial mass to determine moisture content and confirm complete drying.

**Measure Bulk Density:**

* Use containers of a standard material and predefined volume.
* Use calibrated scales (digital preferred; if analog, round down values).
* Measure each site’s biochar separately (no mixing).
* Exclude outliers (3 standard deviations from the mean).
* Calculate the final bulk density of biochar in the Production Batch as the mean of all measurements minus one standard deviation.

**Upload Proof:**

* Upload photos of each step to dMRV.

</details>

<details>

<summary>Training and oversight</summary>

**Conduct Training:**

* Train Kiln Operators on:
  * Safety protocols for kiln operation.
  * Biomass preparation (drying, sizing) and moisture content measurement.
  * Correct biomass loading rates to maintain consistent and high temperatures.
  * Rapid quenching.
  * Biochar sampling procedures.
  * Use of dMRV, including photo requirements, GPS tagging, and batch upload requirements.
  * This may be done by the Kiln Supervisor or the Project Developer.

**Site Visits:**

* During and after site visits, or at any other time, flag any non-compliant kiln runs (e.g., secondary combustion failure, missing energy input records, missing data, improper sampling).
* Report findings and required follow-up actions to the Project Developer. Provide findings to be included in the Project Developer's Quality Oversight Report.

</details>

## Appendix 4: Operating procedure for Project Developer

<details>

<summary>Project setup and kiln technology management</summary>

**Define Project Scope**

* Register the project as a single entity operating one or more kilns across one or more sites, within a single country, using the same kiln technology and dMRV approach.
* Ensure all sites and kilns are under the oversight or data access of the Project Developer.

**Select and Deploy Kiln Technology**

* Use pre-approved kiln designs from Rainbow’s published list. For new designs, submit for Rainbow and VVB approval.
* Verify that all kilns employ secondary combustion reactor design, where pyrolysis gases are trapped in a dedicated chimney or chamber and combusted, and are equipped with fixed, continuously-logging thermocouples placed in the same position on all kilns.
* Assign a unique, permanently affixed identifier (e.g., QR code or engraved serial number) to each kiln.
* Document kiln technical features (e.g., chimney design, sensor placement) in dMRV.

**Define Project-Specific Criteria at Validation**

* Biomass feedstock types, proof of waste or invasive species status.
* Sampling and measurement protocols (e.g., H/C ratio, bulk density, methane emissions).
* Training Protocol for Kiln Operators and Kiln Supervisors.
* Project-specific criteria for evaluating temperature curves, including acceptable temperature ranges and durations, ramp-up period, and definition of the main pyrolysis phase. Criteria shall be designed to flag incomplete biomass drying and improper feedstock loading rates.

**Select and Validate dMRV Platform**

* Use pre-approved kiln designs from Rainbow’s published list. For new designs, ensure the platform meets Rainbow’s requirements and can track all of the required data points.
* Submit the platform for Rainbow validation before use.

</details>

<details>

<summary>Oversight of all kiln runs</summary>

**Review dMRV Data**

* Check every kiln run for:
  * Temperature curves: pyrolysis zone maintained ≥350°C throughout (excluding ramp-up and quenching), and project-specific quality criteria met.
  * Biomass moisture content: mean at or below the applicable threshold (≤20% for woody biomass, ≤15% for all other biomass or mixed biomass), and no individual measurement above 25%.
  * Biomass and biochar amounts are broadly consistent with photographic evidence.
  * Quenching was performed promptly and documented with time-stamped photos or video.
  * Biochar volume or mass is recorded.
  * Sampling records confirm a subsample was set aside and added to the Site Composite Pile.
* Alternatively, outsource the checking step to a dMRV provider.

**Coordinate Biochar Sampling**

* Ensure Kiln Supervisors combine Site Composite Samples into the Production Batch Composite Pile and send the Production Batch Representative Sample to an accredited laboratory for:
  * Organic carbon content (each Production Batch)
  * H/C<sub>org</sub> ratio (and inertinite content and residual organic carbon, if using the 1000-year pathway) (each Production Batch)
  * Environmental pollutants (once per year, or anytime biomass feedstock changes).

**Flag Non-Conformities**

* Exclude ineligible kiln runs (e.g., incomplete data, improper pyrolysis).
* Document reasons for exclusion in the Oversight Report. Note that excluded kiln runs do not count towards the Production Batch size limit.

**Coordinate Methane Emission Testing**

* Schedule Testing:
  * Conduct testing annually or whenever biomass feedstock changes.
  * Test three representative kiln runs (same kiln type and feedstock).
* Use Accredited Providers:
  * Ensure testing is done by organizations accredited with ASTM D7036, ISO 17025, or approved by state/regional authorities.
* Document Results:
  * Upload methane emission measurements, proof of calibration, and a signed measurement report to dMRV or share as a separate report with Rainbow and the VVB.

</details>

<details>

<summary>Training and support</summary>

**Train Kiln Operators on:**

* Safety protocols for kiln operation.
* Biomass preparation (drying, sizing) and moisture content measurement.
* Correct biomass loading rates to maintain consistent and high temperatures.
* Rapid quenching.
* Biochar sampling procedures.
* Use of dMRV, including photo requirements, GPS tagging, and batch upload requirements.
* This may be done by the Kiln Supervisor or the Project Developer.

**Train Kiln Supervisors on:**

* All topics covered in Kiln Operator training, so that Supervisors can effectively assess and support Kiln Operators during site visits.
* Biochar amount measurements, including bulk density measurement procedures and moisture content measurement using oven drying or a laboratory-grade moisture analyzer.
* How to adhere to the biochar sampling plan.

**Upload training records to dMRV, including:**

* Attendance logs.
* Photos/videos of training sessions.
* Test results or proof of completion.

**Offer Ongoing Support:**

* Provide refresher training and troubleshooting support (e.g., temperature curve analysis, flame curtain quality, moisture measurement).

</details>

<details>

<summary>Quality Oversight Report</summary>

To be completed for each Production Batch.

**Compile Data**

* List all kiln runs and their status (eligible/ineligible).
* Document the cumulative biomass used, biochar produced, and biochar applied in an eligible end use, noting any discrepancies and providing justification.
* Document non-conformities (e.g., missing data, improper sampling) and remediation steps.

**Include any site visit findings**

* Summarize Kiln Supervisor observations from any annual site visits that took place during the time period in question, including findings on biomass handling, kiln operation, and sampling compliance.
* List any non-conformities or failures to adhere to best practices identified during visits, and their remediation.

**Submit to VVB**

* Provide the report to the Validation and Verification Body (VVB) for audit.
* Address any VVB recommendations (e.g., additional site visits, data corrections).

</details>


# Risk assessment template

This methodology uses the risk assessment template version 1.0

:point\_right: Download the template [here](https://docs.google.com/spreadsheets/d/1wY6p8B2SyqHMY8QTjpk2pl9RTekFI1bHlbvE9ZGPueE/edit?usp=drive_link)

{% embed url="<https://docs.google.com/spreadsheets/d/1wY6p8B2SyqHMY8QTjpk2pl9RTekFI1bHlbvE9ZGPueE/edit?usp=sharing>" %}


# Mineralization of alkaline materials (ex situ)

| **Methodology name** | Mineralization of alkaline materials (ex situ) |
| -------------------- | ---------------------------------------------- |
| **Version**          | 1.1                                            |
| **Methodology ID**   | RBW-CDR-MIN-V1.1                               |
| **Release date**     | March 19th, 2026                               |
| **Status**           | In use                                         |

## Introduction

It is widely acknowledged that in addition to reducing global greenhouse gas (GHG) emissions, [carbon dioxide must be removed from the atmosphere](#user-content-fn-1)[^1] and permanently sequestered. One way to do this is through [mineral carbonation](#user-content-fn-2)[^2]/mineralization of concrete and alkaline wastes that contain metal ions, destined for permanent incorporation into permanent products. In this process, captured CO<sub>2</sub> is exposed to and reacts with alkaline materials, generating stable carbonates that can [permanently ](#user-content-fn-3)[^3]store the CO<sub>2</sub>.

This methodology document outlines the general requirements for mineral carbonation of materials projects certified under the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules).

<details>

<summary><strong>Acknowledgements</strong> <span data-gb-custom-inline data-tag="emoji" data-code="1f91d">🤝</span></summary>

*This methodology was developed by Rainbow with valuable input and support from the Rainbow Mineralization Working Group members and other expert contributors.*

*We would like to thank Christina Stavridi, Bernardo Martinez, and Gabriel Carrero (Carbon Limit), Colin Hills (University of Greenwich), Jamie Rogers (CarbonCure), Paula Carey and Aaron Lyons (Carbon8), Stephen Roscoe (O.C.O), and Roxby Hartley (EcoEngineers) for their insights and contributions throughout the development process.*

</details>

## Glossary

<table data-header-hidden><thead><tr><th width="234"></th><th></th></tr></thead><tbody><tr><td><strong>Mineralization, Mineral Carbonation</strong></td><td>A chemical process where CO<sub>2</sub> reacts with alkaline materials (e.g., concrete, cement, industrial residues) to form stable carbonates (e.g. CaCO<sub>3</sub>), permanently storing CO<sub>2</sub>. Mineralization and carbonation are used interchangeably in the present methodology.</td></tr><tr><td><strong>Ex situ</strong></td><td>Processes that occur in controlled, engineered environments, such as reactors or industrial facilities, rather than <em>in situ</em> approaches that take place in the natural environment (e.g. enhanced rock weathering).</td></tr><tr><td><strong>Carbonated Material</strong></td><td>The solid product resulting from mineral carbonation, containing CO<sub>2</sub> locked in stable carbonate form (e.g., carbonated concrete or aggregate).</td></tr><tr><td><strong>Carbonation curing</strong></td><td>A process where CO<sub>2</sub> is introduced to concrete or cement-based materials during the curing stage, to accelerate strength development and chemically bind CO<sub>2</sub> into the material.</td></tr><tr><td><strong>Carbonation batch</strong></td><td>The carbonated material produced using the same input materials (alkaline feedstock and CO<sub>2</sub>) and operating conditions. It is assumed that all carbonated material from the same carbonation batch has similar characteristics.</td></tr><tr><td><strong>Alkaline Feedstock</strong></td><td>Materials that contain metal oxides (e.g., calcium, magnesium, iron) that react with CO<sub>2</sub> to form carbonates.</td></tr><tr><td><strong>Biogenic CO</strong><sub><strong>2</strong></sub></td><td>CO<sub>2</sub> originating from biomass sources. Its carbonation leads to net carbon removals, and is eligible for removal carbon credits. </td></tr><tr><td><strong>Atmospheric CO</strong><sub><strong>2</strong></sub> </td><td>CO<sub>2</sub> captured directly from the atmosphere, typically from Direct Air Capture (DAC) or ambient air. Its carbonation leads to net carbon removals, and is eligible for removal carbon credits. </td></tr><tr><td><strong>Fossil CO</strong><sub><strong>2</strong></sub> </td><td>CO<sub>2</sub> originating from fossil fuels. Its carbonation leads to carbon storage, and is eligible for avoidance carbon credits. </td></tr><tr><td><strong>Calcination CO</strong><sub><strong>2</strong></sub> </td><td>CO<sub>2</sub> originating from lime that is calcinated in cement production, from breaking up CaCO<sub>3</sub> into CO<sub>2</sub> and calcium silicates. Its carbonation leads to carbon storage, and is eligible for avoidance carbon credits. </td></tr><tr><td><strong>Fugitive CO</strong><sub><strong>2</strong></sub><strong> Emissions</strong></td><td>Unintended leaks of CO<sub>2</sub> from equipment (e.g., reactors, pipelines, trucks). Not to be confused with the <a href="/pages/4uybo1rKTeqN3arLDfI4#leakage">Leakage</a> eligibility criteria. </td></tr><tr><td><strong>Ordinary Portland Cement (OPC)</strong></td><td>The most common type of cement, produced by heating limestone and other materials to form clinker, which is then ground into a fine powder. </td></tr><tr><td><strong>Supplementary cementitious materials (SCM)</strong></td><td>Industrial by-products (e.g. fly ash, slag) or natural pozzolans used to partially replace OPC in concrete. They can both replace and reduce clinker-related emissions, and serve as reactive alkaline materials that bind CO<sub>2</sub> into stable carbonates.</td></tr></tbody></table>

{% content-ref url="/pages/D1bECpowUAiJorSGzbQY" %}
[Glossary](/glossary)
{% endcontent-ref %}

[^1]: IPCC, 2022: Summary for Policymakers. In: Climate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, UK and New York, NY, USA. doi: 10.1017/9781009157926.001

[^2]: Baciocchi R and Costa G (2021) CO<sub>2</sub> Utilization and Long-Term Storage in Useful Mineral Products by Carbonation of Alkaline Feedstocks. *Front. Energy Res.* 9:592600. DOI: 10.3389/fenrg.2021.592600. URL.

[^3]: Baciocchi, R., Costa, G., 2021. CO2 Utilization and Long-Term Storage in Useful Mineral Products by Carbonation of Alkaline Feedstocks. Front. Energy Res. 9. [URL](https://doi.org/10.3389/fenrg.2021.592600).


# Eligibility and scope

## Eligible technologies

All projects certified under this methodology must perform accelerated and/or enhanced [carbonation ](#user-content-fn-1)[^1]of alkaline minerals by CO<sub>2</sub>, in an ex-situ environment, to:

* generate [additional ](#user-content-fn-2)[^2]carbon removals and/or
* reduce cement usage.

Many different technological setups are eligible under the present methodology and widely described in the [scientific literature](#user-content-fn-3)[^3]. Eligible project setups **may include but are not limited to** the following technological processes, final products, CO<sub>2</sub> sources, and alkaline materials:

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><p><strong>Eligible technologies</strong></p><ul><li>carbonation curing of cementitious materials</li><li>carbonation during fresh concrete mixing/hydration</li><li>carbonation of solid materials, to add to e.g. concrete or asphalt</li><li>carbonation of liquids such as concrete slurry water, to add to e.g. concrete or asphalt</li></ul></td></tr><tr><td><p><strong>Eligible products</strong></p><ul><li>Ready mix concrete, mixed and installed</li><li>Pre-cast concrete blocks</li><li><a data-footnote-ref href="#user-content-fn-4">SCMs</a>, aggregates and other solids; destined for use in concrete, asphalt, road subbase or construction fill</li><li>Landfilled solid materials, or "no use"</li></ul></td></tr><tr><td><p><strong>Eligible CO</strong><sub><strong>2</strong></sub><strong> sources</strong></p><ul><li>atmospheric CO<sub>2</sub> from direct air capture (DAC) or ambient air</li><li><a data-footnote-ref href="#user-content-fn-5">waste/byproduct</a> biogenic CO<sub>2</sub> from point-source capture (e.g. bioenergy production)</li><li>fossil CO<sub>2</sub> from point-source capture (e.g. coal plants)</li><li><a data-footnote-ref href="#user-content-fn-6">calcination CO<sub>2</sub></a>, or other non-fossil CO<sub>2</sub> from heavy industries</li><li>mixed CO<sub>2</sub> from waste incineration</li><li>pure or mixed CO<sub>2</sub> streams of any type listed above</li></ul></td></tr><tr><td><p><strong>Eligible alkaline sources</strong></p><ul><li>Coal fly ash</li><li>Cement residues (e.g. cement kiln dust)</li><li>Concrete production waste (e.g. concrete wastewater)</li><li>Cement in fresh mixed concrete</li><li>Recycled concrete</li><li>Paper mill residues</li><li>Municipal incineration, biomass incineration and <a data-footnote-ref href="#user-content-fn-7">CHP</a> waste (e.g., bottom ash, APC residues)</li><li>Steel manufacturing waste</li><li>Nickel tailings</li><li>Red mud from aluminum processing</li><li>Natural rock, mining waste</li></ul></td></tr></tbody></table>

Projects that contain components not listed above, but that meet the requirements of the present methodology and the Rainbow Standard Rules, shall be considered on a case-by-case basis.

Projects under this methodology are eligible for

* removal Rainbow Carbon Credits (RCCs) from mineralization with biogenic, ambient and atmospheric CO<sub>2</sub>,
* avoidance RCCs from mineralization with fossil and calcination[^6] CO<sub>2</sub>, and
* avoidance RCCs from reduction of cement use.

Carbon removals under this methodology are estimated to have a permanence horizon of **at least 1000 years**. Reversal risks and baseline removals are assessed according to this duration.

Credits are issued on the basis of carbonated materials production.

{% hint style="success" %}
Mineralization with fossil and calcination CO<sub>2</sub> counts as Carbon Capture and Storage (CCS) and is issued avoidance credits.

These do not count for carbon dioxide removal (CDR), and are referred to as **carbon storage** throughout the methodology.
{% endhint %}

## Centralized vs distributed sites <a href="#certification-requirements" id="certification-requirements"></a>

Mineralization projects may be highly distributed, deploying the same mineralization technology and process to many different sites. For example, mineralization may occur directly in concrete mixing trucks, with small amounts of carbon storage taking place at each carbonation site.

To account for this, projects shall be classified as either centralized vs distributed. A distributed project is defined as one where:

* Each mineralization site is expected to issue fewer than 100 RRCs annually, based on carbon storage via mineralization (i.e. excluding reduced cement avoidance), and
* The following characteristics are consistent across sites in a group:
  * Mineralization reaction type, the metal(s) contributing to mineral formation, and expected carbonate compound
  * Expected mineralization timeline post-reactor, based on the kinetics of the specific technology (e.g. full mineralization occurs within 24 hours, 1 week, etc.)
  * Reactor operating temperature and pressure (within a target range of ±10%)

The main distinction is that distributed projects may use empirical data from a representative subset of sites, after meeting rigorous qualification conditions, whereas centralized projects require measurements from all sites.

See the [Sampling and measurements](/methodologies/mineralization-of-alkaline-materials-ex-situ/monitoring-and-sampling#centralized-vs-distributed-sites) sections for full details.

## Certification requirements <a href="#certification-requirements" id="certification-requirements"></a>

#### **Crediting period duration:**

The maximum duration of the crediting period for projects certified under this methodology is 5 years. Upon reaching the maximum duration, a project's crediting period may be renewed, according to the [Crediting Period Renewal](/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal) procedure.

#### **Monitoring period duration**

The default monitoring period duration is one year, but may be shorter at the Project Developer's request. Project Developers shall submit a Monitoring Report at least once per 24 months. Failure to do so shall result in the project being [deregistered](/rainbow-standard-documents/procedures-manual/project-certification-procedure#deregistration).

#### **Site audits**

Project Developers may choose between remote or in-person site audits unless any of the following apply:

* If the **project issues more than 5,000 RCCs/year**, at least 3 sites must have in-person audits. If the project has fewer than 3 sites, all sites must be audited in-person. Sites selected for in-person audits must be representative of all sites. Remaining sites may choose their audit format.
* If **any individual site issues more than 5,000 RCCs/year**, that site must have an in-person audit, regardless of *project-level* volume.

The Rainbow team may require an in-person audit for any project at any time.

#### **Versioning and project compliance**

When this methodology is revised, projects are required to comply with the latest version for subsequent verifications of RCCs.

## Project scope

One project is defined as:

* the operation of one or more mineralization sites, where a mineralization site refers to one reactor or other instrument where mineralization occurs,
* within a single country,
* using the same technology (e.g. carbonation curing of cementitious materials vs. carbonation during fresh concrete mixing/hydration, see [Eligible technologies](#eligible-activities) above),
* using the same monitoring approach (see [Project CO<sub>2</sub> stored](/methodologies/mineralization-of-alkaline-materials-ex-situ/ghg-quantification#project-co2-stored)), and
* operated at sites that are under the oversight or data access of a single Project Developer, regardless of whether the developer directly owns or manages each site.

Additional **sites may be added to the project on an ongoing basis**, provided the sites meet the requirements listed above and in the [Principles & requirements](/methodologies/mineralization-of-alkaline-materials-ex-situ/principles-and-requirements) section. The addition of a site is considered a major project update, which will be assessed by a VVB during the project's next verification audit.

The project scope covers all *additional* removals and induced emissions, caused by the project activity, that would not have occurred in the baseline scenario/in the absence of the project.

{% hint style="info" %}
For example, if the project is co-located with a concrete manufacturing site, the emissions from concrete production (i.e. energy use emissions, cement production, infrastructure embodied emissions...) that would have occurred anyway are not counted towards the project induced emissions.
{% endhint %}

Project Developers shall categorize the project's carbon capture and mineralization sites as either **retrofits/additions on top of existing sites**, or the **installation of new sites**. This helps distinguish between the project scope and the baseline[^8]. Project Developers shall prove the extent of existing operations of any connected activities using historical proof of operations of the existing site/s.

Project Developers shall summarize the following key descriptive meta-information for the project:

* Mineralization reaction type, type of metal/s contributing to mineral formation, and expected carbonate compound type
* Expected mineralization timeline after reactor exit, based on the kinetics of the specific technology (e.g. full mineralization occurs within 24 hours, 1 week, etc.)
* Temperature and pressure of the reactor (within a target range of ±10%)
* Carbon storage measurement approach: [gas inflow-outflow](/methodologies/mineralization-of-alkaline-materials-ex-situ/ghg-quantification#gas-inflow-outflow) or [solid-sample](/methodologies/mineralization-of-alkaline-materials-ex-situ/ghg-quantification#solid-sample)
* [Centralized or distributed](#certification-requirements) project

## Baseline scope

The baseline represents the processes that would have occurred in the absence of the project. Project Developers shall evaluate the baseline according to the following three outcomes, detailed in the sections below:

* Feedstock management: baseline removals
* Material production: Reduced cement use
* Product use phase

#### Feedstock management: baseline removals

This includes **removals from feedstock mineralization that would have occurred anyway**, from business-as-usual (BAU):

* feedstock use or management, for projects mineralizing solid materials such as SCMs and aggregates, and
* use-stage concrete carbonation, for all technology types.

Project Developers shall justify the estimated baseline removals using transparent sources, project-specific estimates, and conservative assumptions, accounting for the specific feedstock type used and its source. Quantification details are in the [GHG quantification](/methodologies/mineralization-of-alkaline-materials-ex-situ/ghg-quantification#id-8422amp7fe3k-2) section.

#### Material production: Reduced cement use

If projects issue **avoidance credits from reduced cement use**, due to improved binder strength from mineralization, the baseline scenario shall include the BAU production of the reduced cement, ensuring that:

* the equivalent amount replaced is conservatively calculated and
* the type of cement modeled in the baseline is an accurate and representative substitute.

Quantification details are in the [GHG quantification](/methodologies/mineralization-of-alkaline-materials-ex-situ/ghg-quantification#id-8422amp7fe3k-2) section. Steps shall be taken to adjust the representative baseline downward to result in below-BAU baseline emissions in the baseline.

#### Product use phase

Project Developers shall identify the baseline material and function that the project carbonated material replaces. They shall justify that the project material meets the same quality and performance standards as the baseline material it replaces. Project Developers shall prove this using representative test results from pilot testing, R\&D laboratories, or full-scale operations.

Project Developers shall justify that using their carbonated product in concrete (or other final product) leads to the same quality and performance as the baseline material, considering:

* durability
* service lifetime
* compressive strength (where relevant)
* use-phase mineralization (where relevant)
* other performance characteristics related to non-concrete end uses.

***

The baseline scenario **structure** remains valid for the entire crediting period but may be significantly revised earlier if:

* The Project Developer notifies Rainbow of a substantial change in project operations or baseline conditions, and/or
* The methodology is revised, affecting the baseline scenario.

The **specific values** within the baseline scenario will be updated during each crediting period, using project data to accurately reflect the equivalent of the project’s operations.

## Mineralization batch

A mineralization batch is the **quantity of mineralized/carbonated material produced using the same input materials (alkaline feedstock and CO**<sub>**2**</sub>**) and operating conditions, at one site**. Details on the delineation of mineralization batches are in Table 1. It is assumed that all carbonated material from the same mineralization batch has similar characteristics relevant to mineralization performance and measurement accuracy (i.e. carbonation rate, bulk density…). This facilitates mineralized material [solid sampling and measurements](/methodologies/mineralization-of-alkaline-materials-ex-situ/ghg-quantification#solid-sample), where a [representative sample](/methodologies/mineralization-of-alkaline-materials-ex-situ/monitoring-and-sampling#sampling-and-measurements) should taken for each mineralization batch.

The project-specific definition of the mineralization batch shall be clearly described in the PDD.

Measurements and reporting are performed at the **mineralization batch level**. Verification and credit issuance may be done per carbonation batch, or annually on the cumulative carbonation batches from that year.

{% hint style="info" %}
It is in the Project Developer's best interest to define mineralization batches at a granular level, and resample and remeasure accordingly. Doing so helps reduce measurement variability and improves confidence that reported CO<sub>2</sub> storage variability falls within an acceptable range. Solid sample measurements are only accepted if the relative standard deviation (RSD) is less than 10%, and the measurement showing the lowest carbon content will be used for the Project and the highest is used for the Baseline.
{% endhint %}

*Table 1 Specific examples of how to delineate a* mineralization *batch are summarized.*

<table data-full-width="false"><thead><tr><th width="176">Characteristic</th><th width="553">Conditions for changing carbonation batch</th></tr></thead><tbody><tr><td><strong>Alkaline feedstock: singular or homogeneous material</strong></td><td><ul><li>A change in <strong>material category</strong>, based on recognized standards (e.g. ASTM, EN),</li><li>A substantial change in <strong>material properties</strong> (recommended ±3%), even within the same product category, such as mineralogical composition (e.g. proportion of CaO, MgO, silicates, aluminates), bulk density or pH</li><li>A change in <strong>supplier or geographic source</strong> of the feedstock*</li></ul></td></tr><tr><td><strong>Alkaline feedstock: composite or heterogeneous material</strong></td><td><ul><li>A change in <strong>material category</strong>, based on recognized standards (e.g. ASTM, EN),</li><li>A substantial change in <strong>material properties</strong> (recommended ±3%), even within the same product category, such as mineralogical composition (e.g. proportion of CaO, MgO, silicates, aluminates), bulk density or pH</li><li>A substantial change in <strong>the fraction of reactive material in the design mix</strong> (recommended ±10%)</li><li>A change in <strong>supplier or geographic source</strong> of the feedstock*</li></ul></td></tr><tr><td><strong>CO</strong><sub><strong>2</strong></sub><strong> input</strong></td><td><ul><li>The <strong>biogenic vs. fossil fraction</strong> of the CO<sub>2</sub> stream changes substantially (recommended ±3%)</li><li>The CO<sub>2</sub> <strong>supplier or geographic source</strong> changes*</li></ul></td></tr><tr><td><strong>Carbonation site</strong></td><td><ul><li>The physical location and/or machinery in which the reaction is occurring.</li></ul></td></tr><tr><td><strong>Duration</strong></td><td><ul><li>A mineralization batch has a maximum validity of <strong>365 days</strong>. After this period, a new batch must be defined and monitored, even if feedstock and CO<sub>2</sub> conditions remain unchanged.</li><li>A mineralization batch may be non-contiguous. For example, if Feedstock 1 is carbonated on Day 1 and again on Day 3 (with a different feedstock used on Day 2), the operations on Days 1 and 3 can be treated as the same batch.</li></ul></td></tr></tbody></table>

\**If the Project Developer can prove that changes in the supplier or geographic source do not lead to material changes in the product used, in ways that affect the parameters used in GHG quantification, then a change in change in supplier or geographic source may be ignored for purpose of defining carbonation batch.*

[^1]: Mineralization and carbonation are used interchangeably in the present methodology.

[^2]: beyond what would have happened in the business-as-usual, baseline scenario

[^3]: * Thonemann, N., Zacharopoulos, L., Fromme, F., & Nühlen, J. (2022). Environmental impacts of carbon capture and utilization by mineral carbonation: A systematic literature review and meta life cycle assessment. *Journal of Cleaner Production*, *332*, 130067. <https://doi.org/10.1016/j.jclepro.2021.130067>. [URL](https://www.sciencedirect.com/science/article/pii/S0959652621042335#bib24).
    * Baciocchi, R., & Costa, G. (2021). CO<sub>2</sub> Utilization and Long-Term Storage in Useful Mineral Products by Carbonation of Alkaline Feedstocks. *Frontiers in Energy Research*, *9*. <https://doi.org/10.3389/fenrg.2021.592600>. [URL](https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2021.592600/full).
    * Liu, Z., & Meng, W. (2021). Fundamental understanding of carbonation curing and durability of carbonation-cured cement-based composites: A review. *Journal of CO*<sub>*2*</sub>*&#x20;Utilization*, *44*, 101428. <https://doi.org/10.1016/j.jcou.2020.101428.‌> [URL](https://www.sciencedirect.com/science/article/abs/pii/S2212982020310581).

      ‌

[^4]: Supplementary cementitious materials

[^5]: It is not permitted to generate CO<sub>2</sub> from biomass solely for the purpose of capture and storage.

[^6]: CO<sub>2</sub> originating from lime that is calcinated in cement production, from breaking up CaCO<sub>3</sub> into CO<sub>2</sub> and calcium silicates. Its carbonation leads to carbon storage, and is eligible for avoidance carbon credits.

[^7]: combined heat and power

[^8]: activities beyond what would have happened in the absence of the project


# Principles & requirements

Project Developers shall demonstrate that they comply with all principles and requirements outlined in the applicable version of the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements), and described below with a specific focus on mineralization.

## Additionality

Project Developers shall demonstrate additionality using the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template) and following the requirements of the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#additionality).

{% tabs %}
{% tab title="Regulatory surplus analysis" %}
**Regulatory surplus analysis** shall demonstrate that there are no regulations that require or mandate project activities.

Project Developers must demonstrate that CO<sub>2</sub> capture was not mandated under an Emissions Trading System (ETS). A site may be eligible if the site had already met its ETS obligations, and the captured CO<sub>2</sub> exceeded those required reductions, and the site complies with the [No double counting ](#n1iy4xaxuthk-1)criteria.

At the European Union level, projects automatically pass the regulatory surplus analysis, which has been conducted by the Rainbow Climate Team. Project Developers are only required to provide a country-level regulatory surplus analysis.
{% endtab %}

{% tab title="Investment analysis" %}
**Investment analysis** may be used to prove that revenue from carbon finance is necessary to make the project investment a financially viable and interesting option. The investment may cover:

* The creation and launching of new sites
* Expansion of capacity of existing activities
* Expansion by installing new processes

Business plans shall be provided as initial proof for investment analysis. During verification, audited financial statements shall be used to demonstrate that the initial estimates from the business plan were reasonable, and that carbon finance was used as initially described for the expected investment.

For launching brand new sites, additionality can be simply demonstrated if the business plan shows that carbon finance is expected to make up at least 80% of the company’s revenue, as detailed in the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template).

Note that for investments in expansion, **only the additional carbon removals and avoidance enabled by the expansion shall be eligible for Rainbow Carbon Credits.**
{% endtab %}

{% tab title="Barrier analysis" %}
**Barrier analysis** may be used to prove that the project faces financial, institutional, or technological barriers to ongoing operations that can only be overcome using carbon finance. Examples include but are not limited to:

* Financial barrier: financial analysis demonstrating that the project is not financially viable, evidenced by net cash being lower than the working capital requirements, or proof that the project is not meeting the projected financial targets in the business plans and loan documents, and that carbon finance would make it financially viable.
* Institutional barrier: description of new regulation that the project must make costly changes to comply with, with financial analysis showing that the project cannot fund the changes on their own, and carbon finance is necessary to make it viable.
* Technological barrier:
  * proof that the project's carbonated product struggles to be cost-competitive with baseline products. Carbon finance may be used to lower the selling price of the project’s product, making it more competitive.
  * proof that the large amount and cost of R\&D required for an innovative technology makes the technology unfeasible to scale without carbon finance.

For any type of barrier analysis, **audited financial statements must be provided** as proof. These documents should either demonstrate the financial status to prove financial barriers, or show that the project could not independently fund solutions to overcome institutional or technological barriers.
{% endtab %}
{% endtabs %}

## Durability <a href="#n1iy4xaxuthk" id="n1iy4xaxuthk"></a>

#### **Durability threshold**

All projects certified under this methodology shall prove **durable carbon removals for at least 1000 years**. The chemically-bound removed carbon is considered [**permanently stored**](#user-content-fn-1)[^1] **upon mineralization**/material production.

The final end use of the material affects its risk of reversal. This risk is mitigated by the project design requirements regarding [eligible uses of carbonated materials](/methodologies/mineralization-of-alkaline-materials-ex-situ/eligibility-and-scope#eligible-technologies), which allow only materials that won't be incinerated (i.e. concrete, asphalt, and landfill).

#### **Reversal risk assessment**

The carbon reversal risks from mineralization of alkaline materials are:

* **Exposure to high temperatures** via combustion, where carbonated material is incinerated or subjected to extreme heat, causing thermal decomposition of carbonate minerals and re-emission of CO<sub>2</sub>.
* **Exposure to strong acids**, where carbonated material comes into contact with acidic environments (e.g. acid rain, acidic groundwater infiltration, or industrial acid exposure), causing dissolution of carbonate minerals and re-emission of CO<sub>2</sub>.

This methodology establishes the following mandatory project requirements to mitigate these risks, detailed in the following sections:

* verification of carbonation extent and mineralogical stability
* evaluation of carbonated material end use

Upon meeting these requirements at project validation, the risk of reversal is considered **negligible** for mineralization of alkaline materials. There are no further project requirements to assess reversal risks or conduct post-crediting monitoring for reversals.

All projects certified under this methodology shall contribute the default minimum 2% of their verified removal RCCs to the Rainbow Buffer Pool, as defined in the Rainbow Standard Rules.

#### Risk mitigation: verification of mineralogical stability

Project Developers shall describe **the type of carbonate minerals produced** and their specific risk of reversal under relevant heat and pH conditions. This assessment shall

* be based on project-specific primary data (e.g. laboratory measurements such as XRD analysis) or secondary data that are highly representative of the project conditions, and
* address the carbonate type produced (e.g. anhydrous vs hydrated), and the resulting implications for resistance to thermal decomposition and acid dissolution.

#### Risk mitigation: evaluation of carbonated material end use

Project Developers shall demonstrate that the **intended end use of carbonated material mitigates reversal risk**. Eligible end uses include but are not limited to incorporation into concrete, construction aggregates, or other non-combustible permanent materials.

Project Developers shall describe the expected end use, including building or structure type and geographic location, and, in relation to the mineralogical stability assessment above, demonstrate minimized risk of exposure to thermal decomposition and acid dissolution.

## No double counting <a href="#n1iy4xaxuthk" id="n1iy4xaxuthk"></a>

Project Developers shall sign the [Rainbow MRV & Registry Terms & Conditions](/other/terms-and-contracts/terms-and-conditions-for-project-developers-mrv-+-registry), committing to follow the requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules), including not double using or double issuing carbon credits.

The following double counting risks have been identified for alkaline material mineralization projects. Project Developers shall follow the outlined requirements for each risk.

<table data-full-width="true"><thead><tr><th width="170">Double counting risk</th><th width="250">Explanation</th><th>Requirement</th></tr></thead><tbody><tr><td>Double issuance of carbon credits with downstream material users</td><td>Users of low-carbon concrete may seek to issue carbon credits in building methodologies in regulated or voluntary carbon markets</td><td><ul><li>Identify all direct downstream users/buyers/actors in their supply chain.</li><li>Provide the company/organization name, name of an individual contact person at the company/organization, and their contact information (email address at minimum).</li><li>Provide signed agreements and/or sales contract clauses stating carbon credits have already been issued, and users will not claim benefits or issue carbon credits for the product.</li></ul></td></tr><tr><td>Double claiming of removals or reductions with EPDs</td><td>If there is an EPD for the carbonated product, then  carbon removals and/or avoidance may be claimed by downstream users throughout the supply chain, who may issue credits or claim other environmental labels for the carbon benefit already counted and sold elsewhere</td><td><ul><li><p>Provide the product’s EPD, including:</p><ul><li>actual GWP values with carbon benefits, as required by norms/standard, and</li><li>a clause specifying when users must exclude carbon benefits in calculations using values from the EPD.</li></ul></li></ul></td></tr><tr><td>Double issuance of carbon credits with upstream CO<sub>2</sub> capture (e.g. DACCS projects)</td><td>Carbon capture projects are well incorporated in carbon markets (e.g. BECCS, DACCS), and Project Developers must agree on which entity is issued credits/how to repartition credits or carbon finance</td><td><ul><li>Identify all CO<sub>2</sub> suppliers in their supply chain.</li><li>Provide the company/ organization name, name of an individual contact person at the company/organization, and their contact information (email address at minimum).</li><li>Provide signed agreements and/or sales contract clauses stating carbon credits have been issued by the CO<sub>2</sub> user, and CO<sub>2</sub> suppliers will not claim/issue the same carbon benefits in the carbonated material.</li></ul></td></tr><tr><td>Double claiming of removals or reductions with ETS</td><td>CO<sub>2</sub> used for mineralization may be captured from heavy emitting industry sites that are covered by an ETS. When the site captures CO<sub>2</sub> emissions, they can claim the benefit in the ETS, or participate in the carbon credit issuing project, but not both.</td><td><ul><li>Demonstrate that the CO<sub>2</sub> supplier is not covered by an ETS.</li><li>If the CO<sub>2</sub> supplier is covered by an ETS, provide their official ETS reporting documents, showing that reductions that were issued carbon credits under the present methodology are not included in ETS reporting.</li></ul></td></tr></tbody></table>

## Co-benefits

Projects should support at least two **quantifiable and verifiable** environmental or social co-benefits, aligned with the [UN Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDGs) framework. Any co-benefits claimed by the Project Developer shall be **quantified, monitored, and audited** for each verification and credit issuance.

Common co-benefits under this methodology are detailed in the table below. Project Developers may suggest and prove other co-benefits not mentioned here.

SDG 13 on Climate Action by default is not considered a co-benefit here, since it is implicitly accounted for in the issuance of carbon credits. If the project delivers climate benefits that are not accounted for in the GHG reduction quantifications, then they may be considered as co-benefits.

*Table 1 Common co-benefits that projects under this methodology may provide are detailed, including types of proof that can be used to justify each co-benefit.*

<table><thead><tr><th width="214">UN SDG</th><th width="266">Example</th><th width="113">Proof</th><th>Indicators</th></tr></thead><tbody><tr><td><strong>SDG 12.2</strong> <em>Achieve the sustainable management and efficient use of natural resources</em></td><td>The project’s <a data-footnote-ref href="#user-content-fn-2">circularity </a>will be measured by the <a data-footnote-ref href="#user-content-fn-3">Material Circularity Indicator (MCI)</a>, according to the Ellen MacArthur Foundation's methodology, and compared to the circularity of the baseline product.</td><td>Types of inputs used and waste status</td><td>% circularity, % improvement from baseline</td></tr><tr><td><strong>SDG 9.4</strong> <em>Upgrade infrastructure and retrofit industries to make them sustainable</em></td><td>Increase strength, durability and lifetime of concrete, extending infrastructure lifespan.</td><td>Internal testing, R&#x26;D results</td><td>% extended lifespan</td></tr><tr><td><strong>SDG 8.4</strong> <em>Improve global resource efficiency in consumption and production</em></td><td>Reusing alkaline waste materials in the mineralization process diverts them from other waste treatment methods.</td><td>Invoices and operations records</td><td>tonnes of waste material used</td></tr><tr><td><strong>SDG 6.3</strong> <em>Improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials</em></td><td>Projects that carbonate and reuse cement wastewater contribute to improved and useful wastewater treatment and water quality</td><td>Invoices and operations records</td><td>m<sup>3</sup> of wastewater used</td></tr></tbody></table>

## Environmental and social safeguards

Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.** Projects must follow all national, local and European (if located in Europe) environmental regulations, and prove such compliance using, for example, permits, certifications, or licenses.

In addition to completing the [Rainbow Mineralization risk assessment](/methodologies/mineralization-of-alkaline-materials-ex-situ/risk-assessment-template) below, Project Developers must prove the following elements:

For **fossil CO**<sub>**2**</sub>**&#x20;use**, Project Developers shall prove that the CO<sub>2</sub> was not generated or emitted for the sole purpose of carbon storage, and that it was captured from an existing CO<sub>2</sub> emission source.

For **biogenic CO**<sub>**2**</sub>**&#x20;use**, Project Developers shall prove that the original biomass used to generate the biogenic CO<sub>2</sub> meets the EU's [RED III](https://eur-lex.europa.eu/eli/dir/2018/2001) Article 29 sustainability criteria for biomass (even if the project is not located in the EU). This includes the following, summarized here for informative purposes only:

* If the biomass is proven to be waste, no further sustainability requirements apply (refer to the positive list in the Rainbow [Biomass feedstock](/methodologies/biomass-carbon-removal-and-storage-bicrs/carbon-capture/biomass-feedstock#waste-status) module).
* If the biomass is not waste, Project Developers shall prove that it did not come from:
  * Primary or old-growth forests
  * Highly biodiverse forests or other wooded land designated as such by competent authorities.
  * Protected areas for rare or endangered ecosystems/species (unless proven that biomass production does not interfere with conservation goals).
  * Highly biodiverse grasslands
  * Heathland, wetlands, or peatlands
  * Recently deforested, converted or degraded ecosystems (within past 20 years)
* Forestry biomass shall follow the requirements listed above, and
  * Respect international, national and regional legal requirements
  * Promote forest regeneration by avoiding large clear-cuts or extraction of stumps/roots
  * Protect biodiversity and soil quality
  * Come from sustainably managed forests

#### Environmental and social risk assessment

Project Developers shall fill in the [Rainbow Mineralization risk assessment](/methodologies/mineralization-of-alkaline-materials-ex-situ/risk-assessment-template), to evaluate the identified environmental and social risks of projects. The identified risks include:

* Heavy metal leaching from stored alkaline feedstock
* Dust and particulate generation from alkaline feedstock storage and handling
* Water use in the mineralization process
* Fugitive CO<sub>2</sub> leaks during the mineralization process
* Hazardous waste generation from the use of chemical additives
* Leaching pollutants from carbonated products during the use phase
* Demand for fossil CO<sub>2</sub> as a valuable product increases fossil fuel output
* Pressure on unsustainable or nonrenewable biomass use for biogenic CO<sub>2</sub> generation
* Environmental impacts from opening a new mine or quarry to obtain alkaline feedstock

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

## Leakage <a href="#ekfzu5nkmddm" id="ekfzu5nkmddm"></a>

Mineralization of materials must not contribute to activity shifting leakage. The following leakage risks are covered by other requirements in this methodology:

* **Displacement of baseline mineralization**: any atmospheric carbon removal via mineralization that occurs in the baseline shall be modeled in the [Baseline Scenario](/methodologies/mineralization-of-alkaline-materials-ex-situ/ghg-quantification#baseline-co2-stored), and effectively deducted from the project's carbon storage.
* **Increased emissions during use**: leakage emissions from use of carbonated products downstream of the project are mitigated by the [Baseline setting](/methodologies/mineralization-of-alkaline-materials-ex-situ/eligibility-and-scope#baseline-scope) requirements, where project materials must have the same performance as baseline/replaced products.

No further methodology requirements apply. Project Developers shall follow the [Leakage](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#leakage) requirements in the Rainbow Standard Rules to comply with this requirement.

## Monitoring

Monitoring Plans for this methodology shall include, but are not limited to, tracking of the following information **for each Mineralization Batch.**

#### Eligibility criteria compliance

* Proof of regulatory additionality, that CO<sub>2</sub> didn't have to be captured, wasn't covered by ETS (or mention no change)
* Proof of permanence/low reversal risk, end use of product (or mention no change)
* Proof of no double counting: EPDs, ETS (or mention no change)
* If using biomass feedstock, proof of adherence to Environmental and social safeguards requirements (or mention no change)
* Any co-benefits claimed

#### GHG quantification

* Amount CO<sub>2</sub> leakage during transport
* Repartition of CO<sub>2</sub> types purchased, entering carbonation facility
* Total amount of carbonated material produced per monitoring period, in tonnes of material
* Carbon storage measurements, either:
  * Solid phase:
    * CO<sub>2</sub> measured in solid samples of carbonated material
  * Gas inflow-outflow:
    * Volumetric flow and concentration of CO<sub>2</sub> inflow and outflow
    * Gas void fraction of alkaline feedstock (if carbonating solid materials)
    * Bulk density of the alkaline feedstock (if carbonating solid materials)
    * Amount of carbonated material produced daily, in tonnes of material
    * Ongoing demonstration of equipment calibration and QA/QC procedures
* Transport distance or amount of fuel, and transport mode, for CO<sub>2</sub> delivery, alkaline feedstock delivery, and final product delivery (if >50 km)
* Amount and type of alkaline feedstock used
* Baseline removal calculations from alkaline feedstock carbonation
* Baseline and project removal calculations from concrete use phase carbonation
* Amount cement needed in baseline and project scenario, and chosen cement emission factor (*only for projects issuing avoidance credits from reduced cement use*)
* Energy and/or material use from CO<sub>2</sub> capture, CO<sub>2</sub> purification, alkaline feedstock processing, and carbonation process

The Project Developer is the party responsible for adhering to the Monitoring Plan.

Monitoring Plans shall include the following information for each monitored parameter:

* monitoring frequency
* emission sources and sinks
* data source
* measurement methods/procedures, and their accuracy and calibration
* quality assessment or quality control procedures
* responsible party for collecting and archiving data

[^1]: Baciocchi, R., Costa, G., 2021. CO2 Utilization and Long-Term Storage in Useful Mineral Products by Carbonation of Alkaline Feedstocks. Front. Energy Res. 9. [URL](https://doi.org/10.3389/fenrg.2021.592600).

[^2]: Goddin, J., Marshall, K., Pereira, A., Tuppen, C., Herrmann, S., Jones, S., Krieger, T., Lenges, C., Coleman, B., Pierce, C., Iliefski-Janols, S., Veenendaal, R., Stoltz, P., Ford, L., Goodman, T., Vetere, M., Mistry, M., Graichen, F., Natarajan, A., Sullens, W., 2019. Circularity Indicators: An Approach to Measuring Circularity, Methodology. <https://doi.org/10.13140/RG.2.2.29213.84962>

[^3]: Ellen Macarthur Foundation, ANSYS Granta, 2019. An approach to measuring circularity. Published in 2015, adapted in 2019. [URL](https://emf.thirdlight.com/link/3jtevhlkbukz-9of4s4/@/preview/1?o)


# GHG quantification

General GHG quantification rules can be found in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules).

Calculations of GHG emissions for the baseline and project scenarios shall follow a robust, recognized method and good practice guidance. The overall methodological approach is a comparative life cycle assessment (LCA) at the project-scale, based on [ISO 14064-2:2019](#user-content-fn-1)[^1].

Mineralization projects certified under this methodology may be eligible for **removal and avoidance Rainbow Carbon Credits**.

{% hint style="info" %}
**Avoidance RCCs from fossil or calcination CO**<sub>**2**</sub>**&#x20;storage** are calculated using the same approach as for removals from biogenic and atmospheric CO<sub>2</sub>, and are simply assigned a different credit type (avoidance instead of removal).
{% endhint %}

{% hint style="info" %}
**Avoidance RCCs from reduced cement use** are calculated and issued according to a separate accounting mechanism, described below. This conservative approach results in double counting the project's induced emissions, and avoids the need for allocation of emissions/removals.
{% endhint %}

GHG quantification shall be completed for each monitoring period. The duration of the monitoring period is chosen by the Project Developer and may be either each [mineralization batch](/methodologies/mineralization-of-alkaline-materials-ex-situ/eligibility-and-scope#mineralization-batch), each calendar year, another duration shorter than 1 year, or a maximum of 18 months.

This methodology shall be used in conjunction with the Rainbow modules listed below. **Modules are like mini-methodologies** that only cover a part of the project life-cycle. Combining the relevant modules for a project results in a complete picture of the required data, calculations, monitoring plans, and other information needed for a full GHG quantification.

<table data-view="cards"><thead><tr><th></th><th data-hidden data-card-target data-type="content-ref"></th><th data-hidden data-card-cover data-type="image">Cover image</th></tr></thead><tbody><tr><td>Processing and energy use</td><td><a href="/pages/BTxxPIM3a4Nai1Wkwu2Y">/pages/BTxxPIM3a4Nai1Wkwu2Y</a></td><td><a href="/files/xqDoBuMbX7fcBqJ8AanC">/files/xqDoBuMbX7fcBqJ8AanC</a></td></tr><tr><td>Transportation</td><td><a href="/pages/VTWdCc7guKu1x0azAizi">/pages/VTWdCc7guKu1x0azAizi</a></td><td><a href="/files/XAxrYlLSh0qtvbDkKkqp">/files/XAxrYlLSh0qtvbDkKkqp</a></td></tr><tr><td>Infrastructure and machinery</td><td><a href="/pages/IwqpSqlee22qTIPti3Sl">/pages/IwqpSqlee22qTIPti3Sl</a></td><td><a href="/files/gE6Zo8o6awA0p9LnSTnF">/files/gE6Zo8o6awA0p9LnSTnF</a></td></tr></tbody></table>

## Functional unit <a href="#id-8422amp7fe3k" id="id-8422amp7fe3k"></a>

Two different functional units are used:

* **1 tonne of mineralized material produced** (e.g. 1 tonne of carbonated concrete, 1 tonne of carbonated aggregate...)
* **1 tonne of captured CO**<sub>**2**</sub>

Credits are issued on the basis of mineralized material production, so this may be considered the main functional unit. Captured CO<sub>2</sub> is used as a secondary functional unit for comparability across CDR technologies.

## System boundary

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td>The project system boundary shall include only the activities that are additional to the business as usual (BAU) scenario.</td></tr><tr><td>The baseline scenario system boundary shall include the processes that would have occurred in the absence of the project.</td></tr></tbody></table>

{% hint style="info" %}
For example,

* if the project performs direct carbonation of fresh concrete during hydration, the project boundary shall not include the upstream emissions from cement production.
* if the project captures biogenic CO<sub>2</sub> flue gas from an anaerobic digestion site, the project boundary shall not include the emissions from anaerobic digestion, or the embodied emissions from the digester, because these would have occurred anyway. The project boundary shall include the embodied emissions from the CO<sub>2</sub> capture machinery added to the digester, because this was installed and used specifically for the purpose of carbon capture.
* if the project uses a portion of a concrete facility's flue gas (diverting the CO<sub>2</sub> stream, using part for mineralization, and returning the unused portion to the main flue gas stream to be emitted), the project boundary shall not include the emission of unused CO<sub>2</sub> that returns to the flue gas stream.
  {% endhint %}

A summary of the calculation approach is presented below, and detailed descriptions and equations for calculating GHGs are in the respective [Project](#letyqrgxkbuh) and [Baseline](#id-8422amp7fe3k-2) scenario sections.

{% tabs %}
{% tab title="Summary: Carbon storage from mineralization " %}
For **removals and avoidance from mineralization**:

* The project system boundary shall include at least the following elements where relevant and additional (i.e. beyond BAU):
  * production of any non-waste inputs and additives
  * transport of inputs to the project site (e.g. CO<sub>2</sub>, recycled concrete, alkaline feedstock...)
  * onsite energy use (electricity, fuels, heat...) related to e.g. preparation of feedstock, and the mineralization process
  * fugitive CO<sub>2</sub> leaks during CO<sub>2</sub> transport
  * carbon storage
  * see [Figure 1](#letyqrgxkbuh) below for the system boundary diagram.
* The baseline system boundary shall include:
  * any removals that would have occurred naturally from mineralization of the alkaline feedstock, and/or
  * any use-phase carbonation benefits that would have naturally occurred at greater rates had the project not altered the material or process.

Removals and avoidance from mineralization are calculated using the following high-level equations, detailed in their respective sections below.

<details>

<summary><strong>Calculations: Removals and avoidance from mineralization</strong></summary>

$$\textbf{(Eq.1)}\ S\_{net}= \Sigma{S}*{baseline} - \Sigma{S}*{project} - \Sigma{E}\_{project}$$

where,

* $$S\_{net}$$ represents the net carbon storage from the project during the monitoring period, in tonnes of CO$$\_2$$eq. This **storage may be counted as removals or avoidance**, depending on the type of CO<sub>2</sub> stored, as calculated in Eq. 2 and 3. Its sign is positive.
* $$S\_{baseline}$$ represents any baseline GHG removals from mineralization of alkaline minerals in their alternative use, representing permanent storage that would have occurred anyway in the absence of the project, in tonnes of CO$$\_2$$eq, calculated in Eq. 7. Its sign is negative.
* $$S\_{project}$$ represents the project's gross GHG storage from mineralization, in tonnes of CO$$\_2$$eq, calculated in Eq. 15 or 19. Its sign is negative.
* $$E\_{project}$$ represents the project's induced GHG emissions, in tonnes of CO$$\_2$$eq, calculated in Eq. 8. Its sign is positive.

$$\textbf{(Eq.2)}\ Removal\ RCCs = S\_{net}\* F\_{bio,\ atm}$$

Where,

* $$Removal\ RCCs$$ represents the amount of **removal** Rainbow Carbon Credits to be issued during the monitoring period, from carbon storage from mineralization.
* $$S\_{net}$$ was calculated in Eq. 1.
* $$F\_{bio,\ atm}$$ represents the fraction of CO<sub>2</sub> that is biogenic or atmospheric, as described in the [Allocation of captured carbon: removals vs. avoidance](#allocation-of-captured-carbon-removals-vs.-avoidance) section

$$\textbf{(Eq.3)}\ Avoidance\ RCCs = S\_{net}\* (1-F\_{bio,\ atm})$$

Where,

* $$Avoidance\ RCCs$$ represents the amount of **avoidance** Rainbow Carbon Credits to be issued during the monitoring period, from carbon storage from mineralization.
* $$S\_{net}$$ was calculated in Eq. 1.
* $$F\_{bio,\ atm}$$ represents the fraction of CO<sub>2</sub> that is biogenic or atmospheric.

</details>
{% endtab %}

{% tab title="Summary: Reduced cement" %}
For **avoided GHGs from reduced cement**:

* The project system boundary shall include emissions from the manufacture of the *actual quantity of cement used in the concrete mix designs,* in which the carbonated materials are used.
* The baseline system boundary shall include emissions from the manufacture of the quantity of cement that would have been required to achieve the same functional performance using conventional materials or methods, *for the given concrete mix design*. This will likely represent a larger amount of cement than in the project scenario, since mineralization projects may enhance binder strength and reduce the total cement required.

Avoided GHGs from reduced cement are calculated using the equation below.

{% hint style="warning" %}
These calculations **do not account for carbon storage**, and **do not allow for allocation of induced emissions** between the mineralization removal and the avoidance/reduced product.
{% endhint %}

<details>

<summary><strong>Calculations - Avoidance from reduced cement</strong></summary>

$$\textbf{(Eq.4)}\ E\_{project,\ cement} = E\_{project}+ (A\_{cement,\ project} \* EF\_{cement})$$

where,

* $$E\_{project,\ cement}$$ represents the total project scenario emissions from manufacturing and using cement for the monitoring period, in tonnes of CO$$\_2$$eq. It is composed of normal cement manufacturing emissions, upstream of the project activity and which were excluded from the Storage calculations, plus the additional induced emissions due to the project mineralization activity.
* $$E\_{project}$$ represents the induced GHG emissions from the project during the verification period, in tonnes of CO$$\_2$$eq, calculated in Eq. 8.
* $$A\_{cement,\ project}$$ represents the amount of cement used by the project in the monitoring period, in tonnes of cement.
* $$EF\_{cement}$$ represents the emission factor for cement, in tonnes of CO$$\_2$$eq per tonne of cement. Possible sources for this emission factor are described in the [Baseline scenario](#emission-factor-of-cement) section.

$$\textbf{(Eq.5)}\ E\_{baseline, cement} = A\_{cement, baseline}\*EF\_{cement}$$

where,

* $$E\_{baseline,\ cement}$$ represents the baseline scenario emissions from manufacturing and using a functionally equivalent amount of cement for the monitoring period, in tonnes of CO$$\_2$$eq.
* $$A\_{cement,\ baseline}$$ represents the amount of cement needed in the baseline scenario to fulfill the same function as the project-manufactured cement. This is expected to be higher than the amount needed in the project scenario, thanks to the project's improvements.
* $$EF\_{cement}$$ represents the emission factor for cement, as described in Eq. 4. The same emission factor shall be used for the project and baseline scenario.

$$\textbf{(Eq.6)}\ E\_{avoided} = E\_{baseline,\ cement} - E\_{project,\ cement}$$

where,

* $$E\_{avoided}$$ represents the avoided GHG emissions from the project scenario, in tonnes of CO$$\_2$$eq.
* $$E\_{baseline,\ cement}$$ was calculated in Equation 5.
* $$E\_{project,\ cement}$$ was calculated in Equation 4.

</details>
{% endtab %}
{% endtabs %}

## Allocation

### Allocation of captured carbon: removals vs. avoidance

Credits can be issued from mineralization processes that result in both

* [**CDR**](#user-content-fn-2)[^2]**/removals**, from using biogenic and atmospheric (e.g. DAC) CO<sub>2</sub>, and
* [**CCS**](#user-content-fn-3)[^3]**/avoidance**, from using fossil and calcination CO<sub>2</sub>.

The same calculation method applies to all CO<sub>2</sub> sources, they are simply assigned different credit types upon issuance (i.e. removal vs avoidance, see Eq. 2 and 3).

If the CO<sub>2</sub> stream used in the mineralization batch is **100% biogenic/atmospheric** or **100% fossil/calcination**, no allocation is needed. All carbon storage and project induced emissions are fully attributed to removal or avoidance, respectively.

If the **CO**<sub>**2**</sub>**&#x20;stream is mixed**, Project Developers must determine the proportion of biogenic/atmospheric vs. fossil/calcination carbon, according to Article 39 of the[ EU ETS monitoring and reporting](#user-content-fn-4)[^4] (even for non-EU based projects), summarized here for informative purposes only:

* conservatively assume all CO<sub>2</sub> is fossil/calcination CO<sub>2</sub>, or
* use mass balance of material inputs by type, or
* use measurement method, e.g. C14 testing, or
* use other standards and analytical methods, subject to approval by Rainbow and the VVB.

The proportion of CO<sub>2</sub> types shall be used to allocate the following, which are accounted for in Eq. 2 and 3:

* **Carbon storage:** CO<sub>2</sub> flows shall assume a proportional repartition of the two CO<sub>2</sub> types in the different CO<sub>2</sub> fates (e.g. successfully carbonated CO<sub>2</sub>, inflow and outflow CO<sub>2</sub>, unsuccessfully carbonated CO<sub>2</sub> left in pore space...).
* **Induced emissions:** project emissions shall be proportionally assigned to removal or avoidance based on the share of CO<sub>2</sub> input from each source.

{% hint style="info" %}
For example, if a project:

* has a mixed CO<sub>2</sub> stream of 50% fossil CO<sub>2</sub> and 50% biogenic CO<sub>2</sub>
* measures total gross carbon storage of 100 tCO<sub>2</sub>eq
* calculates project induced emissions of 10 tCO<sub>2</sub>eq, plus 1 tonne of fugitive CO<sub>2</sub> leaked from transport

**Gross carbon storage** repartitioned proportionally:

* 50 tCO<sub>2</sub>eq from fossil CO<sub>2</sub>
* 50 tCO<sub>2</sub>eq from biogenic CO<sub>2</sub>

**Project induced emissions** repartitioned proportionally:

* 5 tCO<sub>2</sub>eq from fossil CO<sub>2</sub>
* 5 tCO<sub>2</sub>eq from biogenic CO<sub>2</sub>

**Fugitive CO**<sub>**2**</sub>**&#x20;leaked** **from transport**, repartitioned proportionally:

* 0.5 tonnes fossil CO<sub>2</sub> leaked, counted as 0.5 tCO<sub>2</sub>eq (fossil CO<sub>2</sub> has a GWP of 1)
* 0.5 tonnes biogenic CO<sub>2</sub> leaked, counted as 0 tCO<sub>2</sub>eq (biogenic CO<sub>2</sub> has a GWP of 0)

This would result in

* Avoidance credits from fossil CO<sub>2</sub> mineralization = $$50-5-0.5 = 44.5\ tCO\_2eq$$
* Removal credits from biogenic CO<sub>2</sub> mineralization = $$50-5-0 = 45.0\ tCO\_2eq$$
  {% endhint %}

### Allocation between existing activities and baseline activities

When a **process is shared between the project scope and** [**BAU** ](#user-content-fn-5)[^5]**activities** (e.g. total electricity use at a site performing both cement manufacturing and mineralization), only the portion attributable to the project and additional to the baseline should be included. This allocation should follow one of the approaches below:

* Subdivide the system and isolate measurements to collect only input/output data directly relevant for the project scope (e.g. install electricity meters at the entry point of the mineralization process).
* If subdivision is not feasible, allocate shared processes based on a relevant underlying characteristic of the shared systems (e.g. by mass for jointly transported materials, by economic value for co-products with distinct markets...).

This allocation shall be applied at the data collection stage. Project Developers shall do this allocation outside of the GHG quantification equations, and submit allocated data into the removal and avoidance calculations (with justification/proof of work for allocation).

## Assumptions <a href="#id-8422amp7fe3k" id="id-8422amp7fe3k"></a>

1. By default, future uses (beyond the product's first life) or end-of-life treatment of the carbonated material will not lead to reversals. This assumes no significant changes in environmental conditions (e.g. pH or fire exposure) that would cause CO<sub>2</sub> release.
2. A standard transport distance of 50 km is assumed for final product (concrete and/or carbonated solid materials) delivery. Transport emissions for distances below this threshold are considered equivalent between the baseline and project scenarios, and can be excluded from the project system boundary. Transport emissions for distances above this threshold shall be included in project induced emissions calculations.
3. For directly carbonated cement (e.g. during curing or hydration/mixing), it is assumed that either no significant amount of unreacted CO<sub>2</sub> remains trapped in the pore space, or that any trapped CO<sub>2</sub> will eventually react fully with the cement matrix.
4. All carbonated material from the same mineralization batch has similar characteristics.

## Baseline scenario <a href="#id-8422amp7fe3k" id="id-8422amp7fe3k"></a>

The baseline scenario is twofold, and is detailed in following sections:

* **Removals from mineralization** that would have occurred anyway, from alternative feedstock use/management (for mineralization of solid materials such as SCMs and aggregates) and in use-stage concrete carbonation (for all technology types).
* **Avoidance from reduced cement** shall be considered for projects issuing avoidance credits from reduced cement use, thanks to improved binder strength.

### Baseline CO<sub>2</sub> storage

The baseline scenario shall account for natural mineralization from both:

* the alternate fate of **non-cement alkaline feedstock**, and
* the use-phase natural mineralization of **cement-based feedstock,** that would have occurred anyway.

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><p>For <strong>alkaline feedstocks other than cement</strong>, Project Developers shall assess the natural mineralization of the feedstock upon exposure to atmospheric CO<sub>2</sub>, if it hadn't been used by the project for accelerated carbonation. The extent of natural carbonation depends on the:</p><ul><li>alternative fate of alkaline feedstock</li><li>type and duration of exposure to CO<sub>2</sub></li><li>mineralogy</li><li>particle size</li></ul><p>Project Developers shall either:</p><ul><li>estimate baseline removals in alkaline feedstock using a description and proof of common practices for managing the alkaline material, mineralization models, scientific literature, or <a data-footnote-ref href="#user-content-fn-6">internal experiments</a>, or</li><li>only if the feedstock is recycled concrete aggregate, opt for a default assumed carbon removal rate in the baseline scenario of <a data-footnote-ref href="#user-content-fn-7">6.67 kgCO<sub>2</sub>eq/m<sup>3</sup></a> of recycled concrete, in loose aggregate form.</li></ul></td></tr><tr><td><p>For <strong>direct use of cement as a feedstock</strong> (e.g. carbonation curing), some natural mineralization of feedstock occurs during its use-phase in concrete. If the project technology <strong>only accelerates the rate of this carbonation</strong>, rather than causing additional net carbonation gains, then the portion of mineralization that would have occurred anyway (albeit at a slower pace) shall not be credited. Project Developers shall demonstrate that the CO<sub>2</sub> mineralized by the project would not have occurred naturally without the project intervention. This may be justified by:</p><ul><li>The fundamental design or operating principles of the technology, or</li><li>Selecting an appropriate post-treatment measurement time that excludes mineralization likely to occur during early use-phase conditions, or</li><li>Modeling the expected BAU mineralization, using recognized datasets or modeling tools, or</li><li>Opting for a default assumed carbon removal rate in the baseline scenario of <a data-footnote-ref href="#user-content-fn-8">125 kgCO<sub>2</sub>eq</a>/tonne of carbonated cement.</li></ul></td></tr></tbody></table>

Any natural carbon unaccounted for, that would have occurred without the intervention, shall be counted as baseline removals.

If a first screening assessment based on conservative estimates demonstrates combined baseline removals (sum of alkaline feedstock and concrete use phase) are <1% of the net project removals, then baseline removals may be set to 1%, and the Project Developer does not need to collect more precise baseline removal information. Otherwise, the Project Developer may choose to collect/model baseline removals in detail in order to prove and apply a lower baseline removal rate.

<details>

<summary>Calculations: Baseline CO<sub>2</sub> stored</summary>

$$\textbf{(Eq.7)}\ S\_{baseline}= S\_{mineralization feedstock}+S\_{use\ phase\ carbonation}$$

Where

* $$S\_{baseline}$$ was described in Eq 1
* $$S\_{mineralization\ feedstock}$$ represents baseline carbon storage from natural mineralization of alkaline feedstock, corresponding to the amount of feedstock used by the project in the monitoring period, in tCO<sub>2</sub>eq.
* $$S\_{use\ phase\ carbonation}$$ represents baseline removals from mineralization of cement during the concrete use-phase that are larger than the use-phase carbonation for the project material, corresponding to the amount of concrete or cement produced by the project in the monitoring period, in tCO<sub>2</sub>eq.

</details>

### Baseline induced emissions

Baseline induced emissions are **only considered for avoidance credits from avoided cement production**. In this case, baseline induced emissions shall include the emissions from producing an equivalent amount of cement to serve the same purpose (compressive strength, lifetime...) as the cement produced in the project scenario.

Emissions are calculated based on the quantity and emission intensity of cement used in the project scenario compared to the baseline. While the emission factor of cement production remains the same (since mineralization projects typically do not alter upstream or downstream cement/concrete production), the **total amount of cement needed in the concrete design mix may differ**. This is because the project may create a stronger binder, requiring less cement than conventional practices.

{% tabs %}
{% tab title="Quantity of cement" %}
To determine the quantity of cement avoided, Project Developers shall provide the cement usage ratio between the project and baseline scenarios for each end use of the carbonated material.

This shall be **proven using the stated concrete mix designs** used by the client using the carbonated material, demonstrating a lower cement use than otherwise used, or similar project-specific estimates (i.e. not default global replacement rates).
{% endtab %}

{% tab title="Emission factor of cement" %}
Cement emission factors shall be taken from the following sources, in decreasing order of preference:

* project-specific sources, provided by the client using the carbonated material (e.g. EPDs), or
* low-carbon cement thresholds (e.g. provided by the Global Cement and Concrete Association [Low Carbon Rating](https://gccassociation.org/lcr-cement/))
* the Ecoinvent database, presented in [Appendix 1](/methodologies/mineralization-of-alkaline-materials-ex-situ/appendix#appendix-1-ecoinvent-activities), with a 20% deduction applied for conservativeness.

Other sources of emission factors may be submitted by the Project Developer, and approved by the Rainbow Certification Team and the VVB. Any emission factor must meet the data requirements outlined in the Rainbow Standard Rules, and come from traceable, transparent, unbiased, and reputable sources. A **conservative uncertainty deduction shall be applied if the value is not project-specific.**
{% endtab %}
{% endtabs %}

Calculations from this life cycle stage are presented above in Eq. 4-6 in the [system boundary](#calculations-avoidance-from-reduced-cement) section above.

## Project scenario <a href="#letyqrgxkbuh" id="letyqrgxkbuh"></a>

An example of a typical project design and system boundary is shown in Figure 1. Each life cycle stage is detailed in the following sections.

<figure><img src="/files/XHTzwsvfSkps8zk9Bpoo" alt=""><figcaption><p>Figure 1 System diagram showing what is included and excluded in GHG quantification of the project scenario. Life cycle stages are color coded, and correspond to the sections below, where each stage is described in detail. The dashed line represents the system boundary, showing which processes' emissions are included in the GHG quantification, and which are excluded.</p></figcaption></figure>

<details>

<summary>Calculations: Total project induced emissions</summary>

$$\textbf{(Eq. 8)}\ E\_{project}= E\_{CO\_2\ capture} +E\_{feedstock}+E\_{mineralization}$$

Where,

* $$E\_{project}$$ was described in Eq. 1.
* $$E\_{CO\_2\ capture}$$ is calculated in Eq. 9.
* $$E\_{feedstock}$$ is calculated in Eq. 13.
* $$E\_{mineralization}$$ is calculated in Eq. 14.

</details>

### Project CO<sub>2</sub> capture

This stage includes process emissions from the CO<sub>2</sub> capture facility, CO<sub>2</sub> transport emissions, and CO<sub>2</sub> leakage during transport.

{% tabs %}
{% tab title="CO2 capture" %}
Induced emissions from the CO<sub>2</sub> capture process shall only include emissions/activities that would not have occurred in the baseline.

Typically, CO<sub>2</sub> capture is done on industrial sites that are already operating and emitting CO<sub>2</sub>. In this case, emissions from the industrial site operations and embodied emissions shall not be counted towards the CO<sub>2</sub> capture. Furthermore, the CO<sub>2</sub> itself is considered a waste product, and according to the waste cutoff LCA principle, is modeled as entering the project system boundary with no environmental burden/emissions.

Processes that may be considered in this stage may include but are not limited to:

* additional **infrastructure/machinery/instruments that are required for carbon capture** (note that any pieces that contribute to less than 1% of the project gross removals may be excluded, up to a collective total of 2% of gross removals, according to the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/ghg-quantification). This can be assessed with a screening LCA using estimates, and if deemed substantial, more precise data shall be provided).
* additional **energy use required for carbon capture**: Project Developers shall isolate the amount of energy used at the site that is only for carbon capture, that is not related to the site's BAU activities.
* energy or material use from **purification and processing of CO**<sub>**2**</sub>**&#x20;streams**, for example through chemical (e.g. amine-based absorption) or physical treatment (cryogenic separation or membrane separation).

For infrastructure calculations and emission factors, see the [Infrastructure and machinery ](/modules/infrastructure-and-machinery)module. For energy use calculations and emission factors, see the [Processing and energy use](/modules/processing-and-energy-use) module.
{% endtab %}

{% tab title="CO2 transport" %}
Induced emissions from the transport of CO<sub>2</sub> to the mineralization site shall be included. This may include transport via truck, pipeline, ship, or other methods.

For transport calculations and emission factors, see the [Transportation ](/modules/transportation)module.
{% endtab %}

{% tab title="CO2 leakage during transport" %}
The following three methods are recommended for measuring and reporting CO<sub>2</sub> leakage during transport, but other methods suggested by the Project Developer may be considered on a case by case basis:

* **Difference in CO**<sub>**2**</sub>**&#x20;shipped/received:** Project Developers record the amount of CO<sub>2</sub> leaving the capture site, and the amount entering the mineralization process. Any difference is assumed to be CO<sub>2</sub> leaked during transport, and counted as project induced emissions.
* **Literature-based leakage rates:** Project Developers may propose conservative leakage rates from scientific literature, if they are well documented, from reputable sources, and are representative of the project-specific technology.
* **Justification that leakage is negligible**, under at least one of the following conditions:
  * it is 100% biogenic and/or atmospheric CO<sub>2,</sub> or
  * it came from a flue gas stream, where the unused flue gas is emitted anyway, or
  * transport technologies are proven to have negligible CO<sub>2</sub> leakage (e.g. pressurized insulated containers)
    {% endtab %}
    {% endtabs %}

<details>

<summary>Calculations: Project CO<sub>2</sub> capture</summary>

$$\textbf{(Eq. 9)}\ E\_{CO\_2\ capture}=E\_{CO\_2\ capture\ process}+E\_{CO\_2\ capture\ infra}+E\_{CO\_2\ transport}+E\_{CO\_2\ transport\ leakage}$$

Where

* $$E\_{CO\_2\ capture}$$ represents the total project emissions from the CO<sub>2</sub> capture life cycle stage, in tCO<sub>2</sub>eq.
* $$E\_{CO\_2\ capture\ process}$$ represents the emissions from any additional energy or consumable materials used in the CO<sub>2</sub> capture process, calculated using the [Processing and energy use](/modules/processing-and-energy-use) module, in tCO<sub>2</sub>eq.
* $$E\_{CO\_2\ capture\ infra}$$ represents the emissions from any additional infrastructure or machinery used for CO<sub>2</sub> capture, calculated using the [Infrastructure and machinery ](/modules/infrastructure-and-machinery)module, in tCO<sub>2</sub>eq.
* $$E\_{CO\_2\ transport}$$ represents the emissions from transporting CO<sub>2</sub> to the mineralization site, calculated using the [Transportation ](/modules/transportation)module, in tCO<sub>2</sub>eq.
* $$E\_{CO\_2\ transport\ leakage}$$ represents the emissions from fugitive CO<sub>2</sub> leaked during CO<sub>2</sub> transport, in tCO<sub>2</sub>eq. It may be calculated using Eq 10, 11, 12, or a different approach.

$$\textbf{(Eq. 10)}\ E\_{CO\_2\ transport\ leakage}= Purchased\_{CO\_2}-Inflow\_{CO\_2}$$

Where,

* $$E\_{CO\_2\ transport\ leakage}$$ was described in Eq. 9.
* $$Purchased\_{CO\_2}$$ represents the total mass of CO<sub>2</sub> leaving the CO<sub>2</sub> supplier and destined for the mineralization site, throughout the monitoring period, in tCO<sub>2</sub>eq.
* $$Inflow\_{CO\_2}$$ represents the mass of gaseous CO<sub>2</sub> entering the mineralization process (e.g. entering a reactor) throughout the monitoring period, in tCO<sub>2</sub>eq. It may be calculated using Eq. 20, or provided via other operations records.

$$\textbf{(Eq. 11)}\ E\_{CO\_2\ transport\ leakage}= Purchased\_{CO\_2} \times R\_{leakage}$$

Where,

* $$E\_{CO\_2\ transport\ leakage}$$ was described in Eq. 9.
* $$Purchased\_{CO\_2}$$ was described in Eq. 10.
* $$R\_{leakage}$$ represents the default leakage rate of the given transport mode (e.g. truck, pipeline...), for all transport modes used in project operations, in tCO<sub>2</sub> lost/tCO<sub>2</sub>, or as a fraction.

$$\textbf{(Eq. 12)}\ E\_{CO\_2\ transport\ leakage}= T\_{CO\_2} \times R\_{leakage,\ T}$$

Where,

* $$E\_{CO\_2\ transport\ leakage}$$ was described in Eq. 9.
* $$T\_{CO\_2}$$ represents the truck or ship transport segment considered, in tCO<sub>2</sub>\*km.
* $$R\_{leakage}$$ represents the default leakage rate of the given transport mode (e.g. truck, pipeline...), in tCO<sub>2</sub> lost/tCO<sub>2</sub>\*km.

</details>

### Project feedstock provisioning

This life cycle stage shall include the production, processing, and transport of alkaline feedstock to be carbonated.

***

Requirements for modeling induced emissions from **feedstock production** are presented in Table 2.

*Table 2 The approach for modeling GHG emissions from various types of feedstock are presented here.*

<table><thead><tr><th width="173">Feedstock type</th><th width="185">Example</th><th>GHG quantification</th></tr></thead><tbody><tr><td><strong>Waste, no value</strong></td><td>Recycled concrete aggregate</td><td>Feedstock enters the project system boundary with no emissions. The system boundary starts with the transport step where feedstock is diverted from its BAU use and sent to the project site, or the first non-BAU treatment step, whichever comes first.</td></tr><tr><td><strong>Produced for the sole purpose of mineralization</strong></td><td>Olivine</td><td>All feedstock production/mining/sourcing emissions shall be counted towards project induced emissions.</td></tr><tr><td><strong>Valuable product, but not produced for the purpose of mineralization</strong></td><td>Ordinary Portland cement (OPC) for carbonation curing</td><td>Production emissions are excluded, because they would have happened anyway/would be the same in the baseline scenario. The system boundary shall only include any processing steps specifically to prepare the feedstock for mineralization.</td></tr><tr><td><a data-footnote-ref href="#user-content-fn-9"><strong>Valuable co-product</strong></a></td><td>Steel slag</td><td>A share of the production emissions shall be allocated to the co-product, preferably based on economic allocation</td></tr></tbody></table>

***

Examples of **feedstock processing/preparation for mineralization** that may be considered in this stage may include but are not limited to:

* feedstock preparation/processing to increase mineral purity (e.g. magnetic separation of iron), to increase carbonation rates
* feedstock preparation/processing to increase surface area (e.g. grinding), to increase carbonation rates
* heating, drying, wetting, to obtain optimal feedstock moisture content and diffusivity

For calculations and emission factors, see the [Processing and energy use](/modules/processing-and-energy-use) module.

***

**Transportation** of alkaline feedstock shall include the delivery transport from the alkaline material production source to the carbonation site. For calculations and emission factors, see the [Transportation ](/modules/transportation)module.

<details>

<summary>Calculations: Project feedstock provisioning</summary>

$$\textbf{(Eq. 13)}\ E\_{feedstock}=E\_{feedstock\ production}+E\_{feedstock\ processing}+E\_{feedstock\ transport}$$

Where

* $$E\_{feedstock}$$ represents the total project emissions from the feedstock provisioning life cycle stage, in tCO<sub>2</sub>eq.
* $$E\_{feedstock\ production}$$ represents the emissions from feedstock production, in tCO<sub>2</sub>eq. This may be zero if the feedstock is a waste, may share emissions allocated between a coproduct, or may fully assume emissions if it is produced for the purpose of mineralization.
* $$E\_{feedstock\ processing}$$ represents the emissions from any additional energy or mineralization materials used in feedstock processing (e.g. griding, heating...), calculated using the [Processing and energy use](/modules/processing-and-energy-use) module, in tCO<sub>2</sub>eq.
* $$E\_{feedstock\ transport}$$ represents the emissions from transporting feedstock from its production site to the mineralization site, calculated using the [Transportation](/modules/transportation) module, in tCO<sub>2</sub>eq.

</details>

### Project mineralization process

This stage includes induced emissions from the mineralization process, including energy use, input and machinery use, and transport/delivery of the carbonated material; plus any CO<sub>2</sub> leaked from the reactor. All induced emissions from the mineralization process shall be included and counted towards the project GHG quantification, because they are all by definition additional to baseline conditions and part of the mineralization project.

{% tabs %}
{% tab title="Energy and input use" %}
This shall include energy use (electricity, heat and fuel) for heating, maintaining temperature, and compression/maintaining pressure, to be measured directly for each reported period. These may be provided by, for example:

* measurements for the whole site, and allocated to the project if needed (e.g. site-wide electricity bills), or
* measurements for specific machinery used by the project (e.g. energy meters), or
* calculated using machinery power requirements and operation hours.

Depending on the project-specific technology, this may also include but is not limited to:

* additives to increase dissolution rates (where dissolution of metal ions is the precursor to mineralization )
* water

For energy use calculations and emission factors, see the [Processing and energy use](/modules/processing-and-energy-use) module.
{% endtab %}

{% tab title="Infrastructure/machinery" %}
All significant embodied emissions from machinery and infrastructure directly related to the mineralization process shall be included. For infrastructure calculations and emission factors, see the [Infrastructure and machinery ](/modules/infrastructure-and-machinery)module.
{% endtab %}

{% tab title="Transport/delivery" %}
**Transport of the final product** shall be included for any transport beyond 50 km, which is [assumed ](#user-content-fn-10)[^10]to be the standard transport distance for conventional concrete and aggregates.

This is included because it cannot necessarily be assumed that the project and baseline transport is the same. Indeed, concrete is a commodity with relatively localized markets, whereas the project's innovative product may have buyers that are outside the typical radius of basic concrete transport.

For calculations and emission factors, see the [Transportation](/modules/transportation) module.
{% endtab %}

{% tab title="CO2 leakage" %}
Project Developers shall either provide the amount of CO<sub>2</sub> leaked or vented from a mineralization reactor, or justify why this amount can be assumed to be negligible.

**Proof of the amount of CO**<sub>**2**</sub>**&#x20;leaked** may include but is not limited to:

* sensor measurements (actual sensor readings, or the amount of the detection threshold if the measured amount is zero)
* reactor design documents showing an allowable or target limit of CO<sub>2</sub> leakage
* any approach mentioned in Article 41-46 of the[ EU ETS monitoring and reporting](#user-content-fn-4)[^4]
* mass balance of CO<sub>2</sub> combining gas inflow-outflow and solid sample measurements, described [below](#project-co2-stored).

**Fugitive CO**<sub>**2**</sub>**&#x20;emissions may be considered negligible** if:

* it is 100% biogenic and/or atmospheric CO<sub>2,</sub> or
* it came from a flue gas stream, where the unused flue gas is emitted anyway, or
* reactor design documents show negligible (<0.5%) CO<sub>2</sub> leakage, and Project Developers prove adherence to reactor maintenance and calibration

This may be measured as CO<sub>2</sub> leaked per hour of operation, or per tonne of carbonated material produced. The allocation of carbon type (fossil/calcination vs biogenic/atmospheric) shall be determined by the process detailed in the [Allocation of captured carbon](#allocation-of-captured-carbon-removals-vs.-avoidance) section.
{% endtab %}
{% endtabs %}

<details>

<summary>Calculations: Project mineralization process</summary>

$$\textbf{(Eq.14)}\ E\_{mineralization}=E\_{mineralization \ energy}+E\_{mineralization \ infra}+E\_{transport}+E\_{CO\_2\ leak}$$

Where

* $$E\_{carbonation}$$ represents the total project emissions from the onsite carbonation life cycle stage, in tCO<sub>2</sub>eq per monitoring period.
* $$E\_{mineralization\ energy}$$ represents the emissions from energy or consumable inputs used in the mineralization process, calculated using the [Processing and energy use](/modules/processing-and-energy-use) module, in tCO<sub>2</sub>eq.
* $$E\_{mineralization\ infra}$$ represents the emissions from infrastructure or machinery used for mineralization (i.e. reactors), calculated using the [Infrastructure and machinery ](/modules/infrastructure-and-machinery)module, in tCO<sub>2</sub>eq per monitoring period.
* $$E\_{transport}$$ represents the emissions from transporting the carbonated material from its production site to the user, calculated using the [Transportation ](/modules/transportation)module, in tCO<sub>2</sub>eq per monitoring period. It is only considered if the transport distance is greater than 50 km.
* $$E\_{CO\_2\ leak}$$ represents the emissions from direct CO<sub>2</sub> leakage from the reactor/mineralization site to the atmosphere, in tCO<sub>2</sub>eq per monitoring period. Project Developers shall calculate this in external files, using their preferred measurement setup, and report the final value per monitoring period in the MRV.

</details>

### Project CO<sub>2</sub> storage

Carbon storage shall be determined using project-specific measurements and CO<sub>2</sub> mass balance calculations, using either:

1. **Solid sample:** Periodic measurements on a representative sample of solid carbonated material, measuring its carbon content compared to a baseline material, using [TGA ](#user-content-fn-11)[^11]or dry combustion/TCA[^12]
2. **Gas inflow-outflow:** continuous measurements of CO<sub>2</sub> gas inflow minus outflow.

Each method is described in detail below. [Cross verification](#user-content-fn-13)[^13] of carbon storage measurements with another method is encouraged but not required.

#### Solid sample

All solid sample carbon content measurement shall be conducted on:

* A carbonated sample from the project, and
* A non-carbonated control sample of the same material.

The difference in CO<sub>2</sub> content between the two, measured using [TGA ](#user-content-fn-11)[^11]or dry combustion/TCA[^12], shall be used to quantify the amount of CO<sub>2</sub> removed by the project activity.

To ensure consistency:

* Project and control samples must be collected at the same time interval after exiting the reactor (e.g. 24 hours, 1 week, 1 month).
* Both samples must be stored under identical conditions between mineralization and measurement to avoid variations due to natural ambient mineralization.

All measurements shall be performed on **at least one** [**representative sample**](#user-content-fn-14)[^14] at the following frequency:

* For each [mineralization batch](/methodologies/mineralization-of-alkaline-materials-ex-situ/eligibility-and-scope#mineralization-batch) (with batch validity limited to 1 year), or
* At least once per quarter, or
* Every 500 tonnes CO<sub>2</sub> removed, **whichever comes first**.

Refer to the [Sampling and measurements](/methodologies/mineralization-of-alkaline-materials-ex-situ/monitoring-and-sampling#sampling-plan) section for detailed procedures on sampling approach, frequency, and traceability.

<details>

<summary>Calculations: Project CO<sub>2</sub> storage, solid-sample</summary>

$$\textbf{(Eq. 15)}\ S\_{project}= \Delta CO\_2eq\*A\_{P,\ material, MP}$$

Where,

* $$S\_{project}$$ represents total carbon storage from the project in the monitoring period, in tCO<sub>2</sub>eq.
* $$\Delta CO\_2eq$$ represents the increase in CO<sub>2</sub> storage in the carbonated material vs the baseline material, as an absolute increase of tCO<sub>2</sub>eq/t carbonated material. Calculated in Eq. 16.
* $$A\_{P,\ material,MP}$$ represents the amount of carbonated material produced by the project in the monitoring period, in tonnes of dry material.

$$\textbf{(Eq. 16)}\ \Delta CO\_2eq=CO\_2eq\_{project}-CO\_2eq\_{control}$$

Where,

* $$\Delta CO\_2eq$$ was described in Eq. 15.
* $$CO\_2eq\_{project}$$ represents the concentration of CO<sub>2</sub> equivalent in the carbonated project material, derived from measured carbonate content using an approved solid sample measurement (TGA or dry combustion), in tCO<sub>2</sub>eq/t of dry material. It is calculated in equations below for each measurement method.
* $$CO\_2eq\_{control}$$ represents the concentration of CO<sub>2</sub> equivalent in the non-carbonated control material, derived from measured carbonate content using the same measurement approach as for $$CO\_2eq\_{project}$$ . It is calculated in equations below for each measurement method.

Project Developers shall use either Eq. 17 or Eq. 18 to measure project and control $$CO\_2eq$$.

$$\textbf{(Eq. 17)}\ CO\_2eq\_{project,\ TGA} = %CO\_{2, loss} \div100$$

Where,

* $$CO\_2eq\_{project,\ TGA}$$ represents the concentration of CO<sub>2</sub>eq in the material, tCO<sub>2</sub>eq/t of dry material, derived from measured carbonate content using **TGA.** The same equation shall be used for $$CO\_2eq\_{control}$$.
* $$%CO\_{2, loss}$$ represents the mass loss percentage of CO<sub>2</sub>, directly measured using TGA at 600–800 °C, in % mass loss or tCO<sub>2</sub> lost/100 t dry material. Divided by 100 to convert to t/t.

$$\textbf{(Eq. 18)}\ CO\_2eq\_{project,\ dry\ combustion} = %C\_{mass} \div 100 \times C\ to\ CO\_2$$

Where,

* $$CO\_2eq\_{project,\ dry\ combustion}$$ represents the concentration of CO<sub>2</sub>eq in the material, tCO<sub>2</sub>eq/t of dry material, derived from measured carbonate content using **dry combustion.** The same equation shall be used for $$CO\_2eq\_{control}$$.
* $$%C\_{mass}$$ represents the measured inorganic or total carbon content of the material, in % mass of carbon or t C/100 t dry material. Divided by 100 to convert to t/t.
* $$C\ to\ CO\_2$$ represents the molecular weight conversion factor between carbon and CO<sub>2</sub>, and equals 3.67.

</details>

#### Gas inflow outflow

Gas inflow-outflow measurements shall be taken continuously (at least 1x per minute) and summarized and reported daily.

Gas measurements shall use a calibrated flow metering with ±1.0% accuracy or better. Project Developers shall provide equipment calibration certificates and QA/QC procedures.

{% hint style="warning" %}
Any projects using:

1. Technology type: carbonated solid materials to add to e.g. concrete or asphalt, and
2. Measurement type: gas inflow-outflow,

shall also account for unreacted CO<sub>2</sub> trapped in pore space of the carbonated material. This shall be calculated using conversions and subtracted from carbon storage measurements, according to Eq. 22.
{% endhint %}

<details>

<summary>Calculations: Project CO<sub>2</sub> storage, gas inflow-outflow</summary>

$$\textbf{(Eq. 19)}\ S\_{project}= \sum (Inflow\_{CO\_2}- Outflow\_{CO\_2}- Pore\_{CO\_2})$$

Where,

* $$S\_{project}$$ represents total carbon storage from the project, summed over the monitoring period, in tCO<sub>2</sub>eq.
* $$Inflow\_{CO\_2}$$ represents the daily recorded mass of gaseous CO<sub>2</sub> entering the carbonation process (e.g. entering a reactor), in tCO<sub>2</sub>eq, calculated in Eq. 20.
* $$Outflow\_{CO\_2}$$ represents the daily recorded mass of gaseous CO<sub>2</sub> exiting the carbonation process (e.g. exiting a reactor), in tCO<sub>2</sub>eq, calculated in Eq. 20.
* $$Pore\_{CO\_2}$$ represents the unreacted CO<sub>2</sub> stuck in pore space of the carbonated material, in tCO<sub>2</sub>eq, calculated in Eq. 21. **It shall only be included for projects that carbonate solid materials** (e.g. carbonating SCMs to add to concrete).

$$\textbf{(Eq. 20)}\ Flow\_{CO\_2,\ i}= V\_{CO\_2,\ i}\*C\_{CO\_2,\ i}$$

Where,

* $$Flow\_{CO\_2\ i}$$ represents the flow of CO<sub>2</sub> for $$i$$ types of CO<sub>2</sub>, either inflow or outflow from the carbonation process, in tCO<sub>2</sub>eq/day.
* $$V\_{CO\_2,\ i}$$ represents the volume of CO<sub>2</sub> inflow or outflow of the carbonation process, at standard temperature and pressure, in m<sup>3</sup> of gas/day.
* $$C\_{CO\_2,\ i}$$ represents the [**weighted average**](#user-content-fn-15)[^15] **daily concentration** of CO<sub>2</sub> inflow or outflow of the carbonation process, at standard temperature and pressure, in tCO<sub>2</sub>/m<sup>3</sup> of gas.

$$\textbf{(Eq. 21)}\ Pore\_{CO\_2} = \frac{p}{RT} \times \epsilon \times y\_{CO\_2} \times \frac{M\_{CO\_2}}{\rho\_{bulk}} \times A\_{P,\ material,\ daily}$$

* $$Pore\_{CO\_2}$$ represents CO<sub>2</sub> trapped in pore space in the carbonated material, in tCO<sub>2</sub>eq/t carbonated material. **This term is only required for projects carbonating solid materials, to add to e.g. concrete or asphalt**.
* $$\frac{p}{RT}$$ represents the molar concentration of an ideal gas (in this case, CO<sub>2</sub>), in mol/m<sup>3</sup>. Under standard conditions, the terms would be total gas pressure ($$p= 101325\ Pa$$ ), temperature ( $$T=298\ K$$), and the ideal gas constant ( $$R=8.3145J/ (mol\*K)$$), for a total term value of 40.89 mol/m<sup>3</sup>.
* $$\epsilon$$ represents the gas void fraction of the material (i.e. fraction of volume per m<sup>3</sup> that is pore space), unitless. This value may be measured, or estimated using secondary literature for well-defined, common, homogeneous alkaline feedstocks.
* $$y\_{CO\_2}$$ represents the molar fraction of CO<sub>2</sub> in the pore gas, measured via gas analysis or conservatively assumed, unitless. It can conservatively be assumed to equal 1 (100% CO<sub>2</sub> atmosphere).
* $$M\_{CO\_2}$$ represents the molar mass of CO<sub>2</sub>, which equals 0.000044 t/mol.
* $$ho\_{bulk}$$ represents the bulk density of the dry carbonated material, measured or estimated using secondary sources, in kg/m<sup>3</sup>.
* $$A\_{P,\ material,\ daily}$$ represents the amount of carbonated material produced by the project per day, in tonnes of dry material.

</details>

## Data sources

The required **primary data** for GHG quantification from all projects, regardless of measurement approach, are presented in Table 3. Required primary data for projects using solid-sample carbon storage measurements are in Table 4, and for projects using gaseous inflow-outflow are in Table 5. These data shall be provided for each monitoring period, unless specified otherwise, and made publicly available.

*Table 3 Summary of primary data needed from **all projects** and their source. Asterisks (\*) indicate which data are only required for initial project certification and GHG quantification, and do **not** need to be monitored and updated during verification. Two asterisks (\*\*) indicate which data are only necessary if the project is eligible for avoidance credits from reduced cement use.*

<table><thead><tr><th>Category</th><th width="226.6328125">Parameter</th><th width="166.80078125">Unit</th><th width="188.828125">Source</th></tr></thead><tbody><tr><td>CO<sub>2</sub> capture</td><td>Amount of CO<sub>2</sub> leaving CO<sub>2</sub> capture facility</td><td>t CO<sub>2</sub> per monitoring period</td><td>Operations records, sales contracts, invoices</td></tr><tr><td>CO<sub>2</sub> capture</td><td>Repartition of CO<sub>2</sub> types purchased, entering mineralization facility</td><td>fraction</td><td>Operations records, sales contracts, invoices</td></tr><tr><td>CO<sub>2</sub> capture</td><td>Transport distance or amount of fuel, and transport mode, for CO<sub>2</sub> delivery</td><td>tonne*km, or kg fuel, or L fuel</td><td>Operations records</td></tr><tr><td>CO<sub>2</sub> capture</td><td>Amount and type of infrastructure/machinery used for CO<sub>2</sub> capture<strong>*</strong></td><td>kg, tonne, or m3; and material type</td><td>Technical design documents</td></tr><tr><td>Feedstock provisioning</td><td>Amount and type of alkaline feedstock used</td><td>tonne/monitoring period</td><td>Operations records</td></tr><tr><td>Feedstock provisioning</td><td>Transport distance or amount of fuel, and transport mode, for alkaline feedstock delivery</td><td>tonne*km, or kg fuel, or L fuel</td><td>Operations records</td></tr><tr><td>Mineralization process</td><td>Amount and type of infrastructure/machinery used for mineralization<strong>*</strong></td><td>kg, tonne, or m3; and material type</td><td>Technical design documents</td></tr><tr><td>Baseline CO<sub>2</sub> storage</td><td>Baseline removal calculations from alkaline feedstock mineralization</td><td>kgCO<sub>2</sub>eq/tonne feedstock</td><td>Models, calculations</td></tr><tr><td>Baseline CO<sub>2</sub> storage</td><td>Baseline and project concrete use phase carbonation calculations</td><td>kgCO<sub>2</sub>eq/tonne concrete</td><td>Models, calculations</td></tr><tr><td>CO<sub>2</sub> capture</td><td>Energy and/or material use from CO<sub>2</sub> capture</td><td>kg, liter, kWh, MWh, GWh, m3; and material type</td><td>Operations records</td></tr><tr><td>CO<sub>2</sub> capture</td><td>Energy and/or material use from CO<sub>2</sub> purification</td><td>kg, liter, kWh, MWh, GWh, m3; and material type</td><td>Operations records</td></tr><tr><td>Feedstock provisioning</td><td>Energy and/or material use from alkaline feedstock processing</td><td>kg, liter, kWh, MWh, GWh, m3; and material type</td><td>Operations records</td></tr><tr><td>Mineralization process</td><td>Energy and/or material use from mineralization</td><td>kg, liter, kWh, MWh, GWh, m3; and material type</td><td>Operations records</td></tr><tr><td>CO<sub>2</sub> storage</td><td>Transport distance or amount of fuel, and transport mode, for carbonated material delivery (if distance >50 km)</td><td>tonne*km, or kg fuel, or L fuel</td><td>Operations records</td></tr><tr><td>CO<sub>2</sub> storage</td><td>Amount of carbonated material produced in the monitoring period</td><td>tonne</td><td>Operations records</td></tr><tr><td>Avoidance: Project induced emissions</td><td>Amount cement needed in project scenario<strong>**</strong></td><td>kg cement used/monitoring period</td><td>Operations records</td></tr><tr><td>Avoidance: Baseline induced emissions</td><td>Amount cement needed in baseline scenario<strong>**</strong></td><td>kg cement equivalent calculated/ monitoring period</td><td>Cement mix designs, statements from clients, mandatory concrete mixes</td></tr><tr><td>Avoidance: Project and Baseline induced emissions</td><td>Cement mix design and emission factor for avoided cement<strong>**</strong></td><td>kgCO<sub>2</sub>eq/tonne cement</td><td>Project-specific sources (e.g. EPDs), low-carbon cement thresholds (e.g. provided by the Global Cement and Concrete Association <a href="https://gccassociation.org/lcr-cement/">Low Carbon Rating</a>), or Ecoinvent</td></tr></tbody></table>

***

*Table 4 Summary of primary data needed from projects using **solid-sample** CO*<sub>*2*</sub>*&#x20;storage measurements, and their source. Project Developers shall provide only one of the two data sources listed.*

<table><thead><tr><th>Category</th><th width="258">Parameter</th><th width="215.07421875">Unit</th><th>Source</th></tr></thead><tbody><tr><td>CO<sub>2</sub> storage</td><td>TGA: Carbon storage in project and control materials</td><td>mass loss percentage of CO<sub>2</sub></td><td>Laboratory measurements</td></tr><tr><td>CO<sub>2</sub> storage</td><td>Dry combustion: Carbon storage in project and control materials</td><td>% mass of carbon or t C/100 t dry material</td><td>Laboratory measurements</td></tr></tbody></table>

***

*Table 5 Summary of primary data needed from projects using **gas inflow-outflow** CO*<sub>*2*</sub>*&#x20;storage measurements, and their source.*

<table><thead><tr><th>Category</th><th width="283.78125">Parameter</th><th width="176.09375">Unit</th><th>Source</th></tr></thead><tbody><tr><td>CO<sub>2</sub> storage</td><td>Volumetric flow of CO<sub>2</sub> inflow and outflow</td><td>m<sup>3</sup> of gas/day</td><td>Primary measurements, sensors</td></tr><tr><td>CO<sub>2</sub> storage</td><td>Concentration of CO<sub>2</sub> inflow and outflow</td><td>t CO<sub>2</sub>/m<sup>3</sup> gas</td><td>Primary measurements, sensors</td></tr><tr><td>CO<sub>2</sub> storage</td><td><span class="math">\epsilon</span> gas void fraction of the material (<em>if carbonating solid materials)</em></td><td>fraction of volume per m<sup>3</sup></td><td>Measured or estimated using secondary sources</td></tr><tr><td>CO<sub>2</sub> storage</td><td><span class="math">y_{CO_2}</span> molar fraction of CO<sub>2</sub> in the pore gas (<em>if carbonating solid materials)</em></td><td>unitless</td><td>Gas analysis or conservatively assumed to equal 1</td></tr><tr><td>CO<sub>2</sub> storage</td><td><span class="math">ho_{bulk}</span> bulk density of the dry carbonated material (<em>if carbonating solid materials)</em></td><td>kg/m<sup>3</sup></td><td>Measured or estimated using secondary sources</td></tr><tr><td>CO<sub>2</sub> storage</td><td>Amount of carbonated material produced daily</td><td>tonne</td><td>Operations records</td></tr></tbody></table>

The ecoinvent database version 3.12 (hereafter referred to as ecoinvent) shall be the main source of emission factors unless otherwise specified. Ecoinvent is preferred because it is traceable, reliable, and well-recognized. The ecoinvent processes selected are detailed in [Appendix 1](/methodologies/mineralization-of-alkaline-materials-ex-situ/appendix#appendix-1-ecoinvent-activities).

## Uncertainty assessment

An uncertainty assessment is presented below for all aspects of GHG quantification set **at the methodology level**. The findings from this assessment are then applied **at the project level**, where project-specific GHG quantification also undergoes an uncertainty assessment.

The **overall project GHG quantification uncertainty** is determined by qualitatively combining both the methodology-level and project-specific uncertainties for each identified source of uncertainty.

The following [assumptions](#id-8422amp7fe3k-1) have low uncertainty:

* Baseline delivery of concrete or aggregates is 50 km.
* Directly carbonated cement will have no CO<sub>2</sub> trapped in pore space.

The following [assumptions](#id-8422amp7fe3k-1) have moderate uncertainty:

* Future uses or end-of-life treatment of the carbonated material will not lead to reversals.
* All carbonated material from the same mineralization batch has similar characteristics.

The **baseline scenario selection** at the methodology level has low uncertainty, because it requires a project-specific assessment of the specific amount and type. The specific circumstances, amount and type of baseline material must be proven by the Project Developer, and their uncertainty shall be assessed at the project level. The amount of expected, counterfactual baseline removals has high uncertainty, but must be selected conservatively according to the [baseline scope](/methodologies/mineralization-of-alkaline-materials-ex-situ/eligibility-and-scope#baseline-scope) requirements.

The **equations** have low uncertainty, because they consist of straightforward conversions. No **models** are used in this methodology. **Secondary data** include default baseline mineralization rates for a selection of alkaline feedstocks, which shall be applied conservatively, according to the [baseline scope](/methodologies/mineralization-of-alkaline-materials-ex-situ/eligibility-and-scope#baseline-scope) requirements.

The uncertainty at the module level is estimated to be low. This translates to an **expected discount factor of at least 3%** for projects using this module.

[^1]: ISO 14064-2:2019. Greenhouse gases — Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements.

[^2]: carbon dioxide removal

[^3]: carbon capture and storage

[^4]: Commission Implementing Regulation (EU) 2018/2066 of 19 December 2018 on the monitoring and reporting of greenhouse gas emissions pursuant to Directive 2003/87/EC of the European Parliament and of the Council and amending Commission Regulation (EU) No 601/2012. [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02018R2066-20240701).

[^5]: business as usual

[^6]: accepted only with satisfactory documentation, transparency and published data

[^7]: Håkan Stripple, Christer Ljungkrantz, Tomas Gustafsson, Ronny Andersson, 2018. CO<sub>2</sub> uptake in cement containing products: Background and calculation models for IPCC implementation (No. B 2309), ISBN: 978-91-88787-89-7. IVL Swedish Environmental Research Institute, Stockholm, Sweden. [URL](https://cembureau.eu/media/p02hmc2l/ivl-report-CO%3Csub%3E2%3C/sub%3E-uptake-in-cement-containing-products-isbn-number-b2309.pdf). Page 25.

    Initial result of 10 kgCO<sub>2</sub>eq/m<sup>3</sup> concrete block at end of life. Converted to kgCO<sub>2</sub>eq/m<sup>3</sup> loose recycled concrete aggregate assuming densities of 2.4 t/m<sup>3</sup> solid concrete block density, and 1.6 t/m<sup>3</sup> loose recycled concrete aggregate bulk density.

[^8]: Andersson, R., Fridh, K., Stripple, H., Häglund, M., 2013. Calculating CO2 Uptake for Existing Concrete Structures during and after Service Life. Environ. Sci. Technol. 47, 11625–11633. <https://doi.org/10.1021/es401775w>

[^9]: i.e. if the feedstock is a valuable co-product of a process with a different main product, but where the co-product is typically sold and used

[^10]: based on expert opinion and stakeholder advice

[^11]: &#x20;Thermogravimetric analysis&#x20;

[^12]: Total carbon analysis

[^13]: e.g. both solid and gaseous methods, or frequent in-house solid sample analysis via acid digestion

[^14]: A representative sample is a portion of carbonated material that accurately reflects the carbonation batch and production output during the relevant time period, capturing any temporal or random variation. Best practice is to create this sample as a composite of multiple sub-samples taken from different points in the batch.

[^15]: i.e. the concentration is averaged across all measurement intervals, weighted by the volume of gas measured at each interval, to reflect its relative contribution to the total flow.


# Sampling and measurements

The following sampling and measurement requirements only apply to projects measuring [carbon storage](https://docs.rainbowstandard.io/methodologies/mineralization-of-alkaline-materials-ex-situ/pages/jjuMyYGKeSOvf1hhQ90n#project-CO<sub>2</sub>-stored) using **solid-sample CO**<sub>**2**</sub>**&#x20;storage measurement methods.** Projects using gaseous inflow-outflow measurements are exempt from these sampling protocols, as their measurement approach directly tracks CO<sub>2</sub> flux in real time.

## Solid sample measurements

All solid sample measurements shall be done by an **external laboratory**, accredited and compliant with ISO/IEC 17025, or accredited by national accreditation bodies that certify compliance with ISO 17025 or equivalent, such as COFRAC (France), UKAS (UK) or ANAB (USA).

Project Developers shall use one of the following high-accuracy measurements:

* **Thermogravimetric analysis (TGA)**, e.g. ISO 11358-1:2014, ISO 19579:2006 and ISO 21687:2007
* **Dry combustion** (Total Carbon Analysis, or TCA) methods, following e.g. ISO 10694:1995, ISO 13878:1998, and ISO 15178:2000

These measurements shall be done in 3 or more replicates.

For dry combustion measurements, Project Developers must determine fraction of total measured carbon that is attributable to stable mineral carbonates (e.g., CaCO<sub>3</sub> or MgCO<sub>3</sub>). This may be determined once, upfront, for the project's alkaline feedstock, and applied throughout the crediting period until a different feedstock is used. This ensures that only creditable carbon increases resulting from the project activity are counted, excluding carbon stored in less stable or non-mineral phases. Accepted methods for confirming carbonate speciation include, but are not limited to, X-ray diffraction (XRD) with Rietveld refinement and infrared spectroscopy (FTIR).

{% hint style="warning" %}
**Heterogeneous materials and sampling error**

Rainbow recognizes that certain feedstocks (particularly those with highly heterogeneous composition or particle size) pose challenges for obtaining representative samples when using TGA or dry combustion. While alternative methods like acid digestion with CO₂ quantification or furnace-based mass loss may help reduce sampling error through bulk measurements, they currently introduce unacceptably high analytical uncertainty and are therefore not permitted under this methodology.

However, Rainbow remains open to the adoption of such methods, if supported by credible evidence or research demonstrating that they yield results consistent with high-accuracy reference methods (e.g. TGA, dry combustion). Upon review and approval of such evidence, these methods may be accepted with appropriate safeguards and limitations in place to ensure integrity and comparability of results.
{% endhint %}

## Centralized vs distributed sites

Mineralization projects may be classified as centralized or distributed, as defined in the [Eligibility and scope](/methodologies/mineralization-of-alkaline-materials-ex-situ/eligibility-and-scope#certification-requirements) section. These two project types have the following different sampling requirements.

Distributed projects can use empirical data from a representative subset of sites to prove that **mineralization rates are sufficiently similar across grouped sites** (RSD[^1]<10%) when alkaline feedstock is the same.

Once this is demonstrated, the project can shift to reduced sampling, where **only one site continues to take samples and perform laboratory measurements**. Those results may then be applied to other sites in the same group, under the conditions agreed upon by the Project Developer, the Rainbow Certification team and the VVB. The lowest-measured mineralization rate shall be used to issue credits.

Grouped sites must use the same alkaline feedstock. The criteria for determining whether feedstocks are considered the same, or should be treated as distinct, are outlined in the [Mineralization batch ](/methodologies/mineralization-of-alkaline-materials-ex-situ/eligibility-and-scope#mineralization-batch)section.

This approach can be planned from the start and included in the project design, or implemented partway through the crediting period. In the latter case, the supporting data and updated Monitoring Plan must be reviewed and approved by the VVB.

Grouped sites that are not taking samples and measurements shall **continue to provide all other data required for GHG quantification**, such as alkaline feedstock type and amount, onsite energy use, and transport distances. These sites are only exempt from taking samples and laboratory measurements of carbonated materials.

To maintain data quality, Project Developers shall **perform random cross checks annually**, taking samples from non-measuring grouped sites to confirm that their mineralization rates remain within the expected range. The number of sites and samples depends on the project size, and shall be decided by the Rainbow Certification team and the Project Developer on a case by case basis.

{% hint style="info" %}
At present, this approach is applied separately for each project. The Rainbow team is actively interested in developing a generalized methodology, with clearly defined conditions for when mineralization rates from one site can be applied to other sites. However, until compelling research is available to support such a generalizable framework, each project will continue to be required to provide its own proof.
{% endhint %}

## Measurement frequency and representativeness

Project Developers must perform carbon storage measurements, in replicates of 3 or 6, on a representative sample, at the frequency outlined below. The approach to obtain a representative sample and measurement is:

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><p>At the <strong>start of verification</strong>, for the first <a href="/pages/kHOXdTujJkRrkrTca0Un#mineralization-batch">mineralization batch</a>, measurements shall be taken at high frequency until the project demonstrates stable operating conditions and establishes operational stability and consistent results.</p><ul><li>It is recommended to conduct 10 separate measurements, each on a composite sample from 3 sub-samples each, in 3 or 6 replicates depending on the <a href="#solid-sample-measurements">measurement type</a> used, at the beginning of the crediting period. The variability of these measurements should not exceed an <a data-footnote-ref href="#user-content-fn-1">RSD</a> of 10%.</li><li>The <strong>lowest value</strong> of recent stable measurements shall be used for initial credit issuance once measurement consistency is established. This shall be updated regularly for ongoing verification.</li><li>This frequency may be adjusted based on the project’s technological maturity, existing data, and expected variability. For example, this step may be skipped if the project can prove stable operating conditions were established before the start of the crediting period.</li></ul></td></tr><tr><td><p>For <strong>ongoing monitoring and verification</strong>, measurements shall be repeated:</p><ul><li>For each <a href="/pages/kHOXdTujJkRrkrTca0Un#mineralization-batch">mineralization batch</a> (with batch validity limited to 1 year), or</li><li>At least once per quarter, or</li><li>Every 500 tonnes CO<sub>2</sub> removed, <strong>whichever comes first</strong>.</li></ul><p>Each ongoing verification measurement shall:</p><ul><li>Be based on a <a data-footnote-ref href="#user-content-fn-2">representative sample</a>. Best practice is to create this sample as a homogenized composite of at least 3 sub-samples taken from different points in the batch.</li><li>Be analyzed in replicates of 3</li><li>Achieve an <a data-footnote-ref href="#user-content-fn-1">RSD</a> ≤ 10% between the replicate measurements; otherwise, measurements must be repeated.</li><li>The <strong>lowest of the replicate values</strong> shall be retained and used for crediting.</li></ul></td></tr></tbody></table>

Samples shall be taken in a way that minimize bias and are representative of the entire mineralization batch. This includes but is not limited to taking samples at appropriate times and locations from the reactor/pile. Project Developers shall justify their approach for taking representative samples in the sampling records.

Taking representative samples of heterogeneous materials like concrete is challenging due to high baseline variability in carbonate and carbon content: factors not affected by the project activity or controlled by the Project Developer. To address this, it is recommended to separate the reactive fraction (e.g. cement paste) from aggregates before sampling. Otherwise:

* Natural variability in aggregate mineralization may obscure the smaller, project-induced changes in mineralization in the cement fraction, and
* The overall carbon content difference between project and baseline samples may not be statistically significant, even if a measurable effect exists within the cement fraction alone.

## Sampling records

<table data-card-size="large" data-view="cards"><thead><tr><th></th></tr></thead><tbody><tr><td><p><strong>Upon validation</strong>, Project Developers shall submit a <strong>Sampling Plan</strong>, that details:</p><ul><li><p>procedure to ensure representative sampling, including:</p><ul><li>tools or equipment for taking samples,</li><li>homogenization techniques,</li><li>sample storage conditions</li><li>the approach for random timing and location (i.e. within the pile, or the production line) of sub-samples,</li></ul></li><li>the proposed frequency and number of measurements performed in the first reporting period, to establish a robust dataset (mean and distribution),</li><li>approach to ensure the control/uncarbonated samples are representative of project samples, and exposed to the same conditions,</li><li>the post-mineralization timing of sample collection (e.g. 24 hours, 1 week), justified in terms of the mineralization kinetics of the specific technology.</li></ul></td></tr><tr><td><p>For <strong>each Reporting Period</strong>, Project Developers shall submit a <strong>Sampling Record</strong> documenting all sampling activities. This record must include the following information, for both project and control materials:</p><ul><li>Date and time of carbonated material production</li><li>Date and time of sampling</li><li>Name or ID of the person(s) performing sampling</li><li>Amount of material in sub-sample and composite sample</li><li>Processing or preparation steps before analysis</li><li>Description of representative sampling method</li><li>Sample ID for traceability</li><li>Notes on anomalies, if any</li></ul></td></tr></tbody></table>

[^1]: relative standard deviation

[^2]: A representative sample is a portion of carbonated material that accurately reflects the carbonation batch and production output during the relevant time period, capturing any temporal or random variation.


# Risk assessment template

This methodology uses the risk assessment template version 1.0

:point\_right: Download the template [here](https://docs.google.com/spreadsheets/d/1iFDaSH4SXatFuZIsdpQwlsSMKgpiL8PMDL-QHcuKF-4/edit?usp=sharing)

{% embed url="<https://docs.google.com/spreadsheets/d/1iFDaSH4SXatFuZIsdpQwlsSMKgpiL8PMDL-QHcuKF-4/edit?usp=sharing>" %}


# Appendix

## Appendix 1: Ecoinvent activities

<table data-full-width="false"><thead><tr><th width="223">Input</th><th>Ecoinvent activity name</th></tr></thead><tbody><tr><td>grid electricity</td><td><ul><li>market for electricity, low voltage</li><li>market for electricity, medium voltage</li></ul></td></tr><tr><td>onsite solar electricity</td><td>electricity production, photovoltaic, 570kWp open ground installation, multi-Si</td></tr><tr><td>diesel fuel material</td><td><ul><li>market for diesel, low-sulfur</li><li>market for diesel</li></ul></td></tr><tr><td>diesel burning</td><td><ul><li>diesel, burned in agricultural machinery</li><li>diesel, burned in diesel-electric generating set, 18.5kW</li></ul></td></tr><tr><td>natural gas burning</td><td>natural gas, burned in gas turbine</td></tr><tr><td>heat, from steam</td><td>market for heat, from steam, in chemical industry</td></tr><tr><td>heat, from municipal incineration</td><td>heat, from municipal waste incineration to generic market for heat district or industrial, other than natural gas</td></tr><tr><td>heat, from biomethane burning</td><td>market for heat, central or small-scale, biomethane</td></tr><tr><td>heat, from straw burning in a furnace</td><td>heat production, straw, at furnace 300kW</td></tr><tr><td>heat, from natural gas</td><td><ul><li>market for heat, district or industrial, natural gas</li><li>market for heat, central or small-scale, natural gas</li></ul></td></tr><tr><td>water</td><td><ul><li>market for tap water</li><li>market for water, decarbonised</li><li>market for water, deionised</li></ul></td></tr><tr><td>non-hazardous landfill</td><td><ul><li>market for process-specific burdens, slag landfill</li><li>market for process-specific burdens, sanitary landfill</li><li>market for process-specific burdens, inert material landfill</li></ul></td></tr><tr><td>hazardous waste treatment</td><td><ul><li>market for hazardous waste, for incineration</li><li>market for hazardous waste, for underground deposit</li></ul></td></tr><tr><td>cement production</td><td><ul><li>cement production, Portland</li><li>cement production, Portland Slag (with ground granulated blast furnace slag)</li><li>cement production, Pozzolana Portland (with fly ash)</li><li>cement, all types to generic market for cement, unspecified</li></ul></td></tr><tr><td>Ground granulated blast furnace slag (GGBS)</td><td>market for ground granulated blast furnace slag</td></tr><tr><td>Gypsum additive</td><td>market for gypsum, mineral</td></tr></tbody></table>

For further clarification or implementation support, contact the methodology development team at [climate@rainbowstandard.io](mailto:climate@riverse.io).


# Version history

<table><thead><tr><th width="340.1796875">Change</th><th width="185.5703125">Justification</th><th width="117.796875">Date</th><th width="122.85546875">Version changed</th></tr></thead><tbody><tr><td>First release of methodology for public consultation</td><td>-</td><td>June 23, 2025</td><td>V1 Public consultation (PC)</td></tr><tr><td>Final publication of methodology</td><td>-</td><td>September 10, 2025</td><td>V1.0 PC to V1.0</td></tr><tr><td>Add <span class="math">A_{P,\ material,\ daily}</span> to equation 21</td><td>Equation fix</td><td>March 19, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>Restructure sections: added Baseline Scope, renamed Eligible technologies to Eligibility and scope, renamed Eligibility criteria to Principles &#x26; requirements, moved Monitoring Plan to Principles &#x26; requirements</td><td>Align with Standard Rules V7 requirements</td><td>March 19, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>Remove TRL, move Substitution criteria requirements to Baseline Scope section</td><td>Align with Standard Rules V7 requirements</td><td>March 19, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>New Certification Scope section with requirements for crediting and monitoring period, project updates with methodology revisions, and site audits.</td><td>Align with Standard Rules V7 requirements</td><td>March 19, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>Remove limits on number of co-benefits, and require quantification and monitoring of all co-benefits</td><td>Align with Standard Rules V7 requirements</td><td>March 19, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>Environmental and social risk mitigation plan required for moderate or higher risks, instead of high risk</td><td>Align with Standard Rules V7 requirements</td><td>March 19, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>Remove project-level reversal risk assessment requirements</td><td>Align with Standard Rules V7 requirements</td><td>March 19, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>Remove ex-ante validation section</td><td>Align with Standard Rules V7 requirements</td><td>March 19, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>Methodology-level reversal risk assessment</td><td>Align with Standard Rules V7 requirements</td><td>March 19, 2026</td><td>V1.0 to V1.1</td></tr><tr><td>Change GHG quantification from ecoinvent v3.11 to v3.12</td><td>Using more recent version of database</td><td>March 19, 2026</td><td>V1.0 to V1.1</td></tr></tbody></table>


# Biogas from anaerobic digestion

This methodology covers projects that produce biogas from anaerobic digestion of agricultural products, residues and wastes. It includes both energy production from biogas and the production of digestate, a valuable organic amendment.

| **Methodology name** | Biogas from anaerobic digestion |
| -------------------- | ------------------------------- |
| **Version**          | 3.2                             |
| **Methodology ID**   | RBW-ENGY-01-ADGAS-V3.2          |
| **Release date**     | June 20th, 2025                 |
| **Status**           | In use                          |

#### Glossary

See the glossary for methodology-specific terminology :point\_down:

{% content-ref url="/pages/D1bECpowUAiJorSGzbQY" %}
[Glossary](/glossary)
{% endcontent-ref %}

<table data-header-hidden><thead><tr><th width="220"></th><th></th></tr></thead><tbody><tr><td><strong>Biogas</strong></td><td>A mixture of gasses produced by the anaerobic digestion of organic matter, primarily composed of biogenic methane and carbon dioxide. It can be used directly as a renewable energy source, or can be purified to biomethane.</td></tr><tr><td><strong>Biogenic methane</strong></td><td>Methane produced from the decomposition of organic matter, as opposed to methane derived from fossil fuels. It has a slightly lower global warming potential than fossil-based methane. </td></tr><tr><td><strong>Biomethane</strong></td><td>Methane that has been purified from biogas to meet quality standards for natural gas. It can be used for heating, electricity generation, or as vehicle fuel.</td></tr><tr><td><strong>Dedicated crop</strong></td><td>Crops specifically grown for use as feedstock in energy production, such as maize or sorghum, as opposed to crops grown for food or other purposes. They are cultivated during the main growing season and harvested at maturity.</td></tr><tr><td><strong>Digestate</strong></td><td>The nutrient-rich residue left after the anaerobic digestion of organic feedstock, which can be used as a fertilizer or soil conditioner.</td></tr><tr><td><strong>Energy cover crop</strong></td><td>Crops like clover or rye that are grown during the off-season for use as biogas feedstock. They prevent soil erosion and are harvested for energy production, unlike traditional cover crops, which are mixed into the soil.</td></tr><tr><td><strong>Feedstock</strong></td><td>Organic materials used as inputs in the production of biogas through anaerobic digestion, such as agricultural residues, food waste, or manure.</td></tr><tr><td><strong>Methane</strong></td><td>A colorless, odorless flammable gas (CH₄) that is the main component of natural gas and biogas. It is a potent greenhouse gas when released into the atmosphere.</td></tr><tr><td><strong>Nitrous oxide</strong></td><td>A potent greenhouse gas (N₂O) occasionally emitted during anaerobic digestion, especially with high-nitrogen feedstock. It has a much higher global warming potential than carbon dioxide.</td></tr></tbody></table>


# Introduction

Use of fossil fuels such as natural gas, oil, and coal are responsible for about 75% of global greenhouse gas (GHG) emissions, and make up 98% of GHG emissions within the energy sector. Alternative energy sources exist with far fewer GHGs emissions, but technological, economic, and administrative barriers prevent and limit their development.

Biogas is a renewable energy source that can be produced via several different pathways. One option is anaerobic digestion, where organic materials such as food waste, animal manure, and agricultural residues are broken down by microorganisms in an oxygen-free environment. Common uses of biogas include:

* Injection: Purification of biogas to biomethane and directly injecting it into the gas network.
* Cogeneration: Generation of electricity and heat by a biogas engine or turbine for a combined heat and power (CHP) system.
* Heat only: Production of heat in a biogas boiler.
* Transport: Compressed natural gas (BioCNG) and liquefied natural gas (BioLNG)

The second output of anaerobic digestion, digestate, is a material rich in organic matter and nutrients that is spread on agricultural fields.

[Numerous life cycle assessments (LCAs)](#user-content-fn-1)[^1] have confirmed that using biogas from anaerobic digestion rather than energy from fossil fuels leads to reduced GHG emissions. Yet, biogas makes up a small share of energy consumption: in 2022 in Europe, [20 times](#user-content-fn-2)[^2] more natural gas was used than biogas,.

[^1]: * Hijazi, O., Munro, S., Zerhusen, B., Effenberger, M., 2016. Review of life cycle assessment for biogas production in Europe. Renewable and Sustainable Energy Reviews 54, 1291–1300. [URL](https://doi.org/10.1016/j.rser.2015.10.013)
    * Salvador, R., Barros, M.V., Rosário, J.G.D.P.D., Piekarski, C.M., da Luz, L.M., de Francisco, A.C., 2019. Life cycle assessment of electricity from biogas: A systematic literature review. Environmental Progress & Sustainable Energy 38, 13133.[ ](https://doi.org/10.1002/ep.13133)[URL](https://doi.org/10.1002/ep.13133)
    * Esteves, E.M.M., Herrera, A.M.N., Esteves, V.P.P., Morgado, C. do R.V., 2019. Life cycle assessment of manure biogas production: A review. Journal of Cleaner Production 219, 411–423. [URL](https://doi.org/10.1016/j.jclepro.2019.02.091)

[^2]: * Eurostat 2024. Supply, transformation and consumption of renewables and wastes. DOI: <https://doi.org/10.2908/NRG_CB_RW>. Accessed May 2024.

    - Eurostat 2024. Supply, transformation and consumption of gas. DOI: <https://doi.org/10.2908/NRG_CB_GAS>. Accessed May 2024. ↑


# Eligible technologies

Projects eligible under this methodology are the anaerobic digestion sites where feedstock inputs are collected, anaerobic digestion occurs, and biogas/energy is generated. The Project Developers are the operators of the anaerobic digestion sites.

The only use of biogas eligible in the current version of the methodology is **purifying biogas to biomethane and direct injection into the gas grid.** Other uses may be considered on a case by case basis, if Project Developers provide sufficient proof that they 1) still adhere to the eligibility criteria and 2) have a rigorous, conservative GHG reduction quantification method for components that differ from the method described in the present document.

The only use of digestate eligible for carbon credits under this methodology is application to agricultural soils as an organic amendment and fertilizer. Such activities shall be credited with avoided synthetic mineral fertilizer production and use. If digestate is used in a different application, the project is still eligible for credits on the basis of their energy production activities.

## Project Scope

One project corresponds to one anaerobic digestion site. It is not possible under this methodology to group multiple sites together as one project.

An anaerobic digestion site is defined as a site with one operations permit and shared infrastructure (e.g. digestion tanks, storage, and treatment facilities).

Only the activities at the biogas site that are deemed additional are part of the project scope.

Projects certified under this methodology shall have a maximum crediting period duration of 5 years, which can be renewed for a total of 20 years. See the [Crediting Period Renewal](/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal) section of the Procedures Manual for procedural details.


# Eligibility criteria

Project developers shall demonstrate that they meet all eligibility criteria outlined in the Rainbow Standard Rules and described below with a specific focus on biogas from anaerobic digestion.

Eligibility criteria that do not require specific methodology instructions are not described here. This includes:

* Measurability
* Real
* Technology readiness level
* Minimum impact

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[Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules)
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## Additionality <a href="#id-5c2h1zk45n99" id="id-5c2h1zk45n99"></a>

Project Developers shall demonstrate additionality using the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template) and following the requirements of the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#additionality).

{% tabs %}
{% tab title="Regulatory surplus analysis" %}
Regulatory surplus analysis shall demonstrate that there are no regulations that **require or mandate** biogas production from anaerobic digestion. It is acceptable if regulations **promote** or **set targets for biogas production**, because the resulting increase in biogas production shall be accounted for in the baseline scenario (see [GHG reduction quantification](/methodologies/biogas-from-anaerobic-digestion/ghg-reduction-quantification#m8t0mn694gpw) section).

At the European Union level, projects automatically pass the regulatory surplus analysis, which has been conducted by the Rainbow Climate Team. Although the [Renewable Energy Directive](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A02018L2001-20220607) promotes biogas production/use, it does not require its production. Project Developers are only required to provide a country-level regulatory surplus analysis.
{% endtab %}

{% tab title="Investment analysis" %}
**Investment analysis** may be used to prove that revenue from carbon finance is necessary to make the new project investment a financially viable and interesting option. The investment may cover:

* the development and launch of a brand new biogas site, or
* an expansion to increase production capacity, such as adding new biogas digesters.

Business plans shall be provided as initial proof for investment analysis. During verification, audited financial statements shall be used to demonstrate that the initial estimates from the business plan were reasonable, and that carbon finance was used as initially described for the expected investment.

Note that for investments in expansion, **only the additional carbon reductions enabled by the expansion shall be eligible for Rainbow Carbon Credits.**
{% endtab %}

{% tab title="Barrier analysis" %}
**Barrier analysis** may be used to prove that the project faces financial, institutional, or technological barriers to ongoing operations that can only be overcome using carbon finance. Examples include but are not limited to:

* Financial barrier: financial analysis proving that the project is operating at a loss, and carbon finance would make it financially viable.
* Financial barrier: financial analysis demonstrating that the project is not financially viable, evidenced by net cash being lower than the working capital requirements, or proof that the project is not meeting the projected financial targets (e.g. IRR) in the business plans and loan documents, and that carbon finance would make it financially viable.
* Institutional barrier: description of new regulation that the project must make costly changes to comply with, financial analysis showing that the project cannot fund the changes on their own, and carbon finance is necessary to make it viable.

For any type of barrier analysis, **audited financial statements must be provided** as proof. These documents should either demonstrate the financial status to prove financial barriers, or show that the project could not independently fund solutions to overcome institutional or technological barriers.
{% endtab %}
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## No double counting <a href="#d9hoavm4p30z" id="d9hoavm4p30z"></a>

Project developers shall sign the [Rainbow MRV & Registry Terms & Conditions](https://drive.google.com/file/d/1Ol88SJX7HWGnZ9pxKfn8cekGU-RmCo6v/view?usp=sharing), committing to follow the requirements outlined in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules), including not double using or double issuing carbon credits.

Projects shall comply with the requirements set out in the [Rainbow Double Counting Policy](broken://pages/n4GJ8lK65zU6YPQ1KvGS).

{% content-ref url="/pages/n4GJ8lK65zU6YPQ1KvGS" %}
[Broken mention](broken://pages/n4GJ8lK65zU6YPQ1KvGS)
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No additional measures for double issuance are required under this methodology, because double issuance among actors in the supply chain is unlikely.

## Co-benefits <a href="#j7l12crxdi5d" id="j7l12crxdi5d"></a>

Projects should support at least two **quantifiable and verifiable** environmental or social co-benefits, aligned with the [UN Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDGs) framework. Any co-benefits claimed by the Project Developer shall be **quantified, monitored, and audited** for each verification and credit issuance.

Common co-benefits under this methodology are detailed in the table below. Project Developers may suggest and prove other co-benefits not mentioned here.

SDG 13 on Climate Action by default is not considered a co-benefit here, since it is implicitly accounted for in the issuance of carbon credits. If the project delivers climate benefits that are not accounted for in the GHG reduction quantifications, then they may be considered as co-benefits.

*Table 1 Common co-benefits that projects under this methodology may provide are detailed, including types of proof that can be used to justify each co-benefit.*

<table data-header-hidden data-full-width="true"><thead><tr><th width="265"></th><th width="469"></th><th></th></tr></thead><tbody><tr><td><strong>UN SDG</strong></td><td><strong>Description</strong></td><td><strong>Proof</strong></td></tr><tr><td>SDG 7.2 Increase substantially the share of renewable energy in the global energy mix</td><td>Promoting renewable energy over fossil fuel energy is important not only for reducing GHG emissions, but also for energy security, diversification, and conservation of finite resources. By definition, producing biogas from anaerobic digestion contributes to increasing the share of renewable energy in energy mixes.</td><td>Energy produced (kWh), from injection receipts from gas network.</td></tr><tr><td>SDG 8.2 Achieve higher levels of economic productivity through diversification, technology upgrading and innovation</td><td>Anaerobic digestion sites, often managed by farmers, provide an opportunity for income diversification, helping small-scale farmers remain viable in a challenging agricultural landscape. This is particularly beneficial given the <a data-footnote-ref href="#user-content-fn-1">decline in the number of small farms and the economic vulnerabilities faced by European farmers</a>.</td><td>Fraction of farmer income from anaerobic digestion site operation.</td></tr><tr><td>SDG 8.4 Improve global resource efficiency in consumption and production</td><td>Almost <a data-footnote-ref href="#user-content-fn-2">11 million tonnes </a>of mineral nitrogen and phosphorus fertilizer are used annually in the EU. Their production requires large amounts of fossil energy consumption and mining of finite resources. Anaerobic digestion recycles nutrients by converting agricultural residues into digestate, which returns nutrients to agricultural soils.</td><td>Amount of digestate applied to soils, calculations and conversions done in Rainbow’s model.</td></tr><tr><td>SDG 12.2 - Achieve the sustainable management and efficient use of natural resources</td><td>The project’s circularity will be measured by the Material Circularity Indicator (MCI), according to the Ellen MacArthur Foundation's methodology.</td><td>Primary data collected from the project for the GHG reduction quantification, which are also used in the Circularity Assessment.</td></tr><tr><td>SDG 12.5 - Reduce waste generation through prevention, reduction, recycling and reuse</td><td>Projects may use waste from agro-industrial processes as feedstock inputs, <a data-footnote-ref href="#user-content-fn-3">preventing other possibly harmful waste disposal or inefficient recycling</a>.</td><td>Records of feedstock inputs showing the amount of waste used.</td></tr><tr><td>SDG 13. Take urgent action to combat climate change and its impacts.</td><td>Anaerobic digestion projects reduce emissions of methane, a GHG with an especially high climate change impact and global warming potential in the short-term. Climate change impacts over 100 years are used as the basis to calculate GHG reductions and issue carbon credits, but reducing climate change impacts in the short-term by reducing methane emissions is an additional climate co-benefit.</td><td>Percent GHG emission reduction compared to the baseline scenario using <a data-footnote-ref href="#user-content-fn-4">IPCC 2021 GWP20</a> values.</td></tr><tr><td>15.1 Ensure the conservation, restoration and sustainable use of terrestrial and inland freshwater ecosystems and their services</td><td>Energy cover crops can be grown and used for biogas production, and replace either bare soil or non-harvested cover crops. Compared to bare soil, energy cover crops can <a data-footnote-ref href="#user-content-fn-5">provide numerous ecosystem services</a> such as reduced nitrogen leaching, improved soil health, and soil carbon sequestration (which is not included in the GHG reduction quantification).</td><td>Records of feedstock inputs showing energy cover crops, plus justification that energy cover crops are managed in a sustainable way.</td></tr></tbody></table>

## Substitution <a href="#dggddzk3w6cy" id="dggddzk3w6cy"></a>

The biomethane generated and injected into the gas grid must be a valid substitute for natural gas, as modeled in the baseline scenario.

This is typically already required by energy companies that manage the gas network that the biomethane is injected into. Project Developers shall provide contracts with the relevant energy company, where clauses require the final product to meet specific characteristics making it substitutable for natural gas.

The co-product of anaerobic digestion, digestate, must be a valid substitute for mineral fertilizer, which digestate is assumed to replace in the baseline scenario. Numerous scientific studies have confirmed that digestate has a high fertilization value, sometimes [comparable with that of mineral fertilizer](#user-content-fn-6)[^6]. Fertilization value is largely dependent on nutrient concentration, which shall be measured via laboratory tests for a sample of digestate from each project.

The amount of mineral fertilizer avoided in the project scenario shall correspond to the nutrient content of the digestate (see the Project avoided mineral fertilizer section for more details). This ensures that digestate is modeled as a realistic substitute for mineral fertilizer based on project-specific data.

{% hint style="info" %}
For example, if the digestate produced by a project has low nutrient concentration and low fertilization value, it will only be credited for avoiding a small amount of mineral fertilizer.
{% endhint %}

## Environmental & social do no harm <a href="#n6ud2rhvauo0" id="n6ud2rhvauo0"></a>

Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.**

Projects must follow all European, national, and local environmental regulations related to, for example, anaerobic digestion management, feedstock storage, feedstock sourcing, digestate storage, and digestate spreading.

To be eligible under this methodology, **projects shall use no more than 10% dedicated crops in their feedstock input mixture in the first year** of the crediting period. This decreases to 5% in the second year, and 3% in the remaining years. This shall be monitored each year during the crediting period.

It is environmentally preferable to use waste, manure, and slurry as feedstocks rather than intermediate energy crops, but this may not be preferable to farmers/biogas producers for financial or productivity reasons. Although this methodology does not impose a strict threshold on intermediate energy crops in the feedstock mix, the example below highlights how biogas producers are incentivized to use waste, manure, and slurry as feedstocks.

{% hint style="info" %}
Projects are incentivized to use manure and slurry as feedstocks because they are issued **credits for avoided emissions** thanks to improved storage conditions (see the Project Scenario Feedstock provisioning, transport and storage section and the Baseline Scenario Manure and slurry storage and spreading section). Different feedstocks lead to, on average:

* 0.065 tCO2eq avoided/tonne of cow manure
* 0.133 tCO2eq avoided/tonne of chicken manure
* 0.128 tCO2eq avoided/tonne of slurry

At the same time, use of intermediate energy crops leads to fewer issued credits because it causes the project to incur GHG emissions (see the Project Scenario Feedstock provisioning, transport and storage section). Across all intermediate energy crop categories considered in the GHG reduction quantification, the average emissions are

* 0.183 tCO2eq emitted/tonne of intermediate energy crop.

For example, if a project replaces 1,000 tonnes of intermediate energy crop by 1,000 tonnes of cow manure in their feedstock mix, this would result in 65 + 183 = 248 more Rainbow Carbon Credits issued.
{% endhint %}

### ESDNH risk assessment

Project Developers shall fill in the [Biogas from anaerobic digestion risk assessment](/methodologies/biogas-from-anaerobic-digestion/option-1-biogas-risk-evaluation-template-embed), to evaluate the identified environmental and social risks of projects,. The identified risks include:

* Use of dedicated crops, leading to competition for food and agricultural land;
* Reliance on energy crops rather than waste, manure, and/or slurry;
* Distant transport of feedstock inputs (>100 km) leading to increased greenhouse gas emissions from transport;
* Energy intensive processing;
* Methane leaks from digestion process and storage facilities;
* Leaching of runoff from manure, slurry or digestate storage, increasing eutrophication risks;
* Leaching of excess nutrients from digestate spreading, increasing eutrophication risks;
* Air quality, volatile odors from manure, slurry or digestate storage;
* Landscape conversion from rural to industrial;
* Workers health and safety.

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

{% content-ref url="/pages/IA7D8rG4ulcO5Tukokpe" %}
[Risk assessment template](/methodologies/biogas-from-anaerobic-digestion/option-1-biogas-risk-evaluation-template-embed)
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Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

## Leakage <a href="#g1d4tt1wjh13" id="g1d4tt1wjh13"></a>

{% tabs %}
{% tab title="Activity shifting" %}
There is a risk of activity shifting leakage related to biomass feedstock, potentially causing indirect land-use change (ILUC). This occurs when deforestation or conversion of natural ecosystems happens elsewhere to compensate for agricultural land lost to feedstock cultivation.

Project Developers shall determine and transparently communicate in the PDD the leakage risk from their biomass feedstock (see example below).

The risk level is based on the [European Union’s RED II ](#user-content-fn-7)[^7]criteria for sustainable biomass and the definitions of low and high ILUC risk for biofuels, bioliquids, and biomass fuels.

Projects using less than 90% low ILUC risk feedstock inputs are ineligible for Rainbow Carbon Credits.

Low ILUC risk biomass is defined as biomass that does not cause significant expansion into land with high carbon stock. This includes but is not limited to:

* Wastes and residues
  * Manure, slurry
  * Straw
  * Agri-industry processing residues (e.g. sugar beet pulp)
* Cover crops, catch crops, intermediate crops, and intercrops
  * rye, maize, sunflower, alfalfa, and triticale silage, from crops grown outside the main growing period
* Bioenergy crops on marginal or degraded land
  * energy crops grown at any time of the year, if the Project Developer can prove that the land was unable to be cultivated in the past 5 years.

Feedstock inputs that are high ILUC risk include but are not limited to:

* Whole-crop maize cultivated during the main growing season
* Maize silage cultivated during the main growing season

{% hint style="info" %}
The following examples demonstrate how to interpret a project's leakage risk from activity shifting.

In the first example below, the project demonstrates that 100% of the feedstock mix is categorized as low ILUC risk, so the project is eligible for Rainbow Carbon Credits.

In the second example below, the project demonstrates that only 85% of the feedstock mix is categorized as low ILUC risk. This is below the 90% threshold stated above in, so the project is ineligible for Rainbow Carbon Credits.
{% endhint %}

Example 1

<table data-header-hidden><thead><tr><th width="205"></th><th width="104"></th><th width="144"></th><th></th><th></th></tr></thead><tbody><tr><td><strong>Feedstock input</strong></td><td><strong>Amount (tonnes)</strong></td><td><strong>Percent of feedstock mix</strong></td><td><strong>Growing season</strong></td><td><strong>Low ILUC risk?</strong></td></tr><tr><td>Cow manure</td><td>4,000</td><td>20%</td><td>NA</td><td>Yes</td></tr><tr><td>Sugar beet pulp</td><td>7,000</td><td>35%</td><td>NA</td><td>Yes</td></tr><tr><td>Sunflower silage energy crop</td><td>9,000</td><td>45%</td><td>Summer (intermediate crop)</td><td>Yes</td></tr></tbody></table>

Example 2

<table data-header-hidden><thead><tr><th width="205"></th><th width="104"></th><th width="142"></th><th></th><th></th></tr></thead><tbody><tr><td><strong>Feedstock input</strong></td><td><strong>Amount (tonnes)</strong></td><td><strong>Percent of feedstock mix</strong></td><td><strong>Growing season</strong></td><td><strong>Low ILUC risk?</strong></td></tr><tr><td>Whole-crop maize</td><td>3000</td><td>15%</td><td>Main crop</td><td>No</td></tr><tr><td>Silo juice</td><td>2000</td><td>10%</td><td>NA</td><td>Yes</td></tr><tr><td>Rye silage energy crop</td><td>8000</td><td>40%</td><td>Summer (intermediate crop)</td><td>Yes</td></tr><tr><td>Maize silage energy crop</td><td>7000</td><td>35%</td><td>Late summer/fall (intermediate crop)</td><td>Yes</td></tr></tbody></table>
{% endtab %}

{% tab title="Upstream and downstream emissions" %}
Leakage may occur when emissions are shifted upstream or downstream in the supply chain and outside the project’s direct scope. These emissions shall be included by default in the GHG reduction quantification, as part of the life-cycle approach. The upstream and downstream emissions included in the quantification are detailed in the Baseline scenario and Project scenario sections
{% endtab %}
{% endtabs %}

## Targets alignment <a href="#ekfzu5nkmddm" id="ekfzu5nkmddm"></a>

Biogas from anaerobic digestion projects must prove that they lead to at least a **45% reduction in GHG emissions** compared to the baseline scenario. This is aligned with the [European Union’s 2040 Climate targets](https://climate.ec.europa.eu/eu-action/climate-strategies-targets/2040-climate-target_en), as described in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules#id-359ombk3pgqj).

The scope of the reduction is the system boundary used in GHG quantification, described in the Baseline scenario and Project scenario sections below.

This shall be proven using the GHG reduction quantification method described below.

[^1]: * Waarts, Y., Jans, V., Dengerink, J., van Vliet, J., Arets, E., Sassen, M., Guijt, J., van Vugt, S., 2019. A living income for smallholder commodity farmers and protected forests and biodiversity: how can the private and public sectors contribute? Wageningen Economic Research.
    * Rossi, R., 2022. Small farms’ role in the EU food system (No. PE 733.630). European Parliamentary Research Service. ↑
    * Bordet-Gaudin, R., Logeais, C., Ulrich, A., 2021. Le niveau de vie des ménages agricoles est plus faible dans les territoires d’élevage - Insee Première - 1876 \[WWW Document]. Institut national de la statistique et des études économiques. URL[ https://www.insee.fr/fr/statistiques/5434584](https://www.insee.fr/fr/statistiques/5434584) (accessed 7.16.24).

[^2]: Eurostat 2023. Agri-environmental indicator - mineral fertilizer consumption. [URL](https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Agri-environmental_indicator_-_mineral_fertiliser_consumption#Analysis_at_country_level). Accessed May 2024

[^3]: Buckwell, A. Nadeu, E. 2016. Nutrient Recovery and Reuse (NRR) in European agriculture. A review of the issues, opportunities, and actions. RISE Foundation, Brussels.

[^4]: Intergovernmental Panel on Climate Change 2021. Chapter 7: The Earth’s Energy Budget, Climate Feedbacks, and Climate Sensitivity. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, doi:10.1017/9781009157896.009.

[^5]: Launay, C., Houot, S., Frédéric, S. et al., 2022. Incorporating energy cover crops for biogas production into agricultural systems: benefits and environmental impacts. A review. Agron. Sustain. Dev. 42, 57. <https://doi.org/10.1007/s13593-022-00790-8>

[^6]: * Czekała, W., Jasiński, T., Grzelak, M., Witaszek, K., Dach, J., 2022. Biogas Plant Operation: Digestate as the Valuable Product. Energies 15, 8275. <https://doi.org/10.3390/en15218275>
    * Kovačić, Đ., Lončarić, Z., Jović, J., Samac, D., Popović, B., Tišma, M., 2022. Digestate Management and Processing Practices: A Review. Applied Sciences 12, 9216.[ https://doi.org/10.3390/app12189216](https://doi.org/10.3390/app12189216)

[^7]: * Directive (EU) 2018/2001 of the European Parliament and of the Council of 11 December 2018 on the promotion of the use of energy from renewable sources (recast) (Text with EEA relevance.), 2018., OJ L. [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32018L2001).
    * Commission Delegated Regulation (EU) 2019/807 of 13 March 2019 supplementing Directive (EU) 2018/2001 of the European Parliament and of the Council as regards the determination of high indirect land-use change-risk feedstock for which a significant expansion of the production area into land with high carbon stock is observed and the certification of low indirect land-use change-risk biofuels, bioliquids and biomass fuels, 2019. , OJ L. [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=uriserv:OJ.L_.2019.133.01.0001.01.ENG).


# GHG quantification

## General <a href="#id-3swbg5v0nj0e" id="id-3swbg5v0nj0e"></a>

General GHG reduction quantification rules can be found in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules#id-2rag48j2fj2l).

Calculations of GHG emissions for the baseline and project scenarios shall follow a robust, recognized method and good practice guidance. The overall methodological approach is a **comparative life cycle assessment (LCA) at the project-scale, based on**[ **ISO 14064-2:2019**](#user-content-fn-1)[^1].

Biogas from anaerobic digestion projects are only eligible for **avoidance Rainbow Carbon Credits**.

Biogas from anaerobic digestion projects have one shared universal **main function: energy production**.

Projects that use manure and/or slurry as feedstock inputs have an additional function: improved manure/slurry management, which leads to fewer GHG emissions during storage and spreading, and higher nutrient availability reducing the need for mineral fertilizers.

The baseline scenario represents the **functionally equivalent** set of activities that would occur in the absence of the project. Therefore, the baseline scenario includes:

* conventional energy production (mix of fossil fuels and biogas already present in the energy mix).

**If the project uses manure and/or slurry**, the baseline scenario also includes:

* conventional manure and slurry management with higher GHG emissions, and
* avoided mineral fertilizer production from manure and slurry application.

## Functional unit <a href="#o9yblpbimj4a" id="o9yblpbimj4a"></a>

If the only function of the project is energy production, the functional unit is 1 GWh of energy delivered.

If the project uses manure and/or slurry as feedstock inputs, then the functional unit is 1 GWh of energy delivered plus the management and use of the equivalent amount of manure/slurry.

## Data sources <a href="#ut21m91isk9g" id="ut21m91isk9g"></a>

The required **primary data** for GHG reduction calculations from projects are presented in Table 2. These data shall be included in the project’s Project Design Document (PDD) and made publicly available.

*Table 2 Summary of primary data needed from projects and their source for initial project certification and validation. Asterisks (\*) indicate which data are required to be updated annually during verification (see Monitoring Plan section).*

<table data-header-hidden data-full-width="true"><thead><tr><th></th><th></th><th></th></tr></thead><tbody><tr><td><strong>Parameter</strong></td><td><strong>Unit</strong></td><td><strong>Source proof</strong></td></tr><tr><td>Amount and type of feedstock used*</td><td>tonne of fresh matter</td><td>Track records from the biogas site</td></tr><tr><td>Average weighted distance for transporting each feedstock type from its source until the biogas site</td><td>km</td><td>Track records from the biogas site; map with the two points location and distance</td></tr><tr><td>Average number of days manure and slurry are kept stored, if applicable (optional)</td><td>Days</td><td>Estimate</td></tr><tr><td>On-site electricity consumption during the reference year*</td><td>kWh/year</td><td>Electricity bills</td></tr><tr><td>The external volume of the site's main digester</td><td>m³</td><td>Licensing or design official document containing this parameter</td></tr><tr><td>Biomethane injected into the grid</td><td>m³ and GWh</td><td>Gas grid injection receipts</td></tr><tr><td>Digestate covered during storage</td><td>Percent</td><td>Any official document containing this parameter or estimates based on the volume of each storage facility</td></tr><tr><td>Repartition of solid, liquid and raw digestate stored and spread*</td><td>Percent</td><td>Records of digestate sales plus description of if/how digestate is separated</td></tr><tr><td>Whether leaks are recovered and recirculated during purification</td><td>Yes/No</td><td>Any official document containing this parameter</td></tr><tr><td>Efficiency of purification process (optional)</td><td>Percent of methane released with offgas</td><td>Machinery technical specifications</td></tr><tr><td>Average number of days that feedstock spends in the digester (residence time)</td><td>Days</td><td>Any official document containing this parameter or estimates</td></tr><tr><td>Nitrogen (total N), potassium (K2O) and phosphorus (P2O5) content in the digestate, per digestate type</td><td>kg/tonne of material</td><td>Official laboratory tests</td></tr><tr><td>Average distance that digestate is transported by road transport, per digestate type</td><td>km</td><td>Track records from the biogas site; map with the two points location and distance</td></tr></tbody></table>

**Secondary data** taken from the literature are used to define default values, or provide conversion rates, to obtain the following elements:

* Nitrogen, dry matter content, and biochemical methane potential (BMP) of cow and chicken manure and slurry (Table 3);
* Percentage of Nitrogen in manure, slurry and different types of digestate (raw, liquid and solid) lost as N2O during storage (Table 3);
* Rate of N2O emissions per kg of manure, slurry, digestate, and mineral fertilizer spread on agricultural fields (Table 3 and Table 6);
* Amount of N, K2O and P2O5 mineral fertilizer avoided per tonne of manure and slurry
* Average number of days manure and slurry are stored in the baseline scenario;
* Characteristics of methane, biogas and biomethane;
* Leakage rates of methane throughout the biogas production from digestion, purification, boiler for internal use, injection and distribution;
* Percent of biogas produced that is used internally;
* Emission rates of methane and N2O from combustion of biomethane, in kg/MJ;
* Amount and density of digestate produced from feedstock inputs;
* Gas mix in the baseline scenario, considering the market shares for natural gas, biomethane and biogas;
* These values and their sources are provided in the Assumptions section.

The [ecoinvent database version 3.1](#user-content-fn-2)[^2]1 (hereafter referred to as ecoinvent) shall be the main source of emission factors unless otherwise specified. Ecoinvent is preferred because it is traceable, reliable, and well-recognized. The ecoinvent processes selected are detailed in Appendix 1.

## Assumptions <a href="#dy4zenx6oxaa" id="dy4zenx6oxaa"></a>

1. Feedstock inputs that are categorized as **waste come with no impacts** from their production or first life. They enter the project system boundary during the transport to the biogas site. This includes inputs such as manure, slurry, silo grain residue, spent beer grains, recirculated digestate, or damaged produce that can’t be sold.
2. In the baseline scenario, the transport distance for manure and/or slurry collection to the storage and use point is [assumed to be 10 km](#user-content-fn-3)[^3].
3. Emissions of N2O and methane due to manure and slurry storage before the digestion process are linearly related to the amount of days manure and slurry are stored on site. If Project Developers do not have an estimation of this value, an average of 15 days is assumed. In the baseline scenario, this is assumed to be 180 days.
4. Emissions of N2O from slurry storage, in the project scenario, are[ sufficiently small (0.01-0.05% life cycle GHG emissions)](#user-content-fn-4)[^4] that they can be excluded. This is because N2O emissions from slurry storage are generally small, plus the shortened storage duration in the project scenario minimizes them further.
5. Manure and slurry from pigs, horses, sheep, and other animals are modeled using the same characteristics as cow manure. Only chicken manure is treated differently, due to its high nitrogen content (Table 3).
6. Buildings and main infrastructure at the biogas site have an assumed lifetime of 20 years. Infrastructure amounts are modeled and extrapolated from the main digester exterior volume (m³) to simplify data collection, after numerous certification projects showed small impacts from infrastructure (1-2% of project life cycle GHG emissions). The ecoinvent process for the anaerobic digestion plant present in Appendix 1 is used, considering 1 m³ of digester volume annually.
7. Activated carbon used for biogas purification is modeled using a ratio of 0.2 tonnes of activated carbon/GWh of energy produced. The value was taken from biogas projects previously certified by Rainbow, and results are not sensitive to changes in this value.
8. In the project scenario, the amount of biogas self-consumed for onsite heating is assumed to be 4%. Results are not sensitive to changes in this value, which can regularly vary from 2-6% according to previous project data.
9. The mass of digestate produced is estimated to be 85-95% of the mass of feedstock inputs. A [benchmark of 90%](#user-content-fn-5)[^5] is often considered, according to the literature, expert partner consultation, and a sample of projects’ applications for environmental licenses, where they must do a detailed estimate of digestate production (“Facilities classified for environmental protection”, in French *Installations classées pour la protection de l'environnement*, ICPE). **A conservative value of 85% was chosen.** Indeed, the annual amount of digestate produced is not measured at project sites. Rather, sites measure the amount sold. Due to temporal, seasonal restrictions on when digestate can be spread, **the amount sold over one calendar year does not correspond to the amount produced in that year**. Records of digestate sold are still collected from project developers to validate that this is a reasonable approximation.
10. Methane emissions during digestate storage are reduced when the digestate is covered (e.g. airtight covers on tanks, not piles of solid digestate under a roof or rain covers). It is assumed that covers[ reduce methane emissions by 80%](#user-content-fn-4)[^4].
11. Nutrient availability in digestate, manure and slurry is [equivalent to that of mineral fertilizer](#user-content-fn-6)[^6]. For example, 1 kg of nitrogen applied to soils in digestate is assumed to substitute 1 kg of mineral nitrogen fertilizer.

*Table 3a Summary of cow and chicken manure characteristics (from* [*Esnouf et al., 2021* ](#user-content-fn-4)[^4]*unless otherwise stated).*

<table><thead><tr><th>Parameter</th><th width="174">Value for Chicken</th><th>Value for Cow</th></tr></thead><tbody><tr><td>Fresh matter as nitrogen (%)</td><td><a data-footnote-ref href="#user-content-fn-7">1.4</a></td><td>-</td></tr><tr><td>Dry matter in manure (%)</td><td>-</td><td>24</td></tr><tr><td>-Dry matter as nitrogen (%)</td><td>-</td><td>2.7</td></tr><tr><td>Nitrogen lost as N2O per 180 days of storage (%)</td><td>2</td><td>2</td></tr><tr><td>Rate of N2O released from manure spreading (kgN2O/t of manure spread)</td><td>0.177</td><td>0.177</td></tr><tr><td><a data-footnote-ref href="#user-content-fn-8">Biochemical methane potential (BMP) (m3 CH4/tonne fresh manure)</a></td><td>86</td><td>51</td></tr><tr><td>Methane emissions during storage (as % of BMP)</td><td>1.5</td><td>1.5</td></tr></tbody></table>

*Table 3b Summary of slurry characteristics (from* [*Esnouf et al., 2021* ](#user-content-fn-4)[^4]*unless otherwise stated).*

| Parameter                                                                                 | Value |
| ----------------------------------------------------------------------------------------- | ----- |
| Dry matter in slurry (%)                                                                  | 4.27  |
| Dry matter as nitrogen (%)                                                                | 7.11  |
| Nitrogen lost as N2O per 180 days of storage (%)                                          | 0.08  |
| Rate of N2O released from slurry spreading (kgN2O/t of manure spread)                     | 0.057 |
| [Biochemical methane potential (BMP) (m3 CH4/tonne fresh slurry)](#user-content-fn-8)[^8] | 19    |
| Methane emissions during storage (as % of BMP)                                            | 36    |

## Project Scenario <a href="#d3aqtkgwavb7" id="d3aqtkgwavb7"></a>

<figure><img src="/files/2AiXsWeScnluV7PPXnm6" alt=""><figcaption><p><em>Figure 1 The system boundary and scope of the project scenario are shown. They are broken down into four life cycle stages, each described in the corresponding sections below.</em></p></figcaption></figure>

The project scenario consists of anaerobic digestion, which serves three functions: **1) biomethane production**, **2) digestate production**, and if the project uses manure or slurry as a feedstock, **3) improved manure/slurry management**. This process is broken down into 4 life cycle stages, displayed in Figure 1:

* Feedstock provisioning, transport, and storage;
* Digestion and biomethane management;
* Digestate storage and spreading;
* Avoided fertilizer production.

### Feedstock provisioning, transport, and storage <a href="#relo88za3zpv" id="relo88za3zpv"></a>

Project Developers shall provide the amount of each type of feedstock input used annually in tonnes of fresh matter.

Feedstock input types considered in the model include several types of energy cover crops, straw, whole-grain corn crops, manure, slurry, recirculated digestate, and various agro-industrial waste/by-products.

The production and cultivation impacts from non-waste feedstock inputs are modeled using the ecoinvent processes outlined in Appendix 1. These include dedicated crops, energy cover crops, and straw.

Project Developers shall provide the distance that feedstock inputs are transported from their origin to the site. Transport is assumed to be done by truck (see ecoinvent process in Appendix 1). When there are multiple sources of a feedstock, the average weighted distance for each feedstock type shall be used.

Manure and slurry may be stored onsite for several days or weeks if they cannot be added to the digester immediately upon their delivery to the biogas site. During this storage period, methane and N2O are emitted linearly over time. When they are stored for 180 days (a conventional non-biogas scenario), 2% of its nitrogen is emitted as N2O, plus some methane expressed as a fraction of BMP (Table 3). Manure is **stored at biogas sites for fewer days than in a conventional scenario**, which results in fewer N2O and methane emissions. The ratio of average days manure and slurry are stored at the biogas site, to the average storage duration of 180 days, is [used to adjust the N2O and methane emission benchmarks](#user-content-fn-4)[^4] detailed in Table 3 (see example in the box below).

{% hint style="info" %}
For example, if manure is stored at the biogas site 18 days on average before being added to the digester, this represents 10% of the average 180 days of conventional manure storage. As shown in Table 3, when manure is stored for 180 days:

* 2% of its nitrogen is emitted as N2O, and
* 1.5% of its BMP is emitted as methane.

When this storage time is shortened to 18 days in the biogas scenario, (10% of the conventional storage duration):

* the nitrogen emission rate is reduced to 0.2% (10% of 2%), and
* the methane emission rate is reduced to 0.15% of BMP (10% of 1.5%).
  {% endhint %}

Project Developers rarely have detailed receipts and tracking proof of feedstock inputs, even if they informally manage this very precisely for operations. In the absence of proof, calculations are used here to **cross check expected biogas production from the given feedstock inputs vs the actual amount of biogas produced**. Project Developers shall calculate the expected annual biogas production using the biochemical methane potential (BMP) of the sum of each feedstock input, available in [public databases](#user-content-fn-9)[^9] (Equation 6). The calculated expected methane produced value should be [within 10%](#user-content-fn-10)[^10] of the actual methane produced value based on injection receipts, calculated in the following section in Equation 11. Discrepancy here suggests high uncertainty which may result in a higher discount factor (see Uncertainty Assessment section).

<details>

<summary><strong>Calculations - Feedstock provisioning, transport, and storage</strong></summary>

This step calculates the GHG emissions from the producing/cultivating feedstock inputs and transporting them to the biogas site. If the project uses manure as an input, this stage calculates the N2O emissions from its storage.

$$\textbf{(Eq.1)}\ E\_{production} = \ \sum(Non\ waste\_{feedstock, i}\*EF\_{feedstock, i})$$

where,

* $$E\_{\ production}$$ represents the sum of GHG emissions due to feedstock type *i* production, in kgCO$$\_2$$eq.
* $$Non\ waste\_{feedstock, i}$$ represents the amount of feedstock type *i*, in tonnes of fresh matter, for non-waste feedstock only.
* $$EF\_{\ feedstock, i}$$ represents the emission factor of feedstock type *i* production in kgCO$$\_2$$eq/tonne. Refer to for the ecoinvent process used.

$$\textbf{(Eq.2)}\ E\_{transport} = \sum(W\_i\*D\_i)\*EF\_{truck\ transport}$$

where,

* $$E\_{transport}$$ represents the sum of GHG emissions due to feedstock transport, in kgCO$$\_2$$eq.
* $$W\_i$$ represents the sum of feedstock type $$i$$ weight, in tonnes, for all feedstocks regardless of waste status (waste or non-waste).
* $$D\_i$$ represents the distance of the feedstock collection, in kilometers.
* $$EF\_{truck\ transport}$$ represents the emission factor of truck transport in kgCO$$\_2$$eq/t.km. Refer to Appendix 1 for the ecoinvent process used.

Equation 3 shall be used if the project uses manure as a feedstock input.

$$\begin{aligned}\textbf{(Eq.3)}\ E\_{P\ N2O\ manure\ storage} = \sum \&W\_{manure, i}*\ % N*R\_{N\ as\ N2O}\ &*N\_{to\ N2O}*\frac{Days\ stored}{180}\*\ GWP\_{N2O}\end{aligned}$$

where,

* $$E\_{P\ N2O\ manure\ storage}$$ represents the sum of GHG emissions from N$$\_2$$O due to the storage of manure type *i* (chicken or cow) in the project scenario, in kgCO$$\_2$$eq.
* $$W\_{manure, i}$$ represents the mass of manure type *i* used as feedstock in the project scenario, in kg.
* $$% N$$ represents the percent of manure mass as nitrogen.
  * For chicken manure, this is 1.4% of fresh matter as nitrogen, as shown in Table 3 in the Assumptions section.
  * For cow and all other manure types, this is 0.65% of fresh matter as nitrogen, as shown in Table 3 in the Assumptions section (2.7% of dry matter as nitrogen \* 24% dry matter)
* $$R\_{N\ as\ N2O}$$ represents the rate of nitrogen emitted as N$$\_2$$O from conventional manure storage of 180 days. According to Table 3, this equals 2%.
* $$Days\ stored/180$$ represents the number of days manure is kept stored in the project scenario. A default value of 15 days can be assumed if no project data is available. 180 represents the conventional manure storage duration of 180 days.
* $$N\_{to\ N2O}$$ represents the conversion of nitrogen to N$$\_2$$O equivalents by multiplying by the ratio of their molecular mass (1.57).
* $$GWP\_{N2O}$$ represents the global warming potential of N$$\_2$$O over 100 years, which is [273 kgCOeq/kg N2O](#user-content-fn-11)[^11].

Equation 4 shall be used if the project uses manure and/or slurry as a feedstock input.

$$\begin{aligned}\textbf{(Eq.4)}\ E\_{P\ CH4\ storage} = \sum \&W\_{i}*{BMP}*{i}\*E*{BMP\ CH4}*\ &{\rho CH}*{4}\*{\frac{Days\ stored}{180}\*GWP}*{bio\ CH4}\end{aligned}$$

where,

* $$E\_{\ P\ CH4\ storage}$$ represents the emissions of methane from storage of manure and/or slurry
* $$W\_{i}$$ is explained in equation 2, and only applies to manure and slurry
* $$BMP\_{i}$$ represents the biomethane potential of feedstock type\
  $$i$$, in nm$$^3$$ of CH$$\_4$$ per tonne of fresh matter, presented in Table 3.
* $$E\_{BMP\ CH4}$$ represents methane emissions during storage as % of BMP, presented in Table 3.
* $${\rho CH}\_{4}$$ represents the methane density, which is[ 0.75](#user-content-fn-12)[^12] kg/m³.
* $$Days\ stored/180$$ was described in Equation 3.
* $${GWP}\_{bio\ CH4}$$ represents the global warming potential of biogenic CH$$\_4$$ over 100 years, which is 27[^13] kgCO$$\_2$$eq/kg CH$$\_4$$

$$\textbf{(Eq.5)}\ Total\ E\_{feedstock} = E\_{production} + E\_{transport} + E\_{manure\ storage, i}$$

where,

* $${Total\ E}\_{feedstock}$$ represents the sum of GHG emissions due to feedstock production, transport, and if applicable, manure storage.

$$\textbf{(Eq.6)}\ CH\_{4\ expected\ m³} = \ \sum({Feedstock}*{i}\*BMP*{i})$$

where,

* $$CH\_{4\ expected\ m³}$$ represents the expected amount of methane produced during the reference year in m³. This value is cross checked against the actual $$CH\_{4\ total\ produced\ m³}$$from Equation 11 to evaluate the validity and uncertainty in reported feedstock input amounts and types (see description [above](#relo88za3zpv)).
* $$BMP\_{i}$$ is explained in Eq.4.

</details>

### Digestion and biomethane management <a href="#id-6oxm2svxe98p" id="id-6oxm2svxe98p"></a>

Project Developers shall provide the amount of electricity used onsite annually, in kWh/year, and the electricity source (e.g. grid or onsite solar). A black-box approach is used for electricity consumption, and only the total amount of electricity used on-site is required (i.e. not broken down into different uses).

Leakages of methane throughout the project steps are calculated using leakage rates from the literature, and are summarized in Table 4. Even though modern anaerobic digestion plants only leak small amounts of methane, they can represent [important sources of GHG emissions through the life cycle](#user-content-fn-14)[^14]. Project sites have sensors to measure large, exceptional methane leaks, but the **amounts considered in the GHG reduction quantification are below the threshold of most sensors**.

*Table 4 Rates of methane and biogas leakage from different steps in the project scenario, based on volume of gas.*

| **Process**         | [**Leak rate original data**](#user-content-fn-4)[^4]                                                               | **Leak rate as percent of methane produced** | [**Source in Esnouf et al., 2021**](#user-content-fn-4)[^4] |
| ------------------- | ------------------------------------------------------------------------------------------------------------------- | -------------------------------------------- | ----------------------------------------------------------- |
| Digestion           | 0.5% biogas produced leaked by volume                                                                               | 0.28%                                        | page 36                                                     |
| Boiler leakage      | 0.25% internally used methane by volume leaked from the boiler                                                      | 0.0055%                                      | page 35, assuming 4% biogas produced used internally        |
| Purification of gas | <ul><li>Project data, or</li><li>default value of 0.7%, or</li><li>0%</li></ul><p>of methane produced by volume</p> | 0.7%                                         | page 38                                                     |
| Injection           | 0.1% input biomethane leaked by volume                                                                              | 0.097%                                       | page 76                                                     |
| Distribution        | 0.13% input biomethane leaked by volume                                                                             | 0.126%                                       | Table 52                                                    |
| **Sum**             |                                                                                                                     | **1.20%**                                    |                                                             |

Project Developers should provide methane leakage rates from offgas during the purification step. This is typically provided in technical documents or contracts for purification machinery. If this value is not available, a default leakage rate of 0.7% of methane by volume will be used. If offgas is captured and used, this value may be zero.

The amount of biogas self-consumed in a boiler for onsite heating is assumed to be 4% (see [Assumptions](#dy4zenx6oxaa) section).

The biogas and biomethane characteristics presented in Table 5 are used.

*Table 5 Characteristics of biogas and biomethane*

| Parameter                         | Biogas    | Biomethane |
| --------------------------------- | --------- | ---------- |
| Lower heating value (LHV) (MJ/m³) | 22.7[^15] | 36[^16]    |
| Methane content (% volume)        | 55[^17]   | 97[^18]    |

The amount of activated carbon used in purification is estimated to be 0.2 tonnes/GWh of energy produced (see [Assumptions](#dy4zenx6oxaa) section). Other processes related to purification were excluded, given that they are consistently [minor sources of impacts in biogas LCAs](#user-content-fn-19)[^19].

The most impactful direct emissions from the biomethane combustion step were taken from Table 53 in [Esnouf et al., 2021](#user-content-fn-4)[^4]. This includes 4.93e-7 kg N2O/MJ biomethane, and 1.96E-06 kg biogenic CH4/MJ biomethane.

All infrastructure and machinery are included in this step, even if some are actually used for digestate or feedstock storage described in other sections.

Infrastructure and machinery are modeled in ecoinvent with a process that includes production, transport and disposal of the main materials for an agricultural biogas plant (see Appendix 1). The ecoinvent process represents a site with a main digester of 500 m3.

Project Developers shall provide the **external volume of their site’s main digester**, in m3. This is used to adjust the amount of the ecoinvent infrastructure and machinery process used. For example, if the project’s main digester has a volume of 250 m3, it will only be assigned half of the impacts modeled in the ecoinvent process.

It is assumed that infrastructure has a lifetime of 20 years. This means that for calculating impacts of 1 year of operations of the project, infrastructure and machinery will be allocated 1/20th of their total impacts.

<details>

<summary><strong>Calculations - Digestion and biomethane management</strong></summary>

This step calculates the GHG emissions from anaerobic digestion and biomethane management ($$Total\ E\_{Digestion}$$).

$$\textbf{(Eq.7)}\ E\_{electricity} = Electricity\_{kWh}\*\ EF\_{electricity}$$

where,

* $$E\_{electricity}$$ represents the sum of GHG emissions due to on-site electricity consumption, in kgCO$$\_2$$eq.
* $$Electricity\_{kWh}$$ represents the total on-site electricity consumption, in kWh.
* $$EF\_{electricity}$$ represents the emission factor for electricity, in kgCO$$\_2$$eq/kWh. Refer to Appendix 1 for the ecoinvent process used.

$$\textbf{(Eq.8)}\ E\_{AC} = W\_{AC/GWh}\*GWh\_{produced}\*EF\_{AC}$$

where,

* $${\ E}\_{AC}$$ \_r\_epresents the sum of GHG emissions due to on-site activated carbon consumption, in kgCO$$\_2$$eq.
* $$W\_{AC/GWh}$$ represents the weight of activated carbon used per GWh of energy produced, which is assumed to be 0.2 tonnes/GWh.
* $${GWh}\_{produced}$$ represents the GWh of energy produced by the project annually.
* $${EF}\_{AC}$$ represents the emission factor for activated carbon, in kgCO$$\_2$$eq/kg. Refer to Appendix 1 for the ecoinvent process used

$$\textbf{(Eq.9)}\ E\_{infrastructure} = EF\_{anaerobic\ plant}\*\ \frac{D\_{volume\ m^{3}}}{500m^{3}} \div 20\ years$$

where,

* $$E\_{infrastructure}$$ represents the sum of GHG emissions due to infrastructure and machinery manufacture, transport and end of life, in kgCO$$\_2$$eq.
* $$EF\_{anaerobic\ plant}$$ represents the emission factor of an anaerobic digestion site's infrastructure and machinery. It is modeled for a site with a main digester exterior volume of 500 m$$^3$$. Refer to Appendix 1for the ecoinvent process used.
* $$D\_{volume\ m^{3}}$$ represents the volume of the project site's main digester, in m³. It is divided by 500 m$$^3$$ to obtain the fraction of the ecoinvent process impacts to assign to the project
* $$20\ years$$ represents the assumed site lifetime, and is used to normalize infrastructure and machinery impacts to 1 year.

Methane leakages during the digestion, purifying, injection, and distribution phases are detailed below.

$$\begin{aligned}\textbf{(Eq.10)}\ L\_{CH4\ tota{l%}} = \&L\_{digestion%}\*Biogas\_{% CH4}\\&+ (L\_{boiler%}\*Biogas\_{internal%}\*Biogas\_{% CH4}) \\&+ ((\ L\_{injection%}+ L\_{distribution%})\*Biomethane\_{% CH4})\\&+ L\_{purification%}\end{aligned}$$

where,

* $$L\_{CH4\_\ total%}$$ represents the total amount of methane losses in the system, as a percentage of total volume of methane produced.
* $$L\_{digestion%}$$represents the percentage of biogas produced that is leaked during the digestion process. This value is assumed 0.5%, as presented in Table 4.
* $$L\_{boiler%}$$ represents the percentage of internally used methane that is leaked, which is 0.25% according to Table 4.
* $$Biogas\_{internal%}$$represents the percentage of biogas produced that is used internally, assumed 4%, as presented in the Assumptions section.
* $$Biogas\_{% CH4}$$represents the percentage of methane in biogas. This value is assumed to be 55%, as presented in the Assumptions section.
* $$\ L\_{injection%}$$ represents the percentage of biomethane leaked during the gas injection into the grid, which is 0.1% according to Table 4.
* $$L\_{distribution%}$$represents the percentage of biomethane leaked during the biomethane distribution to the final user, which is 0.13% according to Table 4.
* $$Biomethane\_{% CH4}$$ represents the percentage of methane in biomethane. This value is considered 97%, as presented in Assumptions section.
* $$L\_{purification%}$$represents the percentage methane produced that is leaked in the purification process. This value is estimated at 0.7% if data is not available for the project.

Losses from Eq. 10 add up to 1.2% losses of total methane produced, if the default value for purification leakage of 0.7% is used (Table 4). The amount of methane produced before losses is presented in Eq. 11.

$$\textbf{(Eq.11)}\ CH\_{4\ total\ produced\ m^3} = \frac{{Biomethane}*{injected\ m³\ }\*{Biomethane}*{% CH4}}{(1 - L\_{CH4\ total})}$$

where,

* $$CH\_{4\ total\ produced\ m^3}$$ represents the volume of methane produced, in m³, before losses. This value shall be cross checked against the expected CH$$\_4$$ produced, calculated in Equation 6.
* $${Biomethane}\_{injected\ m³\ }$$ represents the m$$^3$$ of biomethane injected into the gas grid annually.

$$\textbf{(Eq.12)}\ E\_{loss\ bio\ CH4}\ = \ CH\_{4\ total\ produced\ m³}*L\_{CH4\ total%}*{\rho CH}*{4}\*{GWP}*{bio\ CH4}$$

where,

* $$E\_{loss\ bio\ CH4}$$ represents the sum of GHG emissions from biogenic CH$$\_4$$ leakages, in kgCO$$\_2$$eq.
* $${\rho CH}*{4}$$ and $${GWP}*{bio\ CH4}$$ were explained in Equation 1.

The amount of methane and N2O emissions from biomethane combustion shall also be considered, to match the scope of the baseline scenario, which includes natural gas combustion.

$$\begin{aligned}\textbf{(Eq.13)}\ E\_{loss\ CH4\ combustion} = \&Biomethane\_{injected\ m^3}*Biomethane\_{LHV}\\*\ \&CH\_{4\ ER}\*GWP\_{biog\ CH4}\end{aligned}$$

where,

* $$E\_{loss\ CH4\ combustion}$$ represents GHG emissions from biogenic CH$$\_4$$ leakages, in kgCO$$\_2$$eq, due to biomethane combustion.
* $$Biomethane\_{injected\ m³}$$ is described in Equation 11.
* $$Biomethane\_{LHV}$$ represents the lower heating value of biomethane, presented in Table 5 in the Assumptions section\_.\_
* $$CH\_{4\ ER}$$ represents biomethane's combustion emission rate, in kg CH$$\_4$$/MJ biomethane.
* $${GWP}\_{bio\ CH4}$$ was described in Equation 4.

$$\textbf{(Eq.14)}\ E\_{N2O} = Biomethane\_{injected\ m³}*{Biomethane}*{LHV}\*N2O*{ER}*{GWP}\_{N2O}$$

where,

* $$E\_{N2O}$$ represents the sum of N$$\_2$$O direct emissions due to methane combustion, in kgCO$$\_2$$eq.
* $$Biomethane\_{injected\ m^3}$$ is described in Equation 11.
* $$Biomethane\_{LHV}$$ is described in Equation 13.
* $$N2O\_{ER}$$ represents biomethane's combustion emission rate, in kg N$$\_2$$O/MJ biomethane.
* $$GWP\_{N2O}$$ is explained in Equation 3.

$$\textbf{(Eq.15)}\ E\_{direct\ emissions} = \ E\_{loss\ CH4,\ biog} + {\ E}*{loss\ CH4\ combustion} + E*{N2O}$$

where,

* $$E\_{direct\ emissions}$$ represents the sum of direct GHG emissions (CH$$\_4$$ and N$$\_2$$O) due to leakages and losses in the digestion, purifying, injection, distribution and combustion steps, in kgCO$$\_2$$eq.

$$\textbf{(Eq.16)}\ Total\ E\_{digestion} = E\_{electricity} + E\_{AC} + E\_{infrastructure} + E\_{direct\ emissions}$$

where,

* $${Total\ E}\_{digestion}$$ represents the sum of GHG emissions due to the digestion, purifying, injection, and distribution step, in kgCO$$\_2$$eq.

</details>

### Digestate storage and spreading <a href="#j6yugui08a8f" id="j6yugui08a8f"></a>

The **amount of digestate produced annually** is estimated to be 85% of the mass of feedstock inputs (see the Assumptions section).

Project Developers shall provide the **repartition of digestate types** (raw, liquid, and/or solid phase) that are stored and spread. If the repartition is different for the storage and spreading stages (e.g. stored raw, spread as liquid and solid), then the repartition that leads to higher project emissions shall be applied to all digestate management, in order to maintain a conservative approach. Data shall come from the repartition of digestate types sold annually.

{% hint style="info" %}
For example, if 6000 tonnes of feedstock inputs are used annually, the assumed total amount of digestate produced is 6000\*85% = 5100 tonnes of digestate.

If the **digestate is not separated** into liquid and solid phases, then raw digestate storage and spreading is considered, with the relevant raw digestate emission rates.

If the **digestate is separated**, then sales data will be used to determine the repartition of solid and liquid digestate (sales data do not represent production data, as described in the Assumptions section).

If the project sells 4500 tonnes of liquid digestate and 500 tonnes of solid digestate annually, then the ratio is 90% liquid and 10% solid. Then, according to the production value of 6000 tonnes, we would assume that 90% liquid (5400 tonnes) and 10% solid (600 tonnes) digestate was produced.
{% endhint %}

Project Developers shall provide an estimate of the residence time, (the number of days feedstock spends in the digester).

**Methane emissions during digestate storage** are calculated as a function of residence time in the digester and percent of methane produced that is emitted, as illustrated in Figure 10.1 of [Hartig 2010](#user-content-fn-20)[^20]. The linear regression equation obtained from that dataset is presented in Eq. 21, and shall be used to predict methane leakage rates from digestate storage for a given project’s residence time.

It is assumed that storing digestate under airtight covers reduces methane emissions from storage by 80%. Project Developers shall report what fraction of their digestate storage is covered vs. uncovered.

**Nitrous oxide emissions from digestate storage** are calculated using 1) the amount of digestate stored, 2) the nitrogen content of digestate, provided by Project Developers in the form of laboratory analyses and 3) emission rates from the literature, summarized in Table 6.

*Table 6 Percent of nitrogen present in digestate that is emitted as N2O from* [*digestate storage*](#user-content-fn-4)[^4] *and* [*spreading*](#user-content-fn-21)[^21]*.*

| Step      | Digestate form         | Value (%) |
| --------- | ---------------------- | --------- |
| Spreading | Raw, liquid, and solid | 1         |
| Storage   | Raw                    | 0.08      |
| Storage   | Liquid                 | 0.08      |
| Storage   | Solid                  | 2         |

Digestate transport from the biogas site to the farm for spreading is included when this transport is done by truck. No impacts are included for transport via irrigation pipeline, assuming that they would be below the impact threshold.

**Nitrous oxide emissions from digestate spreading** on soil is calculated using 1) the amount of digestate spread (which may differ from the amount stored if some digestate is recirculated as feedstock), 2) the nitrogen content of digestate, provided by Project Developers in the form of laboratory analyses and 3) an emission rate of 1% of nitrogen added to soils in digestate is lost in N2O, according to the [IPCC Tier 1 emission factor for organic amendments](#user-content-fn-22)[^22].

<details>

<summary><strong>Calculations - Digestate storage and spreading</strong></summary>

This step calculates the GHG emissions from the digestate produced (stored and spread) life cycle stage ($$Total E\_{digestate}$$).

$$\textbf{(Eq.17)}\ D\_{raw} = (\sum({feedstock}*{i})\*Digestate*{%}) - D\_{recirculated}$$

where,

* $$D\_{raw}$$ represents the **total amount** of raw digestate produced, stored and spread by the project annually, in tonnes of fresh matter.
* $$\sum({feedstock}\_{i})$$ represents the sum of all feedstock inputs, in tonnes of fresh matter.
* $$Digestate\_{%}$$ represents the ratio of the total feedstock input mass that becomes digestate at the end of the digestion. This is assumed to be 85% as presented in the Assumptions section.
* $$D\_{recirculated}$$ represents the amount of digestate produced that is recirculated in the digester, in tonnes of fresh matter.

$$\textbf{(Eq.18)}\ D\_{i.t} = D\_{raw}\*D\_{type\ i%}$$

where,

* $$D\_{i.t}$$ represents the amount of digestate type *i* (raw, liquid, or solid form) **produced** (stored and spread), in tonnes of fresh matter. If no digestate separation process occurs, the amount of digestate produced is equal to the amount of raw digestate produced ($$D\_{raw\.t}$$*)*.
* $$D\_{raw}$$ was calculated in Equation 17.
* $$D\_{type\ i%}$$ represents the percent of all digestate produced that is digestate type *i* (whether raw, liquid, or solid).

$$\textbf{(Eq.19)}\ D\_{\ CH4\ loss%} = (8.34 - 1.48\*ln(residence\ time))/100$$

where,

* $$D\_{CH4%}$$ represents methane leakage from digestate storage, as a function of total methane produced.
* $$residence\ time$$ represents the average number of days that feedstock spends in the digester.

$$\textbf{(Eq.20)}\ D\_{% weighted\ avg\ covered} = \frac{\sum(D\_{i.t}\*D\_{i\ stored\ covered\ %})}{\sum(D\_{i.t})}$$

where,

* $$D\_{% weighted\ avg\ covered}$$ represents the weighted average percent of all digestate types that are stored under covered conditions.
* $$D\_{i.t}$$ is calculated in Equation 18.
* $$D\_{i\ stored\ covered\ %}$$ represents the percentage of digestate type *i* stored under covered conditions.

$$\begin{aligned}\textbf{(Eq.21)}\ E\_{reduction\ CH4\ covered} = &(D\_{% weighted\ avg\ covered}\*{LR}*{covered})\ &+ \ (1 - D*{% weighted\ avg\ covered})\end{aligned}$$

where,

* $$E\_{reduction\ CH4\ covered}$$ represents the total weighted average of methane emission reductions thanks to covering digestate during storage.
* $$D\_{% weighted\ avg\ covered}$$ was calculated in Equation 20.
* $${LR}\_{covered}$$ represents the leakage reduction of methane obtained by covering digestate during storage. This value is 0.2.

$$\textbf{(Eq.22)}\ E\_{D.\ CH4} = {CH\_{4\ {total\ produced\ m³}*{}}}*{\ }\*{\rho CH}*{4}\*D*{CH4\ loss%}*E\_{reduction\ CH4\ covered}*{GWP}\_{bio\ CH4}$$

where,

* $$E\_{D.\ CH4}$$ represents the sum of GHG emissions from methane due to digestate storage, in kgCO$$\_2$$eq.
* $$CH\_{4\ {total\ produced\ m³}\_{}}$$represents the amount of methane produced during the reference year in m³, from Equation 1.
* $$D\_{CH4\ loss%}$$ was calculated in Equation 19.
* $$E\_{reduction\ CH4\ covered}$$ was calculated in Equation 21.
* $${\rho CH}*{4}$$ and $${GWP}*{bio\ CH4}$$ is explained in Equation 1.

$$\textbf{(Eq.23)}\ E\_{D.\ N2O\ storage\ } = \sum(D\_{i.t}\*D\_{i.N}*D\_{i.N\ los{s\ storage}*{%}})\*N*{to\ N2O}*{GWP}\_{N2O}$$

where,

* $$E\_{D.\ N2O\ storage\ }$$ represents the sum of GHG emissions due to N$$\_2$$O leakages during digestate storage, in kgCO$$\_2$$eq.
* $$D\_{i.t}$$ is calculated in Equation 18.
* $$D\_{i.N}$$ represents the Nitrogen content in the digestate type *i* (raw, liquid, or solid), in kg/tonne.
* $$D\_{i.N\ los{s\ storage}\_{%}}$$ represents the percentage of Nitrogen leaked during digestate type *i* storage, as presented in Table 6.
* $$N\_{to\ N2O}$$ and $${GWP}\_{N2O}$$ are explained in Equation 3.

$$\textbf{(Eq.24)}\ E\_{D.\ N2O\ spreading} = \sum(D\_{i.t}\*D\_{i.N})*D\_{i.N\ los{s\ spreading}*{%}}\*N*{to\ N2O}*{GWP}\_{N2O}$$

where,

* $$E\_{D.\ N2O\ spreading\ }$$ represents the sum of GHG emissions from N$$\_2$$O during digestate spreading, in kgCO$$\_2$$eq.
* $$D\_{i.t}$$ is calculated in Equation 18.
* $$D\_{i.N}$$ is explained in Equation 23.
* $$D\_{i.N\ los{s\ spreading}\_{%}}$$ represents the percentage of nitrogen emitted as N$$\_2$$O during digestate type *i* spreading, as presented in Table 6.
* $$N\_{to\ N2O}$$ and $${GWP}\_{N2O}$$ are explained in Equation 3.

$$\textbf{(Eq.25)}\ E\_{\ transport} = \sum(D\_{i\ t}\*D\_{i.spreading.km})\*EF\_{truck\ transport}$$

where,

* $$E\_{\ transport}$$ represents the sum of GHG emissions due to the transport of digestate from the biomethane site until the spreading point, in kgCO$$\_2$$eq.
* $$D\_{i.t}$$ is calculated in Equation 18.
* $$D\_{i.\ spreading.km}$$ represents the distance from the biogas site to the location where the digestate type *i* will be spread, measured in kilometers.
* $$\ EF\_{truck\ transport}$$ represents the emission factor of truck transport in kgCO$$\_2$$eq/t.km. Refer to Appendix 1 for the ecoinvent process used.

$$\textbf{(Eq.26)}\ Total\ E\_{digestate} = E\_{D.\ CH4\ } + E\_{D.\ N2O\ loss\ storage\ } + E\_{D.\ N2O\ loss\ spreading\ } + E\_{\ transport}$$

where,

* $${Total\ E}\_{digestate}$$ represents the sum of GHG emissions due to the digestate storage and spreading life cycle stage, in kgCO$$\_2$$eq.
* $$E\_{D.\ CH4}$$ was calculated in Equation 22.
* $$E\_{D.\ N2O\ loss\ storage\ }$$ was calculated in Equation 23.
* $$E\_{D.\ N2O\ loss\ spreading\ }$$was calculated in Equation 24.
* $$E\_{\ transport}$$ was calculated in Equation 25.

</details>

### Project avoided fertilizer <a href="#ea2yoslt0lu9" id="ea2yoslt0lu9"></a>

The project is credited with avoiding synthetic mineral fertilizer production thanks to digestate spreading. This is because the project is multifunctional and makes a co-product digestate, which is treated using the common LCA practice of system expansion and substitution\[48].

Project Developers shall provide the nutrient contents of all digestate types, measuring total N, P2O5, and K2O.

Amount of digestate spread is described and calculated in the previous section.

As described in the Assumptions section, nutrient availability in digestate is equivalent to that of mineral fertilizer, so for example spreading 1 kg of P2O5 from digestate is modeled as substituting the production of 1 kg of P2O5 mineral fertilizer production.

Along with avoiding nitrogen fertilizer production, digestate spreading also avoids N2O emissions from fertilizer spreading. These are calculated using the amount of nitrogen avoided by digestate, and nitrogen emission rates from mineral fertilizers, which equals 1% of applied N emitted as N2O.

<details>

<summary><strong>Calculations - Project avoided fertilizer</strong></summary>

This step calculates the GHG emissions from the project’s avoided fertilizer production and use ($$Total E\_{P.avoided fertilizer}$$).

$$\textbf{(Eq.27)}\ E\_{P.\ NPK\ avoided} = - \sum\_{i}^{}\sum\_{j}^{}(D\_{i\ spread.t}\*C\_{i.\ j})\ \*EF\_{j\ fertilizer}$$

where,

* $${\ E}\_{P.\ NPK\ avoided}$$ represents the sum of GHG emissions avoided due to the substitution of mineral fertilizer production by digestate spreading, in kgCO$$\_2$$eq. *P* denotes the project scenario, to differentiate between the same variable calculated in the baseline scenario.
* $$D\_{i.t}$$ is calculated in Equation 18
* $$C\_{i,\ j}$$ represents the content of nutrient 𝑗 (N, P205,and K2O) in digestate type 𝑖, in kg nutrient/tonne of digestate.
* $$EF\_{j\ fertilizer}$$ represents the emission factor of production of synthetic N, P2O5, or K2O fertilizer in kgCO$$\_2$$eq/kg. Refer to Appendix 1 for the ecoinvent process used.

$$\textbf{(Eq.28)}\ E\_{P.N2O\ avoided} = - \sum (D\_{i\ spread.t}\*D\_{i.N})\*ER\_{N\ as\ N2O}\ *N\_{to\ N2O}*{GWP}\_{N2O}$$

where,

* $$E\_{P.N2O\ avoided}$$ represents the sum of GHG emissions avoided due to the substitution of mineral fertilizer use, and subsequent N$$\_2$$O emissions, by digestate spreading, in kgCO$$\_2$$eq. *P* denotes the project scenario, to differentiate between the same variable calculated in the baseline scenario.
* $$D\_{i.t}$$ is calculated in Equation 18.
* $$D\_{i.N}$$ is explained in Equation 23.
* $$ER\_{N\ as\ N2O}$$ represents the rate of applied nitrogen emitted as N$$\_2$$O, which equals 1%.
* $$N\_{to\ N2O}$$ and $${GWP}\_{N2O}$$ are explained in Equation 3.

$$\textbf{(Eq.29)}\ Total\ E\_{P.avoided\ fertilizer} = E\_{P.\ NPK\ avoided} + E\_{P.N2O\ avoided}$$

where,

* $${Total\ E}\_{P.avoided\ fertilizer}$$ represents the sum of fertilizer GHG emissions avoided due to the use of digestate as an organic amendment, in kgCO$$\_2$$eq.

</details>

## Baseline scenario <a href="#m8t0mn694gpw" id="m8t0mn694gpw"></a>

The baseline scenario represents the GHG emissions that would occur without the project. It includes **functionally equivalent processes that provide the same products/services as the Project Scenario.**

As described in the Project Scenario section, the project delivers the following products/services, with their corresponding baseline scenario processes:

* Biomethane production and injection into the gas grid: this is assumed to replace the average **market mix of gas from the grid,** primarily natural gas, with a fraction of biomethane and biogas already present in the mix.
* Digestate production: this is assumed to replace synthetic mineral fertilizer production and application, which is already considered within the project scenario using system expansion and substitution (see [Project avoided fertilizer section](#ea2yoslt0lu9)). It is not considered in the baseline scenario.
* Manure and slurry management (if the project uses manure and/or slurry): this is assumed to replace **conventional manure and slurry storage and spreading**, which includes emissions from storage, and avoided mineral fertilizer production.

<figure><img src="/files/RoJ3NHf9XycVYiBptpec" alt=""><figcaption><p><em>Figure 2 The system boundary and scope of the baseline scenario are shown. They are broken down into three life cycle stages, each described in the corresponding sections below.</em></p></figcaption></figure>

The baseline scenario includes 1 to 3 life cycle stages, depending on the project operations, displayed in Figure 2:

* Energy production
* Manure and slurry storage and spreading (if the project uses manure and/or slurry)
* Avoided fertilizer production and use (if the project uses manure and/or slurry)

The baseline scenario **structure** remains valid for the entire crediting period but may be significantly revised earlier if:

* The Project Developer notifies Rainbow of a substantial change in project operations or baseline conditions, and/or
* The methodology is revised, affecting the baseline scenario.

The **specific values** within the baseline scenario will be updated during each crediting period, using project data to accurately reflect the equivalent of the project’s operations.

### Energy production <a href="#wuq5tihnlrk7" id="wuq5tihnlrk7"></a>

If the project injects biomethane into the gas grid, the baseline scenario is the market mix of gasses in the national gas supply. This shall include the **share of biogas and biomethane already used at the national level**.

Natural gas, biogas and biomethane production are modeled using ecoinvent processes detailed in Appendix 1. For natural gas, the process includes all upstream impacts of gas extraction, production, distribution, and combustion in a gas turbine. Biogas and biomethane processes include their production, and combustion was excluded assuming its impact would be very small because they are not fossil fuels.

The total amount of gas considered in the baseline scenario shall equal the amount of energy from biomethane injected by the project biogas site (provided by Project Developers), minus the calculated amount of biomethane lost during the distribution stage, in MJ.

The total amount of gas in the baseline scenario shall be broken down into the amount of natural gas, biogas and biomethane using data from Eurostat datasets covering biogas[^23] and [natural gas ](#user-content-fn-24)[^24]consumption. An example is provided below.

{% hint style="info" %}
For example, for France, gas consumption for 2022 (the most recent year where complete data are available in Eurostat) shows that 1,570,871 m3 of natural gas and 68,736 m3 of biogasses were consumed. This corresponds to 96% natural gas and 4% biogasses. As a result, 1 MJ of biomethane injected by the project is assumed to replace 0.96 MJ of natural gas and 0.04 MJ of biogas.

If data are available on the national repartition of biogasses, the latter amount may be further specified. For example, in France in 2021,[ 4,338 GWh of biomethane and 2,700 GWh of biogas](#user-content-fn-25)[^25] were produced. This repartition can be applied to the 0.04 MJ of biogasses mentioned above, to obtain 0.015 MJ of biogas and 0.025 MJ of biomethane.
{% endhint %}

If heat and/or electricity are exported by the project instead of gas injection, the baseline scenario shall include the national mixes of heat and/or electricity, based on Eurostat data for the most recent year (or data of a similar high-quality source). The amount of heat and/or electricity in the baseline scenario shall equal the equivalent amount of energy from heat and/or electricity exported from the project scenario to the grid/external industrial processes (i.e. excluding the amount that is self consumed).

If manure or slurry are not used as feedstock inputs at the biogas site, **then this section is the only component of the baseline scenario**.

<details>

<summary><strong>Calculations - Energy Production</strong></summary>

This step calculates the GHG emissions from the baseline energy production life cycle stage, where biomethane is injected into the gas grid ($$Total E\_{Energy Production}$$).

$$\textbf{(Eq.30)}\ Gas\_{delivered\ MJ} = Biomethane\_{injected\ m³}*(1\ - \ L\_{distribution%})*{Biomethane}\_{LHV}$$

where,

* $$Gas\_{delivered\ MJ}$$ represents the total amount of energy from gas delivered after distribution, in MJ.
* $$Biomethane\_{injected\ m³}$$ represents the amount of biomethane injected into the grid, in m³, from the gas grid injection receipts, described in Equation 11.
* $$L\_{distribution%}$$represents the percentage of biomethane leaked during the biomethane distribution to the final user, which is 0.13% according to Table 4, described in Equation 10.
* $${Biomethane}\_{LHV}$$ represents the lower heating value of biomethane, presented in Table 5 in the Assumptions section.

$$\textbf{(Eq.31)}\ E\_{NG} = Gas\_{delivered\ MJ}\*NG\_{grid\ %}\*EF\_{NG}$$

where,

* $$E\_{\ NG}$$ represents the sum of GHG emissions due to natural gas production and use according to the market shares, in kgCO$$\_2$$eq.
* $$Gas\_{delivered\ MJ}$$ is calculated in Equation 30.
* $$NG\_{%\ grid}$$ represents the fraction of natural gas in the grid, using data from Eurostat datasets covering biogas[^23] and [natural gas ](#user-content-fn-24)[^24]consumption.
* $$EF\_{NG}$$ represents the emission factor of natural gas, in kgCO$$\_2$$eq/MJ. Refer to Appendix 2 for the ecoinvent process used.

$$\textbf{(Eq.32)}\ E\_{bio} = \sum Gas\_{delivered\ MJ}\*{Gas}*{i.%\ grid}/{LHV}*{i}\*E{F\ bio}\_{i}$$

where,

* $$E\_{bio}$$ represents the sum of GHG emissions due to biogas and biomethane production according to the market shares, in kgCO$$\_2$$eq.
* $$Gas\_{delivered\ MJ}$$ is calculated in Equation 30
* $${Gas}\_{i.\ %\ grid}$$ represents the fraction of biogas type *i* (biogas and biomethane) in the grid.
* $${LHV}\_{i}$$ represents the lower heating value used to convert MJ to m³ of biogas type $$i$$ (biogas and biomethane), presented in Table 5 in the Assumptions section.
* $$EF\_{bio\ i}$$ represents the emission factor of biogas type *i*, in kgCO$$\_2$$eq/m³.

$$\textbf{(Eq.33)}\ Total\ E\_{Energy\ Production} = E\_{NG} + E\_{bio}$$

where,

* $${Total\ E}\_{Energy\ Production}$$ represents the sum of GHG emissions due to gas production and use in the baseline scenario, in kgCO$$\_2$$eq.

</details>

### Manure and slurry storage and spreading <a href="#hb2ey9fna52s" id="hb2ey9fna52s"></a>

This stage shall only be included in the baseline scenario if the biogas project uses manure or slurry as a feedstock input.

This stage includes N2O and methane emissions from manure/slurry storage and spreading, and GHG emissions from transport.

Project Developers shall provide the amount of manure and/or slurry used as feedstock inputs annually, in tonnes of fresh matter.

Project Developers shall specify if manure is from poultry vs any other type of animal. Manure from pigs, horses, sheep, and other animals are modeled using the same characteristics as cow manure, as described in the Assumptions section. Because poultry slurry is uncommon, all slurry is modeled as cow slurry.

Nitrogen content, N2O emission factors, and methane emission rates from storage and spreading for manure and slurry are summarized in Table 3.

<details>

<summary><strong>Calculations - Manure and slurry storage and spreading</strong></summary>

This step calculates the GHG emissions from the baseline Manure and Slurry Storage life cycle stage ($$Total E\_{M S}$$).

$$\textbf{(Eq.34)}\ E\_{B.\ transport}\ = \ \sum(M\_{i} + S*D\_{i})*\ EF\_{truck\ transport}$$

where,

* $$E\_{\ B.\ transport}$$ represents the sum of GHG emissions from transporting manure and slurry from the location they are stored to where they are spread, in kgCO$$\_2$$eq.
* $$M\_{i}$$ represents the amount of manure of type *i* (chicken or cow) used as feedstock in the project scenario, in tonnes of fresh matter.
* $$\ S$$ represents the amount of slurry used as feedstock in the project scenario, in tonnes of fresh matter.
* $$D\_{i}$$ represents the distance of manure/slurry transport for spreading, in kilometers. This is assumed to be 10 km, see the Assumtions section.
* $$\ EF\_{truck\ transport}$$ represents the emission factor of truck transport in kgCO$$\_2$$eq/t.km. Refer to Appendix 1 for the ecoinvent process used.

GHG emissions due to direct N$$*2$$O **emissions from manure storage follow the same calculation presented in Equation 3**, using a $$Days\ stored$$ parameter value of $$180$$. This shall be calculated as a parameter called $$E*{B\ N\_2O\ M.\ storage}$$. GHG emissions due to direct CH$\_4$ emissions from manure and slurry storage follow the same calculation presented in Equation 4, using a days stored parameter value of $$180$$. This shall be calculated as a parameter called $$E\_{B\ CH\_4\ storage}$$.

$$\textbf{(Eq.35)}\ E\_{\ N2O\ M.\ spreading} = \sum M\_{i}\*\ R\_{N2O\ spreading}\ \*{GWP}\_{N2O}$$

where,

* $$E\_{\ N2O\ M.\ spreading}$$ represents the sum of GHG emissions resulting from N$$\_2$$O being directly emitted into the air due to the spreading of manure, in kgCO$$\_2$$eq.
* $$M\_{i}$$ is described in Equation 34.
* $$R\_{N2O\ spreading}$$ represents the rate of N$$\_2$$O released from manure spreading, and equals 0.177 kg N$$\_2$$O/tonne of manure spread, regardless of manure type (Table 3).
* $${GWP}\_{N2O}$$ is described in Equation 3.

$$\textbf{(Eq.36)}\ E\_{N2O\ S.\ \ storage}\ = S\*\ S\_{%\DM}\*S\_{% DM\ as\ \ N}\ \*S\_{% N\ as\ \ N2O}*N\_{to\ N2O}*{GWP}\_{N2O}$$

where,

* $$E\_{N2O\ S.\ \ storage}$$ represents the sum of GHG emissions resulting from N$$\_2$$O being directly emitted into the air due to the storage of slurry, in kgCO$$\_2$$eq.
* $$S$$ is described in Equation 34.
* $$S\_{%\ DM}$$ represents the dry matter content of slurry, which is 4.27% (Table 3).
* $$S\_{%\ DM\ as\ N}$$ represents the percentage of dry matter as nitrogen in slurry, which is 7.11% (Table 3).
* $$S\_{% N\ as\ \ N2O}$$ represents the percentage of nitrogen lost as N$$\_2$$O during storage of slurry, which is 0.0008% (Table 3).
* $$N\_{to\ N2O}$$ and $${GWP}\_{N2O}$$ are explained in Equation 3.

$$\textbf{(Eq.37)}\ E\_{\ N2O\ S.\ \ spreading}\ = S\*\ S\_{%\ N2O\ spreading}\*{GWP}\_{N2O}$$

where,

* $$E\_{\ N2O\ S.\ \ spreading}$$ represents the sum of GHG emissions resulting from N$$\_2$$O being directly emitted into the air due to the spreading of slurry, in kgCO$$\_2$$eq.
* $$S$$ is described in Equation 34.
* $$S\_{%\ N2O\ spreading}$$ represents the rate of N$$\_2$$O released from slurry spreading, and equals 0.057 kg N$$\_2$$O/tonne of manure spread (Table 3).
* $${GWP}\_{N2O}$$ is described in Equation 3.

$$\begin{aligned}\textbf{(Eq.38)}\ {Total\ E}*{MS} =\ \&E*{B.\ transport} + E\_{B\ N2O\ M.\ storage}\\+\ \&E\_{B\ CH4\ storage} + E\_{N2O\ M.\ spreading}\\+\ \&E\_{N2O\ S.\ storage} + E\_{N2O\ S.\ spreading}\end{aligned}$$

where,

* $${Total\ E}\_{MS}$$ represents the sum of GHG emissions due to manure and slurry transport, storage, and spreading in the baseline scenario.

</details>

### Baseline avoided fertilizer <a href="#id-7tp9zig2mswv" id="id-7tp9zig2mswv"></a>

This stage shall only be included in the baseline scenario if the biogas project uses manure or slurry as a feedstock input.

This stage is included to ensure that both the impacts and benefits of manure and slurry management are accounted for in the baseline scenario. It **conservatively accounts for the tradeoff between diverting manure and slurry from use as organic soil amendments to biogas production**. This [diversion is modeled as avoided synthetic mineral fertilizer production and use](#user-content-fn-4)[^4], due to manure and slurry being used as organic soil amendments.

Similar to the Project avoided fertilizer section, it is assumed that nutrient availability is the same between manure/slurry and mineral fertilizer. For example, 1 kg of P2O5 from manure is modeled as substituting the production of 1 kg of P2O5 mineral fertilizer production.

Avoided N2O emissions are the same as in the [Project avoided fertilizer section](#ea2yoslt0lu9).

Project Developers shall provide the amounts of manure and slurry used as feedstock inputs, and values from the literature shall be used for converting to amounts of synthetic fertilizer avoided (Table 7).

*Table 7 Rates of avoided synthetic fertilizer production and use, from manure and slurry use as organic soil amendments in the baseline scenario (*[*Esnouf et al., 2021, Tables 35 and 38*](#user-content-fn-4)[^4]*).*

| Avoided fertilizer type | Manure (kg/tonne manure) | Slurry (kg/tonne slurry) |
| ----------------------- | ------------------------ | ------------------------ |
| Nitrogen (N)            | 2.19                     | 1.67                     |
| Potassium (K2O)         | 12.7                     | 2.05                     |
| Phosphorus (P2O5)       | 2.75                     | 1.59                     |

<details>

<summary><strong>Calculations - Baseline avoided Fertilizer</strong></summary>

This step calculates the GHG emissions from the baseline scenario’s avoided fertilizer production and use ($$Total E\_{B.avoided\ fertilizer}$$).

$$\textbf{(Eq.39)}\ E\_{B.\ NPK\ avoided} = - \sum\_{i}^{}\sum\_{j}^{}\ (F\_{i}\*{RR}*{i.\ j}\ \*EF*{j\ fertilizer})$$

where,

* $$E\_{B.\ avoided\ NPK}$$ represents the sum of emissions avoided due to the use of manure or slurry as a fertilizer, in kgCO$$\_2$$eq. $$B$$ denotes the baseline scenario, to differentiate between the same variable calculated in the project scenario.
* $$F\_{i}$$ represents the amount of feedstock (manure or slurry) in tonnes of fresh matter.
* $${RR}\_{i.\ j}$$ represents the replacement rate of nutrient 𝑗 (N, K2O, and P2O5) from each feedstock type *i,* in kg nutrient/tonne of feedstock.
* $$EF\_{j\ fertilizer}$$ is described in Equation 27.

$$(Eq.\ 40)\ E\_{B.N2O\ avoided} =- \sum F\_{i}\*{RR}*{i,\ N}\*ER*{N\ as\ N2O}*N\_{to\ N2O}*{GWP}\_{N2O}$$

where,

* $${\ E}\_{B.N2O\ avoided}$$ represents the sum of GHG emissions avoided due to the substitution of mineral fertilizer use, and subsequent N$$\_2$$O emissions, by manure and/or slurry spreading, in kgCO$$\_2$$eq. $$B$$ denotes the baseline scenario, to differentiate between the same variable calculated in the project scenario.
* $$F\_{i.}$$ is described in Equation 39.
* $${RR}\_{i,\ N}$$ represents the replacement rate of N fertilizer in kg per tonne of feedstock type *i* (Table 7).
* $$ER\_{N\ as\ N2O}$$ represents the rate of applied nitrogen emitted as N$$\_2$$O, which equals 1%.
* $$N\_{to\ N2O}$$ and $${GWP}\_{N2O}$$ are explained in Equation 3.

$$textbf{(Eq.41)}\ Total\ E\_{B.avoided\ fertilizer} = \ \ {\ E}*{B.\ NPK\ avoided} + E*{B.N2O\ avoided}$$

where,

* $${Total\ E}\_{B.avoided\ fertilizer}$$ represents the sum of fertilizer GHG emissions avoided due to the use of manure and/or slurry as an organic amendment, in kgCO$$\_2$$eq.

</details>

## Avoided GHG emissions <a href="#tzch6efwpcl5" id="tzch6efwpcl5"></a>

Avoided GHG emissions are calculated by subtracting the sum of the project scenario GHG emissions from the sum of the baseline GHG scenario emissions.

<details>

<summary><strong>Comparative GHG assessment calculation</strong></summary>

The total baseline GHG emissions, total project GHG emissions, and the project's avoided emissions are calculated as follows.

$$\begin{aligned}\textbf{(Eq.42)}\ E\_{Project} =\ &{Total\ E}*{feedstock} + {Total\ E}*{digestion}\ + &{Total\ E}*{digestate} + {Total\ E}*{P.avoided\ fertilizer}\end{aligned}$$

$$\textbf{(Eq.43)}\ E\_{baseline} = {Total\ E}*{energy\ production} + {Total\ E}*{MS} + {Total\ E}\_{B.avoided\ fertilizer}$$

$$\textbf{(Eq.44)}\ E\_{avoided}\ = \ E\_{baseline}\ - \ E\_{project}$$

</details>

## Uncertainty assessment <a href="#pd871xwykcd1" id="pd871xwykcd1"></a>

See general instructions for uncertainty assessment in the [Rainbow Standard Rules](broken://pages/dvlxlSmHdCnP6F88tvDZ#uncertainty-assessment). The outcome of the assessment shall be used to determine the percent of avoided emissions to eliminate with the [**discount factor**](#user-content-fn-26)[^26].

The [assumptions ](#dy4zenx6oxaa)that are estimated to have **high uncertainty** (i.e. high variability and high impact) are:

* The amount of digestate produced is estimated from 85-95% of feedstock input weight. A conservative assumption of 85% was taken.
* Digestate stored in a covered area with gas recovery has 20% of gasses leaked

The [assumptions ](#dy4zenx6oxaa)that are estimated to have **moderate uncertainty** are:

* Nutrient availability in digestate is equivalent to that of mineral fertilizer

The [assumptions ](#dy4zenx6oxaa)that are estimated to have **low uncertainty** are:

* Waste feedstock inputs come with no production impacts.
* The distance for waste feedstock collection of manure and/or slurry in the baseline scenario is assumed to be 10 km).
* In case Project Developers do not have an estimation of days manure is stored onsite, an average of 15 days is considered. In the baseline scenario, this is assumed to be 180 days.
* N2O emissions from slurry storage are generally small and, therefore, excluded from the project scenario’s GHG assessment.
* Manure and slurry from pigs, horses, sheep, and other animals are modeled considering the same characteristics as cow manure.
* In the project scenario, buildings and main infrastructure have a lifetime of 20 years and overall infrastructure impact based on the external volume of the main digester, leading to grouping infrastructure equipment and network into the same category rather than assessing specific equipment's impacts.
* Activated carbon used by the project is accounted for in a ratio of 0.2 t/GWh of energy produced .
* The amount of biogas self-consumed is assumed to be 4%

The baseline scenario selection has low uncertainty and is mostly standardized. It accounts for project-specific information regarding the amount of biomethane injected into the gas grid, type of feedstock, quality of digestate, and national gas market share statistics.

Numerous equations and models are used in this methodology and have low uncertainty:

* Most are basic conversions that have been taken from the scientific literature, especially [Esnouf et al., 2021](#user-content-fn-4)[^4], which is a rigorous, detailed LCA of biomethane production that underwent critical review and was published by INRAE Transfert, a subsidiary of the French National Institute for Research in Agronomics.
* The linear regression model from [Hartig 2010](#user-content-fn-20)[^20] has moderate uncertainty
  1. Estimates and secondary data used in this methodology have varying levels of uncertainty and are assessed in Table 8.
  2. The uncertainty at the methodology level is estimated to be low. This translates to an **expected discount factor of at least 3%** for projects under this methodology.

*Table 8 Presentation of all secondary data and estimates used, and an assessment of their uncertainty.*

<table data-full-width="true"><thead><tr><th width="240">Parameter</th><th width="205">Reference in document</th><th>Uncertainty assessment</th></tr></thead><tbody><tr><td>Chicken manure fresh matter as nitrogen (%)</td><td>Table 3</td><td>The rate of fresh matter as nitrogen contained in chicken manure was taken from a study conducted in 2015. There is low uncertainty in this data sample since chicken feed patterns are assumed to not have significantly changed.</td></tr><tr><td>Cow manure and slurry dry matter and nitrogen content</td><td>Table 3</td><td>These values come from<a data-footnote-ref href="#user-content-fn-4"> Esnouf et al., 2021,</a> Table 18. Their source was internal expertise and databases from the French National Institute for Research in Agronomics (<em>INRAE</em>), which is expected to have high quality data for these values that are relatively simple to measure. That study underwent critical review. Uncertainty is low.</td></tr><tr><td>Nitrogen lost as N2O during manure and slurry storage (%)</td><td>Table 3, Table 6</td><td>These values come from <a data-footnote-ref href="#user-content-fn-4">Esnouf et al., 2021</a>, Table 34 and 37. Their source was <a data-footnote-ref href="#user-content-fn-27">INRAE 2013</a>. These are estimated to be reputable scientific sources, but due to the sensitivity of this value, it is estimated to have moderate uncertainty.</td></tr><tr><td>Rate of N2O released from manure and slurry spreading (kgN2O/t of manure)</td><td>Table 3</td><td>These values come from<a data-footnote-ref href="#user-content-fn-4"> Esnouf et al., 2021</a>, Tables 35 and 38 and were calculated in the study. This is estimated to be a reputable scientific source, but due to the sensitivity of this value, it is estimated to have moderate uncertainty.</td></tr><tr><td>Nitrogen lost as N2O during digestate, storage (%)</td><td>Table 6</td><td>These values come from<a data-footnote-ref href="#user-content-fn-4"> Esnouf et al., 2021</a>, Table 18. Their source was <a data-footnote-ref href="#user-content-fn-27">INRAE 2013</a>. These are estimated to be reputable scientific sources, but due to the sensitivity of this value, it is estimated to have moderate uncertainty.</td></tr><tr><td>Nitrogen lost as N2O during digestate, spreading (%)</td><td>Table 6</td><td>This value comes from the <a data-footnote-ref href="#user-content-fn-22">IPCC Guidelines for National Greenhouse Gas Inventories</a>. Although it is a reputable source, the value taken is a highly generalized global average and actually depends on soil and climatic factors. It is estimated to have moderate uncertainty.</td></tr><tr><td>Lower heating value of biogas and biomethane (MJ/m³)</td><td>Table 5</td><td>These characteristics come from the ecoinvent database and International Energy Agency, both of which are reliable sources. Biomethane LHV has low uncertainty since it is a consistent value, but biogas LHV has high uncertainty since the gas content, and therefore energy content, of biogas is variable.</td></tr><tr><td>Density (kg/m³)</td><td>Equation 4, 12 and 22</td><td>Methane density was obtained from a textbook on anaerobic digestion, and has low uncertainty.</td></tr><tr><td>Methane content (% volume)</td><td>Table 5</td><td>Methane percentages in biogas and biomethane were taken from the European Biogas Association. Biomethane has low uncertainty since it is a consistent value, but biogas has high uncertainty since its composition is variable.</td></tr><tr><td>Biomethane combustion N2O and CH4 emission rates</td><td><a href="#id-6oxm2svxe98p">Digestion and biomethane management</a></td><td>These values come from <a data-footnote-ref href="#user-content-fn-4">Esnouf et al., 2021</a>, Table 53, and results are not sensitive to them. They are estimated to have low uncertainties.</td></tr><tr><td>Leakage rates in the digestion, purification, boiler, injection and distribution process (%)</td><td>Table 4</td><td>These values come from <a data-footnote-ref href="#user-content-fn-4">Esnouf et al., 2021.</a> There is high uncertainty in this data sample. Even though the study is recent and uses reliable data, leakages depend on project-specific factors such as the site design and age. Projects certified under Rainbow's biogas methodology are considerably new (built after 2018), which justifies adopting the values for recently built sites from the data sample.</td></tr><tr><td>Manure and slurry avoided fertilizer (kg/tonne)</td><td>Table 7</td><td>The amount of N, K2O, and P2O5 avoided fertilizer per tonne of manure and slurry used in the baseline scenario was taken from the <a data-footnote-ref href="#user-content-fn-4">Esnouf et al., 2021</a>, Tables 35 and 38. There is low uncertainty in these data samples.</td></tr><tr><td>Baseline grid gas mix</td><td>Baseline <a href="#wuq5tihnlrk7">Energy production</a></td><td>In the baseline scenario, the mix of gasses for energy production is taken from national gas grid market shares from the Eurostat database. These data are estimated to have moderate uncertainty, because the most recent data available are from 2022, and because of inherent uncertainty and compatibility issues inherent in such macro, national data.</td></tr></tbody></table>

[^1]: ISO 14064-2:2019. Greenhouse gases — Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements.

[^2]: Wernet, G., Bauer, C., Steubing, B., Reinhard, J., Moreno-Ruiz, E., Weidema, B., 2016. The ecoinvent database version 3 (part I): overview and methodology. Int J Life Cycle Assess 21, 1218–1230. <https://doi.org/10.1007/s11367-016-1087-8>

[^3]: Kamilaris, A., Prenafeta-Boldú, F.X., 2021. Examining the perspectives of using manure from livestock farms as fertilizer to crop fields based on a realistic simulation. Computers and Electronics in Agriculture 191, 106486.[ https://doi.org/10.1016/j.compag.2021.106486](https://doi.org/10.1016/j.compag.2021.106486)

[^4]: Esnouf A., Brockmann D., Cresson R. (2021) Analyse du cycle de vie du biométhane issu de ressources agricoles - Rapport d’ACV. INRAE Transfert, 170pp.

[^5]: Lamolinara, B., Pérez-Martínez, A., Guardado-Yordi, E., Guillén Fiallos, C., Diéguez-Santana, K., Ruiz-Mercado, G.J., 2022. Anaerobic digestate management, environmental impacts, and techno-economic challenges. Waste Management 140, 14–30.[ https://doi.org/10.1016/j.wasman.2021.12.035](https://doi.org/10.1016/j.wasman.2021.12.035)

[^6]: Vargas-Gonzalez, M., Verzat, B., Carlu, E., Graveaud, F., 2015. Résumé de l’étude sur l’évaluation des impacts GES de l’injection du biométhane dans les réseaux de gaz naturel. Rapport Final. Quantis, ENEA Consulting, GnRF

[^7]: Gangagni Rao Anupoju, Ahuja, S., Bharath Gandu, Sandhya K, Kranti Kuruti and Venkata Swamy Yerramsetti (2015). Biogas from Poultry Litter: A Review on Recent Technological Advancements. Springer eBooks, pp.133–147. doi:<https://doi.org/10.1007/978-3-319-17915-5\\_8>.

[^8]: Methasim project data 2021 <https://ifip.asso.fr/base-de-donnees-methasim/>

[^9]: * Lallement, A., Peyrelasse, C., Lagnet, C., Barakat, A., Schraauwers, B., Maunas, S., Monlau, F., 2023. A Detailed Database of the Chemical Properties and Methane Potential of Biomasses Covering a Large Range of Common Agricultural Biogas Plant Feedstocks. Waste 1, 195–227. <https://doi.org/10.3390/waste1010014>
    * International Energy Agency, 2020. Average biogas production yield by tonne of feedstock type – Charts – Data & Statistics \[WWW Document]. IEA. [URL ](https://www.iea.org/data-and-statistics/charts/average-biogas-production-yield-by-tonne-of-feedstock-type)(accessed 5.22.24).

[^10]: Holliger, C., Fruteau de Laclos, H., Hack, G., 2017. Methane Production of Full-Scale Anaerobic Digestion Plants Calculated from Substrate’s Biomethane Potentials Compares Well with the One Measured On-Site. Front. Energy Res. 5.[ https://doi.org/10.3389/fenrg.2017.00012](https://doi.org/10.3389/fenrg.2017.00012)

[^11]: Intergovernmental Panel on Climate Change 2021. Chapter 7: The Earth’s Energy Budget, Climate Feedbacks, and Climate Sensitivity. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, doi:10.1017/9781009157896.009

[^12]: Teferra, D.M., Wubu, W., Teferra, D.M., Wubu, W., 2018. Biogas for Clean Energy, in: Anaerobic Digestion. IntechOpen.[ https://doi.org/10.5772/intechopen.79534](https://doi.org/10.5772/intechopen.79534)

    \\

[^13]: Intergovernmental Panel on Climate Change 2021. Chapter 7: The Earth’s Energy Budget, Climate Feedbacks, and Climate Sensitivity. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, doi:10.1017/9781009157896.009.

[^14]: Kolb, S., Plankenbühler, T., Hofmann, K., Bergerson, J., Karl, J., 2021. Life cycle greenhouse gas emissions of renewable gas technologies: A comparative review. Renewable and Sustainable Energy Reviews 146, 111147.[ https://doi.org/10.1016/j.rser.2021.111147](https://doi.org/10.1016/j.rser.2021.111147)

[^15]: from ecoinvent 3.10 database "market for biogas - RoW"

[^16]: International Energy Agency, 2020. An introduction to biogas and biomethane – Outlook for biogas and biomethane: Prospects for organic growth – Analysis \[WWW Document]. IEA. URL[ https://www.iea.org/reports/outlook-for-biogas-and-biomethane-prospects-for-organic-growth/an-introduction-to-biogas-and-biomethane](https://www.iea.org/reports/outlook-for-biogas-and-biomethane-prospects-for-organic-growth/an-introduction-to-biogas-and-biomethane) (accessed May 2024).

[^17]: Teferra, D.M., Wubu, W., Teferra, D.M., Wubu, W., 2018. Biogas for Clean Energy, in: Anaerobic Digestion. IntechOpen.[ https://doi.org/10.5772/intechopen.79534](https://doi.org/10.5772/intechopen.79534)

[^18]: EBA’s BIOMETHANE fact sheet. (2013). Available at: <https://www.europeanbiogas.eu/wp-content/uploads/files/2013/10/eba_biomethane_factsheet.pdf>. Accessed May 2024.

[^19]: * Hijazi, O., Munro, S., Zerhusen, B., Effenberger, M., 2016. Review of life cycle assessment for biogas production in Europe. Renewable and Sustainable Energy Reviews 54, 1291–1300.[ https://doi.org/10.1016/j.rser.2015.10.013](https://doi.org/10.1016/j.rser.2015.10.013)
    * Singlitico, A., Goggins, J., Monaghan, R.F.D., 2019. The role of life cycle assessment in the sustainable transition to a decarbonised gas network through green gas production. Renewable and Sustainable Energy Reviews 99, 16–28.[ https://doi.org/10.1016/j.rser.2018.09.040](https://doi.org/10.1016/j.rser.2018.09.040)

[^20]: Hartig, S., 2010. Guide sur le biogaz: De la production à l‘utilisation (No. 5e édition). Fachagentur Nachwachsende Rohstoffe e. V. (FNR), Centre de compétence Développement des ressources humaines (DRH) – Programmes Méditerrane & Moyent-Orient (division 33A0).

[^21]: IPCC, 2019. Chapter 11: N2O Emissions from Managed Soils, and CO2 Emissions from Lime and Urea Application, in: 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories Volume 4 Agriculture, Forestry and Other Land Use. [Table 11.1](https://www.ipcc-nggip.iges.or.jp/public/2019rf/pdf/4_Volume4/19R_V4_Ch11_Soils_N2O_CO2.pdf).

[^22]: [IPCC. 2019.](https://www.ipcc-nggip.iges.or.jp/public/2019rf/pdf/4_Volume4/19R_V4_Ch11_Soils_N2O_CO2.pdf) IPCC 2019, 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, eds. E. Calvo Buendia, K. Tanabe, A. Kranjc, J. Baasansuren, M. Fukuda, S. Ngarize, A. Osako, Y. Pyrozhenko, P. Shermanau, S. Federici. Switzerland: IPCC.

[^23]: [Eurostat, 2024. Supply, transformation and consumption of renewables and wastes \[dataset\]](https://ec.europa.eu/eurostat/databrowser/view/NRG_CB_RW__custom_7083896/default/table?lang=en). Online data code: nrg\_cb\_rw.

[^24]: [Eurostat, 2024. Supply, transformation and consumption of gas \[dataset\]](https://ec.europa.eu/eurostat/databrowser/view/NRG_CB_GAS__custom_7082962/default/table?lang=en). Online data code: nrg\_cb\_gas.

[^25]: [European Commission, 2021. Biomethane Fiche– France](https://energy.ec.europa.eu/system/files/2023-09/Biomethane_fiche_FR_web.pdf)

[^26]: A percentage of verified Rainbow Carbon Credits eliminated from each project and never issued. This acts as a safeguard against uncertainty in GHG reduction quantifications and overestimated carbon removal/avoidance.

[^27]: INRAE. (2013). Action. 9 Développer la méthanisation, et installer des torchères, pour réduire les émissions de CH4 liées au stockage des effluents d’élevage. 382–403.


# Monitoring plan

Monitoring Plans for this methodology shall include at a minimum, but are not limited to, tracking of the following information:

* amount of biomethane injected into the grid
* mass and waste status of each feedstock input in tonnes of fresh matter (ensuring the dedicated crop and ILUC risk thresholds are not surpassed, see Environmental and Social Do No Harm and Leakage)
* repartition of solid, liquid and raw digestate
* amount and type of electricity use on-site
* description of any major changes in operations

The Project Developer is the party responsible for adhering to the Monitoring Plan.


# Circularity Assessment

Projects **that reduce GHG emissions and are issued Rainbow Carbon Credits typically also contribute to a circular economy.** The assessment of a project's circularity is **considered under the co-benefits criteria** and represents the Sustainable Development Goal (SDG) number 12.2.

The **Material Circularity Indicator (MCI)** is the selected measure of circularity, due to its comprehensive assessment of material flows and alignment with global standards, notably established by The Ellen MacArthur Foundation.

The MCI examines the mass of material flows throughout a product's lifecycle. It evaluates how efficiently materials circulate within a closed-loop system, assigning “more circular” scores to systems that minimize waste and optimize resource reuse. The formula uses input parameters such as material feedstock amount and type (e.g. from recycled, reused, or biological sources), recycling rates, and lifespan extension potential to quantify a product's circularity.

A detailed description and formulas for calculating the MCI are documented in the dedicated [methodology document](#user-content-fn-1)[^1], on pages 22 to 31 (following the Product-level Methodology under the Whole product approach). Figure 3 summarizes the MCI material flows for biogas and natural gas production.

The MCI is a unitless indicator that varies from 0 to 1, where 0 represents a fully linear product and 1 is fully circular. The project scenario MCI is compared to the baseline scenario MCI, **measuring how much more circular the project scenario is than the baseline**.

The MCI methodology has been applied to biogas production using the input data presented in Table 9.

<figure><img src="/files/D1j2q2IQdR0k8593LGmf" alt=""><figcaption></figcaption></figure>

*Figure 3* *Summarized representation of the MCI material flows. \*Energy recovery as part of a circular strategy only applies to biological materials following the MCI's conditions.*

*Table 9 All variables needed to calculate the Material Circularity Indicator (MCI) for the Rainbow Biogas from anaerobic digestion methodology are detailed below. The full methodology and equations can be found in the dedicated* [*methodology document*](#user-content-fn-1)[^1]*.*

<table data-full-width="true"><thead><tr><th width="111">Symbol</th><th width="240">Definition by the MCI</th><th width="411">Guidelines for the project scenario</th><th>Guidelines for the baseline scenario</th></tr></thead><tbody><tr><td>M</td><td>Mass of a product</td><td><p>Total mass (kg) of gas produced, calculated based on the GWh of energy input into the gas grid in the project scenario according to:</p><p>where,</p><ul><li>represents the mass of gas produced in one year, calculated based on the number of Functional Units produced (GWh) in the base year and the gas' LHV in kWh/m³.</li><li>represents the amount of GWh injected into the grid, from the gas grid injection receipts.</li><li>represents the gas calorific value, in kWh/m³. This is assumed to be 10, converted from Table 5.</li><li>represents the biomethane density, in kg/m³, which is assumed 0.75 kg/m³.</li></ul><p>In the project scenario, the digestate produced shall also be considered in the final product weight as it has economic value. Thus,</p><p>where,</p><ul><li>represents the product's final mass in the project scenario, calculated based on M and the amount of fertilizer thanks to the use of digestate.</li><li>represents the amount of digestate produced. This is calculated according to the amount of feedstock input, according to Eq.2, in kg (without considering the transport emission factor).</li></ul></td><td></td></tr><tr><td>Fr</td><td>Fraction of mass of a product's feedstock from recycled sources</td><td>Assumed zero</td><td></td></tr><tr><td>Fu</td><td>Fraction of mass of a product's feedstock from reused sources</td><td>Assumed zero</td><td></td></tr><tr><td>Fs</td><td>Fraction of a product's biological feedstock from Sustained production.</td><td>In the project scenario, feedstock is of biological origin except dedicated crops. According to Rainbow's biogas methodology section 2.4, projects must adhere to specific limitations when using dedicated crops as feedstock. Consequently, dedicated crops are deemed "virgin" to not benefit from biological feedstock circularity.</td><td>The market gas mix is composed of natural gas, biomethane, and biogas. It is assumed that biological feedstock is used in biogas and biomethane, but not in natural gas production. Thus, Fs in the baseline scenario is the sum of the fraction of biogas and biomethane in the grid.</td></tr><tr><td>V</td><td>Material that is not from reuse, recycling or biological material from sustained production.</td><td>The amount of virgin materials used in the project scenario is the equivalent of dedicated crops used.</td><td>All the input materials, except the fraction related to biogas/biomethane described above, are considered virgin as no reuse, recycled, or biological materials are assumed in a status quo scenario.</td></tr><tr><td>Cr</td><td>Fraction of mass of a product being collected to go into a recycling process</td><td>Assumed zero because after the gas and digestate use, no product is left for recycling.</td><td></td></tr><tr><td>Cu</td><td>Fraction of mass of a product going into component reuse</td><td>Assumed zero as, after the gas use, no product is left for reuse except digestate in the project scenario (which is considered in the composting process below).</td><td></td></tr><tr><td>Cc</td><td>Fraction of mass of a product being collected to go into a composting process</td><td><p>This fraction represents the amount of digestate relative to the total mass of the final product</p><p>().</p></td><td>Although the fraction of biogas and biomethane in the baseline scenario generate digestate, the amount would be very small, and does not have a significant impact on the MCI. Thus, it is excluded from the calculation.</td></tr><tr><td>Ce</td><td>Fraction of mass of a product being collected for energy recovery where the material satisfies the requirements for inclusion</td><td>This fraction represents the amount of biomethane relative to the total mass of the final products ().</td><td>Energy recovery as part of a circular strategy only applies to biological materials, according to the MCI methodology. This value is assumed to be zero for natural gas. Thus, the final value considered is the sum of the fraction of biogas and biomethane in the grid.</td></tr><tr><td>Wo</td><td>Mass of unrecoverable waste through a product's material going into landfill, waste to energy and any other type of process where the materials are no longer recoverable</td><td>Following the MCI calculation methodology, this value is zero as all final product mass can be recovered.</td><td>Following the MCI calculation methodology, this value is equal to the mass of the final product (M) minus the fraction of biogas and biomethane in the grid.</td></tr><tr><td>Ec</td><td>Efficiency of the recycling process used for the portion of a product collected for recycling</td><td>Not considered as no recycled material is used.</td><td></td></tr><tr><td>Wc</td><td>Mass of unrecoverable waste generated in the process of recycling parts of a product</td><td>Not considered as no recycled material is used.</td><td></td></tr><tr><td>Ef</td><td>Efficiency of the recycling process used to produce recycled feedstock for a product</td><td>Not considered as no recycled material is used.</td><td></td></tr><tr><td>Wf</td><td>Mass of unrecoverable waste generated when producing recycled feedstock for a product</td><td>Not considered as no recycled material is used.</td><td></td></tr><tr><td>W</td><td>Mass of unrecoverable waste associated with a product</td><td>Following the MCI calculation methodology, this value is zero as all the final product mass can be recovered.</td><td>Following the MCI calculation methodology, this value is equal to the mass of the final product (M) minus the fraction of biogas/biomethane.</td></tr><tr><td>LFI</td><td>Linear flow index (LFI)</td><td>Varies from 0 to 1, where 1 is a completely linear flow and 0 is a completely restorative flow. In a circular project, the LFI shall be closer to zero, while the baseline shall be closer to 1.</td><td></td></tr><tr><td>L</td><td>Actual average lifetime of a product</td><td>Biomethane shall have similar properties to natural gas to be injected into the gas grid. It is assumed that the actual average lifetime of the product in both scenarios is equivalent, and therefore doesn’t affect the comparative calculations. It is assumed to be 1.</td><td></td></tr><tr><td>Lav</td><td>Average lifetime of an industry-average product of the same type</td><td></td><td></td></tr><tr><td>U</td><td>Actual average number of <a data-footnote-ref href="#user-content-fn-2">functional units</a> achieved during the use phase of a product</td><td>Biomethane shall have similar properties to natural gas to be injected into the gas grid. It is assumed that the actuarial average number of functional units of the product in both scenarios is equivalent, and therefore doesn’t affect the comparative calculations. It is assumed to be 1.</td><td></td></tr><tr><td>Uav</td><td>Average number of functional units achieved during the use phase of an industry-average product of the same type</td><td></td><td></td></tr><tr><td>X</td><td>Utility of a product (function of the product's lifespan and intensity of use)</td><td>Following the MCI methodology calculation, this is equal to 1.</td><td></td></tr><tr><td>MCIp</td><td>Material Circularity Indicator of a product</td><td>Varies from 0 to 1, where 0 represents a fully linear product and 1 is fully circular.</td><td></td></tr></tbody></table>

[^1]: Goddin, J., Marshall, K., Pereira, A., Tuppen, C., Herrmann, S., Jones, S., Krieger, T., Lenges, C., Coleman, B., Pierce, C., Iliefski-Janols, S., Veenendaal, R., Stoltz, P., Ford, L., Goodman, T., Vetere, M., Mistry, M., Graichen, F., Natarajan, A., Sullens, W., 2019. Circularity Indicators: An Approach to Measuring Circularity, Methodology. <https://doi.org/10.13140/RG.2.2.29213.84962>

[^2]: Represent the function of a product's use


# Version history

<table data-full-width="true"><thead><tr><th width="399">Description of the change</th><th width="292">Justification</th><th width="157">Date</th><th>Version changed to</th></tr></thead><tbody><tr><td>Remove biogas torching parameter</td><td>Below impact threshold</td><td>May 2023</td><td>V1.1</td></tr><tr><td>Define gas self consumption rate of 4%</td><td>GHG results not sensitive, simplify data collection</td><td>May 2023</td><td>V1.1</td></tr><tr><td>Set digestate produced to 85% of the sum of feedstock input fresh mass</td><td>Precise values rarely available</td><td>May 2023</td><td>V1.1</td></tr><tr><td>Add possibility to have digestate separated during storage, and during spreading</td><td>Improved accuracy</td><td>June 2023</td><td>V1.1</td></tr><tr><td>Specify amounts and nutrient content of different phases of digestate (raw, liquid, solid)</td><td>Improved accuracy</td><td>June 2023</td><td>V1.1</td></tr><tr><td>Remove transport of manure and slurry in baseline and project scenario</td><td>Assumed to be the same in both scenarios, no effect in a comparative LCA</td><td>June 2023</td><td>V1.1</td></tr><tr><td>Add options for digestate transport via irrigation pipes or truck transport</td><td>Improved accuracy, more relevant options for Project Developers</td><td>June 2023</td><td>V1.1</td></tr><tr><td>Calculate digestate storage methane emission rate based on residence time in digester, rather than fixed rate of 2% of biogas produced</td><td>Improved accuracy</td><td>July 2023</td><td>V2.1</td></tr><tr><td>Updated parameter on amount of methane leaked during purification</td><td>Error in units conversion</td><td>September 2023</td><td>V2.2</td></tr><tr><td>Add possibility for projects to provide their own data on methane leakage rates during purification, instead of standard leakage rate of 0.7% of biogas leaked</td><td>Improved accuracy, increased use of project specific data</td><td>October 2023</td><td>V2.2</td></tr><tr><td>New section Monitoring Plan</td><td>Alignment with Standard Rules V6</td><td>March 2024</td><td>V2.3</td></tr><tr><td>Add share of biogas in the grid to the baseline scenario</td><td>Alignment with Rainbow Standard Rules V6 and increase conservativeness.</td><td>March 2024</td><td>V2.3</td></tr><tr><td>Added equations for calculation GHG reductions</td><td>Increased transparency.</td><td>May 2024</td><td>V3.0</td></tr><tr><td>Aligned terminology with ISO 14064-2:2019</td><td>Improved consistency with the voluntary carbon market. LCA principles still apply.</td><td>May 2024</td><td>V3.0</td></tr><tr><td>Added risk assessment template for environmental and social do no harm</td><td>Provide more detailed and prescriptive assessment framework, clearer instructions for project developers.</td><td>May 2024</td><td>V3.0</td></tr><tr><td><p>Removed text for sections that are the same for all methodologies:</p><ul><li>Measurability</li><li>Real</li><li>Additionality</li><li>Technology readiness level</li><li>Minimum impact</li><li>Independently verified</li></ul></td><td>Repeated text from the Standard Rules.</td><td>May 2024</td><td>V3.0</td></tr><tr><td>Added Monitoring Plan section</td><td>Alignment with Rainbow Standard Rules V6.</td><td>May 2024</td><td>V3.0</td></tr><tr><td>Remove Rebound Effect and Independently Validated criteria</td><td>Alignment with Rainbow Standard Rules V6.</td><td>May 2024</td><td>V3.0</td></tr><tr><td>Added uncertainty assessment section</td><td>Alignment with Rainbow Standard Rules V6.</td><td>May 2024</td><td>V3.0</td></tr><tr><td>Model infrastructure instead of full data collection, move under “Digestion and biomethane management” section</td><td>Simplification, results not sensitive to impacts</td><td>May 2024</td><td>V3.0</td></tr><tr><td>Model activated carbon based on energy production, instead of direct data collection</td><td>Simplification, results not sensitive to impacts</td><td>May 2024</td><td>V3.0</td></tr><tr><td>Change biomethane combustion methane emissions from fossil to biogenic</td><td>Error</td><td>May 2024</td><td>V3.0</td></tr><tr><td>Reintroduce transport of manure and slurry in baseline scenario</td><td>Completeness, often collected project transport distance anyway</td><td>May 2024</td><td>V3.0</td></tr><tr><td>Add five different energy cover crop options, instead of a single proxy</td><td>Improved accuracy, increased use of project specific data</td><td>May 2024</td><td>V3.0</td></tr><tr><td>New Leakage requirements</td><td>More rigorous eligibility criteria, and clear requirements and instructions for Project Developers (after public consultation)</td><td>July 2024</td><td>V3.0</td></tr><tr><td>Include methane emissions from manure and slurry storage in project and baseline scenarios</td><td>Public consultation feedback, erroneously assumed previously that they are the same in project and baseline scenarios</td><td>July 2024</td><td>V3.0</td></tr><tr><td>Create project scope requirements</td><td>Specify the project scope as one anaerobic digestion site</td><td>October 2024</td><td>V3.1</td></tr><tr><td>Add minimum list of ESDNH risks</td><td>Align with Standard Rules V6.2</td><td>October 2024</td><td>V3.1</td></tr><tr><td>Change GHG quantification from ecoinvent v3.10 to v3.11</td><td>Using more recent data</td><td>June 2025</td><td>V3.2</td></tr></tbody></table>


# Appendix

### Appendix 1: Ecoinvent processes <a href="#wbz6nzu461u" id="wbz6nzu461u"></a>

*List of ecoinvent 3.11 processes used in the GHG reduction quantification model*

<table><thead><tr><th width="296">Input</th><th>Ecoinvent activity name</th></tr></thead><tbody><tr><td>Energy crop: maize silage</td><td>maize silage production | maize silage | Cutoff, U, RoW</td></tr><tr><td>Energy crop: sunflower</td><td>market for sunflower silage | sunflower silage | Cutoff, U, GLO</td></tr><tr><td>Energy crop: rye grass</td><td>market for ryegrass silage | ryegrass silage | Cutoff, U, GLO</td></tr><tr><td>Energy crop: other grass silage</td><td>grass silage production, Swiss integrated production, intensive | grass silage, Swiss integrated production | Cutoff, U, CH</td></tr><tr><td>Energy crop: alfalfa, and triticale</td><td>alfalfa-grass mixture production, Swiss integrated production | alfalfa-grass mixture, Swiss integrated production | Cutoff, U, CH</td></tr><tr><td>Straw</td><td>wheat grain production | straw | Cutoff, U, RoW</td></tr><tr><td>Energy crop: whole corn</td><td>sweet corn production | sweet corn | Cutoff, U, RoW</td></tr><tr><td>Transport, truck</td><td>market for transport, freight, lorry, 3.5-7.5 metric ton, diesel, EURO 5 | transport, freight, lorry, 3.5-7.5 metric ton, diesel, EURO 5 | Cutoff, U, RER</td></tr><tr><td>Electricity</td><td>market for electricity, medium voltage | electricity, medium voltage | Cutoff, U (geography set to project country)</td></tr><tr><td>Activated carbon</td><td>market for activated carbon, granular | activated carbon, granular | Cutoff, U, GLO</td></tr><tr><td>Nitrogen fertilizer</td><td>market group for inorganic nitrogen fertilizer, as N | inorganic nitrogen fertilizer, as N | Cutoff, U, RER</td></tr><tr><td>Potassium fertilizer</td><td>market group for inorganic potassium fertilizer, as K2O | inorganic potassium fertilizer, as K2O | Cutoff, U, RER</td></tr><tr><td>Phosphorus fertilizer</td><td>market group for inorganic phosphorus fertilizer, as P2O5 | inorganic phosphorus fertilizer, as P2O5 | Cutoff, U, RER</td></tr><tr><td>Biogas plant construction</td><td>anaerobic digestion plant construction, agriculture, with methane recovery | anaerobic digestion plant, agriculture, with methane recovery | Cutoff, U, RoW</td></tr><tr><td>Natural gas</td><td>natural gas, burned in gas turbine | natural gas, burned in gas turbine | Cutoff, U (geography set to project country)</td></tr><tr><td>Biogas</td><td>market for biogas | biogas | Cutoff, U, RoW</td></tr><tr><td>Biomethane</td><td>market for biomethane, high pressure | biomethane, high pressure | Cutoff, U, RoW</td></tr></tbody></table>


# Risk assessment template

This methodology uses the risk assessment template version 1.0

:point\_right: Download the template [here](https://docs.google.com/spreadsheets/d/1LH5Tczcqk6zAH-N6hel3Cavh0xl2TivrhI1Cnpu20-A/edit?usp=sharing)

{% embed url="<https://docs.google.com/spreadsheets/d/1LH5Tczcqk6zAH-N6hel3Cavh0xl2TivrhI1Cnpu20-A/edit?usp=sharing>" %}


# Refurbishing of electronic devices

This methodology covers projects that refurbish electronic devices, extend their usable lifetime, reduce electronics waste and avoid production of new devices. The eligible device types include smartphones, tablets, laptops, desktop computers, and screens.

| **Methodology name** | Refurbishing of electronic devices |
| -------------------- | ---------------------------------- |
| **Version**          | 2.6                                |
| **Methodology ID**   | RBW-REC-01-ELEC-V2.6               |
| **Release date**     | January 27th, 2026                 |
| **Status**           | In use                             |

#### Glossary

<table data-header-hidden><thead><tr><th width="221"></th><th></th></tr></thead><tbody><tr><td><strong>Buyback</strong></td><td>Buying used devices from consumers.</td></tr><tr><td><strong>Device A</strong></td><td>In this methodology, Device A refers to the first life of the refurbished device in the project scenario, and the waste device in the baseline scenario. </td></tr><tr><td><strong>Device B</strong></td><td>In this methodology, Device B refers to the refurbished device in the project scenario, and the new manufactured device in the baseline scenario. </td></tr><tr><td><strong>Functioning device</strong></td><td>A device that is successfully refurbished by the refurbishing project. It replaces a new manufactured device.</td></tr><tr><td><strong>Non-functioning device</strong></td><td>A device that is not successfully refurbished by the refurbishing project. It may be recycled, dismantled for spare parts to be used by the refurbisher, or sold for spare parts.</td></tr><tr><td><strong>Refurbishing</strong></td><td>The process of repairing and restoring used devices to good working order. </td></tr><tr><td><strong>Residual value</strong></td><td>The value (economic and lifetime) of a used device that is still remaining when it is sold and/or sent for refurbishing.</td></tr><tr><td><strong>Scrap materials</strong></td><td>Parts of used devices that are no longer functioning and are replaced by spare parts in the refurbishing process. </td></tr><tr><td><strong>Small IT and telecommunication equipment</strong></td><td>A category of electronic waste (e-waste) defined by the <a href="https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02012L0019-20180704">WEEE directive</a>, composed of devices no larger than 50 cm external dimension, including mobile phones, GPS, routers, personal computers, and printers.</td></tr><tr><td><strong>Sold devices</strong></td><td>A functioning device that was successfully refurbished and sold functioning by the refurbishing project. It fully meets the market requirements and replaces a new manufactured device.</td></tr><tr><td><strong>Spare parts</strong></td><td>Functioning parts used in the refurbishing process to replace non-functioning parts, such as a battery or display. They may be new manufactured parts, or harvested from dismantled non-functioning devices. </td></tr><tr><td><strong>WEEE</strong></td><td>Waste from Electrical and Electronic Equipment, also called e-waste</td></tr></tbody></table>

See the glossary for methodology-specific terminology :point\_down:

{% content-ref url="/pages/D1bECpowUAiJorSGzbQY" %}
[Glossary](/glossary)
{% endcontent-ref %}


# Introduction

Small IT and telecommunication equipment constitute [about 2% of global greenhouse gas (GHG)](#user-content-fn-1)[^1] emissions and is one of the [fastest growing sectors in emissions](#user-content-fn-2)[^2]. In addition to climate change impacts, these electronic devices also require mining rare minerals and materials, and make up a rapidly growing stream of hazardous waste.

[Most environmental impacts of electronic devices come from their manufacturing stage](#user-content-fn-3)[^3]. Therefore, a major lever to reduce GHG emissions in this sector is to increase the lifetime of devices, so that fewer devices are produced. One method for increasing device lifetime is **device repair and refurbishing**.

Refurbishing of electronics involves restoring previously owned and used electronic devices to a functional state. It requires a diagnosis, cleaning, repairs, replacing parts, and testing to ensure performance. **Extending the lifespan of these devices reduces the production of new devices and reduces electronic waste**. Refurbishment of electronic devices is gaining mainstream acceptance from consumers but still faces barriers from high costs of repair, market fragmentation, and lack of consumer trust.

[^1]: Freitag, C., Berners-Lee, M., Widdicks, K., Knowles, B., Blair, G. S., \&amp; Friday, A. (2021). The real climate and transformative impact of ICT: A Critique of estimates, trends, and regulations. Patterns, 2(9), 100340. <https://doi.org/10.1016/j.patter.2021.100340>

[^2]: European Commission, Joint Research Centre, Moeslinger, M., Almasy, K., Jamard, M. et al., Towards an effective right to repair for electronics – Overcoming legal, political and supply barriers to contribute to circular electronics in the EU, Publications Office of the European Union, 2022, <https://data.europa.eu/doi/10.2760/42722> ↑

[^3]: Bachér, J., Dams, Y., Duhoux, T., Deng, Y., Teittinen, T., 2020. Electronics and obsolescence in a circular economy (No. Eionet Report-ETC/WMGE 2020/3). European Environment Agency, European Topic Centre on Waste and Materials in a Green Economy.


# Eligibility and scope

## Eligible technologies

Projects eligible under this methodology are the activities that carry out the technical aspects of refurbishment. Refurbishment is defined according to the [EU Regulation 2024/1781](#user-content-fn-1)[^1] as "*actions carried out to prepare, clean, test, service and, where necessary, repair a product or a discarded product in order to restore its performance or functionality within the intended use and range of performance originally conceived at the design stage at the time of the placing of the product on the market*". Activities that only collect used devices (e.g. buyback schemes) or serve as marketplaces for refurbishers are **not eligible** projects.

Marketplaces may act as intermediaries between Rainbow and refurbishers to assist in the certification process. Signed agreements shall be provided ensuring that the refurbishers are the principal and final beneficiaries of carbon finance.

Devices eligible under this methodology include: small consumer electronics such as **smartphones, laptops, tablets, desktop computers, gaming consoles, and monitors**. Other device types may be included in future versions of this methodology.

This methodology distinguishes between **two types of refurbishing processes**:

* **Light** refurbishing is focused on testing device functionality, fixing cosmetic damage, and/or restoring software. It is a more simple process because it doesn’t involve replacing parts.
* **Full** refurbishing is an intensive process that involves light refurbishing plus replacing some device components and reassembling products. It is more costly and rigorous.

Both full and light refurbishing activities are eligible for Rainbow Carbon Credits (RCCs) under this methodology.

Note that the project shall be defined as the project activities that are justified as **additional**. This may include a refurbishing site’s entire operations or only an expansion project. See the Additionality section and the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#additionality) for more details.

{% content-ref url="/pages/CRADNrj4mfS258PN3x7N" %}
[Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules)
{% endcontent-ref %}

## Certification requirements

#### **Crediting period duration**

The maximum duration of the crediting period for projects certified under this methodology is 5 years. Upon reaching the maximum duration, a project's crediting period may be renewed, according to the [Crediting Period Renewal](/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal) procedure.

#### **Monitoring period duration**

The default monitoring period duration is one year, but may be shorter at the Project Developer's request. Project Developers shall submit a Monitoring Report at least once per 24 months. Failure to do so shall result in the project being [deregistered](/rainbow-standard-documents/procedures-manual/project-certification-procedure).

#### **Site audits**

Validation site audits for projects under this methodology may be performed **either remotely or in-person**, depending on the project size. Projects that issue more than 10,000 RCCs per year must undergo an in-person site audit. Projects that issue less than 10,000 RCCs per year may choose between an in-person or remote audit. The Rainbow team may require an in-person site audit for any project, regardless of the size.

#### **Versioning and project compliance**

When this methodology is revised, projects are required to comply with the latest version for subsequent verifications of RCCs.

## Project scope

One project corresponds to the refurbishing sites within one registered company located within one country. There is no limit to the number of sites registered within one project, but all sites must be registered, according to the site registration requirements outlined in the Rainbow Standard Rules.

{% hint style="info" %}
For example, if an international electronic device refurbishing company has refurbishing sites located in both France and Germany, two separate projects must be registered: one for the operations in France, and one for Germany.
{% endhint %}

The project scope includes the additional refurbishment activities made possible through carbon finance. Refurbishing used electronic devices serves two purposes:

1. managing the device at end-of-life (Device A), and
2. restoring it to create a functioning “new” device (Device B).

The project scope includes a cradle-to-grave assessment of all processes needed to fulfill these functions, where the processes differ from business-as-usual activities. These processes are organized into three life-cycle stages, all of which are included in the project system boundary as defined in the [GHG quantification](/methodologies/refurbishing-of-electronic-devices/ghg-reduction-quantification) section:

* Device A: e-waste collection, based on project operational data regarding device collection
* Device A: e-waste treatment and processing of scrap materials that couldn't be successfully refurbished, based on average country-specific e-waste management practices
* Device B: refurbishment process, based on project operational data

Only devices that have not already been refurbished are eligible under this methodology.

## Baseline scope

The baseline scope includes the set of business-as-usual (BAU) activities and their resulting GHG emissions that would have occurred in the absence of the project refurbishment activity. An activity-specific baseline scenario is used, based on current market conditions reflecting the actual practices for e-waste end-of-life and new device refurbishing.

This is reflected in the two main functions accounted for in the baseline scenario:

1. waste treatment of the device after its first life (Device A), and
2. provisioning of a new device (Device B).

These processes are organized into three life-cycle stages, all of which are included in the baseline system boundary as defined in the [GHG quantification](/methodologies/refurbishing-of-electronic-devices/ghg-reduction-quantification) section:

* Device A: e-waste collection, based on a conservative estimate of e-waste device collection
* Device A: e-waste treatment, based on average country-specific e-waste management practices.
* Device B: manufacturing new devices, based on representative market data for device production emission factors, the proportion of devices currently procured through refurbishment, reflecting existing industry practice

A conservative and representative baseline is ensured by accounting for two main factors in the substitutability of refurbished devices for new devices:

* **Device quality:** Project developers must demonstrate refurbished project devices are appropriate substitutes for newly manufactured devices, ensuring that the baseline remains representative of the project scenario. To do so, the developer must provide **evidence of the quality of refurbished devices**, confirming that they meet the standards required to serve as valid replacements for new products. Acceptable evidence may include documentation of quality control procedures, the device grading system, and the quality thresholds that devices must meet to be sold rather than recycled.
  * Devices sold by the project that are **not fully functional shall not be considered as substitutes for new devices**, and therefore will not be counted towards avoided emissions from new device production. The avoided emissions from e-waste treatment are still counted.
* **Device lifetime**: **Refurbished devices are assumed to have shorter lifetimes than new devices.** This difference in performance is acceptable because it is accounted for in the GHG reduction calculations to calculate the number of RCCs to issue a project (see Equation 19 in the section [GHG quantification](/methodologies/refurbishing-of-electronic-devices/ghg-reduction-quantification#aq9a8bw7wcjk)).
  * Lifetimes for selected devices are presented in Table 3 in the [GHG quantification](/methodologies/refurbishing-of-electronic-devices/ghg-reduction-quantification#assumptions) section.

{% hint style="info" %}
For example, if a refurbished device has **half of the expected lifetime** of a new device, it is only counted as **avoiding half of a new device**.
{% endhint %}

The baseline scenario **structure** remains valid for the entire crediting period but may be significantly revised earlier if:

* The Project Developer notifies Rainbow of a substantial change in project operations or baseline conditions, and/or
* The methodology is revised, affecting the baseline scenario.

The **specific values** within the baseline scenario will be updated during each crediting period, using project data to accurately reflect the equivalent of the project’s operations.

Projects certified under this methodology shall have a maximum crediting period duration of 5 years, which can be renewed for a total of 20 years. See the [Crediting Period Renewal](/rainbow-standard-documents/procedures-manual/project-certification-procedure#crediting-period-renewal) section of the Procedures Manual for procedural details.

[^1]: European Parliament and Council of the European Union. (2024). *Regulation (EU) 2024/1781 of the European Parliament and of the Council of 13 June 2024 establishing a framework for the setting of ecodesign requirements for sustainable products, amending Directive (EU) 2020/1828 and Regulation (EU) 2023/1542 and repealing Directive 2009/125/EC (Text with EEA relevance)*. EUR-Lex. [URL](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32024R1781).


# Principles & requirements

Project Developers shall demonstrate that they comply with all principles and requirements outlined in the applicable version of the [Rainbow Standard Rules](https://docs.rainbowstandard.io/rainbow-standard-documents/rainbow-standard-rules/general-eligibility-criteria), and described below with a specific focus on electronic device refurbishing.

{% content-ref url="/pages/CRADNrj4mfS258PN3x7N" %}
[Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules)
{% endcontent-ref %}

## Additionality

Project Developers shall demonstrate additionality using the [Rainbow Additionality Template](/rainbow-standard-documents/procedural-templates/additionality-evaluation-template) and following the requirements of the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#additionality).

{% tabs %}
{% tab title="Regulatory surplus analysis" %}
Regulatory surplus analysis shall demonstrate that there are no regulations that **require or mandate** collection, refurbishment, and resale of electronic devices. It is acceptable if regulations **promote** or **set targets for these activities**, because the resulting increase in these activities shall be accounted for in the baseline scenario.

At the European Union level, projects automatically pass the regulatory surplus analysis, which has been conducted by the Rainbow Climate Team. The EU has introduced the Waste Electrical and Electronics Equipment (WEEE) Directive ([Directive 2012/19/EU](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02012L0019-20180704)), the Restriction of the Use of Certain Hazardous Substances in EEE (RoHS) Directive ([Directive 2011/65/EU](http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02011L0065-20160715)), Waste Framework Directive ([Directive 2008/98/EC](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex%3A32008L0098)), and the [Circular Economy Action Plan](https://environment.ec.europa.eu/strategy/circular-economy-action-plan_en) to prevent WEEE generation and promote re-use, recycling, and other forms of WEEE recovery. **None of these legislations require electronic device refurbishing** at the EU level. Project Developers are only required to provide a country-level regulatory surplus analysis.

Any increase in electronic device refurbishing and WEEE recycling thanks to the support of these regulations is accounted for in the GHG reduction quantification. For example, current rates of WEEE recycling are used in the GHG [GHG quantification](/methodologies/refurbishing-of-electronic-devices/ghg-reduction-quantification#e-waste-treatment) section of the baseline scenario, and the current share of refurbished devices sold annually in the project country is considered in the [GHG quantification](/methodologies/refurbishing-of-electronic-devices/ghg-reduction-quantification#aq9a8bw7wcjk)section of the baseline scenario.

\
:flag\_fr: In France, the EU WEEE Directive was transposed via the Arrêté du 27 octobre 2021 (published in [JORF n°0255 on 31 October 2021](https://www.legifrance.gouv.fr/jorf/jo/2021/10/31/0255)). Under this regulation, projects must demonstrate that they contribute additional progress toward the national target of collecting and reusing 2% of electrical and electronic equipment (EEE).
{% endtab %}

{% tab title="Investment analysis" %}
**Investment analysis** may be used to prove that revenue from carbon finance is necessary to make the project investment financially viable.

{% hint style="info" %}
For example, Project Developers can apply investment analysis to the following situations to prove additionality (non-exhaustive list) :

* the development and launch of a brand new refurbishing project, or
* an expansion to scale up activities, such as expanding device collection capacity, or accelerating the refurbishing procedure with new equipment to be able to process more devices annually.
  {% endhint %}

**Projects shall demonstrate that their Internal Rate of Return (IRR) is below 28.5% in order to meet the financial additionality threshold.** This threshold corresponds to three times the sectoral Weighted Average Cost of Capital (WACC), based on benchmark data from the [Damodaran database](https://pages.stern.nyu.edu/~adamodar/).

The IRR shall be calculated based on the projected net cash flows over the project’s economic lifetime, using the following approach:

\
$${NPV} = \text{discount rate } r \text{ such that } \sum\_{t=0}^{n} \frac{CF\_t}{(1 + r)^t} = 0$$

Where:

* NPV = net present value
* $$CF\_t$$​ = net cash flow in year t
* r = internal rate of return
* n = project duration (in years)

Only projects with an IRR **strictly below 28.5%** will be considered as financially additional under this criterion.

Business plans shall account for any public funding or other financial support received by the project. During verification, audited accounting documents shall be used to demonstrate that the projected net cash flows from the calculation above was reasonable, and that carbon finance was used as initially described.

Note that **for investments in expansion, only the additional carbon reductions enabled by the expansion shall be eligible for Rainbow Carbon Credits**.
{% endtab %}

{% tab title="Barrier analysis" %}
**Barrier analysis** may be used to prove that the project faces financial, institutional, or technological barriers to ongoing operations that can only be overcome using carbon finance.

{% hint style="info" %}
Examples of barriers that could justify additionality include but are not limited to:

* Financial barrier: financial analysis proving that the project is operating at a loss, or not financially viable or stable, and carbon finance would make it financially viable.
* Technological barrier: proof that the project suffers from a lack of skilled workers (since refurbishment is a manual, technical process), which negatively affects the overall quality or logistics of the project. Carbon finance may help overcome this barrier by providing training for employees.
* Technological barrier: Refurbishment in Europe may struggle to be cost-competitive with new device sales, or refurbishment occurring elsewhere. Carbon finance may be used to lower the selling price of the project’s refurbished devices, making them a more attractive and competitive option.
  {% endhint %}

Projects shall demonstrate that their **EBITDA/Revenues is below 9%** in order to pass the financial additionality threshold. The EBITDA shall be calculated using the following formula:

$$
EBITDA = Net Income + Interest + Taxes + Depreciation + Amortization
$$

All financial analyses shall account for any public funding or other financial support received by the project.
{% endtab %}
{% endtabs %}

For any type of barrier analysis, audited financial documents shall be provided as proof. These documents should either demonstrate the financial status to prove financial barriers, or show that the project could not independently fund solutions to overcome institutional or technological barriers.

## No double counting <a href="#gp50rvxdsjp3" id="gp50rvxdsjp3"></a>

Project developers shall sign the [Rainbow MRV & Registry Terms & Conditions](https://drive.google.com/file/d/1Ol88SJX7HWGnZ9pxKfn8cekGU-RmCo6v/view?usp=sharing), committing to follow the No Double Counting requirements outlined in the Rainbow Standard Rules, including not double using or double issuing carbon credits.

No additional measures for double issuance are required because double issuance among actors in the supply chain is unlikely, given that device collectors and marketplaces are not eligible under this methodology.

{% content-ref url="/pages/n4GJ8lK65zU6YPQ1KvGS" %}
[Broken mention](broken://pages/n4GJ8lK65zU6YPQ1KvGS)
{% endcontent-ref %}

## Co-benefits

Projects should support at least two **quantifiable and verifiable** environmental or social co-benefits, aligned with the [UN Sustainable Development Goals](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDGs) framework. Any co-benefits claimed by the Project Developer shall be **quantified, monitored, and audited** for each verification and credit issuance.

Common co-benefits under this methodology are detailed in the table below. Project Developers may suggest and prove other co-benefits not mentioned here.

SDG 13 on Climate Action by default is not considered a co-benefit here, since it is implicitly accounted for in the issuance of carbon credits. If the project delivers climate benefits that are not accounted for in the GHG reduction quantifications, then they may be considered as co-benefits.

*Table 1 Common co-benefits that projects under this methodology may provide are detailed, including types of proof that can be used to justify each co-benefit.*

<table><thead><tr><th width="221">UN SDG</th><th width="297.6666259765625">Description</th><th>Proof</th></tr></thead><tbody><tr><td><strong>SDG 5.1</strong>- Achieve gender equality and empower all women and girls</td><td><p>​Women are less likely to work in the technology sector, and when they do they are usually paid less than men.</p><p>Electronic device refurbishing projects may promote gender parity in the information and communications technologies (ICT) workplace by having a large female workforce and having equal pay between men and women for doing the same job.</p></td><td><ul><li>Average hourly earnings of men and women by age and disabilities (if any)</li><li>Standalone official policy for equal pay or current scenario in the sustainability report</li></ul></td></tr><tr><td><strong>SDG 8.5</strong> - Achieve full and productive employment and decent work for all women and men, including for young people and persons with disabilities</td><td>Electronic device refurbishing projects often hire people with disabilities, who tend to have lower rates of employment (e.g. <a data-footnote-ref href="#user-content-fn-1">55% activity rate of people with some disability in the EU</a> vs 74% overall activity rate).</td><td>Official record of number of employees with a disability vs total employees of the workforce</td></tr><tr><td><strong>SDG 12.2</strong> - Achieve the sustainable management and efficient use of natural resources</td><td>The project’s circularity will be measured by the Material Circularity Indicator (MCI), according to the Ellen MacArthur Foundation's methodology.</td><td>Primary data collected from the project for the GHG reduction quantification, which are also used in the Circularity Assessment</td></tr><tr><td><strong>SDG 12.4</strong> - Achieve the environmentally sound management of chemicals and all wastes throughout their life cycle</td><td>Electronic devices contain precious metals and rare earth elements. By refurbishing electronic devices, and recycling the precious metals and rare earth elements they contain, projects <a data-footnote-ref href="#user-content-fn-2">avoid the destructive mining and extraction of these finite, virgin elements</a>.</td><td>Number of devices refurbished. Amount of rare earth elements avoided calculated in Rainbow life cycle inventory models.</td></tr><tr><td><strong>SDG 12.5</strong> - Reduce waste generation through prevention, reduction, recycling and reuse</td><td>The project diverts e-waste from improper disposal. In the EU, an average of 44% of small IT and telecommunication equipment e-waste is not treated in proper waste management channels. All e-waste collected in the project scenario is properly managed (via refurbishing or recycling).</td><td><p>Number and type of waste input devices.</p><h4 id="environmental-and-social-safeguards"><br></h4></td></tr></tbody></table>

## Environmental and social safeguards

Project Developers shall prove that the **project does not contribute to substantial environmental and social harms.**

Additional proof may be required for certain high-risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

#### Environmental and social risk assessment

Project Developers shall fill in the [Rainbow- Electronic device refurbishing risk assessment](/methodologies/refurbishing-of-electronic-devices/risk-evaluation-template), to evaluate the identified risks of electronic device refurbishing. The identified risks include:

* Improper on-site storage of non-functional e-waste
* Energy intensive processing
* Greenhouse gas emissions from transport for collection
* Greenhouse gas emissions from transport for shipping
* Worker health and safety
* Frequent replacement of devices due to shortened lifetime (rebound effect)
* Frequent replacement of devices due to economic incentives (rebound effect)

{% hint style="info" %}
All risk assessments must also address the [Minimum environmental and social risks ](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment)defined in the Rainbow Standard Rules.
{% endhint %}

{% content-ref url="/pages/3o5w7slzA8KYqfkoj4VT" %}
[Risk assessment template](/methodologies/refurbishing-of-electronic-devices/risk-evaluation-template)
{% endcontent-ref %}

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a [Risk Mitigation Plan](/rainbow-standard-documents/rainbow-standard-rules/principles-and-requirements#environmental-and-social-risk-assessment), which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

{% hint style="info" %}
Note that the **life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks**. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.
{% endhint %}

## Leakage <a href="#viuf5av97jb8" id="viuf5av97jb8"></a>

{% tabs %}
{% tab title="Activity shifting" %}
Leakage may occur when carbon-emitting activities are geographically displaced or relocated to areas outside the project boundaries as a direct result of the project's implementation. For electronic device refurbishing, this includes:

There is a risk that e-waste is transferred to different countries with less stringent waste treatment standards than their original country. This can occur in the form of:

* non-functioning parts or devices that are discarded at the refurbishing facility, and/or
* the refurbished device itself, which will undergo waste treatment in the country where it is sold and distributed.
  {% endtab %}

{% tab title="Upstream and downstream emissions" %}
Upstream and downstream emissions shall be included by default in the GHG reduction quantification, as part of the life-cycle approach. The upstream and downstream emissions included in the quantification are detailed in the Baseline scenario and Project scenario section
{% endtab %}
{% endtabs %}

{% hint style="info" %}
Project Developers shall transparently evaluate the likelihood of the above leakage risks in the PDD, plus any other project-specific leakage risks deemed relevant by the Project Developer, the Rainbow Certification Team, or the VVB.
{% endhint %}

## Monitoring

Monitoring Plans for this methodology shall include, but are not limited to, tracking of the following information:

* Amount and type of devices collected
* Transportation distances of these devices for collection, and for possible secondary transport
* Amount and type of functional and non-functional devices sold
* Number of devices undergoing full refurbishment, light refurbishment, recycled, and saved for spare parts.
* Quantified value of any co-benefits claimed.

See Table 2 in the [Data Sources](/methodologies/refurbishing-of-electronic-devices/ghg-reduction-quantification#data-sources) section for more details.

Monitoring Plans shall include the following information for each monitored parameter:

* monitoring frequency
* emission sources and sinks
* data source
* measurement methods/procedures, and their accuracy and calibration
* quality assessment or quality control procedures
* responsible party for collecting and archiving data

[^1]: Eurostat 2024. Activity rates by level of disability (activity limitation) and educational attainment level. DOI: <https://doi.org/10.2908/LFSA\\_ARGAEDDL>. Accessed April 2024. ↑

[^2]: Işıldar, A., Rene, E.R., van Hullebusch, E.D., Lens, P.N.L., 2018. Electronic waste as a secondary source of critical metals: Management and recovery technologies. Resources, Conservation and Recycling, Sustainable Resource Management and the Circular Economy 135, 296–312. <https://doi.org/10.1016/j.resconrec.2017.07.031> ↑


# GHG quantification

## General

General GHG reduction quantification rules can be found in the [Rainbow Standard Rules](/rainbow-standard-documents/rainbow-standard-rules/ghg-quantification).

Calculations of GHG emissions for the baseline and project scenarios shall follow the method detailed below, based on [ISO 14064-2:2019](#user-content-fn-1)[^1].

Electronic device refurbishing projects are only eligible for **avoidance Rainbow Carbon Credits**.

Electronic device refurbishing projects serve two functions: **waste treatment from a device’s first life** (Device A), and the **provisioning of a “new” device** in its second life (Device B). Both of these functions are included in the project and baseline scenario. See Figure 1 and Figure 2 for a depiction of project and baseline scenario system boundaries.

The baseline scenario represents the **functionally equivalent** set of activities that would occur in the absence of the project. Therefore, the baseline scenario is the average e-waste treatment of Device A, and the market mix for production of a new Device B. **This market mix includes the fraction of refurbished devices that are already on the market** (see [Appendix 6](/methodologies/refurbishing-of-electronic-devices/appendix#id-5lf32r1yzlvs))**.**

The distribution, packaging, use, and waste treatment of Device B are not included in the calculations because they are assumed to be the same in both scenarios. Therefore, **the downstream system boundary is Device B at the factory gate**.

Calculations and data collection are based on annual project operations.

## Functional Unit

Electronic device refurbishing projects are multifunctional (see General section above) so the **functional unit is twofold:**

* production of one electronic device (Device B), plus
* treatment of the corresponding amount of e-waste treated (from Device A) to generate this one device.

## Data Sources

The required **primary data** for GHG reduction calculations from projects are presented in Table 2:

*Table 2 Summary of primary data needed from projects and their source. Asterisks (\*) indicate which data are required to be updated annually during verification (see Monitoring Plan section).*

<table data-header-hidden><thead><tr><th width="397"></th><th width="173"></th><th></th></tr></thead><tbody><tr><td><strong>Parameter</strong></td><td><strong>Unit</strong></td><td><strong>Source proof</strong></td></tr><tr><td>Amount of sold devices (sold in a functioning state) during the reference year, by type and sourcing country (listed in Table 3).*</td><td>Units of device, by type</td><td>Track records from the refurbishing site</td></tr><tr><td>Mass of devices (optional)</td><td>grams/device type</td><td>Internal document containing this parameter</td></tr><tr><td>Distance traveled during collection from the sourcing place/country until the refurbishing site, and mode of transport (road or air freight).*</td><td>km</td><td>Track records from the refurbishing site</td></tr><tr><td>If applicable, secondary transport to send collected devices from the project site to another more specialized refurbishing site.*</td><td>Number of devices by type, and distance (km)</td><td>Track records from the refurbishing site/invoices</td></tr><tr><td><p>Percent of input used devices, broken down by device type, that undergo:</p><ul><li>light refurbishment,</li><li>full refurbishment,</li><li>are recycled, and</li><li>are saved for spare parts or sold as non-functional devices.*</li></ul></td><td>Percentage (%)</td><td>Track records from the refurbishing site</td></tr><tr><td>(Optional) The average buyback price per device category.</td><td><p>Currency</p><p>(Euro - € or dollar - $)</p></td><td>Invoices</td></tr></tbody></table>

**Secondary data** taken from the literature are used to define default values for the following elements:

* Device expected lifetime (new and refurbished)
* Device mass (if not provided by the Project Developer)
* Emission factors from device production (when not available in the ecoinvent database, see paragraph below)

These values and their sources are provided in Table 3 in the [#assumptions](#assumptions "mention") section

The [ecoinvent ](#user-content-fn-2)[^2]database version 3.12 (hereafter referred to as ecoinvent) shall be the main source of emission factors unless otherwise specified. Ecoinvent is preferred because it is traceable, reliable, and well-recognized. The ecoinvent processes selected are detailed in [Appendix](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7)

## Assumptions

1. Electronic devices are evaluated in categories of device types rather than specific device models to facilitate data collection. It is assumed that **devices in the same device type category have** **similar characteristics** (mass, emission factor, lifetime), as defined in Table 3. Only the device type "monitor" is separated into large and small monitors, due to the influence of monitor size on manufacturing impacts.
2. Some devices are not able to be refurbished to a functioning state, but contain some functional parts. Typically, the device is disassembled to harvest those scrap parts to use as spare parts for other refurbished devices. To maintain a conservative approach, these devices are assumed to go to electronic waste recycling.
3. In the baseline scenario, the distance for e-waste collection of Device A and transport to the waste treatment center is assumed to be 100 km.
4. The distribution of devices in the baseline and project scenarios is assumed to be the same, and is therefore excluded from quantifications. This is a conservative assumption, because [new devices in the baseline scenario are likely manufactured in Asia or the USA](#user-content-fn-3)[^3] and transported long distances. In contrast, the project scenario consists of mostly inter-EU shipping of devices across much shorter distances.
5. Packaging, use, and waste treatment of Device B are assumed to be the same in the baseline and project scenarios, and are therefore excluded from quantifications.
6. Refurbished devices are assumed to have shorter lifetimes than new devices, as presented in Table 3. To account for this difference, it is assumed that **the amount of device production avoided in the baseline scenario is proportional to the ratio of new and refurbished device lifetimes**. See the [Baseline Scope ](/methodologies/refurbishing-of-electronic-devices/eligible-technologies#baseline-scope)section for more details. Lifetimes for Apple and non-Apple devices are assumed to be the same.
7. Detailed project data on the refurbishing process is rarely available. It is a manual process, and most impacts in the life cycle come from production of spare parts. Therefore, **impacts of the refurbishing process are assumed to equal the ratio of impacts of new and refurbished devices** in the detailed life cycle assessment on electronic device refurbishing, published by The French Agency for Ecological Transition (*Agence de la transition écologique, ADEME*), referred to hereafter as the [ADEME study](#user-content-fn-4)[^4]. Refurbishing impact ratios for Apple and non-Apple devices are assumed to be the same. See [#refurbishing-process](#refurbishing-process "mention") Full refurbishment impacts section, for more details.
8. For the device type "monitor", if Project Developers do not have monitor/screen size data and are therefore unable to provide a distribution of monitor/screen sizes, it is assumed that all monitors fall into the <25" screen category. This assumption is conservative, as smaller monitors are associated with lower impacts from new device production, resulting in reduced avoided emissions.

*Table 3 Summary of assumed lifetimes, masses, and emission factors of new and refurbished electronic devices. Refer to the* [*Appendices* ](/methodologies/refurbishing-of-electronic-devices/appendix)*for details and sources.*

<table data-header-hidden data-full-width="true"><thead><tr><th></th><th></th><th></th><th></th><th></th><th></th></tr></thead><tbody><tr><td><strong>Device type</strong></td><td><a data-footnote-ref href="#user-content-fn-5"><strong>Emissions new (kgCO2eq)</strong></a></td><td><a data-footnote-ref href="#user-content-fn-6"><strong>Emissions refurbished (kgCO2eq)</strong></a></td><td><a data-footnote-ref href="#user-content-fn-7"><strong>Average mass (kg)</strong></a></td><td><a data-footnote-ref href="#user-content-fn-8"><strong>Lifetime new (year)</strong></a></td><td><a data-footnote-ref href="#user-content-fn-8"><strong>Lifetime refurbished (year)</strong></a></td></tr><tr><td>Smartphone</td><td>49</td><td>4</td><td>0.2</td><td>3</td><td>2</td></tr><tr><td>iPhone</td><td>64</td><td>5</td><td>0.2</td><td>3</td><td>2</td></tr><tr><td>Laptop</td><td>167</td><td>18</td><td>1.6</td><td>5</td><td>3</td></tr><tr><td>MacBook</td><td>158</td><td>17</td><td>1.7</td><td>5</td><td>3</td></tr><tr><td>PC</td><td>225</td><td>23</td><td>5.4</td><td>5</td><td>3</td></tr><tr><td>iMac</td><td>250</td><td>26</td><td>4.5</td><td>5</td><td>3</td></tr><tr><td>Tablet</td><td>84</td><td>10</td><td>0.5</td><td>3</td><td>2</td></tr><tr><td>iPad</td><td>58</td><td>7</td><td>0.5</td><td>3</td><td>2</td></tr><tr><td>Gaming console</td><td>293</td><td>67</td><td>3.0</td><td>5</td><td>3</td></tr><tr><td>Monitor &#x3C;25 cm</td><td>357</td><td>36</td><td><a data-footnote-ref href="#user-content-fn-9">4.5</a></td><td>7</td><td>4</td></tr><tr><td>Monitor >25 cm</td><td>538</td><td>54</td><td>6.6</td><td>7</td><td>4</td></tr></tbody></table>

**Residual value of input devices** is detailed in [#refurbishing-process](#refurbishing-process "mention"), Residual value of input devices section and refers to the allocation of impacts from the production of Device A to the refurbished Device B, based on its residual economic value. This is calculated using the ratio of the buyback price to the price of the newly manufactured device. This ratio is calculated for each device type, and assumed to be the same for all models within that category.

## Project Scenario

![Figure 1 The system boundary and scope of the project scenario are shown. They are broken down into three life cycle stages, each described in the corresponding sections below. X% allocation is described in  section](/files/h8aEFdnFdf2efJ2xvi26)

The project scenario consists of refurbishing used electronic devices, which serves two functions: **1) waste treatment of the device after its first life** (Device A) and **2) refurbishing to produce a “new“ device** (Device B). This process is broken down into 3 life cycle stages, and displayed in Figure 1:

* Device A e-waste collection
* Device A e-waste treatment of scrap materials
* Device B refurbishing process

### E-waste collection

The mass of e-waste collected equals the total mass of input used devices collected at the refurbishing site annually.

Total mass of devices shall be calculated using the number of devices collected for each device type (provided by the Project Developer), multiplied by the assumed mass of each device type shown in Table 3.

For calculating transport distance, Project Developers shall provide the country and/or city where used electronic devices are transported from, and provide the average distance from the collection source to the refurbishing project site.

It is assumed that transport within Europe is done 100% by truck, and overseas transport is done by long-distance air freight.

<details>

<summary><strong>Calculations project e-waste collection</strong></summary>

This step calculates the GHG emissions from transporting used devices during the collection process ($$Total$$ $$E\_{P.collection}$$).

$$\textbf{(Eq.1)}\ N\_{i.\ collected} = \sum({\ N}*{i.sold\ }/\ (1\ - \ Re*{rate.\ i}))$$

where,

* $$N\_{i.\ collected}$$ represents the amount of input collected devices of type $$i$$ collected by the project, in number of devices.
* $$N\_{i.\ sold}$$ represents the number of devices by type $$i$$ sold in a functioning state, and shall be provided by the Project Developer for each verification.
* $${{Re}*{rate.i}}*{\ }$$represents the fraction of input used devices of device type *i* that are recycled, saved for spare parts, or not successfully refurbished to a functioning state by the project, and shall be provided by the Project Developer for each verification.

$$\textbf{(Eq.2)}\ Total\ E\_{P.collection} = \sum(N\_{i.collected}\*W\_{i}\*D\_{C.i}*R\_{C.i})*\ EF\_{\ transport}$$

where,

* $${Total\ E}\_{P.collection\ }$$ represents the sum of GHG emissions due to the transport of devices collected for refurbishing in the project scenario, in kgCO$$\_2$$eq.
* $$N\_{i.collected}$$ was calculated in Equation 1.
* $$W\_{i}$$ represents the weight in kilograms of device *i*, according to the presented in Table 3.
* $$D\_{C.i}$$ represents the distance traveled for device collection in km, provided by the Project Developer per sourcing country/city ($$C$$) and device type ($$i$$).
* $$R\_{C.i}$$ represents the fraction of the devices collected per sourcing country/city ($$C$$) and device type ($$i$$).
* $$\ EF\_{\ transport}$$ represents the emission factor for transport in kgCO$$\_2$$eq/kg.km according to the ecoinvent database and includes truck or air freight. Refer to [Appendix](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7) for the ecoinvent processes used.

</details>

### E-waste treatment of non-refurbished devices <a href="#cjv1j3sjdull" id="cjv1j3sjdull"></a>

Devices collected by the project that cannot be refurbished undergo e-waste recycling. Refurbishing projects typically have contracts with e-waste recycling companies that collect and recycle such devices.

Project Developers shall provide the fraction of devices that are recycled, and they will be modeled as mechanical e-waste recycling with shredding and separation (see ecoinvent processes in [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7)).

Some non-refurbished devices may be kept onsite to harvest spare parts in the future, but due to limited project data on this topic, they are assumed to be recycled.

Devices that are sold by the project in a non-functional state shall be treated in the calculations as recycled devices.

<details>

<summary><strong>Calculations project e-waste treatment</strong></summary>

This step calculates the GHG emissions from transporting and recycling the used electronic devices that are unsuitable for being refurbished ($${Total\ E}\_{P.waste\ treatment}$$).

$$\textbf{(Eq.3)}\ E\_{recycling} = \sum(N\_{i.collected}\*W\_{i}*Re\_{rate.i}*\ EF\_{recycling.\ i})$$

where,

* $$E\_{recycling}$$ represents the sum of GHG emissions due to the recycling process of devices/scrap not suitable for refurbishing, in kgCO$$\_2$$eq.
* $$N\_{i.collected}$$ and $${{Re}*{rate.i}}*{\ }$$ were described in Equation 1.
* $$W\_{i}$$ is described in the section [#calculations-project-e-waste-collection](#calculations-project-e-waste-collection "mention") section of the Project scenario.
* $$EF\_{recycling.\ i}$$represents the emission factor of recycling each device type. Refer to [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7) for the ecoinvent processes used.

$$\textbf{(Eq.4)}\ E\_{transport} = \sum(N\_{i.collected}\*W\_{i}\*Re\_{rate.i})*D\_{scrap}*\ EF\_{\ truck\ transport}$$

where,

* $$E\_{transport}$$ represents the sum of GHG emissions due to the transport of devices/scrap not suitable for refurbishing that are sent to recycling, in kgCO$$\_2$$eq
* $$N\_{i.collected}$$ and $${{Re}*{rate.i}}*{\ }$$ were described in Equation 1.
* $$W\_{i}$$ is described in the section[#calculations-project-e-waste-collection](#calculations-project-e-waste-collection "mention").
* $${D\_{scrap}}\_{\ }$$represents the distance in km until the waste treatment facility. If not known, this value is considered 100km.
* $$EF\_{truck\ transport}$$represents the emission factor of truck transport. Refer to [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7) for the ecoinvent processes used.

$$\textbf{(Eq.5)}\ Total\ E\_{P.waste\ treatment} = \ E\_{recycling\ } + E\_{transport}$$

where,

* $$\ Total\ E\_{P.waste\ treatment}$$represents the sum of GHG emissions in the project scenario e-waste treatment of non-refurbished devices, in kgCO$$\_2$$eq.

</details>

### Refurbishing process

This life cycle stage is composed of four main processes, each described below:

* light refurbishing impacts
* full refurbishing impacts
* residual value of input devices, and
* secondary transport of devices.

**Light refurbishment impacts:** The refurbishing process is split into two categories: light and full refurbishment, representing the degree of intervention needed to restore the device to a functioning state. Light refurbishment involves testing device functionality, and cosmetic and software improvements, and does not require the replacement of parts (e.g. new battery, new screen…). This distinction was chosen because [most environmental impacts](#user-content-fn-10)[^10] from the refurbishing process come from production of new replacement pieces.

* Light refurbishment includes inputs of electricity for testing and software improvement, and cleaning alcohol, tissues, and cloth for cleaning, and is modeled after the detailed LCA of electronic device refurbishing from the ADEME study.

**Full refurbishment impacts:** Full refurbishment includes light refurbishment plus repair and replacement of non-functional pieces. Detailed project data on all replacement pieces and inputs are rarely available, so full refurbishment impacts are modeled following the ADEME study.

* Results from this study are used to obtain the **ratio of impacts of a refurbished device to the impacts of the corresponding new device** ([Appendix 3](/methodologies/refurbishing-of-electronic-devices/appendix#id-21d91pp0841i))**.** This ratio is then applied to the new device production impacts summarized in Table 3 to obtain the desired amount of emissions from refurbishing. The emissions from refurbishing are modeled using the mix of ecoinvent processes used in light refurbishment described above, plus production of commonly replaced parts including screens, batteries, microphones and speakers.

{% hint style="info" %}
For example, the ADEME study found that production of a new laptop emitted 168 kgCO<sub>2</sub>eq, and the process for refurbishing a laptop emitted 18 kgCO<sub>2</sub>eq, so the refurbishing impact ratio of laptops is 11%.

In this model, the emission factors used for new laptop and Macbook production are 170 and 161 kgCO<sub>2</sub>eq. These are multiplied by the refurbishing impact ratio of 11% to obtain refurbishing impacts of one laptop and Macbook of 19 and 18 kgCO<sub>2</sub>eq.
{% endhint %}

**Residual value of input devices:** In life cycle assessments, when a project uses waste as an input, it typically enters the project system boundary with zero environmental impacts. Refurbishing projects collect and refurbish used devices that are not always at the end of their life, and **are not truly waste**. They may still be functional and hold residual value from their first life. This is evidenced by the fact that Project Developers sometimes pay for used devices, as opposed to waste collection, where the waste generator has to pay for waste treatment.

* In this case, some environmental [impacts from the device’s first life should be allocated to the refurbished device](#user-content-fn-10)[^10]. It is assumed that **only devices that undergo light refurbishment were in good condition and had residual value,** and are allocated a share of GHG emissions from the device’s first life. On the other hand, devices that undergo full refurbishment are assumed to be non-functional waste and are not allocated any environmental impacts from their first life.
* The residual value and corresponding **allocated emissions are based on the ratio of the buyback price to the selling price of a new manufactured device**. An average ratio shall be used for each device type, and is shown in Table 4. Alternatively, Project Developers may provide a similar project-specific database with their own buyback data.

{% hint style="info" %}
**For example**, if Smartphone A has an average buyback price of 100€, and it is sold new for 400€, its residual value is 25% of its original value. Then when it undergoes light refurbishment by the project, it is modeled as an input with 25% of its initial production impacts.

If production of a new Smartphone A emits 80 kgCO<sub>2</sub>eq, and it has a residual value of 25%, then the calculations shall include it as an input with 20 kgCO<sub>2</sub>eq.
{% endhint %}

*Table 4 Residual value of device types. See* [*Appendix 7*](/methodologies/refurbishing-of-electronic-devices/appendix#oi5bmdhs49zb) *for more details for smartphone, iPhone, tablet, and iPad. The average value of these device types was applied to the remaining device types due to a lack of device-specific buyback data.*

| Device               | Percent of residual value |
| -------------------- | ------------------------- |
| Smartphone           | 11%                       |
| iPhone               | 14%                       |
| Tablet               | 20%                       |
| iPad                 | 12%                       |
| Laptop               | 14%                       |
| Macbook              | 14%                       |
| PC                   | 14%                       |
| iMac                 | 14%                       |
| Gaming console       | 14%                       |
| Monitor (both sizes) | 14%                       |

**Secondary transport of devices:** After the device is collected by the refurbishing project and sorted, it may be sent to a different refurbishment site, for example to do specialty repairs. Project Developers shall report such secondary transport by providing the distance transported, and the number and type of devices making this transport.

<details>

<summary><strong>Calculation refurbishing process</strong></summary>

This step calculates the GHG emissions from the refurbishing process $$(Total\ E\_{P.refurbishing\ process})$$ broken down into four main processes: 1) light refurbishing impacts, 2) full refurbishing impacts, 3) residual value of input devices, and 4) secondary transport of devices.

$$\textbf{(Eq.6)}\ N\_{light\ ref.i}\ = \sum(N\_{i.collected}\*R{ef}\_{light.i})$$

where,

* $$N\_{light\ ref.i}$$ represents the number of devices of type $$i$$ undergoing the light refurbishing process and sold in a functional state.
* $$N\_{i.collected}$$ is calculated in the section [#calculations-project-e-waste-collection](#calculations-project-e-waste-collection "mention")
* $$R{ef}\_{light.i}$$ represents the fraction of devices of type $$i$$ undergoing the light refurbishing process and sold in a functional state.

$$\begin{aligned}\textbf{(Eq.7)}\ E\_{light\ ref} = \sum N\_{light\ ref.i}\ *(\ \&alcohol*EF\_{\ alcohol}\ +\ \&paper\ *EF\_{paper}\ +\ \&cloth*EF\_{cloth}\ +\ \&electricity\*EF\_{national\ grid\ electricity})\end{aligned}$$

where,

* $$E\_{light\ ref}$$ represents the sum of GHG emissions due to the light refurbishing of a device type.
* $$N\_{light\ ref.i}$$is calculated in Equation 6.
* *alcohol*, *paper, cloth* and *electricity* represent the amount of cleaning alcohol, paper and cloth needed to clean a device. These amounts were taken per device type from the [ADEME study](#user-content-fn-4)[^4], pages 45, 77, and 103.
* $$EF\_{\ alcohol}$$ represents the emission factor, in kgCO$$\_2$$eq, for cleaning alcohol composed of 70% ethylene and 30% water. Refer to [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7) for the ecoinvent process used.
* $$EF\_{paper}$$ represents the emission factor, in kgCO$$\_2$$eq, of paper. Refer to [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7) for the ecoinvent process used.
* $$EF\_{cloth}$$ represents the emission factor, in kgCO$$\_2$$eq, of cloth used for cleaning. Refer to [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7) for the ecoinvent process used.
* $$EF\_{national\ grid\ electricity}$$ represents the emission factor, in kgCO$$\_2$$eq, of electricity in the national grid where the project is located, used for software and functionality testing. Refer to [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7) for the ecoinvent process used.

$$\textbf{(Eq.8)}\ N\_{full\ ref.i}\ = \sum(N\_{i.collected}\*R{ef}\_{full.i})$$

where,

* $$N\_{full\ ref.i}$$ represents the number of devices of type $$i$$ undergoing the full refurbishing process and sold in a functional state.
* $$N\_{i.collected}$$ is described in the section [#calculations-project-e-waste-collection](#calculations-project-e-waste-collection "mention").
* $$R{ef}\_{full.i}$$ represents the fraction of devices of type $$i$$ undergoing the full refurbishing process and sold in a functional state.

$$\textbf{(Eq.9)}\ E\_{full\ ref} = \sum N\_{full\ ref.i}\ \*R\_{full\ ref.i}\*EF\_{full\ ref}$$

where,

* $$E\_{full\ \ ref}$$ represents the sum of GHG emissions due to the full refurbishing of a device type.
* $$N\_{full\ ref.i}$$is calculated in Equation 8.
* $$R\_{full\ ref.i}$$ represents the rate of full refurbishment activities modeled per device type *i*. This reflects the "amount" of refurbishment used as an input for that device. See [Appendix 3](/methodologies/refurbishing-of-electronic-devices/appendix#id-21d91pp0841i) for its calculation and the amounts.
* $$EF\_{full\ ref}$$ represents the emission factor, in kgCO$$\_2$$eq, of one full refurbishment activity. This activity includes a mix of ecoinvent processes, described in [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7) and section [#refurbishing-process](#refurbishing-process "mention").

$$\textbf{(Eq.10)}\ E\_{residual} = \sum N\_{light\ ref.i}\ \* \frac{Av.acquisition\_{price.i}}{Av.selling\_{price.i}} \* EF\_{new\ i}$$

where,

* $$E\_{residual}$$ represents the sum of residual GHG emissions from the device's first life allocated to the refurbished device, for all devices.
* $$N\_{light\ ref.i}$$ is calculated in Equation 6.
* $$Av.acquisition\_{price.i}$$represents the average price paid for the collected used devices of type *i* (also called the buyback price)*.*
* $$Av.selling\_{price.i}$$represents the average selling price of a new device of type $$i$$.
* $${{EF}*{new\.i}}*{\ }$$ represents the emission factor in kgCO$$\_2$$eq/kg due to the production of the new device type $$i$$. The emission factors of new devices are presented in Table 3.

$$\begin{aligned}\textbf{(Eq.11)}\ E\_{secondary\ transport} = \sum&(N\_{secondary\ transport,i}\*W\_{i}*D\_{secondary\ transport})\ &*\ EF\_{\ truck\ transport}\end{aligned}$$

where,

* $$E\_{secondary\ transport}$$ represents the sum of GHG emissions from secondary transport.
* $$N\_{secondary\ transport,i}$$ is the number of devices of device type $$i$$ that are sent for secondary transport.
* $$W\_{i}$$ and $$\ EF\_{\ truck\ transport}$$ are described in the [#calculations-project-e-waste-treatment](#calculations-project-e-waste-treatment "mention").
* $$D\_{secondary\ transport}$$ represents the distance traveled for secondary device transport in km per device type $$i$$.

$$\begin{aligned}\textbf{(Eq.12)}\ Total\ E\_{P.refurbishing\ process} = \ \&E\_{light\ ref} + {\ E}*{full\ ref}\ + &{\ E}*{residual} + E\_{secondary\ transport}\end{aligned}$$

where,

* $$Total\ E\_{P.refurbishing\ process}$$represents the sum of GHG emissions in the project scenario refurbishing process LCA step, in kgCO$$\_2$$eq.

</details>

## Baseline scenario <a href="#luws2req6grv" id="luws2req6grv"></a>

<figure><img src="/files/IxxT8PP5wCrvEjMCwff2" alt=""><figcaption><p><em>Figure 2 The system boundary and scope of the baseline scenario are shown. They are broken down into three life cycle stages, each described in the corresponding sections below</em></p></figcaption></figure>

The baseline scenario consists of two main functions: **1) waste treatment of the device after its first life** (Device A) and **2) provisioning of a new device** (Device B). The system boundary of the baseline scenario is shown in Figure 2. This is broken down into 3 life cycle stages, which are detailed in the following sections:

* Device A collection
* Device A e-waste treatment
* Manufacturing of Device B

The baseline scenario **structure** remains valid for the entire crediting period but may be significantly revised earlier if:

* The Project Developer notifies Rainbow of a substantial change in project operations or baseline conditions, and/or
* The methodology is revised, affecting the baseline scenario.

The **specific values** within the baseline scenario will be updated during each crediting period, using project data to accurately reflect the equivalent of the project’s operations.

The structure of the baseline scenario is the same whether the project consists of ongoing operations or an expansion. In the former, project data from **all annual site operations** is considered, and the baseline scenario is defined as the functional equivalent of all annual operations. For an expansion project, **only project data related to the expansion is considered**, because the normal annual operations would be the same in the baseline and project scenario, and can therefore be excluded.

{% hint style="info" %}
**For example**, for an expansion project, if the expansion allows for the refurbishment of an extra 5,000 devices annually in addition to the business-as-usual (BAU) 10,000 devices, then the baseline scenario could include the BAU refurbishment of 10,000 devices plus the new manufacturing of 5,000 devices. The same BAU refurbishment of 10,000 devices could also be included in the project scenario.

The processes related to the BAU refurbishment are then excluded from the GHG reduction quantification of both the project and baseline scenarios since they would have no effect on the avoided emissions. The remaining project activity to consider is the refurbishment of the extra 5,000 devices from the expansion project.
{% endhint %}

### E-waste collection

It is assumed that e-waste is transported by truck 100 km to its waste treatment center.

The mass of e-waste collected in the baseline scenario equals the **total mass of input used devices** collected by the refurbishing project annually.

Total mass of devices shall be calculated using the number of devices collected for each device type (provided by the Project Developer), multiplied by the assumed mass of each device type shown in Table 3.

Project Developers may provide more precise information on the mass of collected devices if it is available.

<details>

<summary><strong>Calculations baseline e-waste collection</strong></summary>

This step calculates the GHG emissions from the baseline e-waste collection life cycle stage ($${Total\ E}\_{B.collection}$$).

$$\textbf{(Eq.13)}\ Total\ E\_{B.collection} = \sum(N\_{i.\ collected}\*W\_{i}\ )\*D\ \*\ EF\_{truck\ transport}$$

where,

* $$Total$$ $$E\_{B.collection\ }$$ represents the sum of GHG emissions in kgCO$$\_2$$eq due to the transport of devices.
* $$N\_{i.\ collected}$$ is calculated in Equation 1.
* $$W\_{i}$$ is described in Equation 2.
* $$D$$ represents the distance of the device collection in kilometers, which is assumed to be 100 km.
* $$\ EF\_{truck\ transport}$$ represents the emission factor of truck transport in kgCO$$\_2$$eq/kg.km. Refer to [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7) for the ecoinvent process used.

</details>

### E-waste treatment

The treatment of e-waste is split between recycling, landfilling and incineration (Figure 2).

The proportion of e-waste recycled is based on national statistics obtained from the Eurostat database for small IT devices, as defined by the WEEE directive. Data for other countries where used devices are frequently sourced are taken from the [UN Global E-waste Monitor](#user-content-fn-11)[^11], and extrapolated where necessary. The dataset and more detailed information are in [Appendix 4](/methodologies/refurbishing-of-electronic-devices/appendix#id-3kg7rf7e4jf).

**First, the fraction of e-waste that is not separately collected** is assumed to be collected with municipal waste and incinerated or landfilled. In 2021, for example, this was an average of [31% ](#user-content-fn-12)[^12]for the countries included in Eurostat.

The repartition between landfilling and incineration (with and without energy recovery) was taken from Eurostat, and the total repartition for all EU countries from 2020 was used. This resulted in [52% incineration and 48% landfilling](#user-content-fn-13)[^13].

**Then, the fraction of e-waste that is separately collected** is considered (average of [69% in the EU in 2021](#user-content-fn-14)[^14]).

* This can be further broken down into the fraction successfully recycled/reused [(average of 79% for EU countries in 2021)](#user-content-fn-12)[^12] and the fraction that could not be recycled/reused (21%). Country specific fractions are used and are presented in [Appendix 4](#id-3kg7rf7e4jf).
* The separately collected e-waste that could not be recycled/reused is assumed to be incinerated and landfilled, with the same proportions described in the Baseline scenario section [#e-waste-treatment](#e-waste-treatment "mention").

<details>

<summary><strong>Calculation baseline e-waste treatment</strong></summary>

This step calculates the GHG emissions from the baseline e-waste treatment life cycle stage ($$Total\ E\_{B.\ waste\ treatment}$$).

$$\begin{aligned}\textbf{(Eq.14)}\ E\_{B.waste} = \sum\ &(N\_{i.\ collected}*W\_{i}\ *(1 - {RR\_{rate. i}}\_{}))\\*&(L\_{rate}*\ EF\_{landfill} + I\_{rate}\*{EF}\_{incineration})\end{aligned}$$

where,

* $$E\_{B.waste\ }$$ represents the sum of GHG emissions due to the **e-waste treatment of devices not separately collected**.
* $$N\_{i.\ collected}$$ and $$\ W\_{i}$$ are described in the section [#calculations-baseline-e-waste-collection](#calculations-baseline-e-waste-collection "mention").
* $$W\_{i}$$ is described in Equation 2.
* $${RR}\_{rate}$$ represents the project's country waste reuse and recycling rate. These rates are presented in [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7).
* $$L\_{rate}$$ and $$I\_{rate}$$ represent the landfilling and incineration rates, respectively, described in section [#e-waste-treatment](#e-waste-treatment "mention").
* $$EF\_{landfill}$$ represents the emission factor of treating e-waste via landfill, in kgCO$$\_2$$eq/kg using ecoinvent database, according to the breakdown of materials on pg. 11 of the [ADEME study](#user-content-fn-4)[^4]:
  * treatment of waste plastic, mixture, sanitary landfill = 50%
  * treatment of waste glass, sanitary landfill = 10%
  * treatment of waste aluminum, sanitary landfill = 40%
* $$EF\_{incineration}$$ represents the emission factor of treating e-waste via incineration, in kgCO$$\_2$$eq/kg using ecoinvent database according to the following split :
  * treatment of waste glass, municipal incineration = 10%
  * treatment of waste plastic, consumer electronics, municipal incineration = 50%
  * treatment of scrap copper, municipal incineration = 20%
  * treatment of scrap aluminum, municipal incineration = 20%

$$\textbf{(Eq.15)}\ E\_{B.separate\ waste} = \sum(N\_{i.\ collected}*W\_{.i}*{RR\_{rate.i}}*{}\*\ EF*{recycling.i}$$*)*

where,

* $$E\_{B.separate\ waste}$$ represents the sum of GHG emissions due to the e-waste treatment of **separately collected devices**.
* $$N\_{i.\ collected}$$ ,$$\ W\_{i\ }$$, and $${RR}\_{rate}$$ are describe above.
* $$EF\_{\ recycling.i}$$ represents the emission factor of recycling device *i*, in kgCO$$\_2$$eq/kg. Refer to [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7) for the ecoinvent process implemented.

$$\textbf{(Eq.16)}\ Total\ E\_{B.\ waste\ treatment} = E\_{B.waste} + {E\_{B.separate\ waste}}$$

where,

* $$Total\ E\_{B.\ waste\ treatment}$$represents the sum of GHG emissions in the baseline scenario e-waste treatment life cycle stage, in kgCO$$\_2$$eq.

</details>

### New device production <a href="#aq9a8bw7wcjk" id="aq9a8bw7wcjk"></a>

The number of new devices to consider in the baseline scenario corresponds to the number of devices successfully refurbished and sold in a functional state in the project scenario. Note that this does not necessarily equal the number of used devices collected, because a fraction of devices can not be successfully refurbished.

To quantify avoided GHG emissions, the **baseline scenario must consider the market share of the project technology already in use**. Currently, new device purchases come from both new manufacturing and existing refurbishing activities, and this is reflected in the baseline scenario (see Figure 2). The proportions of new and refurbished devices are detailed in Table 5.

{% hint style="info" %}
For example, in 2022, 87% of smartphones sold in Europe were new, while 13% were refurbished (Table 5). Thus, each smartphone refurbished by the project is assumed to replace the manufacturing of 0.87 new devices.
{% endhint %}

*Table 5 Market share of refurbished devices sold annually in Europe. See* [*Appendix 6*](/methodologies/refurbishing-of-electronic-devices/appendix#id-5lf32r1yzlvs) *for more details.*

| Device            | Percent Refurbished | Percent new |
| ----------------- | ------------------- | ----------- |
| Smartphone/iPhone | 13%                 | 87%         |
| Tablet/iPad       | 7%                  | 93%         |
| Laptop/Macbook    | 8%                  | 92%         |
| PC/iMac           | 8%                  | 92%         |
| Gaming console    | 6%                  | 94%         |
| Monitor           | 6%                  | 94%         |

The process of manufacturing a new device is taken from the ecoinvent database: laptop, PC, tablet, and monitor (See [Appendix 1](/methodologies/refurbishing-of-electronic-devices/appendix#jfq1kp34xji7)).

GHG emissions from manufacturing Apple devices (iPhones, iPads, iMacs, and Macbooks) are taken from the production-stage impacts reported in Apple’s Product Environmental Reports. An average emission factor for recent models of devices was taken, and the emission factors considered are presented in [Appendix 2](/methodologies/refurbishing-of-electronic-devices/appendix#nnoq7cm16r60).

The emission factor for smartphones was based on ecoinvent data and adjusted to better represent average smartphones. This was necessary because

1. smartphones are one of the most frequently refurbished devices, so special attention should be paid to them
2. [smartphone emission factors are notoriously variable](#user-content-fn-15)[^15], and
3. it has been noted that [ecoinvent smartphone emission factors are underestimated](#user-content-fn-16)[^16]. See [Appendix 5](/methodologies/refurbishing-of-electronic-devices/appendix#oqs0gfvs1gpx) for full details.

The difference in lifetime between refurbished and new devices, described in the [Baseline Scope](/methodologies/refurbishing-of-electronic-devices/eligible-technologies#baseline-scope) section, is accounted for in this life cycle stage. **The amount of new device production avoided in the baseline scenario is proportional to the ratio of new and refurbished device lifetimes**.

{% hint style="info" %}
Note that this ratio is only applied to the new manufacturing of devices, as shown in Table 5, and not applied to avoided refurbished devices in the baseline scenario.
{% endhint %}

The impacts of refurbishing devices are described in the Refurbishing process section above.

<details>

<summary><strong>Calculation new device production</strong></summary>

This step calculates the GHG emissions from the baseline device production life cycle stage ($$Total\ E\_{B.\ new\ device\ production\ \ }$$).

$$\textbf{(Eq.17)}\ E\_{new\.device} = \sum(\ N\_{i.\ sold}\*{frac}*{New}\*EF*{new\.i})$$

where,

* $${E\_{new\.device}}\_{\ }$$ represents the sum of GHG emissions in kgCO$$\_2$$eq due to the **production of new devices** (i.e. excluding the market share of refurbished devices that are already in use).
* $$N\_{i.\ sold\ }$$ was described in Equation 1.
* $${frac}\_{New}$$ refers to the market share (in percentage) of new devices sold annually per device type *i*, as presented in Table 1.
* $${{EF}*{new\.i}}*{\ }$$ represents the emission factor in kgCO$$\_2$$eq/kg due to the production of the new device type *i*. The emission factors of new devices are presented in Table 3.

$$\textbf{(Eq.18)}\ E\_{Ref\ B} = \sum(\ N\_{i.\ sold}\*frac\_{Refurb}\*R\_{full\ ref.i}\*EF\_{full\ ref})$$

where,

* $$E\_{Ref\ B}$$ represents the sum of GHG emissions due to the **refurbishing of used devices** according to the market shares in the baseline scenario.
* $$N\_{i.\ sold\ }$$ was described in Equation 1.
* $${frac}\_{Refurb}$$ refers to the market share (in percentage) of refurbished devices sold annually per device type *i*, as presented in Table 5.
* $$R\_{full\ ref.i}$$ and $$EF\_{full\ ref}$$ are described in Equation 9.

Refurbished devices are assumed to have a shorter lifespan than new devices, as described in the [Baseline Scope](/methodologies/refurbishing-of-electronic-devices/eligible-technologies#baseline-scope) section. This is accounted for in the following adjustment to avoided emissions from new device manufacturing:

$$\textbf{(Eq.19)}\ E\_{new\ device\ lifetime\ adjusted} = \sum(E\_{new\ device\ .i}\*\ Y\_{refurbished.i}/Y\_{new\.i})$$

where,

* $${Y\_{refurbished.i}}\_{\ }$$ represents the expected lifespan of a refurbished device *i* in number of years, as presented in Table 3.
* $$Y\_{new\.i}$$ represents the expected lifespan of a new device *i* in number of years, as presented in Table 3.

The total GHG emission for this life cycle stage are calculated according to the following equation:

$$\textbf{(Eq.20)}\ Total\ E\_{B.\ new\ device\ production} = E\_{Ref} + E\_{new\ device\ lifetime\ adjusted}$$

where,

* $$\ Total\ E\_{B.\ new\ device\ production\ \ }$$represents the sum of GHG emissions in the baseline scenario new device production life cycle stage, in kgCO$$\_2$$eq.

</details>

## Avoided GHG emissions

Avoided GHG emissions are calculated by subtracting the sum of the project scenario GHG emissions from the sum of the baseline GHG scenario emissions.

<details>

<summary><strong>Comparative GHG assessment calculation</strong></summary>

The total baseline GHG emissions, total project GHG emissions, and the project's avoided emissions are calculated as follows.

$$\begin{aligned}\textbf{(Eq.21)}\ Project\ emissions\ = \ \&Total\ E\_{P.collection} \\+ \ \&Total\ E\_{P.waste\ treatment} \\+\ \&Total\ E\_{P.refurbishing\ process}\end{aligned}$$

$$\begin{aligned}\textbf{(Eq.22)}\ Baseline\ emissions = \ &{Total\ E}*{B.collection} \\+ \&Total\ E*{B.\ waste\ treatment} \\+ &{Total\ E}\_{B.\ new\ device\ production\ \ }\end{aligned}$$

$$\textbf{(Eq.\ 23)}\ Avoided\ emissions\ = \ Baseline\ emissions\ - \ Project\ emissions$$

</details>

## Uncertainty assessment

An uncertainty assessment is presented below for all aspects of GHG quantification set **at the methodology level**. The findings from this assessment are then applied **at the project level**, where project-specific GHG quantification also undergoes an uncertainty assessment.

The **overall project GHG quantification uncertainty** is determined by qualitatively combining both the methodology-level and project-specific uncertainties for each identified source of uncertainty.

The [assumptions](#assumptions) that are estimated to have **high uncertainty** (i.e. high variability and high impact) are:

* The amount of devices avoided in the baseline scenario is proportional to the ratio of new and refurbished device **lifetimes**.
* The ratio of new and refurbished device GHG emissions from ADEME can be extrapolated to represent the refurbishing process of all similar devices.
* The residual economic value of used devices represents the GHG emissions that should be allocated from production Device A first life to the refurbished Device B.

The [assumptions](#assumptions) that are estimated to have **moderate uncertainty** are:

* **Similar devices have similar characteristics** (mass, emission factor, lifetime), leading to grouping devices into device type categories rather than assessing specific device models and brands.
* The distribution of Device B in the baseline and project scenarios is assumed to be the same.

The [assumptions](#assumptions) that are estimated to have **low uncertainty** (i.e. low variability and low impact) are:

* Non-functioning parts are assumed to be recycled.
* The distance for e-waste collection of Device A in the baseline scenario is assumed to be 100 km.
* Packaging, use, and waste treatment of Device B are assumed to be the same in the baseline and project scenarios.
* Monitors with no size breakdown are assumed to be <25". This assumption is conservative, as smaller monitors are associated with lower impacts from new device production, resulting in reduced avoided emissions.

The baseline scenario selection has **low uncertainty** and is mostly standardized. It accounts for project-specific information regarding the number, type and fate of devices, and national e-waste management statistics.

The equations used in this methodology consist of basic conversions and have **low uncertainty**.

Many estimates and secondary data are used in this methodology to enable a reasonable amount of project data collection. These data have varying levels of uncertainty, and are assessed in Table 6.

The uncertainty at the methodology level is estimated to be moderate. This translates to an **expected discount factor of at least 10%** for projects under this methodology.

*Table 6 Presentation of all secondary data and estimates used, and an assessment of their uncertainty.*

<table><thead><tr><th width="141">Parameter</th><th width="128">Reference in document</th><th>Uncertainty assessment</th></tr></thead><tbody><tr><td>Emissions new device (kgCO<sub>2</sub>eq)</td><td>Table 3</td><td><p>For Apple devices, an average emission factor for new device production was taken from recent models, and the data samples are presented in <a href="/pages/NBUhyXPRACrQfq8Pp3If#nnoq7cm16r60">Appendix 2</a>. There is low uncertainty in the data samples, since the LCAs come from the manufacturer for the specific model. There is moderate uncertainty related to the distribution of these values, where the different devices have coefficients of variation (standard deviation/mean) of 6-36%.</p><p>For smartphones, the emission factor from ecoinvent has been thoroughly researched and modified to better represent average modern smartphones. Still, there is large variability in smartphone design, and there is high uncertainty in this one representative value.</p><p>Other devices come from ecoinvent processes and similar to smartphones, have variable designs, so there is high uncertainty in using one representative value.</p></td></tr><tr><td>Impact of refurbished (%)</td><td>Table 3</td><td>This percentage comes from the detailed <a href="https://librairie.ademe.fr/ged/7385/ademe_impact_environnemental_reconditionnement_rapport_en.pdf">ADEME refurbishing LCA</a>. That study uses high quality primary data so the values themselves have low uncertainty.</td></tr><tr><td>Average mass (kg)</td><td>Table 3</td><td>The same analysis can be applied from “Emissions new device (kgCO<sub>2</sub>eq)”. However this parameter has a smaller impact on the avoided GHG emissions calculations, so the uncertainty can be considered lower.</td></tr><tr><td>Lifetime new and refurbished (years)</td><td>Table 3</td><td>These values come from the detailed <a href="https://librairie.ademe.fr/ged/7385/ademe_impact_environnemental_reconditionnement_rapport_en.pdf">ADEME refurbishing LCA</a> and are well within the range of expected lifetimes found elsewhere in the literature. Nonetheless, these estimates have a large impact on the results and are expected to have moderate uncertainty.</td></tr><tr><td>Market share refurbished vs new (percent)</td><td>Table 5</td><td>This secondary data is highly influential and is estimated to have low uncertainty for smartphones, where precise data were available for many countries. For other device types, there is moderate uncertainty.</td></tr><tr><td>Residual value of input devices</td><td>Table 4, <a href="#oi5bmdhs49zb">Appendix 7</a></td><td>This measurement comes from device buyback prices and new device prices. For smartphones and tablets, there is low uncertainty here because buyback data came directly from Project Developers, and a large and representative sample of new device prices was taken. For other device types, the lack of buyback price data leads to moderate uncertainty.</td></tr><tr><td>WEEE statistics</td><td><a href="#id-3kg7rf7e4jf">Appendix 4</a></td><td>These values have moderate uncertainty because they come from macro-level national datasets.</td></tr></tbody></table>

[^1]: ISO 14064-2:2019. Greenhouse gases — Part 2: Specification with guidance at the project level for quantification, monitoring and reporting of greenhouse gas emission reductions or removal enhancements.

[^2]: Wernet, G., Bauer, C., Steubing, B., Reinhard, J., Moreno-Ruiz, E., Weidema, B., 2016. The ecoinvent database version 3 (part I): overview and methodology. Int J Life Cycle Assess 21, 1218–1230. <https://doi.org/10.1007/s11367-016-1087-8> ↑

[^3]: [Eurostat 2023](https://ec.europa.eu/eurostat/statistics-explained/index.php?title=International_trade_and_production_of_high-tech_products#Manufacturing_of_high-tech_products), International trade and production of high-tech products. Accessed April 2024.

[^4]: Fangeat Erwann, ADEME, Laurent Eskenzai, Eric Fourboul, Hubblo, Julie Orgelet-Delmas,

    DDemain, Etienne Lees Perasso, Firmin Domon, LCIE Bureau Veritas. 2022. [Assessment of the environmental impact of a set of refurbished products – Final report](https://librairie.ademe.fr/ged/7385/ademe_impact_environnemental_reconditionnement_rapport_en.pdf). 180 pages.

[^5]: Refer to Appendix 1 for the ecoinvent processes used for non-Apple devices, to Appendix 5 for the modifications made to the ecoinvent smartphone production process, and to Appendix 2 for Apple emission factor sources.

[^6]: Based on the[ ADEME study](https://librairie.ademe.fr/ged/7385/ademe_impact_environnemental_reconditionnement_rapport_en.pdf) ratio of GHG emissions of new vs. refurbished devices emissions, described in paragraph 3.4.7. Refer to Appendix 3.

[^7]: Based on the [ADEME study](https://librairie.ademe.fr/ged/7385/ademe_impact_environnemental_reconditionnement_rapport_en.pdf) for smartphone, laptop, PC and tablet. Apple products' weights are presented in Appendix 3.

[^8]: [ADEME study](https://librairie.ademe.fr/ged/7385/ademe_impact_environnemental_reconditionnement_rapport_en.pdf), Table 2, pg 27.

[^9]: Kouloumpis, V., Konstantzos, G.E., Chroni, C., Abeliotis, K. and Lasaridi, K. (2023). Does the circularity end justify the means? A life cycle assessment of preparing waste electrical and electronic equipment for reuse. Sustainable Production and Consumption, \[online] 41, pp.291–304. doi:<https://doi.org/10.1016/j.spc.2023.08.008>.

[^10]: Pamminger, R., Glaser, S., Wimmer, W., 2021. Modelling of different circular end-of-use scenarios for smartphones. Int J Life Cycle Assess 26, 470–482. <https://doi.org/10.1007/s11367-021-01869-2>

[^11]: Cornelis P. Baldé, Ruediger Kuehr, Tales Yamamoto, Rosie McDonald, Elena D’Angelo, Shahana Althaf, Garam Bel, Otmar Deubzer, Elena Fernandez-Cubillo, Vanessa Forti, Vanessa Gray, Sunil Herat, Shunichi Honda, Giulia Iattoni, Deepali S. Khetriwal, Vittoria Luda di Cortemiglia, Yuliya Lobuntsova, Innocent Nnorom, Noémie Pralat, Michelle Wagner (2024). International Telecommunication Union (ITU) and United Nations Institute for Training and Research (UNITAR). 2024. [Global E-waste Monitor 2024](https://ewastemonitor.info/wp-content/uploads/2024/03/GEM_2024_18-03_web_page_per_page_web.pdf). Geneva/Bonn.

[^12]: Eurostat 2023. Waste electrical and electronic equipment (WEEE) by waste management operations - open scope, 6 product categories (from 2018 onwards). DOI: <https://doi.org/10.2908/ENV_WASELEEOS>. Accessed April 2024.

[^13]: Eurostat 2023. Management of waste excluding major mineral waste, by waste management operations. DOI: <https://doi.org/10.2908/ENV_WASOPER>. Accessed April 2024.

[^14]: Eurostat 2023. Waste electrical and electronic equipment (WEEE) by waste management operations - open scope, 6 product categories (from 2018 onwards). DOI: <https://doi.org/10.2908/ENV_WASELEEOS>. Accessed April 2024.

    \\

[^15]: Clément, L.-P.P.-V. .P., Jacquemotte, Q.E.S. and Hilty, L.M. (2020). Sources of variation in life cycle assessments of smartphones and tablet computers. *Environmental Impact Assessment Review*, 84, p.106416. doi:<https://doi.org/10.1016/j.eiar.2020.106416>.

[^16]: Smartphones’ carbon footprints are largely underestimated. (2023). *Le Monde.fr*. \[online] 16 Apr. Available at: <https://www.lemonde.fr/en/pixels/article/2023/04/16/smartphones-carbon-footprints-are-largely-underestimated\\_6023093\\_13.html>.


# Circularity Assessment

**Projects that reduce GHG emissions and are issued Rainbow Carbon Credits typically also contribute to a circular economy.** The assessment of a project's circularity is **considered under the co-benefits criteria**, and represents the [Sustainable Development Goal](https://unstats.un.org/sdgs/indicators/Global-Indicator-Framework-after-2024-refinement-English.pdf) (SDG) number 12.2.

The **Material Circularity Indicator (MCI)** is the selected measure of circularity, due to its comprehensive assessment of material flows and alignment with global standards, notably established by The Ellen MacArthur Foundation.

The MCI examines mass of material flows throughout a product's lifecycle. It evaluates how efficiently materials circulate within a closed-loop system, assigning “more circular” scores to systems that minimize waste and optimize resource reuse. The formula uses input parameters such as material feedstock amount and type (e.g. from recycled, reused or biological sources), recycling rates, and lifespan extension potential to quantify a product's circularity.

[A detailed description and formulas for calculating the MCI are documented](#user-content-fn-1)[^1] in the dedicated [methodology document](https://content.ellenmacarthurfoundation.org/m/77e62bc9924c20d0/original/Circularity-Indicators-Methodology.pdf), on pages 22 to 31, following the Product-level Methodology under the Whole product approach). Figure 3, modified from [Cottafava, D. and Ritzen, M. (2021)](#user-content-fn-2)[^2] summarizes the MCI material flows.

The MCI is a unitless indicator that varies from 0 to 1, where 0 represents a fully linear product and 1 is fully circular. The project scenario MCI is compared to the baseline scenario MCI, **measuring how much more circular the project scenario is than the baseline**.

The MCI methodology has been applied to electronic device refurbishment using the input data presented in Table 7.

<figure><img src="/files/5wQo1I8lJbkH3tFKVPEE" alt=""><figcaption><p><em>Figure 3</em> <em>Summarized representation of the MCI material flows. Only landfill is considered in the MCI for electronic devices. Energy recovery as part of a circular strategy only applies to biological materials following the MCI's conditions.</em></p></figcaption></figure>

*Table 7 All variables needed to calculate the Material Circularity Indicator (MCI) for the Rainbow Electronic Device Refurbishing methodology are detailed below. The full methodology and equations can be found in the dedicated* [*methodology document*](https://content.ellenmacarthurfoundation.org/m/77e62bc9924c20d0/original/Circularity-Indicators-Methodology.pdf)*.*

<table data-header-hidden data-full-width="true"><thead><tr><th width="114"></th><th width="224"></th><th width="358"></th><th></th></tr></thead><tbody><tr><td><strong>Symbol</strong></td><td><strong>Definition by the MCI</strong></td><td><strong>Guidelines for the project scenario</strong></td><td><strong>Guidelines for the baseline scenario</strong></td></tr><tr><td><span class="math">M</span></td><td>Mass of a product</td><td><p>Total mass (kg) of refurbished devices in the project scenario, according to Table 3.</p><p><span class="math">M = \sum ( N_{rec\ and \ ref\ devices.i} \ *\ W_{device.i}</span></p><p>Where <span class="math">N_{rec\ and \ ref\ devices.i}</span> is the number of refurbished devices <span class="math">i</span>, and <span class="math">W_{device.i}</span>represents the weight in kilograms of device <span class="math">i</span></p></td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">Fr</span></td><td>Fraction of mass of a product's feedstock from recycled sources</td><td>Assumed zero</td><td>Assumed zero</td></tr><tr><td><span class="math">Fu</span></td><td>Fraction of mass of a product's feedstock from reused sources</td><td><p>Considers the mass of devices refurbished (<span class="math">M</span>) and the mass of new pieces acquired (<span class="math">N_p</span>, in kg):</p><p><span class="math">Fu = (M-N_p)/M</span></p><p>Project developers shall provide <span class="math">N_p</span> or an assumption based on its activity. If not available, 9% of virgin pieces will be considered in full refurbishing devices.</p></td><td>Assumed zero</td></tr><tr><td><span class="math">Fs</span></td><td>Fraction of a product's biological feedstock from Sustained production.</td><td>It is assumed that no biological feedstock is used in electronic devices.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">V</span></td><td>Material that is not from reuse, recycling or biological material from sustained production.</td><td>The amount of virgin materials used in the project scenario is the same as the Np when virgin material shall be extracted to produce new pieces.</td><td>All the input materials are considered virgin as no reuse or recycled materials are assumed in a status quo scenario.</td></tr><tr><td><span class="math">Cr</span></td><td>Fraction of mass of a product being collected to go into a recycling process</td><td>Value based on the collection rate of each country and its recycling rate as presented in the <a data-mention href="/pages/WPAshv0XY55UIZ6jVXut#calculation-baseline-e-waste-treatment">/pages/WPAshv0XY55UIZ6jVXut#calculation-baseline-e-waste-treatment</a>. After the end of the device's first and second life, the product is assumed to follow the country's recycling rates where waste is generated.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">Cu</span></td><td>Fraction of mass of a product going into component reuse</td><td>Fraction considered under the Cr variable, according to the country's rates.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">Cc</span></td><td>Fraction of mass of a product being collected to go into a composting process</td><td>As no biological feedstock is used in electronic devices, this value is assumed to be zero.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">Ce</span></td><td>Fraction of mass of a product being collected for energy recovery where the material satisfies the requirements for inclusion</td><td>Energy recovery as part of a circular strategy only applies to biological materials, according to the MCI methodology. This value is assumed to be zero.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">Wo</span></td><td>Mass of unrecoverable waste through a product's material going into landfill, waste to energy and any other type of process where the materials are no longer recoverable</td><td>Following the MCI calculation methodology, this value is the same for both scenarios. Due to the comparative approach, it can be excluded.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">Ec</span></td><td>Efficiency of the recycling process used for the portion of a product collected for recycling</td><td>Varies according to the country's rate, presented by <a data-footnote-ref href="#user-content-fn-3">Eurostat (2020)</a>.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">Wc</span></td><td>Mass of unrecoverable waste generated in the process of recycling parts of a product</td><td>Following the MCI calculation methodology, this value is the same for both scenarios. Due to the comparative approach, it can be excluded.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">Ef</span></td><td>Efficiency of the recycling process used to produce recycled feedstock for a product</td><td>Assumed equal to Ec as no data are available specifically for electronic devices. Additionally, since Fr is considered zero, this variable is not impactful.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">Wf</span></td><td>Mass of unrecoverable waste generated when producing recycled feedstock for a product</td><td>Following the MCI calculation methodology, and considering Fr equal to zero, this value is zero.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">W</span></td><td>Mass of unrecoverable waste associated with a product</td><td>Following the MCI calculation methodology and Rainbow's guidelines, this value is the same for both scenarios. Due to the comparative approach, it can be excluded.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">LFI</span></td><td>Linear flow index</td><td>Varies from 0 to 1, where 1 is a completely linear flow and 0 is a completely restorative flow. In a circular project, the LFI shall be closer to zero, while the baseline shall be closer to 1.</td><td>Consider the same guidelines as for the project scenario</td></tr><tr><td><span class="math">L</span></td><td>Actual average lifetime of a product</td><td>Sum of lifespan of the product's first and second life according to Table 3, using an average weighted across all device types refurbished by the project.</td><td>Assumed 1</td></tr><tr><td><span class="math">Lav</span></td><td>Average lifetime of an industry-average product of the same type</td><td>Average lifespan of the product's first life, weighted across all device types refurbished by the project (Table 3)</td><td>Assumed 1</td></tr><tr><td><span class="math">U</span></td><td><a data-footnote-ref href="#user-content-fn-4">Actual average number of functional units</a> achieved during the use phase of a product</td><td>Calculated based on the extended lifetime of the project's product.</td><td>Assumed 1</td></tr><tr><td><span class="math">Uav</span></td><td>Average number of functional units achieved during the use phase of an industry-average product of the same type</td><td>Assumed 1</td><td>Assumed 1</td></tr><tr><td><span class="math">X</span></td><td>Utility of a product (function of the product's lifespan and intensity of use)</td><td>In electronics refurbishing projects, X is higher in the project scenario, as the project extends the product's life (<a href="https://content.ellenmacarthurfoundation.org/m/77e62bc9924c20d0/original/Circularity-Indicators-Methodology.pdf">MCI methodology, p. 29</a>)</td><td>Equal to 1 as the baseline scenario regards the status quo market (average industry scenario).</td></tr><tr><td><span class="math">MCI_p</span></td><td>Material Circularity Indicator of a product</td><td>Varies from 0 to 1, where 0 represents a fully linear product and 1 is fully circular.</td><td>Consider the same guidelines as for the project scenario</td></tr></tbody></table>

[^1]: Goddin, J., Marshall, K., Pereira, A., Tuppen, C., Herrmann, S., Jones, S., Krieger, T., Lenges, C., Coleman, B., Pierce, C., Iliefski-Janols, S., Veenendaal, R., Stoltz, P., Ford, L., Goodman, T., Vetere, M., Mistry, M., Graichen, F., Natarajan, A., Sullens, W., 2019. Circularity Indicators: An Approach to Measuring Circularity, Methodology. <https://doi.org/10.13140/RG.2.2.29213.84962> ↑

[^2]: Circularity indicator for residential buildings: Addressing the gap between embodied impacts and design aspects. Resources, Conservation and Recycling, 164, p.105120. doi:<https://doi.org/10.1016/j.resconrec.2020.105120>.

[^3]: [Eurostat, 2020](https://ec.europa.eu/eurostat/databrowser/view/cei_wm060/default/table?lang=en). Recycling rate of waste of electrical and electronic equipment (WEEE) separately collected. Online data code: CEI\_WM060. (accessed 2023).

[^4]: Represent the function of a product's use


# Version history

<table data-full-width="true"><thead><tr><th width="337">Change</th><th width="382">Justification</th><th width="130">Date</th><th>Version changed</th></tr></thead><tbody><tr><td>Combined the calculations for several types of devices</td><td>Some devices were grouped together and assumed to have the same impacts.</td><td>August 2023</td><td>V1.1 to V1.2</td></tr><tr><td>Added equations for calculation GHG reductions</td><td>Increased transparency.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td>Aligned terminology with ISO 14064-2:2019</td><td>Improved consistency with the voluntary carbon market. LCA principles still apply.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td>Added risk assessment template for environmental and social do no harm</td><td>Provide more detailed and prescriptive assessment framework, clearer instructions for project developers.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td><p>Removed text for sections that are the same for all methodologies:</p><ul><li>Measurability</li><li>Real</li><li>Technology readiness level</li><li>Minimum impact</li><li>Independently verified</li></ul></td><td>Repeated text from the Standard Rules.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td>Added Monitoring Plan section</td><td>Alignment with Riverse Standard Rules V6.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td>Remove Rebound Effect and Independently Validated criteria</td><td>Alignment with Riverse Standard Rules V6.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td>Added uncertainty assessment section</td><td>Alignment with Riverse Standard Rules V6.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td>Include fraction of refurbished devices already on the market in the baseline scenario of GHG reduction quantification</td><td>Alignment with Riverse Standard Rules V6 and increase conservativeness.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td>Assign input used devices a fraction of environmental impacts from their first life, allocated based on their residual value</td><td>Input used devices are no longer considered waste. A more conservative assumption was made.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td>E-waste treatment in the baseline scenario is modeled as a mix of e-waste incineration and landfill, rather than the ecoinvent process for device waste treatment. The latter is now used to model e-waste recycling (see Appendix 1 for ecoinvent activity names)</td><td>More accurate and representative of e-waste treatment practices.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td>Country WEEE rates come from data for only small IT and telecommunications devices, instead of all WEEE.</td><td>Improved precision, because statistics for all WEEE covered devices such as household appliances, lamps, photovoltaic panels.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td>Multiple WEEE rates from different countries are selected based on the source countries of collected devices.</td><td>Improved accuracy. Previously, only one source country could be selected in the calculation model.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td><p>New device emission factors from ecoinvent were updated (see Appendix 1):</p><ul><li>Smartphone: completely revised, see Appendix 5</li><li>Tablet, laptop: removed power adapter production, power adapter waste treatment, and the device waste treatment</li><li>PC: removed device waste treatment</li></ul></td><td>Improved accuracy and harmonization of system boundaries.</td><td>April 2024</td><td>V1.2 to V2.0</td></tr><tr><td>Added additionality section</td><td>Alignment with Riverse Standard Rules V6.</td><td>May 2024</td><td>V2.0 PC to V2.0</td></tr><tr><td>Replace number of devices collected for number of devices sold as main input data, from which other values are calculated</td><td>Devices sold are easier and more reliable to track for Project Developers</td><td>August 2024</td><td>V2.0 to V2.1</td></tr><tr><td>Change USA, China and Turkey e-waste recycling rates in Appendix 4</td><td>Previous rates were erroneously calculated.</td><td>October 2024</td><td>V2.1 to V2.2</td></tr><tr><td>Create project scope requirements</td><td>Specify that operations in different countries must be registered as separate projects</td><td>October 2024</td><td>V2.1 to V2.2</td></tr><tr><td>Add minimum list of ESDNH risks</td><td>Align with Standard Rules V6.2</td><td>October 2024</td><td>V2.1 to V2.2</td></tr><tr><td>Specify minimum frequency of updating baseline scenario</td><td>Clarity and transparency</td><td>October 2024</td><td>V2.1 to V2.2</td></tr><tr><td>Update desktop PC new and refurbished emission factors in Table 3</td><td>Typo in the values in the table, didn't match the values used in the model</td><td>May 2025</td><td>V2.2 to V2.3</td></tr><tr><td>Change GHG quantification from ecoinvent v3.10 to v3.11</td><td>Using more recent data</td><td>May 2025</td><td>V2.2 to V2.3</td></tr><tr><td>Update values in Table 3</td><td>Updated text to match model, after ecoinvent 3.11 update</td><td>September 2025</td><td>V2.3 to V2.4</td></tr><tr><td>Rename screen to monitor</td><td>Improve precision, since many devices contain screens</td><td>September 2025</td><td>V2.3 to V2.4</td></tr><tr><td>Revise light refurbishing process inputs</td><td>Added electricity, and corrected errors in input amounts for several device types</td><td>September 2025</td><td>V2.3 to V2.4</td></tr><tr><td>Add gaming console</td><td>Expanding device type options</td><td>September 2025</td><td>V2.3 to V2.4</td></tr><tr><td>Add large monitor (>25"), set existing monitor option as small monitor (&#x3C;25")</td><td>Expanding device type options</td><td>September 2025</td><td>V2.3 to V2.4</td></tr><tr><td>Additionality: Add requirement that projects in France have EBITDA lower than 10%</td><td>Allows projects in France to comply with <a href="https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000043966440">FR L229-55/R229-101</a></td><td>September 2025</td><td>V2.3 to V2.4</td></tr><tr><td>Add Audit Compliance table</td><td>Clear and transparent auditing instructions</td><td>September 2025</td><td>V2.3 to V2.4</td></tr><tr><td>Increase uncertainty discount from 6% to 10%</td><td>Alignment with Label Bas Carbone circularity methodologies</td><td>December 2025</td><td>V2.4 to V2.5</td></tr><tr><td>Speicfy only devices that have not already been refurbished are eligible.</td><td>Conservative measure</td><td>December 2025</td><td>V2.4 to V2.5</td></tr><tr><td>Restructure sections: added Baseline Scope, renamed Eligible technologies to Eligibility and scope, renamed Eligibility criteria to Principles &#x26; requirements, moved Monitoring Plan to Principles &#x26; requirements</td><td>Align with Standard Rules V7 structure</td><td>December 2025</td><td>V2.4 to V2.5</td></tr><tr><td>Remove TRL and targets alignment criteria, move Substitution criteria requirements to Baseline Scope section</td><td>Align with Standard Rules V7 requirements</td><td>December 2025</td><td>V2.4 to V2.5</td></tr><tr><td>New Certification Scope section with requirements for crediting and monitoring period, project updates with methodology revisions, and site audits.</td><td>Align with Standard Rules V7 requirements</td><td>December 2025</td><td>V2.4 to V2.5</td></tr><tr><td>Remove limits on number of co-benefits, and require quantification and monitoring of all co-benefits</td><td>Align with Standard Rules V7 requirements</td><td>December 2025</td><td>V2.4 to V2.5</td></tr><tr><td>Environmental and social risk mitigation plan required for moderate or higher risks, instead of high risk</td><td>Align with Standard Rules V7 requirements</td><td>December 2025</td><td>V2.4 to V2.5</td></tr><tr><td>Change GHG quantification from ecoinvent v3.11 to v3.12 (average change of 1.7±1% increase in avoided emissions)</td><td>Using more recent data</td><td>January 2026</td><td>V2.5 to V2.6</td></tr><tr><td>Add requirement for projects in France to prove additional gains beyond national target of 2% collection and reuse of WEEE</td><td>Allows projects in France to comply with <a href="https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000043966440">FR L229-55/R229-101</a></td><td>January 2026</td><td>V2.5 to V2.6</td></tr></tbody></table>


# Appendix

### Appendix 1 : Ecoinvent processes <a href="#jfq1kp34xji7" id="jfq1kp34xji7"></a>

*Table A1 List of ecoinvent 3.12 processes used in the GHG reduction quantification model*

<table><thead><tr><th width="215">Device type</th><th>Ecoinvent activity</th></tr></thead><tbody><tr><td><a data-footnote-ref href="#user-content-fn-1">Smartphone</a>*</td><td>consumer electronics production, mobile device, smartphone | consumer electronics, mobile device, smartphone | Cutoff, U, GLO</td></tr><tr><td>Tablet*</td><td>consumer electronics production, mobile device, tablet | consumer electronics, mobile device, tablet | Cutoff, U, GLO</td></tr><tr><td>PC**</td><td>computer production, desktop, without screen | computer, desktop, without screen | Cutoff, U, GLO</td></tr><tr><td>Laptop*</td><td>computer production, laptop | computer, laptop | Cutoff, U, GLO</td></tr><tr><td>Monitor</td><td>display production, liquid crystal, 17 inches | display, liquid crystal, 17 inches | Cutoff, U, GLO</td></tr><tr><td>Transport, truck</td><td>market for transport, freight, lorry 7.5-16 metric ton, EURO5 | transport, freight, lorry 7.5-16 metric ton, EURO5 | Cutoff, U, RER</td></tr><tr><td>Transport, air</td><td>market for transport, freight, aircraft, long haul | transport, freight, aircraft, long haul | Cutoff, U, GLO</td></tr><tr><td>Smartphone recycling</td><td>treatment of used smartphone, mechanical treatment | used smartphone | Cutoff, U, GLO</td></tr><tr><td>Tablet recycling</td><td>treatment of used tablet, mechanical treatment | used tablet | Cutoff, U, GLO</td></tr><tr><td>PC recycling</td><td>treatment of used desktop computer, mechanical treatment | used desktop computer | Cutoff, U, GLO</td></tr><tr><td>Laptop recycling</td><td>treatment of used laptop computer, mechanical treatment | used laptop computer | Cutoff, U, GLO</td></tr><tr><td>Monitor recycling</td><td>treatment of used liquid crystal display, mechanical treatment | used liquid crystal display | Cutoff, U, GLO</td></tr><tr><td>Light refurbishing***</td><td><ul><li>market for ethanol, without water, in 99.7% solution state, from ethylene | ethanol, without water, in 99.7% solution state, from ethylene | Cutoff, U, RER</li><li>market for water, completely softened | water, completely softened | Cutoff, U, RER</li><li>market for tissue paper | tissue paper | Cutoff, U, GLO</li><li>market for textile, knit cotton | textile, knit cotton | Cutoff, U, GLO</li><li>market for electricity, low voltage, country specific</li></ul></td></tr><tr><td>Full refurbishing</td><td><ul><li>market for ethanol, without water, in 99.7% solution state, from ethylene | ethanol, without water, in 99.7% solution state, from ethylene | Cutoff, U, RER***</li><li>market for water, completely softened | water, completely softened | Cutoff, U, RER***</li><li>market for tissue paper | tissue paper | Cutoff, U, GLO***</li><li>market for textile, knit cotton | textile, knit cotton | Cutoff, U, GLO***</li><li>market for battery, Li-ion, NCA, rechargeable, prismatic | Cutoff, U, GLO (0.1 kg)</li><li>market for electronic component, passive, mobile, earpiece and speaker | Cutoff, U, GLO (0.002 kg)</li><li>market for liquid crystal display, unmounted, mobile device | Cutoff, U, GLO (0.1 kg)</li></ul></td></tr><tr><td>E-waste incineration</td><td><ul><li>treatment of waste glass, municipal incineration | waste glass | Cutoff, U, GLO = 10%</li><li>treatment of waste plastic, consumer electronics, municipal incineration | waste plastic, consumer electronics | Cutoff, U, GLO = 50%</li><li>treatment of scrap copper, municipal incineration | scrap copper | Cutoff, U, Europe without Switzerland = 20%</li><li>treatment of scrap aluminum, municipal incineration | scrap aluminum | Cutoff, U, Europe without Switzerland= 20%</li></ul></td></tr><tr><td>E-waste landfill</td><td><ul><li>treatment of waste plastic, mixture, sanitary landfill | waste plastic, mixture | Cutoff, U, RoW = 50%</li><li>treatment of waste glass, sanitary landfill | waste glass l Cutoff, U, GLO = 10%</li><li>treatment of waste aluminum, sanitary landfill | waste aluminum | Cutoff, U, RoW = 40%</li></ul></td></tr></tbody></table>

\*removed the power adapter production and waste treatment, and the device waste treatment

\*\*removed the device waste treatment

\*\*\*amount of each input varies by device type, and values were taken from the ADEME study (see the [Light refurbishing section](/methodologies/refurbishing-of-electronic-devices/ghg-reduction-quantification#refurbishing-process))

### Appendix 2: Emission factors of Apple devices <a href="#nnoq7cm16r60" id="nnoq7cm16r60"></a>

*Table A2 Mass and GHG emissions from production for iPhones gathered from Apple Product Environmental Reports, for a selection of recent models.*

<table data-full-width="true"><thead><tr><th width="101">Year</th><th width="113">Model</th><th width="132">Memory (GB)</th><th width="106">Mass (kg)</th><th width="125">EF (kgCO2e)</th><th width="148">Production (%)</th><th width="211">EF production (kgCO2e)</th><th>Source</th></tr></thead><tbody><tr><td><strong>2022</strong></td><td>14</td><td>128</td><td>0.172</td><td>61</td><td>79%</td><td>48</td><td><a href="https://www.apple.com/iphone-14/specs/">source weight</a></td></tr><tr><td><strong>2022</strong></td><td>14</td><td>256</td><td>0.172</td><td>67</td><td>79%</td><td>53</td><td><a href="https://www.apple.com/environment/pdf/products/iphone/iPhone_14_and_iPhone_14_Plus_PER_Sept2022.pdf">source EF</a></td></tr><tr><td><strong>2022</strong></td><td>14</td><td>512</td><td>0.172</td><td>83</td><td>79%</td><td>66</td><td></td></tr><tr><td><strong>2022</strong></td><td>14 plus</td><td>128</td><td>0.203</td><td>68</td><td>78%</td><td>53</td><td><a href="https://www.apple.com/iphone-14/specs/">source weight</a></td></tr><tr><td><strong>2022</strong></td><td>14 plus</td><td>256</td><td>0.203</td><td>75</td><td>78%</td><td>59</td><td><a href="https://www.apple.com/environment/pdf/products/iphone/iPhone_14_and_iPhone_14_Plus_PER_Sept2022.pdf">source EF</a></td></tr><tr><td><strong>2022</strong></td><td>14 plus</td><td>512</td><td>0.203</td><td>91</td><td>78%</td><td>71</td><td></td></tr><tr><td><strong>2022</strong></td><td>14 pro</td><td>128</td><td>0.206</td><td>65</td><td>81%</td><td>53</td><td><a href="https://support.apple.com/kb/SP875?viewlocale=en_KG&#x26;locale=en_KG">source weight</a></td></tr><tr><td><strong>2022</strong></td><td>14 pro</td><td>256</td><td>0.206</td><td>71</td><td>81%</td><td>58</td><td><a href="https://www.apple.com/environment/pdf/products/iphone/iPhone_14_Pro_PER_Sept2022.pdf">source EF</a></td></tr><tr><td><strong>2022</strong></td><td>14 pro</td><td>512</td><td>0.206</td><td>84</td><td>81%</td><td>68</td><td></td></tr><tr><td><strong>2022</strong></td><td>14 pro</td><td>1TB</td><td>0.206</td><td>116</td><td>81%</td><td>94</td><td></td></tr><tr><td><strong>2022</strong></td><td>14 pro max</td><td>128</td><td>0.240</td><td>73</td><td>79%</td><td>58</td><td><a href="https://support.apple.com/kb/SP876?viewlocale=en_KG&#x26;locale=en_KG">source weight</a></td></tr><tr><td><strong>2022</strong></td><td>14 pro max</td><td>256</td><td>0.240</td><td>80</td><td>79%</td><td>63</td><td><a href="https://www.apple.com/environment/pdf/products/iphone/iPhone_14_Pro_Max_PER_Sept2022.pdf">source EF</a></td></tr><tr><td><strong>2022</strong></td><td>14 pro max</td><td>512</td><td>0.240</td><td>93</td><td>79%</td><td>73</td><td></td></tr><tr><td><strong>2022</strong></td><td>14 pro max</td><td>1TB</td><td>0.240</td><td>124</td><td>79%</td><td>98</td><td></td></tr><tr><td><strong>2023</strong></td><td>15</td><td>128</td><td>0.171</td><td>56</td><td>80%</td><td>45</td><td><a href="https://www.apple.com/iphone-15/specs/">weight source</a></td></tr><tr><td><strong>2023</strong></td><td>15</td><td>256</td><td>0.171</td><td>61</td><td>80%</td><td>49</td><td><a href="https://www.apple.com/environment/pdf/products/iphone/iPhone_15_and_iPhone_15_Plus_PER_Sept2023.pdf">source EF</a></td></tr><tr><td><strong>2023</strong></td><td>15</td><td>512</td><td>0.171</td><td>74</td><td>80%</td><td>59</td><td></td></tr><tr><td><strong>2023</strong></td><td>15 plus</td><td>128</td><td>0.201</td><td>61</td><td>79%</td><td>48</td><td><a href="https://www.apple.com/iphone-15/specs/">weight source</a></td></tr><tr><td><strong>2023</strong></td><td>15 plus</td><td>256</td><td>0.201</td><td>66</td><td>79%</td><td>52</td><td><a href="https://www.apple.com/environment/pdf/products/iphone/iPhone_15_and_iPhone_15_Plus_PER_Sept2023.pdf">source EF</a></td></tr><tr><td><strong>2023</strong></td><td>15 plus</td><td>512</td><td>0.201</td><td>79</td><td>79%</td><td>62</td><td></td></tr><tr><td><strong>2023</strong></td><td>15 pro</td><td>128</td><td>0.187</td><td>66</td><td>83%</td><td>55</td><td><a href="https://www.apple.com/iphone-15-pro/specs/">weight source</a></td></tr><tr><td><strong>2023</strong></td><td>15 pro</td><td>256</td><td>0.187</td><td>71</td><td>83%</td><td>59</td><td><a href="https://www.apple.com/environment/pdf/products/iphone/iPhone_15_Pro_and_iPhone_15_Pro_Max_Sept2023.pdf">EF source</a></td></tr><tr><td><strong>2023</strong></td><td>15 pro</td><td>512</td><td>0.187</td><td>83</td><td>83%</td><td>69</td><td></td></tr><tr><td><strong>2023</strong></td><td>15 pro</td><td>1TB</td><td>0.187</td><td>107</td><td>83%</td><td>89</td><td></td></tr><tr><td><strong>2023</strong></td><td>15 pro max</td><td>256</td><td>0.221</td><td>75</td><td>83%</td><td>62</td><td><a href="https://www.apple.com/iphone-15-pro/specs/">weight source</a></td></tr><tr><td><strong>2023</strong></td><td>15 pro max</td><td>512</td><td>0.221</td><td>87</td><td>83%</td><td>72</td><td><a href="https://www.apple.com/environment/pdf/products/iphone/iPhone_15_Pro_and_iPhone_15_Pro_Max_Sept2023.pdf">EF source</a></td></tr><tr><td><strong>2023</strong></td><td>15 pro max</td><td>1TB</td><td>0.221</td><td>110</td><td>83%</td><td>9</td><td></td></tr></tbody></table>

<table data-header-hidden><thead><tr><th width="666"></th><th></th></tr></thead><tbody><tr><td><em><strong>Mean</strong></em></td><td>64</td></tr><tr><td><em><strong>Median</strong></em></td><td>59</td></tr><tr><td><em><strong>Standard Deviation</strong></em></td><td>14.6</td></tr><tr><td><em><strong>Coefficient of variation (Standard Deviation/Mean) (%)</strong></em></td><td>22.8%</td></tr></tbody></table>

*Table A3 Mass and GHG emissions from production for iPads gathered from Apple Product Environmental Reports, for a selection of recent models*

<table data-header-hidden><thead><tr><th></th><th width="109"></th><th></th><th></th><th></th><th></th><th></th><th></th></tr></thead><tbody><tr><td><strong>Year</strong></td><td><strong>Model</strong></td><td><strong>Memory (GB)</strong></td><td><strong>Mass (kg)</strong></td><td><strong>EF (kgCO2e)</strong></td><td><strong>Production (%)</strong></td><td><strong>EF production (kgCO2e)</strong></td><td><strong>Source</strong></td></tr><tr><td><strong>2021</strong></td><td>9th gen.</td><td>64</td><td>0.487</td><td>75</td><td>78%</td><td>59</td><td><a href="https://support.apple.com/kb/SP849?locale=en_US">weight source</a></td></tr><tr><td><strong>2021</strong></td><td>9th gen.</td><td>128</td><td>0.487</td><td>78</td><td>78%</td><td>61</td><td><a href="https://www.apple.com/by/environment/pdf/products/ipad/iPad_PER_Sept2021.pdf">source EF</a></td></tr><tr><td><strong>2021</strong></td><td>9th gen.</td><td>256</td><td>0.487</td><td>84</td><td>78%</td><td>66</td><td></td></tr><tr><td><strong>2022</strong></td><td>10th gen.</td><td>64</td><td>0.477</td><td>72</td><td>78%</td><td>56</td><td><a href="https://support.apple.com/kb/SP884?locale=en_US">weight source</a></td></tr><tr><td><strong>2022</strong></td><td>10th gen.</td><td>256</td><td>0.477</td><td>82</td><td>78%</td><td>64</td><td><a href="https://www.apple.com/environment/pdf/products/ipad/iPad_PER_Oct2022.pdf">source EF</a></td></tr><tr><td><strong>2023</strong></td><td>no iPad launched*</td><td></td><td></td><td></td><td></td><td></td><td></td></tr></tbody></table>

<table data-header-hidden><thead><tr><th width="666"></th><th></th></tr></thead><tbody><tr><td><em><strong>Mean</strong></em></td><td>61</td></tr><tr><td><em><strong>Median</strong></em></td><td>61</td></tr><tr><td><em><strong>Standard Deviation</strong></em></td><td>3.8</td></tr><tr><td><em><strong>Coefficient of variation (Standard Deviation/Mean) (%)</strong></em></td><td>6.29%</td></tr></tbody></table>

*\*2021 is also considered in the average iPad emissions to have a bigger sample*

*Table A4 Mass and GHG emissions from production for MacBooks gathered from Apple Product Environmental Reports, for a selection of recent models*

<table data-header-hidden><thead><tr><th></th><th width="108"></th><th></th><th width="73"></th><th width="121"></th><th width="124"></th><th></th><th></th></tr></thead><tbody><tr><td><strong>Year</strong></td><td><strong>Model</strong></td><td><strong>Memory (GB)</strong></td><td><strong>Mass (kg)</strong></td><td><strong>EF (kgCO2e)</strong></td><td><strong>Production (%)</strong></td><td><strong>EF production (kgCO2e)</strong></td><td><strong>Source</strong></td></tr><tr><td><strong>2022</strong></td><td>MacBook Air M2 chip</td><td>256</td><td>1.24</td><td>147</td><td>69%</td><td>101</td><td><a href="https://support.apple.com/kb/SP869?locale=en_US">source weight</a></td></tr><tr><td><strong>2022</strong></td><td>MacBook Air M2 chip</td><td>512</td><td>1.24</td><td>171</td><td>69%</td><td>118</td><td><a href="https://www.apple.com/environment/pdf/products/notebooks/M2_MacBook_Air_PER_June2022.pdf">source EF</a></td></tr><tr><td><strong>2022</strong></td><td>13-inch MacBook Pro</td><td>256</td><td>1.4</td><td>167</td><td>71%</td><td>119</td><td><a href="https://support.apple.com/kb/SP870?locale=en_US">source weight</a></td></tr><tr><td><strong>2022</strong></td><td>13-inch MacBook Pro</td><td>512</td><td>1.4</td><td>182</td><td>71%</td><td>129</td><td><a href="https://www.apple.com/environment/pdf/products/notebooks/13-inch_MacBook_Pro_PER_June2022.pdf">source EF</a></td></tr><tr><td><strong>2023</strong></td><td>16-inch MacBook Pro</td><td>M3 Pro 512GB</td><td>2.15</td><td>290</td><td>67%</td><td>194</td><td><a href="https://support.apple.com/kb/SP890?locale=en_US">source weight</a></td></tr><tr><td><strong>2023</strong></td><td>16-inch MacBook Pro</td><td>M3 Max 1TB</td><td>2.16</td><td>348</td><td>72%</td><td>251</td><td><a href="https://www.apple.com/environment/pdf/products/notebooks/16-inch_MacBook_Pro_PER_Oct2023.pdf">source EF</a></td></tr><tr><td><strong>2023</strong></td><td>14-inch MacBook Pro</td><td>M2 Pro 512GB</td><td>1.6</td><td>243</td><td>79%</td><td>192</td><td><a href="https://support.apple.com/kb/SP889?locale=en_US">source weight</a></td></tr><tr><td><strong>2023</strong></td><td>14-inch MacBook Pro</td><td>M2 Pro 1T</td><td>1.6</td><td>272</td><td>79%</td><td>215</td><td><a href="https://www.apple.com/environment/pdf/products/notebooks/14-inch_MacBook_Pro_PER_Jan2023.pdf">source EF</a></td></tr><tr><td><strong>2023</strong></td><td>14-inch MacBook Pro</td><td>M2 Max 1TB</td><td>1.63</td><td>301</td><td>79%</td><td>238</td><td></td></tr><tr><td><strong>2023</strong></td><td>MacBook Air 15-inch M2 chip</td><td>256</td><td>1.51</td><td>139</td><td>73%</td><td>101</td><td><a href="https://www.apple.com/kg/macbook-air-13-and-15-m2/specs/">source weight</a></td></tr><tr><td><strong>2023</strong></td><td>MacBook Air 15-inch M2 chip</td><td>512</td><td>1.51</td><td>152</td><td>73%</td><td>111</td><td><a href="https://www.apple.com/environment/pdf/products/notebooks/MacBook_Air_15-inch_PER_June2023.pdf">source EF</a></td></tr></tbody></table>

<table data-header-hidden><thead><tr><th width="513"></th><th></th></tr></thead><tbody><tr><td><em><strong>Mean</strong></em></td><td>161</td></tr><tr><td><em><strong>Median</strong></em></td><td>129</td></tr><tr><td><em><strong>Standard Deviation</strong></em></td><td>57.6</td></tr><tr><td><em><strong>Coefficient of variation (Standard Deviation/Mean) (%)</strong></em></td><td>35.8%</td></tr></tbody></table>

*Table A5 Mass and GHG emissions from production for iMacs gathered from Apple Product Environmental Reports, for a selection of recent models*

| **Year** | **Model**         | **Memory (GB)**     | **Mass (kg)** | **EF (kgCO2e)** | **Production (%)** | **EF production (kgCO2e)** | **Source**                                                                                                                         |
| -------- | ----------------- | ------------------- | ------------- | --------------- | ------------------ | -------------------------- | ---------------------------------------------------------------------------------------------------------------------------------- |
| **2021** | iMac (24 inches)  | M1 7-core GPU 256GB | 4.47          | 481             | 45%                | 216                        | [weight source](https://support.apple.com/kb/SP839?locale=en_US)                                                                   |
| **2021** | iMac (24 inches)  | M1 8-core GPU 256GB | 4.47          | 486             | 45%                | 219                        | [EF source](https://www.apple.com/environment/pdf/products/desktops/24-inch_iMac_PER_Apr2021.pdf)                                  |
| **2021** | iMac (24 inches)  | M1 8-core GPU 512GB | 4.47          | 511             | 45%                | 230                        |                                                                                                                                    |
| **2022** | no iMac launched  |                     |               |                 |                    |                            |                                                                                                                                    |
| **2023** | iMac (two ports)  | 256                 | 4.43          | 359             | 52%                | 187                        | weight source:[ here](https://support.apple.com/kb/SP896?locale=en_US) and[ here](https://support.apple.com/kb/SP897?locale=fr_FR) |
| **2023** | iMac (four ports) | 512                 | 4.48          | 389             | 52%                | 202                        | [EF source](https://www.apple.com/environment/pdf/products/desktops/iMac_PER_Oct2023.pdf)                                          |

<table data-header-hidden><thead><tr><th width="481"></th><th></th></tr></thead><tbody><tr><td><em><strong>Mean</strong></em></td><td>211</td></tr><tr><td><em><strong>Median</strong></em></td><td>216</td></tr><tr><td><em><strong>Standard Deviation</strong></em></td><td>16.7</td></tr><tr><td><em><strong>Coefficient of variation (Standard Deviation/Mean) (%)</strong></em></td><td>7.92%</td></tr></tbody></table>

### Appendix 3: Refurbishing Impact Ratio <a href="#id-21d91pp0841i" id="id-21d91pp0841i"></a>

*Table A6 The Refurbishing Impact Ratio is calculated by dividing the Results refurbished device column by the Results new device column. This fraction is then applied to the emission factors for new device impacts used in this study to obtain the emissions from the refurbishing process (Table 3).*

| Device type | Results new device (kgCO2eq) | Results refurbished device (kgCO2eq) | Refurbishing Impact Ratio | Source                                                                                                                                                                                              |
| ----------- | ---------------------------- | ------------------------------------ | ------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Smartphone  | 84                           | 7                                    | 8%                        | [ADEME study](https://librairie.ademe.fr/ged/7385/ademe_impact_environnemental_reconditionnement_rapport_en.pdf), p. 152 Table 62                                                                   |
| Tablet      | 74                           | 9                                    | 12%                       | [ADEME study](https://librairie.ademe.fr/ged/7385/ademe_impact_environnemental_reconditionnement_rapport_en.pdf), p. 157. Table 72                                                                  |
| Laptop      | 168                          | 18                                   | 11%                       | [ADEME study](https://librairie.ademe.fr/ged/7385/ademe_impact_environnemental_reconditionnement_rapport_en.pdf), p. 158. Table 74                                                                  |
| PC          | 256                          | 26                                   | 10%                       | [ADEME study (French version)](https://librairie.ademe.fr/ged/6720/ademe_impact_environnemental_reconditionnement_rapport.pdf), p. 107, and 166. Table 86                                           |
| Monitor     | 212                          | 22                                   | 10%                       | Emission factor extrapolated from PC results, adjusted by monitor weight, [ADEME study](https://librairie.ademe.fr/ged/7385/ademe_impact_environnemental_reconditionnement_rapport_en.pdf), pg 166. |

The following equation is used to solve for $$R\_{full\ ref.i}$$, which represents the rate of full refurbishment activities modeled per device type *i*. This reflects the “amount” of refurbishment used as an input for that device. This is used in Equation 9 and Equation 18. Its values for each device type are back calculated using this equation :

$$
\begin{align\*}
Emissions\ refurbished\_i\ (kgCO\_2 eq)\\
&= \ EF\_{new\.i}\ \*\ R\_{Ref. impact.i} \\
&= \ EF\_{Full\ refurbishing.i}\ *\ R\_{full\ ref.i}
\end{align*}
$$

where,

* $$EF\_{new}$$ represents the emission factor of the production of the new device, detailed in Table 3.
* $$R\_{Ref. impact}$$ represents the refurbishing impact ratio of the device.
* $$Emissions\ refurbished\_i\ (kgCO\_2 eq)$$represents the GHG emissions due to the full refurbishing of a device type *i*. These values have been calculated using secondary data and are summarized in Table 3.
* $$EF\_{Full\ refurbishing}$$ represents the emission factor of the full refurbishing process, which is composed of a mix of replacement parts and cleaning supplies, and is detailed in Appendix 1.

### Appendix 4: WEEE statistics <a href="#id-3kg7rf7e4jf" id="id-3kg7rf7e4jf"></a>

*Table A8 The national WEEE waste treatment rates are summarized. Sources are indicated in the column names. Percent of all small IT e-waste that is recycled/reused (column 3) was calculated by multiplying the Percent small IT e-waste separately collected (column 1) by Percent of separately collected small IT e-waste that is recycled/reused (column 2). Percent of all small IT e-waste in municipal waste stream (column 4) was calculated by subtracting Percent of all small IT e-waste that is recycled/reused (column 3) from 100%. Note that when percentages were >100, they were automatically set to 100.*

<table data-header-hidden><thead><tr><th width="143"></th><th width="133"></th><th></th><th></th><th></th></tr></thead><tbody><tr><td><strong>Country</strong></td><td><a data-footnote-ref href="#user-content-fn-2"><strong>Percent small IT e-waste separately collected</strong></a></td><td><a data-footnote-ref href="#user-content-fn-2"><strong>Percent of separately collected small IT e-waste that is recycled/reused</strong></a></td><td><a data-footnote-ref href="#user-content-fn-2"><strong>Percent of all small IT e-waste that is recycled/reused</strong></a></td><td><a data-footnote-ref href="#user-content-fn-2"><strong>Percent of all small IT e-waste in municipal waste stream</strong></a></td></tr><tr><td><strong>Europe average</strong></td><td>72%</td><td>79%</td><td>56%</td><td>44%</td></tr><tr><td><strong>Belgium</strong></td><td>100%</td><td>80%</td><td>80%</td><td>20%</td></tr><tr><td><strong>Bulgaria</strong></td><td>79%</td><td>85%</td><td>68%</td><td>32%</td></tr><tr><td><strong>Czechia</strong></td><td>57%</td><td>100%</td><td>57%</td><td>43%</td></tr><tr><td><strong>Denmark</strong></td><td>38%</td><td>83%</td><td>32%</td><td>68%</td></tr><tr><td><strong>Germany</strong></td><td>89%</td><td>85%</td><td>75%</td><td>25%</td></tr><tr><td><strong>Estonia</strong></td><td>74%</td><td>84%</td><td>62%</td><td>38%</td></tr><tr><td><strong>Ireland</strong></td><td>59%</td><td>86%</td><td>50%</td><td>50%</td></tr><tr><td><strong>Greece</strong></td><td>49%</td><td>60%</td><td>29%</td><td>71%</td></tr><tr><td><strong>Spain</strong></td><td>62%</td><td>68%</td><td>42%</td><td>58%</td></tr><tr><td><strong>France</strong></td><td>91%</td><td>73%</td><td>67%</td><td>33%</td></tr><tr><td><strong>Croatia</strong></td><td>60%</td><td>88%</td><td>52%</td><td>48%</td></tr><tr><td><strong>Italy</strong></td><td>44%</td><td>62%</td><td>27%</td><td>73%</td></tr><tr><td><strong>Cyprus</strong></td><td>75%</td><td>91%</td><td>68%</td><td>32%</td></tr><tr><td><strong>Latvia</strong></td><td>54%</td><td>77%</td><td>41%</td><td>59%</td></tr><tr><td><strong>Lithuania</strong></td><td>80%</td><td>77%</td><td>61%</td><td>39%</td></tr><tr><td><strong>Luxembourg</strong></td><td>64%</td><td>87%</td><td>56%</td><td>44%</td></tr><tr><td><strong>Hungary</strong></td><td>53%</td><td>77%</td><td>41%</td><td>59%</td></tr><tr><td><strong>Malta</strong></td><td>No data</td><td></td><td></td><td></td></tr><tr><td><strong>Netherlands</strong></td><td>77%</td><td>72%</td><td>55%</td><td>45%</td></tr><tr><td><strong>Austria</strong></td><td>96%</td><td>75%</td><td>73%</td><td>27%</td></tr><tr><td><strong>Poland</strong></td><td>No data</td><td></td><td></td><td></td></tr><tr><td><strong>Portugal</strong></td><td>82%</td><td>22%</td><td>18%</td><td>82%</td></tr><tr><td><strong>Romania</strong></td><td>No data</td><td></td><td></td><td></td></tr><tr><td><strong>Slovenia</strong></td><td>100%</td><td>90%</td><td>90%</td><td>10%</td></tr><tr><td><strong>Slovakia</strong></td><td>91%</td><td>92%</td><td>84%</td><td>16%</td></tr><tr><td><strong>Finland</strong></td><td>63%</td><td>95%</td><td>59%</td><td>41%</td></tr><tr><td><strong>Sweden</strong></td><td>53%</td><td>84%</td><td>45%</td><td>55%</td></tr><tr><td><strong>Iceland</strong></td><td>No data</td><td></td><td></td><td></td></tr><tr><td><strong>Liechtenstein</strong></td><td>No data</td><td></td><td></td><td></td></tr><tr><td><strong>Norway</strong></td><td>100%</td><td>77%</td><td>77%</td><td>23%</td></tr><tr><td><a data-footnote-ref href="#user-content-fn-3"><strong>China</strong></a></td><td>NA</td><td>NA</td><td>23%</td><td>77%</td></tr><tr><td><a data-footnote-ref href="#user-content-fn-3"><strong>USA</strong></a></td><td>NA</td><td>NA</td><td>82%</td><td>18%</td></tr><tr><td><a data-footnote-ref href="#user-content-fn-3"><strong>Turkey</strong></a></td><td>NA</td><td>NA</td><td>25%</td><td>75%</td></tr></tbody></table>

### Appendix 5: Ecoinvent activity smartphone changes <a href="#oqs0gfvs1gpx" id="oqs0gfvs1gpx"></a>

[GHG quantification](/methodologies/refurbishing-of-electronic-devices/ghg-reduction-quantification#refurbishing-process) project scenario section explains that the ecoinvent 3.12 smartphone activity was modified. This was because:

* Smartphones are the most frequently refurbished device type, so avoided emission calculations are particularly sensitive to their emission factor
* [Smartphone LCA results are highly variable](#user-content-fn-4)[^4]
* Many [available smartphone emission factors are based on older smartphone models](#user-content-fn-5)[^5], and do not represent the expected emissions of replaced/avoided devices on the market today. [This includes the ecoinvent 3.12 smartphone activity](#user-content-fn-6)[^6], which is based on data from the [Fairphone 1](https://repository.tudelft.nl/islandora/object/uuid%3A13c85c95-cf75-43d2-bb61-ee8cf0acf4ff) released in 2014.

A comparison of detailed life cycle inventories was the preferred approach, but was not possible due to a lack of transparent data on smartphone composition. Notably, the amounts of the most impactful smartphone components (mainboard, printed wiring boards, and integrated circuits) could not be found to adjust inputs to the ecoinvent process.

Instead, smartphone manufacturing emission factors were summarized for the [smartphones that are most recent](#user-content-fn-7)[^7] (released 2022-2024) [and popular in Europe](#user-content-fn-8)[^8], and had publicly available LCAs.

For Apple iPhones (devices with most sales globally), the identified values are presented in Table A2, with an average of 64±15 kg CO2eq/device. Emission factors for other smartphones are summarized in the table below, and show an average emission factor of 49±13 kg CO2eq/device. These values shall be used for the emission factors for iPhones and other smartphones, respectively.

These values are around 25-50% greater than the smartphone production emission factor from ecoinvent 3.10.

To implement this change in the model, the amount of key inputs (mainboard, printed wiring boards, and integrated circuits) in the ecoinvent smartphone process was increased to reach the desired final emission factor.

Additionally, exchanges for the charger production, smartphone waste treatment, and cable waste treatment were removed from the process, to align with the project system boundaries.

*Table A9 The non-Apple GHG emissions from manufacturing of smartphones gathered from manufacturer environmental reports, for a selection of recent and popular smartphone models. EF stands for emission factor.*

| Year | Model  | EF (kgCO2e) | % manufacturing | EF manufacturing (kgCO2e) | Source |                                                                                                                                                     |
| ---- | ------ | ----------- | --------------- | ------------------------- | ------ | --------------------------------------------------------------------------------------------------------------------------------------------------- |
| 2023 | Galaxy | A14         | 42.5            | 78%                       | 33.20  | [Samsung LCA](https://www.samsung.com/global/sustainability/policy-file/AYVhR1k6BicAIx95/LCA%20Results%20for%20Smartphones.pdf)                     |
| 2023 | Galaxy | A54         | 49.2            | 69%                       | 33.90  | [Samsung LCA](https://www.samsung.com/global/sustainability/policy-file/AYVhR1k6BicAIx95/LCA%20Results%20for%20Smartphones.pdf)                     |
| 2023 | Galaxy | S23 FE      | 47.5            | 79%                       | 37.50  | [Samsung LCA](https://www.samsung.com/global/sustainability/policy-file/AYVhR1k6BicAIx95/LCA%20Results%20for%20Smartphones.pdf)                     |
| 2023 | Galaxy | S23         | 53              | 85%                       | 45.00  | [Product environmental report Samsung](https://www.samsung.com/global/sustainability/media/pdf/Galaxy_S23_Plus_Environmental_Report_EN_230201.pdf)  |
| 2023 | Galaxy | S23+        | 58.8            | 84%                       | 49.22  | [Product environmental report Samsung](https://www.samsung.com/global/sustainability/media/pdf/Galaxy_S23_Plus_Environmental_Report_EN_230201.pdf)  |
| 2023 | Galaxy | S23 Ultra   | 70.6            | 85%                       | 60.22  | [Product environmental report Samsung](https://www.samsung.com/global/sustainability/media/pdf/Galaxy_S23_Ultra_Environmental_Report_EN_230201.pdf) |
| 2024 | Galaxy | S24 Ultra   | 66.4            | 86%                       | 56.90  | [Product environmental report Samsung](https://www.samsung.com/global/sustainability/media/pdf/Galaxy_S24_Ultra_Environmental_Report_EN.pdf)        |
| 2024 | Galaxy | S24+        | 54.8            | 85%                       | 46.47  | [Product environmental report Samsung](https://www.samsung.com/global/sustainability/media/pdf/Galaxy_S24+_Environmental_Report_EN.pdf)             |
| 2024 | Galaxy | S24         | 50.3            | 84%                       | 42.25  | [Product environmental report Samsung](https://www.samsung.com/global/sustainability/media/pdf/Galaxy_S24_Environmental_Report_EN.pdf)              |
| 2022 | Huawei | Mate 50 Pro | 81              | 88%                       | 71.33  | [Huawei](https://consumer.huawei.com/en/support/product-environmental-information/)                                                                 |
| 2022 | Huawei | Mate 50     | 75.3            | 88%                       | 65.95  | [Huawei](https://consumer.huawei.com/en/support/product-environmental-information/)                                                                 |

### Appendix 6: Market share of new and used devices <a href="#id-5lf32r1yzlvs" id="id-5lf32r1yzlvs"></a>

The market share of new and used devices sold annually in Europe was used to determine the repartition of avoided new and refurbished devices in the baseline scenario. Most data were available for smartphones, taken from survey responses from 2022, and are presented in Table A10. The average values used for the GHG reduction quantification are a market share of 13% for refurbished smartphones, and 87% for new smartphones, as shown in Table 5.

*Table A10 Breakdown of refurbished and new smartphones sold in European countries in 2022.*

| **Country**     | **Percent Refurbished** | **Percent new** | **Source**                                                                                                                                                            |
| --------------- | ----------------------- | --------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| France          | 19%                     | 81%             | [ARCEP 2024, Figure 23 (data from 2022](#user-content-fn-9)[^9])                                                                                                      |
| UK              | 16%                     | 84%             | [Deloitte Scandanavia 2022](https://drive.google.com/file/d/1COv7zSJjXc09r-lsg9kT-FV5zVLx075W/view?usp=sharing), pg 17                                                |
| Austria         | 15%                     | 85%             | [Deloitte Scandanavia 2022](https://drive.google.com/file/d/1COv7zSJjXc09r-lsg9kT-FV5zVLx075W/view?usp=sharing), pg 17                                                |
| Germany         | 15%                     | 85%             | [Deloitte Scandanavia 2022](https://drive.google.com/file/d/1COv7zSJjXc09r-lsg9kT-FV5zVLx075W/view?usp=sharing), pg 17                                                |
| Scandanavia     | 12%                     | 88%             | [Deloitte Scandanavia 2022](https://drive.google.com/file/d/1COv7zSJjXc09r-lsg9kT-FV5zVLx075W/view?usp=sharing), pg 17                                                |
| The Netherlands | 11%                     | 89%             | [Deloitte Scandanavia 2022](https://drive.google.com/file/d/1COv7zSJjXc09r-lsg9kT-FV5zVLx075W/view?usp=sharing), pg 17                                                |
| Poland          | 10%                     | 90%             | Deloitte Poland 2022,[ pg 27](https://web.archive.org/web/20240303134844/https://www2.deloitte.com/pl/pl/pages/technology/articles/Digital-Consumer-Trends-2022.html) |
| Belgium         | 9%                      | 91%             | [Deloitte Scandanavia 2022](https://drive.google.com/file/d/1COv7zSJjXc09r-lsg9kT-FV5zVLx075W/view?usp=sharing), pg 17                                                |
| Italy           | 7%                      | 93%             | [Deloitte Scandanavia 2022](https://drive.google.com/file/d/1COv7zSJjXc09r-lsg9kT-FV5zVLx075W/view?usp=sharing), pg 17                                                |
| **Average**     | **13%**                 | **87%**         |                                                                                                                                                                       |

Similar detailed data were not available for other device types. Survey responses on the interest in buying a given refurbished device type were used to adjust the smartphone data in Table A10 proportionally to other device types (Table A11). The results from PCs were applied to laptops and gaming consoles, and the results for TVs were used as a proxy for monitors.

*Table A11 Survey results asking respondents if they would be interested in buying the device type refurbished are summarized. The ratio of the results for smartphones compared to other device types was used to proportionally adjust the average percentage of refurbished smartphones gathered in Table A10.*

| **Device type** | [**% interested in buying refurbishe**](#user-content-fn-10)[^10]**d** | **Percent Refurbished** | **Percent new** |
| --------------- | ---------------------------------------------------------------------- | ----------------------- | --------------- |
| Smartphone      | 59%                                                                    | 13%                     | 87%             |
| PC              | 35%                                                                    | 8%                      | 92%             |
| Tablet          | 34%                                                                    | 7%                      | 93%             |
| TV              | 28%                                                                    | 6%                      | 94%             |

### Appendix 7: Residual value calculations <a href="#oi5bmdhs49zb" id="oi5bmdhs49zb"></a>

The devices considered were the [most popular and recent ](#user-content-fn-11)[^11]models estimated on the market in Europe for smartphones and tablets. New prices were taken from the manufacturer’s website where available, or from the manufacturer’s store on Amazon. In both cases, French sources were used. Average buyback prices were shared with Rainbow by Project Developers. Prices reflect annual buyback price for that device category, for devices from Europe, in 2023.

*Table A12 Sample prices for a new Apple iPhone.*

| **Model**                 | **New Price (€)** |
| ------------------------- | ----------------- |
| iPhone 14, 128 GB         | €869              |
| iPhone 14, 256 GB         | €999              |
| iPhone 14, 512 GB         | €1,249            |
| iPhone 14 plus, 128 GB    | €969              |
| iPhone 14 plus, 256 GB    | €1,099            |
| iPhone 14 plus, 512 GB    | €1,349            |
| iPhone 14 pro, 128 GB     | €1,102            |
| iPhone 14 pro, 256 GB     | €1,235            |
| iPhone 14 pro, 512 GB     | €1,490            |
| iPhone 14 pro, 1TB GB     | €1,721            |
| iPhone 14 pro max, 128 GB | €1,249            |
| iPhone 14 pro max, 256 GB | €1,399            |
| iPhone 14 pro max, 512 GB | €1,599            |
| iPhone 14 pro max, 1TB GB | €1,699            |
| iPhone 15, 128 GB         | €969              |
| iPhone 15, 256 GB         | €1,099            |
| iPhone 15, 512 GB         | €1,349            |
| iPhone 15 plus, 128 GB    | €1,119            |
| iPhone 15 plus, 256 GB    | €1,249            |
| iPhone 15 plus, 512 GB    | €1,499            |
| iPhone 15 pro, 128 GB     | €1,229            |
| iPhone 15 pro, 256 GB     | €1,359            |
| iPhone 15 pro, 512 GB     | €1,609            |
| iPhone 15 pro, 1TB GB     | €1,859            |
| iPhone 15 pro max, 256 GB | €1,479            |
| iPhone 15 pro max, 512 GB | €1,729            |
| iPhone 15 pro max, 1TB GB | €1,979            |

| **iPhone summary** |           |
| ------------------ | --------- |
| Average new        | €1,354    |
| Average buyback    | €186      |
| **Residual value** | **13.7%** |

*Table A13 Sample prices for a new Samsung smartphone.*

| **Model**                        | **New Price (€)** |
| -------------------------------- | ----------------- |
| Samsung Galaxy A14 4G, 64 GB     | €132              |
| Samsung Galaxy A14 4G, 128 GB    | €128              |
| Samsung Galaxy A14 5G, 64 GB     | €176              |
| Samsung Galaxy A14 5G, 128 GB    | €256              |
| Samsung Galaxy A34, 128 GB       | €237              |
| Samsung Galaxy A34, 256 GB       | €286              |
| Samsung Galaxy A54 5G, 128 GB    | €309              |
| Samsung Galaxy A54 5G, 256 GB    | €410              |
| Samsung Galaxy S23 FE, 128 GB    | €699              |
| Samsung Galaxy S23 FE, 256 GB    | €759              |
| Samsung Galaxy S23, 128 GB       | €799              |
| Samsung Galaxy S23, 256 GB       | €859              |
| Samsung Galaxy S23+, 256 GB      | €919              |
| Samsung Galaxy S23+, 512 GB      | €993              |
| Samsung Galaxy S23 Ultra, 256 GB | €969              |
| Samsung Galaxy S23 Ultra, 512 GB | €1,039            |
| Samsung Galaxy S24 Ultra, 256 GB | €1,469            |
| Samsung Galaxy S24 Ultra, 512 GB | €1,589            |
| Samsung Galaxy S24 Ultra, 1 TB   | €1,829            |
| Samsung Galaxy S24, 128 GB       | €899              |
| Samsung Galaxy S24, 256 GB       | €959              |
| Samsung Galaxy S24+, 256 GB      | €1,169            |
| Samsung Galaxy S24+, 512 GB      | €1,289            |

| **Smartphone summary** |           |
| ---------------------- | --------- |
| Average new            | €790      |
| Average buyback        | €89       |
| **Residual value**     | **11.3%** |

*Table A14 Sample prices for a new Apple iPad.*

| **Model**                     | **New Price (€)** |
| ----------------------------- | ----------------- |
| iPad Pro 11 inch, 128 GB      | €1,069            |
| iPad Pro 11 inch, 256 GB      | €1,199            |
| iPad Pro 11 inch, 512 GB      | €1,449            |
| iPad Pro 11 inch, 1 TB        | €1,949            |
| iPad Pro 11 inch, 2 TB        | €2,449            |
| iPad Pro 12.9 inch, 128 GB    | €1,469            |
| iPad Pro 12.9 inch, 256 GB    | €1,599            |
| iPad Pro 12.9 inch, 512 GB    | €1,849            |
| iPad Pro 12.9 inch, 1 TB      | €2,349            |
| iPad Pro 12.9 inch, 2 TB      | €2,849            |
| iPad Air, 64 GB               | €789              |
| iPad Air, 256 GB              | €989              |
| iPad 10th gen, 64 GB          | €589              |
| iPad 10th gen, 256 GB         | €789              |
| iPad 9th gen, 64 GB           | €439              |
| iPad 9th gen, 256 GB          | €639              |
| iPad mini, 64 GB              | €659              |
| iPad mini, 256 GB             | €859              |
| iPad Pro 11 inch 5G, 128 GB   | €1,269            |
| iPad Pro 11 inch 5G, 256 GB   | €1,399            |
| iPad Pro 11 inch 5G, 512 GB   | €1,649            |
| iPad Pro 11 inch 5G, 1 TB     | €2,149            |
| iPad Pro 11 inch 5G, 2 TB     | €2,649            |
| iPad Pro 12.9 inch 5G, 128 GB | €1,669            |
| iPad Pro 12.9 inch 5G, 256 GB | €1,799            |
| iPad Pro 12.9 inch 5G, 512 GB | €2,049            |
| iPad Pro 12.9 inch 5G, 1 TB   | €2,544            |
| iPad Pro 12.9 inch 5G, 2 TB   | €3,044            |
| iPad Air 5G, 64 GB            | €989              |
| iPad Air 5G, 256 GB           | €1,189            |
| iPad 10th gen 5G, 64 GB       | €789              |
| iPad 10th gen 5G, 256 GB      | €989              |
| iPad 9th gen 5G, 64 GB        | €609              |
| iPad 9th gen 5G, 256 GB       | €809              |
| iPad mini 5G, 64 GB           | €859              |
| iPad mini 5G, 256 GB          | €1,059            |

| **iPad summary**   |           |
| ------------------ | --------- |
| Average new        | €1,430    |
| Average buyback    | €170      |
| **Residual value** | **11.9%** |

*Table A15 Sample prices for a new Samsung tablet.*

| **Model**                      | **New Price (€)** |
| ------------------------------ | ----------------- |
| Galaxy Tab S9, 128 GB          | 899               |
| Galaxy Tab S9, 256 GB          | 949               |
| Galaxy Tab S9+, 256 GB         | 1149              |
| Galaxy Tab S9+, 512GB          | 1149              |
| Galaxy Tab S9 Ultra, 256 GB    | 1249              |
| Galaxy Tab S9 Ultra, 512 GB    | 1499              |
| Galaxy Tab S9 Ultra, 1 TB      | 1749              |
| Galaxy Tab S9 FE, 128 GB       | 529               |
| Galaxy Tab S9 FE, 256 GB       | 599               |
| Galaxy Tab S9 FE+, 128 GB      | 699               |
| Galaxy Tab S9 FE+, 256 GB      | 799               |
| Galaxy Tab A9, 64 GB           | 189               |
| Galaxy Tab A9, 128 GB          | 219               |
| Galaxy Tab A9+, 64 GB          | 259               |
| Galaxy Tab A9+, 128 GB         | 299               |
| Galaxy Tab S9 5G, 128 GB       | 1099              |
| Galaxy Tab S9 5G, 256 GB       | 1079              |
| Galaxy Tab S9+ 5G, 256 GB      | 1329              |
| Galaxy Tab S9+ 5G, 512GB       | 1449              |
| Galaxy Tab S9 Ultra 5G, 256 GB | 1579              |
| Galaxy Tab S9 Ultra 5G, 1 TB   | 1899              |
| Galaxy Tab S9 FE 5G, 128 GB    | 629               |
| Galaxy Tab S9 FE 5G, 256 GB    | 599               |
| Galaxy Tab S9 FE+ 5G, 128 GB   | 799               |
| Galaxy Tab S9 FE+ 5G, 256 GB   | 899               |
| Galaxy Tab A9 4G, 64 GB        | 217               |
| Galaxy Tab A9+ 5G, 64 GB       | 309               |
| Galaxy Tab A9+ 5G, 128 GB      | 349               |

| **Tablet summary** |           |
| ------------------ | --------- |
| Average new        | €944      |
| Average buyback    | €185      |
| **Residual value** | **19.6%** |

### Appendix 8: Creating two monitor sizes

Monitors were categorized into two size groups: smaller or larger than 25" screen diameter, based on the distribution in Figure 29 here[^12].

For the **<25" monitors**, the ecoinvent activity *"display production, liquid crystal, 17 inches"* was used to estimate emissions.

To approximate emissions the **>25" monitors**, the emission factor from this 17" reference was scaled up using data from an [ADEME study](#user-content-fn-13)[^13] that provides emissions for two screen sizes. This source indicates that increasing screen size from 21.5" to 23.8" (a 11% increase) results in a 12% increase in production-related GHG emissions. Assuming this scaling relationship is linear, a 47% increase in screen size (from 17" to 25") would lead to a 53% increase in emissions. Applying this factor to the original ecoinvent activity yields an emission factor of 538 tCO<sub>2</sub>eq per monitor >25".

According to ecoinvent, the 17" monitor used to model the <25" category weighs 4.5 kg. To estimate the weight of a >25" monitor, it was assumed that weight scales proportionally with screen size. Since a 25-inch monitor is approximately 47% larger than a 17-inch monitor, its weight was scaled up by the same proportion, resulting in an estimated weight of 6.6 kg.

## Appendix 9: Auditing requirements

:point\_right:Download the table [here](https://docs.google.com/spreadsheets/d/1dt50zzOgGJsTTxN13p8rjRWPyzRvwfTwUUy57ZwTzog/edit?gid=0#gid=0)

{% embed url="<https://docs.google.com/spreadsheets/d/1dt50zzOgGJsTTxN13p8rjRWPyzRvwfTwUUy57ZwTzog/edit?gid=0#gid=0>" %}

[^1]: Ecoinvent process was used with the substantial modifications described in Appendix 5.

[^2]: Eurostat 2023. Waste electrical and electronic equipment (WEEE) by waste management operations - open scope, 6 product categories (from 2018 onwards). DOI: <https://doi.org/10.2908/ENV_WASELEEOS>. Accessed April 2024.

[^3]: Cornelis P. Baldé, Ruediger Kuehr, Tales Yamamoto, Rosie McDonald, Elena D’Angelo, Shahana Althaf, Garam Bel, Otmar Deubzer, Elena Fernandez-Cubillo, Vanessa Forti, Vanessa Gray, Sunil Herat, Shunichi Honda, Giulia Iattoni, Deepali S. Khetriwal, Vittoria Luda di Cortemiglia, Yuliya Lobuntsova, Innocent Nnorom, Noémie Pralat, Michelle Wagner (2024). International Telecommunication Union (ITU) and United Nations Institute for Training and Research (UNITAR). 2024. Global E-waste Monitor 2024. Geneva/Bonn.

[^4]: Clément, L.-P.P.-V.P., Jacquemotte, Q.E.S., Hilty, L.M., 2020. Sources of variation in life cycle assessments of smartphones and tablet computers. Environmental Impact Assessment Review 84, 106416. <https://doi.org/10.1016/j.eiar.2020.106416>

[^5]: Suckling, J., Lee, J., 2015. Redefining scope: the true environmental impact of smartphones? Int J Life Cycle Assess 20, 1181–1196. <https://doi.org/10.1007/s11367-015-0909-4&#x20>;

[^6]: Güvendik, M., 2014. From Smartphone to Futurephone: Assessing the Environmental Impacts of Different Circular Economy Scenarios of a Smartphone Using LCA \[Master’s Thesis, Delft University of Technology]. TU Delft Repository.

[^7]: Best selling smartphone \[[WWW Document](https://www.counterpointresearch.com/insights/global-smartphone-sales-top10-best-sellers/)], 2024 . Counterpoint. (accessed April 2024).&#x20;

[^8]: Team Counterpoint, 2023. Top 5 Smartphone Models Share For 8 Countries \[[WWW Document](https://www.counterpointresearch.com/insights/top-5-smartphone-model-share-8-countries/)]. Counterpoint. (accessed April 2024).

[^9]: ARCEP, 2024. Enquete annuelle: pour un numerique soutenable (No. ISSN n°2258-3106). Autorité de régulation des communications électroniques, des postes et de la distribution de la presse. [URL](https://www.arcep.fr/fileadmin/user_upload/observatoire/enquete-pns/edition-2024/enquete-annuelle-pour-un-numerique-soutenable_edition2024.pdf)

[^10]: KANTAR 2023, Potentiel du marché de la seconde vie mobile en France. URL <https://www3.kantar.com/Presentation-Recommerce-05-2023>. (accessed April 2024). Pages 19 and 12.

[^11]: * Team Counterpoint, 2023. Top 5 Smartphone Models Share For 8 Countries \[[WWW Document](https://www.counterpointresearch.com/insights/top-5-smartphone-model-share-8-countries/)]. Counterpoint. (accessed 4.9.24).

    - Tablet Vendor Market Share Europe \[WWW Document], n.d. . StatCounter Global Stats. URL[ https://gs.statcounter.com/vendor-market-share/tablet/europe](https://gs.statcounter.com/vendor-market-share/tablet/europe) (accessed April 2024).

[^12]: ARCEP, 2024. Enquete annuelle: pour un numerique soutenable (No. ISSN n°2258-3106). Autorité de régulation des communications électroniques, des postes et de la distribution de la presse. [URL](https://www.arcep.fr/fileadmin/user_upload/observatoire/enquete-pns/edition-2024/enquete-annuelle-pour-un-numerique-soutenable_edition2024.pdf).

[^13]: ADEME. J. Lhotellier, E.Less, E.Bossanne, S.Pesnel. 2017. Modélisation et évaluation du poids carbone de produits de consommation et biens d’équipements – Rapport. 217 pages. [URL](https://librairie.ademe.fr/consommer-autrement/1190-modelisation-et-evaluation-du-poids-carbone-de-produits-de-consommation-et-biens-d-equipement.html).


# Risk assessment template

This methodology uses the risk assessment template version 1.0

:point\_right: Download the template [here](https://docs.google.com/spreadsheets/d/1ZgH5M4JykJG7c714FNFANriZsVeBI1vrOJ0xAhAzm6U/edit?usp=sharing)

{% embed url="<https://docs.google.com/spreadsheets/d/1ZgH5M4JykJG7c714FNFANriZsVeBI1vrOJ0xAhAzm6U/edit?usp=sharing>" %}


# Biobased construction materials

This methodology covers projects that manufacture biobased construction materials and/or use these materials in building construction or renovation. The eligible biobased materials include, but are not limited to, wood framing, hempcrete, and cellulose insulation, derived from biomass sources such as wood, bamboo, and hemp.

<table data-header-hidden><thead><tr><th width="234"></th><th></th></tr></thead><tbody><tr><td><strong>Methodology name</strong></td><td>Biobased construction materials</td></tr><tr><td><strong>Version</strong></td><td>2.4</td></tr><tr><td><strong>Methodology ID</strong></td><td>RBW-BIOBM-01-CONST-V2.4</td></tr><tr><td><strong>Release date</strong></td><td>October 9th, 2025</td></tr><tr><td><strong>Status</strong></td><td>In use</td></tr></tbody></table>

See the glossary for methodology-specific terminology :point\_down:

#### Glossary

<table data-header-hidden><thead><tr><th width="227"></th><th></th></tr></thead><tbody><tr><td><strong>Biobased construction material</strong></td><td>Materials derived from biomass that are used in construction and other applications</td></tr><tr><td><strong>Biogenic carbon</strong></td><td>Carbon from organic matter that can be sequestered and stored in biobased products during their production, and released back into the atmosphere if they are incinerated or decayed. It is considered part of the short, natural carbon cycle, as opposed to fossil based carbon</td></tr><tr><td><strong>Biomass</strong></td><td>The biodegradable fraction of materials from biogenic origin, such as trees, plants, and agricultural and urban waste</td></tr><tr><td><strong>Carbon storage duration</strong></td><td>The number of years that biogenic carbon will be stored in a construction material. This corresponds to the reference service lifetime for the material’s first use, plus extended storage periods from reuse, recycling, or landfilling</td></tr><tr><td><strong>Environmental Product Declaration (EPD)</strong></td><td>A standardized and independently verified document that communicates the environmental performance of a product, including construction materials, based on a life cycle assessment</td></tr><tr><td><strong>Reference service lifetime</strong></td><td>The expected or predefined period of use for a product or construction material, measured in number of years. Used for assessing its environmental impact over its life cycle</td></tr><tr><td><strong>Modules A-D</strong></td><td>Components and terminology of an environmental assessment under EN 15804, outlining the stages of a life cycle assessment for construction materials. They encompass (A) Production, (B) Construction/Installation, (C) Use, and (D) End of Life</td></tr><tr><td><strong>Project biobased material</strong></td><td>The biobased material from the project that is subject to removal and/or avoidance Rainbow Carbon Credit issuance. Its production/use is the mitigation activity for this methodology.</td></tr></tbody></table>

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[Glossary](/glossary)
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