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, Methodologies, Requirements for Validation and Verification Bodies, and all other documentation found on this site.

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.

Certification steps

A summary of the project certification procedure is provided here. A detailed description of the certification procedure is in the Procedures Manual.

Project status on the registry

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 , , , .

The Conflict of Interest Policy (available ) is a separate document that must be signed by all individuals or parties identified as being at potential risk of a conflict of interest. For a detailed outline of the parties involved, please refer to the diagram found in the section.

All parties involved must sign the policy. The following is the minimum list of stakeholders who must be included:

• Members of the Executive board

• Members of the Secretariat, Standard Advisory Board

👉 Download the template

👉 Download the template

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.

👉 Download the 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.

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.

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.

As required in the Rainbow Double counting policy, Project Developers seeking to obtain the CORSIA or Article 6 label on Rainbow Carbon Credits must provide an official Letter of Authorisation from the Host Country.

👉 Download the template

👉 Download the template

👉 Download the template

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.

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

👉 Download the template

👉 See Archived Rainbow Standard Documents for full versions of previous documents

Purpose of this document

The aim of this document is to present guidelines for Validation and Verification Bodies (VVBs) for conducting comprehensive evaluations of greenhouse gas emission avoidance and/or removals of Project Developers under the Rainbow Standard.

This document delineates the requirements and procedures necessary for ensuring compliance with the Rainbow Standard Rules and Rainbow Procedures Manual. It pertains to the following types of audits:

• Validation Audits

• Verification Audits

Introduction

This guidance is part of the larger framework of the Rainbow Standard system, which encompasses the Rainbow Standard Rules and the methodologies. Moreover, it complements the Rainbow Procedures Manual that delineates project registration and supervision This document offers targeted guidance for auditors performing validation and verification audits within the specialized scope of Project Developers.

The guidelines detailed in this document become binding upon its formal release. Post this date, any VVB that meets the requirements can contribute to the validation and verification of Rainbow Standard Projects.

Existing VVBs must reapply and provide the necessary documentation outlined in this text before continuing validation or verification tasks.

For VVBs who have an existing formalized agreement with Project Developers before the activation date of this guidance, a grace period of twelve months is given to apply again and comply with the new requirements.

Henceforth, Project Developers can only collaborate with VVBs officially recognized by Rainbow, based on the requirements and processes defined herein. Projects already registered that haven't transitioned to the Rainbow Standard Rules might be subjected to different review templates than those mentioned here.\

VVB acknowledgement

I hereby acknowledge that I have read and understand the above requirements.

\

Company name:____________________

\

Name:_________________

\

Signature: ____________________________________ Date:_____________

\

👉 See Archived Rainbow Standard Documents for full versions of previous documents

Change log for Rainbow Standard Rules V6

Change log for Rainbow Standard Rules V5.2

VVB Verification objectives

Once the project has undergone validation, it transitions to the verification phase with a designated Validation and Verification Body (VVB). The primary objectives of VVB verification are to ascertain the project's ongoing integrity, eligibility, and alignment with the initial projections. Verification is done for each year of the crediting period.

This involves a thorough:

• review of the validity and proof of indicators presented in the Monitoring Plan.

• evaluation of any major reported changes to the project, such as changes in operations or production output. Ensure that the project still meets the eligibility criteria.

• validation of updated LCA calculations (using indicators from the Monitoring Plan), and the corresponding amount of RCCs to issue.

The output of this verification will be used to verify and issue the expected amount of RCCs, cancel (in case of underachievement) or issue additional RCCs (in case of overachievement).

The VVB team must follow the procedures outlined in the “Annual monitoring & verification” section of the Rainbow Procedures Manual.

Verification output

Following the comprehensive audit work, the derived results are as follows:

• Consistency: The answers and evidence furnished for each criterion of the Monitoring Plan of the project have been verified and found to be consistent and valid.

• Model: The model employed for CO2 calculation is the same as in the validation process, or is the latest version of related framework

• Data authenticity and estimates: inputs include actual data and where appropriate estimates, and are supported by technical data from reliable and recognised sources;

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information for each Mineralization Batch:

The Project Developer is the party responsible for adhering to the Monitoring Plan.

Monitoring Plans for this methodology shall include, but are not limited to, tracking of the following information for biobased material producers:

• amount and type of biobased building material units sold

• amount, type and source of biobased inputs

• proof of adherence to the No Double Counting criterion

Monitoring Plans for this methodology shall include, but are not limited to, tracking of the following information for building developers using biobased materials:

• amount and type of biobased building material units incorporated into buildings

• proof of completed construction and delivery of building/s

• proof of adherence to the No Double Counting criterion

• if in France, embodied and use-stage GHG emissions of the completed building (see section)

The Project Developer is the party responsible for adhering to the Monitoring Plan.

👉 Download the template here

Monitoring Plans for this methodology shall include, but are not limited to, tracking of the following information by Project Developers:

• Transportation distances for the collection of waste batteries until the project's site.

• Type and chemistry of collected batteries (Battery A).

• Percentage of recycled battery packs, auxiliary components, BMS, and BUs derived from the collected battery packs (Battery A).

• The quantity, type, and weight of second-life batteries sold (Battery B) in a functional state, along with their respective State of Health (SoH) and lifespan (optional). If lifespan data is unavailable, conservative assumptions will be made.

• Quantity and type of new materials used in the second life battery, as well as any new electrolyte solutions incorporated into the sold battery (Battery B).

See Table 2 in the section for more details.

The Project Developer is the party responsible for adhering to the Monitoring Plan.

👉 Download the table here

All requirements for VVB application and accredited VVBs can be found in the .

VVB Validation objectives

Once a project’s PDD has been pre-validated internally by Rainbow, it enters the validation step. The objective of validation is to provide an external evaluation to ensure that:

• the LCA methods employed are robust and accurate,

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.

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.

Project type

The project may be biobased construction material manufacturing. In this case, carbon credits are issued according to the amount of biobased materials sold to building developers during the reference calendar year. The Project Developer may be the biobased construction material manufacturer.

The project may be the use of biobased construction materials in new, permanent building construction or renovation of permanent buildings during the reference calendar year. RCCs are issued according to the amount of biobased construction materials used in the new building construction. The Project Developer may be the building developer, i.e. the entity responsible for technical choices, building design, and oversight of the development.

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.

Buildings are responsible for 21% of global greenhouse gas emissions (GHGs). These can be split into operational emissions (such as energy consumption while buildings are used), and embodied emissions (emissions from the production, maintenance, and waste treatment of building materials). Embodied emissions of buildings account for almost 5-12% of national GHGs across European countries. Much of this impact comes from the energy-intensive production of cement and steel, which are the top two building materials used globally, along with masonry (bricks, blocks, and stone).

Biobased construction materials are composed of matter derived from biogenic origins. They typically have lower embodied GHG emissions than conventional materials because they 1) are mostly composed of renewable, biogenic carbon, which comes with low or even negative embodied emissions, and 2) can have less energy-intensive manufacturing processes.

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.

This methodology covers projects that refurbish or regenerate used batteries, extend their usable lifetime, reduce hazardous waste, and avoid the production of new batteries. Eligible battery applications include starting, lighting, and ignition (SLI) batteries; light means of transport batteries (LMT); electric vehicle (EV) batteries; and energy storage systems (ESS). Eligible battery chemistries include nickel-metal hydride (NiMH), lithium-ion (Li-ion), and lead-acid (Pb-acid) batteries.

👉 Download the template

Small IT and telecommunication equipment constitute about 2% of global greenhouse gas (GHG) emissions and is one of the fastest growing sectors in emissions. 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. 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.

The global demand for batteries is projected to increase fourteenfold by 2030, with the European Union expected to account for 17% of this demand. This is primarily fueled by the rise of electric mobility. In addition to climate change impacts, the production of batteries relies on critical raw materials (CRM) such as lithium, cobalt, antimony, rare earth elements, and natural graphite.

Most environmental impacts of batteries stem from two main stages: (a) the mining and processing of CRM and (b) their disposal at the end of life. Mining for CRMs raises significant environmental and human rights concerns, particularly as 82% of mining areas target materials for renewable energy, often in protected regions with high mine density. Additionally, improper battery disposal can contaminate soil and water, negatively impacting human health. In 2021, the EU's end-of-life battery collection rate was potentially below 50% for some types of less-regulated batteries.

Therefore, a major lever to reduce GHG emissions in this sector is to increase the lifetime of batteries, so that fewer batteries are produced. One method for increasing the battery's lifetime is the preparation for reuse or repurpose through regeneration and refurbishing, giving it a second life.

Battery second life involves restoring previously owned and used batteries to a functional state for continued use, thereby delaying their entry into waste streams. This process includes thorough testing, cleaning, repairs, and, when necessary, replacing components to ensure optimal performance. Extending the lifespan of batteries reduces the production of new batteries and reduces hazardous waste. Refurbishment and regeneration of batteries face barriers from high costs of repair, market fragmentation, and lack of consumer trust and acceptance.

Introduction

It is widely acknowledged that in addition to reducing global greenhouse gas (GHG) emissions, carbon dioxide must be removed from the atmosphere and permanently sequestered. One way to do this is through mineral carbonation/mineralization of concrete and alkaline wastes that contain metal ions, destined for permanent incorporation into permanent products. In this process, captured CO₂ is exposed to and reacts with alkaline materials, generating stable carbonates that can permanently store the CO₂.

This methodology document outlines the general requirements for mineral carbonation of materials projects certified under the .

Modules

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 eligibility criteria, GHG reduction quantification requirements, required data, monitoring plans, and other instructions for Rainbow certification. This methodology shall be used in conjunction with the following Rainbow modules:

Glossary

Appendix 1: Ecoinvent processes

List of ecoinvent 3.11 processes used in the GHG reduction quantification model

👉 Download the template here

Standard Advisory Board

The Standard Advisory Board (SAB) is independent from Rainbow SAS. It is responsible for reviewing suggested changes to the Rainbow Standard Rules, Procedures Manual, and the Rainbow Registry procedures.

Appendix 1: Ecoinvent activities

Appendix 1: Ecoinvent processes

The table below presents a non-exhaustive selection of Ecoinvent activities that may be used in the GHG 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 3.11 processes used in the GHG reduction quantification model, all processes are from the cutoff database

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

Two main types of RCCs are issued by Rainbow: removal RCCs and avoidance RCCs. Both types are measured by calculating the difference in GHG emissions of the project scenario compared to the baseline scenario, following the approach outlined in ISO 14064-2:2019. See details in the GHG Reduction Quantification section.

Removal RCC

Removal RCCs are calculated by evaluating the removal projects’ net GHG emissions (i.e. carbon removal and emissions) compared to the baseline scenario’s (i.e. what would have occurred in the absence of the project). See more details on choosing a baseline scenario in the .

Removal RCCs are issued on Rainbow’s registry under the mechanism label “removal”. They represent one tonne of carbon dioxide equivalent captured and stored: 1 removal RCC = 1 t CO2eq.

Avoidance RCC

Avoidance RCCs are calculated by comparing GHG emissions of the project to the ones of a reference or baseline scenario that would have occurred without the project.

Avoidance RCCs are classified on Rainbow’s registry under the mechanism label “avoidance”. They represent one avoided tonne of carbon dioxide equivalent: 1 avoidance RCC = 1 t CO2eq.

Credit pools

Credit pools are defined as a group of Rainbow Carbon Credits from the same project, mechanism and vintage year. Each transaction in the Rainbow Registry may cover credits from one credit pool. For example, separate transactions are required to retire credits from two different credit pools.

A project is uniquely described on the registry by:

• Project registry ID

• Project name

• Name of the Project Developer

• Location

Each RCC is uniquely described on the registry by:

• unique identifier

• Project registry ID

• Vintage year (year of verified activity in verification)

• Type of mechanism (avoidance or removal)

RCC status on the registry

Rainbow Carbon Credits and provisional credits can have different statuses on the Rainbow Registry:

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

• Permanence horizons: e.g. 100 or 1000 year permanence for removal RCCs

• Compliance with trading schemes: e.g. CORSIA eligible, Article 6 eligible

• Accredited: e.g. ICROA accredited, ICVCM accredited

Provisional credits & Pre-purchase agreements

Provisional credits are estimated upon project validation for the projected volume of emission avoidance/removal over the project’s crediting period. They are conservatively calculated.

Pre-purchase agreements are signed agreements between the PD and a buyer with defined volumes and prices of Rainbow Carbon Credits. These can be made once provisional credits have been estimated and the project has been validated.

Provisional credits are only used to track pre-purchase agreements for buyers. Their property rights can not be transferred to the buyer until the mitigation activity occurs and they are verified (hence become RCCs).

Presentation of Rainbow

Rainbow: A mission-driven company

Rainbow is a simplified joint-stock company ("société par actions simplifiée") with its headquarters situated at 28 Avenue des Pépinières, 94260 Fresnes, France, and is registered in the Créteil Companies and Trade Register with the number 908 082 332.

As a mission-driven entity ("Société à Mission"), Rainbow has a defined purpose pursuant to Article 1835 of the French Civil Code.

The company's mission is to create significant and positive environmental or social impact through its commercial and operational activities, and to conduct its business with exemplary professionalism in the pursuit of the collective interest. In alignment with its mission, the company is dedicated to:

• Advancing solutions that contribute a net environmental or social benefit to both the community and the planet;

• Engaging with partners and customers who share the company's values and objectives;

• Delivering significant value and impact through its partnerships and client interactions;

• Ensuring the dignity of individuals and promoting a healthy work-life balance for its employees.

Rainbow Standard and Rainbow Tech Infrastructure

Building upon its core mission, the simplified joint-stock company Rainbow operates two entities:

• The Rainbow Standard: A European crediting program within the voluntary carbon market, tailored for industrial projects that demonstrate the potential for significant reductions or sequestration of greenhouse gas (GHG) emissions. The Rainbow Standard prescribes exacting certification criteria, rooted in stringent scientific methodology and designed to align with the principal frameworks dedicated to fostering transparency and integrity in the voluntary carbon market.

• The Rainbow Tech Infrastructure: Serving as the operational backbone for the Rainbow Standard, this infrastructure comprises two principal components:

  • The Rainbow Registry: Ensuring traceability and transparency, it maintains detailed records of Rainbow Carbon Credits from issuance to retirement, thereby preventing double counting and adhering to the protocols recommended by carbon market integrity organizations.

Both entities are managed by the Rainbow Executive Team and supported by the internal teams within Rainbow.

Overview of the Rainbow Organization:

Rainbow Standard: Governance, roles, and responsibilities

The Rainbow Standard's governance architecture is designed to ensure scientific rigor, independence and efficiency.

It is spearheaded by two principal independent entities: the Standard Advisory Board and the Technical Advisory Committee.

In addition to these independent governance entities, four specialized Rainbow teams are dedicated to the standard's operational execution:

Conflict of interest, safeguards and grievance mechanisms

All Rainbow ecosystem stakeholders are contractually linked with Rainbow. The following stakeholders are publicly disclosed:

Moreover, any stakeholder of Rainbow’s ecosystem is under .

Finally, Rainbow implements a robust that sets out how the Rainbow organization identifies, manages, prevents, and discloses potential or real conflicts of interest to comply with the applicable regulatory requirements and code of practices.

The following is the minimum list of stakeholders who must sign the policy:

• Members of the Executive board

• Members of the Secretariat, Standard Advisory Board

• Members of the Climate, Certification, R&D and Partnerships teams

• Members the Technical Advisory Board

Rainbow Registry

The Rainbow Registry is openly accessible through Rainbow’s website , and displays the following information to ensure maximum transparency and traceability of Rainbow Carbon Credits:

• Project information, including documentation, detailed calculations, audit/verification/monitoring statements, as well as reports and legal representations

• Transparent issuance tracking, transfer and retirement/cancellation of units

• Individually identified units through unique serial numbers containing sufficient information to avoid double counting (type, geography, vintage)

• Unit status (issued, verified, retired, canceled), with full traceability of the chain of custody

The Rainbow Registry IT security requirements are detailed in the Appendix 6.5.

Discount factor

The Rainbow Certification Team may eliminate a fraction of a project’s estimated RCCs using the uncertainty discount factor to mitigate carbon credit overestimation. These verified avoided/removed emissions are never issued as RCCs.

Application of a discount factor may occur when material uncertainty is identified, for example, in the project’s measured data, assumptions, or the selection of the baseline scenario.

When faced with high uncertainty, steps should be taken to reduce uncertainty, and conservative choices should be made. If uncertainty remains, a discount factor shall be applied. Requirements are described in the Uncertainty Assessment section of the Rainbow Standard Rules.

RCCs that are eliminated with the discount factor are not issued and will not appear on the registry. This discount factor may vary from 0% to more than 10% of estimated RCCs. The amount is evaluated individually for each project.

Buffer pool

All projects that issue removal RCCs must allocate a portion of their verified removal RCCs to the buffer pool. This pool acts as an insurance mechanism, shared across all removal projects, against the risk of reversal of sequestered carbon before the agreed upon commitment period (at least 100 years, for removal RCCs). 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 supplied with RCCs via two paths:

• Default: Each removal project allocates by default at least 3% of its verified removal RCCs to the buffer pool.

• Conditional: If the project has high or very high risks of reversal (according to the project evaluation’s Risk Assessment Template), the Project Developer may choose to develop a risk mitigation plan, or contribute an extra 3% of their verified RCCs to the buffer pool. More details are available in the section on Risk Assessment.

• RCCs are withdrawn from the buffer pool if there is a reversal event (see details in the section).

Under- / Overachievement

As a result of the verification phase, provisional credits either are issued as verified RCCs or are canceled.

Upon verification, three situations are possible: exact estimation, overestimation and under-estimation. Below is an example for 100 estimated provisional removal credits. Note that the actual portion of RCCs going to the buffer pool may vary by project.

Issuance

The issuance of RCCs is operated by the Certification team once the is fully conducted and all audit certificates are available.

The name of the Rainbow Registry operator, from the Certification team, who operates the issuance is registered in the process.

When removal RCCs are issued, a contribution will automatically be transferred from Project accounts to the Rainbow Buffer Pool account. The amount of removal credits to be added to the buffer pool is defined for each project, and displayed on the project page on the registry. The contribution shall equal the percentage confirmed during project validation, and shall be rounded up to the nearest whole RCC (3% by default).

Cancelation

Canceling provisional credits

Provisional credits may be canceled on the registry for several reasons:

• lack of measurement source for a KII

• change in KII or overall process, so that the project no longer avoids/removes carbon as expected

• change in external factors causing the project to lose its additional status (i.e. change in regulation that makes the project activities required)

If pre-purchase agreements were made between buyers and PDs, the buffer pool will not be used to replace canceled provisional credits.

Canceling removal credits due to reversals

Verified removal RCCs may be canceled/withdrawn from the buffer pool if the Project Developer notifies Rainbow of an event that re-emits at least 1 tonne of COeq of the carbon stored in the removal solution, before the commitment period ends. The amount of RCCs withdrawn from the buffer pool equals the tonnes of COeq estimated to have been released as a result of the reversal event. The Project Developer must notify Rainbow within 30 calendar days of becoming aware of the reversal event.

Rainbow Certification Team shall cancel RCCs from the buffer pool of a similar type as the removal RCCs that were reversed.

Canceling credits due to erroneous issuance

Verified RCCs may be deemed erroneously issued due to, for example, calculation errors, use of wrong input data, or inaccurate proof. While the comprehensive audit process renders this highly unlikely, a procedure is prepared out of an abundance of caution.

Erroneous issuance may be signaled by the PD, the VBB, the Rainbow Certification Team, or any stakeholder. The Rainbow Certification 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 shall be frozen during the investigation, and canceled.

• Credits already transferred or retired: the above procedure shall be applied, and an equivalent amount of excess credits will be transferred to the credit user at no cost from the project's next verification and issuance. If no additional credits are available, Rainbow will work with the credit user on a case-by-case basis to agree upon compensation, with Rainbow taking financial responsibility to ensure the credit user incurs no loss.

An Cancelation Report will be generated and attached to the cancelation event in the Registry that states the amount of excess credits erroneously issued and the remediating action.

Retirement

To retire RCCs, the user must log in with their username and password to the Rainbow Registry and click on the option “retirement”. There they must enter the following information:

• Project name and registry ID from which RCCs are to be removed

• Vintage year

• Number of RCCs to be retired

• Reason for retirement: voluntary offset, carbon tax, or another specific offset scheme

A retirement certificate can be downloaded from the Rainbow Registry. Additionally, all retirement transactions are publicly available on the registry (see example ).

Once retired, RCCs can not be transacted, retired or canceled.

Projects eligible under this methodology are the activities that carry out the technical aspects of refurbishing or regeneration of used batteries at the end of their lifecycle in Europe. These batteries can either be reused or repurposed in their second life. Activities that only recycle batteries (e.g. shred them to collect and use metals), collect used batteries (e.g. buyback schemes), serve as marketplaces for resale, or act as Producer Responsibility Operators (PRO) are not eligible projects.

Marketplaces, battery waste management intermediaries, and battery optimization software companies may act as intermediaries between Rainbow and battery second-life projects to assist in the certification process. Signed agreements shall be provided ensuring that the battery second-life project is the principal and final beneficiary of carbon finance.

Treated batteries eligible under this methodology include starting, lighting, and ignition (SLI) batteries; light means of transport batteries (LMT); electric vehicle (EV) batteries; and energy storage systems (ESS). Other collected waste battery types such as portable batteries and portable batteries of general use are not eligible under this methodology. New, unused batteries obtained from overproduction are not eligible under this methodology.

This methodology distinguishes between two types of processes enabling a battery's second life:

• Refurbishing: involves a lighter process to restore battery packs to optimal working conditions. This includes but is not limited to mechanical repairs such as cosmetic damage (casing), deep discharge, component replacement, fuse replacements, battery management system (BMS) repair and balancing, wiring harness repairs, and cleaning the battery. In this process, any damaged or low-quality battery units and auxiliary components are replaced with either reused or new parts. In the EU battery regulation 2023/1542 this is defined as battery remanufacturing.

• Regeneration: in addition to the battery refurbishing steps above, regeneration involves a more complex process of regenerating battery packs through methods such as applying electrical pulses and replacing the battery’s electrolytes to reverse some of the chemical degradation within the battery. The goal is to restore the battery's performance by reverting its degradation process without the need for replacing its core components, usually enabling it to return to its initial use application.

Both refurbishing and regeneration 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/regeneration site’s entire operations or only an expansion project. See the Additionality section of the for more details.

Project scope

One project corresponds to the battery second life sites within one registered company/holding company located within one country.

The general GHG reduction quantification approach and components are outlined below. Detailed instructions and requirements can be found in Rainbow methodologies.

General guidance

Rainbow Carbon Credits shall be calculated by subtracting the GHG emissions and removals of the project scenario from the emissions and removals of a baseline scenario, or reference scenario, that would have occurred without the implementation of the project.

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.

Would you like to be notified of future consultations? Please

Purpose

This methodology covers durable carbon removal through enhanced rock weathering. This includes crushing and spreading specific types of rocks on agricultural soils to increase the rock's surface area exposed to the atmosphere, which speeds up the naturally occurring rock weathering and CO removal process.

Project type

In addition to the general Rainbow requirements outlined in the , eligible projects must:

• Spread eligible feedstock rocks on eligible sites to generate alkalinity and drive net carbon removals.

VVB accreditation

Requirements

VVBs shall have a valid accreditation from either:

• ISO 14065 or equivalent

• COFRAC ISO:17029 or equivalent

• Approval as a Designated Operational Entity (DOE) under UNFCCC-CDM, with scopes: 1, 4, 5 6 or 13

The VVB company shall prove more than 5 years of auditing experience, including at least 2 years in environmental/sustainability auditing (refer to Structure and competencies

VVB shall adhere to Rainbow and confirm their independence from the market and carbon credits transactions.

VVB must demonstrate knowledge of and experience on the its seeks accreditation for by providing:

• CVs of the lead auditors

• Proof of work on at least 2 projects within the sector within the 2 previous years

At application review and on yearly basis the VVB shall:

• Prove that the company is financially sound

• Disclose the Rainbow program any negative media coverage

• Disclose any legal/juridical proceedings

Sectors specific for accreditation

The VVB must demonstrate its knowledge of and experience related to a specific sector on which it can conduct the VVB tasks.

This sector should be one of the following:

1. Industrial circular economy solutions

2. Bioenergies

3. Biomass carbon removal and storage

4. Construction sector

Accreditation process

The VVB submitted the .

Upon receipt of the application, the Rainbow Secretariat reviews the information provided and responds once the review is complete.

• 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 documents to be signed.

VVB must submit a signed copy of the Rainbow , and a signed copy of this current document, Requirements for VVB.

Rainbow Secretariat organizes training with the Certification team, on the Rainbow Standard and the Impact Certification Platform. Methodologic specific training could be planned depending on the scope of the accreditation.

Once all the above is completed, the Rainbow Secretariat delivers an accreditation to the VVB. It can start working with projects seeking validation under the Rainbow program.

The VVB organization is added as an approved VVB on Rainbow’s website.

Structure and Competency of VVB audit teams

Each VVB must employ a minimum of two auditors: one Auditor leader and one Internal reviewer, in addition to the wider audit team. This policy ensures that the Audit Team for every project includes at least two auditors, one to serve as the audit team leader and one to serve as the 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 Team Leader must demonstrate:

• Knowledge of the Rainbow Standard and accompanying documents;

• Knowledge of and experience related to the framework for emissions avoidance or removals project;

• Competency leading audits and coordinating team members.

The audit team must demonstrate collective knowledge and expertise in:

• 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;

The on-the-ground audit team must demonstrate knowledge and expertise in:

• Country-specific knowledge/language skills;

• Interviewing, listening, and observing; and

• Sensitivity towards socio-economic matters and environmental and social safeguards.

Appropriate checks must be completed through:

• A Internal Reviewer, approved by Rainbow as a lead auditor, to perform a final QA/QC (Quality Assurance/Quality Control) review attesting to accuracy of data. The Internal Reviewer is not part of any direct validation or verification activities and shall remain neutral.

• A Conflict of Interest (COI) form that is submitted to Rainbow’s Certification team when an audit team is contracted for validation or verification. The VVB is the responsible party for a Rainbow audit. VVBs must ensure that individual validators and verifiers are qualified with the proper training and skills to conduct verification activities.

Project-specific Validation/Verification teams

The VVB is responsible for assembling a competent and qualified Audit Team to undertake validation / verification activities before commencement of the activities. It must consider the capabilities and capacities of its staff when building the team and skills mentioned in . The Audit Team must have sector-specific competency in relation to the type of project being validated/verified.

CVs of Lead Auditors (Lead Auditor and Internal Reviewer) and a COI form should be submitted to the Certification team for approval prior to carrying out validation/verification services for a project.

Oversight

Sequential verifications

To maintain impartiality and credibility, and reduce complacency and bias, a single VVB may conduct a maximum of three (3) sequential verifications for a specific project.

Upon reaching this limit, the Project Developer is required to engage a different VVB for subsequent verifications. The Project Developer shall be granted a transition period of six (6) months to engage a new VVB for the subsequent verification.

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

Regular audits will be conducted to ensure Project Developers adhere to this rule. Non-compliance may result in penalties or suspension of the project's validation status.

VVB performance

Regular monitoring ensures that VVBs consistently perform accurate, impartial and timely validation and verification audits.

The following metrics will be employed to evaluate a VVB's performance:

• Timeliness: Adherence to stipulated timelines for project validation and verification.

• Accuracy: Correctness of validation and verification processes, calculations, and conclusions.

• Consistency: Uniform application of requirements and methodologies across different projects.

• Communication: Effectiveness and clarity in communication with Project Developers and other stakeholders.

Each VVB is required to submit an annual Performance Report that details its activities, challenges, and areas of improvement relating to its work with the Rainbow certification process. This report should provide insights into the VVB's verification approach, methodologies employed, and training undertaken.

Project Developers are asked to provide feedback on the VVB's performance after each validation and verification process, as part of the This feedback will be integral to the VVB performance review.

The Standard Secretariat annually reviews the annual Performance Reports and assess VVBs based on the established performance metrics. VVBs are encouraged to continually enhance their skills, methodologies, and processes. Training resources, workshops, and seminars will be provided to support this endeavor.

The following sampling and measurement requirements only apply to projects measuring using solid-sample CO₂ storage measurement methods. Projects using gaseous inflow-outflow measurements are exempt from these sampling protocols, as their measurement approach directly tracks CO₂ 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:

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 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

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, 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 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.

Project developers shall demonstrate that they comply with all principles and requirements outlined in the Rainbow Standard Rules, and described below with a specific focus on electronic device refurbishment.

Additionality

To demonstrate additionality, Project Developers shall perform regulatory surplus analysis, plus either investment or barrier analysis, using the Rainbow Additionality Template.

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

Project developers shall sign the , 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.

Co-benefits

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.

ESDNH risk evaluation

Project Developers shall fill in the , 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

Leakage

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.

See Table 2 in the section for more details.

The Project Developer is the party responsible for adhering to the Monitoring Plan.

Crediting process overview

The process for issuing credits under this methodology is described below.

Peer review and validation

ERW projects are notoriously variable, case-specific and subject to rapidly evolving knowledge and innovative measurement techniques. As a result, the present ERW methodology is intentionally not prescriptive at times, allowing project design elements to be evaluated on a case-by-case basis. Project assessments are rather individualized, sometimes relying on complex geochemical justifications, and requiring both technical expertise and a degree of professional judgment.

Therefore, if a project regularly falls outside the recommendations in this methodology, and requires extensive, complex, project-specific assessments, a technical peer review by at least 2 experts may be recommended.

Peer review process

Any of the following parties may request a technical peer review: the Project Developer, the VVB or the Rainbow Certification team. The final decision on whether to initiate peer review rests with the Rainbow Certification team. The review may occur either

1. before the validation audit by a VVB,

2. decided on as an outcome of the validation audit, in which case it occurs after, and/or

3. before or during a verification audit, if the project operations change substantially from the initially validated setup.

It may be in the Project Developer's best interest to initiate a peer review before submitting the project to a validation audit, to identify any potential issues early and facilitate a smooth audit.

The Rainbow Certification team arranges the peer review and acts as the main intermediary between the Project Developer and reviewers. The Project Developer should remain anonymous throughout the review process to reduce potential bias. This stage is charged directly to the Project Developer, and fees may vary by project depending on the scope of the review.

Before the review, the Project Developer and the Rainbow Certification team shall agree upon a scope of review, outlining:

• which eligibility criteria and points need to be reviewed, and which have already been validated as meeting the methodology requirements

• which points, if any, should be reviewed by the VVB if project design changes (e.g. a contingency plan)

• which underlying data must be shared to allow a sufficiently thorough technical assessment by the reviewers

The possible outcomes of a peer review include:

• full approval: the project is validated as-is

• partial approval: the project may operate as designed but certification-related aspects must be updated (e.g. increase in discount factor, changed responses to ESDNH criteria)

• changes requested: the project should change its planned operations, MRV and/or project design

• refusal: unresolvable issues mean that the project should not be certified. The Project Developer may start over with a new project application, with major changes.

The Rainbow Certification team makes the final recommendation for the project's eligibility and required changes, following the Rainbow Project validation review. Changes made as a result of the review should be directly incorporated into a revised PDD as much as possible, or where relevant, may be reflected in separate, additional project documentation. The findings of the technical peer review shall be made available on the registry along with all other project documentation.

Eligible reviewers

The Rainbow Certification team shall review and approve eligible reviewers upon their submission of a Rainbow ERW Technical Reviewer Application form.

Through the application, reviewers shall demonstrate technical, scientific expertise in fields related to ERW, such as geochemistry, mineralogy, soil and crop science, and/or modeling and statistics. The specific reviewer chosen for a given project should have expertise in the topic/s that the project does not clearly meet from the methodology.

Reviewers may be affiliated with universities, research institutes, NGOs, consulting, freelance, or ERW companies that are not related to the project being reviewed. Two reviewers are needed per project review, and a maximum of one reviewer may come from an ERW company.

The Project Developer and the Rainbow Certification team shall select and agree upon the reviewers from the list of eligible reviewers. The Project Developer may refuse a given reviewer to preserve confidentiality.

CDR verification and credit issuance

Issuing credits for ERW projects is complex because there may be a time lag of months to years from when rock is spread on the soil, draws down atmospheric CO₂, and this CO₂ is permanently stored in the ocean as bicarbonate. This methodology considers that carbon removal is:

• Initiated upon feedstock dissolution.

• Sufficiently complete to issue credits upon alkalinity being exported from the NFZ or remaining in soil porewaters at the depth of the NFZ. This amount is adjusted for expected FFZ losses, which are not considered removals, because carbon is not yet permanently stored.

To be eligible to issue credits, Project Developers must measure a statistically significant signal of complete CDR in treatment plots, compared to the baseline scenario/control plots, during the reporting period. One of the following requirements must be met to issue credits for a given reporting period:

• A statistically significant increase in the export of weathering products or the concentration of weathering products in porewaters at the depth of the NFZ, between the treatment and control plots, between the beginning and end of the reporting period. See measurement details .

• A statistically significant decrease of base cation concentration in the NFZ. This may be solid-phase measurements showing either a decrease in:

  • base cation concentration relative to an immobile tracer within the treatment plot, between the beginning and end of the reporting period, or

Successive spreading events

Project Developers may perform additional rounds of feedstock spreading throughout the crediting period. They should apply for validation before any additional spreading round. This ensures that Rainbow, the Project Developer, and if necessary, a VVB can confirm the eligibility of the planned activities for credit issuance. This step helps avoid situations where the Project Developer completes the spreading only to discover an oversight or mistake that renders the spread ineligible.

As part of this process, Project Developers shall notify Rainbow of:

• their intention to conduct additional spreading,

• sites involved,

• timing of the activity,

• amount and source of the feedstock.

This notification may be included proactively during the initial validation audit, in a year prior to the successive spreading event, outlining plans for repeat spreading in later reporting periods. Alternatively, it may be provided on an ongoing basis throughout the crediting period.

CDR from successive spreading events shall be cumulative, with the total CDR considered for the entire project. For credit issuance, it is not necessary to track which removals are attributed to specific spreading events.

Project Developers shall document and update their project induced emissions estimates and accounting timeline from successive spreading events. See below and in the section for a full list of required information to provide/update upon a successive spreading event.

Adding new sites and feedstocks

If the spreading event occurs in new sites or with new feedstocks that weren't included in the initial validation, the Project Developer shall submit a and a , respectively.

Project Developers shall follow the requirements outlined in the corresponding section of the minimum requirements for a .

The Rainbow Certification team and the VVB shall decide whether a is required to assess the eligibility and updated project design considering the new sites and feedstock.

Monitoring Plans for this methodology shall include, but are not limited to, tracking of the following information by Project Developers. The Project Developer is the party responsible for adhering to the Monitoring Plan.

Co-benefits

Below is a selection of co-benefits that are particularly aligned with Rainbow’s program objectives. They are taken from the .

Project Developers shall submit a Feedstock Characterization Report for each spreading event, that includes the applicable information outlined in the following sections: a qualitative , , , and the .

Feedstock description

Project Developers shall provide a comprehensive qualitative description of the feedstock once for each feedstock source (in addition to the quantitative described below). This description shall include: