# Eligibility and scope ## Eligible Project Developers 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.md#appendix-3-operating-procedure-for-kiln-operator), [Kiln Supervisors](/methodologies/distributed-closed-kiln-biochar/appendix.md#appendix-4-operating-procedure-for-kiln-supervisor) and [Project Developers](/methodologies/distributed-closed-kiln-biochar/appendix.md#appendix-5-operating-procedure-for-project-developer).

Type of actor	Operational role	Carbon project role
Kiln Operator	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.	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.
Kiln Supervisor	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.	Visits each Kiln Operator at least once per year, and coordinates biochar bulk density measurements onsite. May provide trainings to Kiln Operators. The Kiln Supervisor shall not receive payments or other incentives related to number of carbon credits issued.
Project Developer	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). May also train, provide dMRV, provide kilns, and operate kilns.	An intermediary between Rainbow and on-the-ground operations, including Kiln Operators and Supervisors. Responsible for centralized project data management, registration, VVB interactions, and ensuring carbon finance is distributed to Kiln Operators.
dMRV provider	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.	The dMRV tool must have all features needed to for kiln operators to prove compliance with methodology requirements. Full requirements here. Can also be a Project Developer.
Technology provider	Provides the physical kiln used to perform pyrolysis and produce biochar.	Must provide kilns that meet methodology requirements, and help define which kilns are the same type, for defining the Production Batch. Full requirements here. Can also be a Project Developer.

## 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.md#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:

Biomass type	Description
Forest waste	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 Necessary tree removal from any forest: Damaged trees, or trees removed for planned forest management such as preventing disease spread or fires Subject to Proof of waste status, Forestry certification, and Leakage requirements.
Agro-food waste	Residues otherwise left on soil or reapplied to soils for nutrient recycling, through mulching, composting, or spreading Residues otherwise burnt in the field, with no substantial return of nutrients or organic carbon to soil Food processing facility waste Subject to Proof of waste status and Leakage requirements.
Invasive species	Woody or herbaceous plants proven to be locally or regionally invasive (non-native and causing environmental or human harm). Subject to Proof of invasive species requirements.

Biomass type

Description

Forest waste

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
Necessary tree removal from any forest: Damaged trees, or trees removed for planned forest management such as preventing disease spread or fires

Subject to Proof of waste status, Forestry certification, and Leakage requirements.

Agro-food waste

Residues otherwise left on soil or reapplied to soils for nutrient recycling, through mulching, composting, or spreading
Residues otherwise burnt in the field, with no substantial return of nutrients or organic carbon to soil
Food processing facility waste

Subject to Proof of waste status and Leakage requirements.

Invasive species

Woody or herbaceous plants proven to be locally or regionally invasive (non-native and causing environmental or human harm).
Subject to Proof of invasive species requirements.

Biomass must be explicitly **subject to** [**stakeholder consultation**](/methodologies/distributed-closed-kiln-biochar/principles-and-requirements.md#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.md#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.

Type	Definition	Requirements
Single feedstock	Each kiln run in the Production Batch uses one biomass feedstock type	Biochar produced from different feedstock types shall be kept physically separate during production, storage, and sampling. Biochar produced from different feedstock types shall be tracked and reported separately in the dMRV system for all measurements and end-use applications.
Mixed feedstock	Each kiln run in the Production Batch uses the same feedstock mix	The mass of each feedstock component is weighed individually and documented prior to each run. The composition of the blend remains consistent within a tolerance of ±10% by mass of each feedstock type across runs.

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.

	Collective	Self-sufficient
Mobile	Portable Community Kilns Kiln is moved from site to site. Central operator provides pyrolysis as a service to multiple farmers. Kiln travels to centralized biomass sources, and biochar is left with farmers or distributed locally.	Portable Farmer Units Kiln is moved from site to site. Farmers pyrolyze their own biomass on-site or nearby, and use biochar on the same farm
Stationary	Shared Pyrolysis Hubs Kiln at a fixed and shared location. Central operator manages the kiln. Biomass comes from several sources, biochar distributed to users who may or may not have provided the biomass.	On-Farm Producers Kiln at a fixed location, at an individual's farm. Farmers pyrolyze their own biomass and use the biochar on their own land.

Collective

Self-sufficient

Mobile

Portable Community Kilns

Kiln is moved from site to site.
Central operator provides pyrolysis as a service to multiple farmers.
Kiln travels to centralized biomass sources, and biochar is left with farmers or distributed locally.

Portable Farmer Units

Kiln is moved from site to site.
Farmers pyrolyze their own biomass on-site or nearby, and use biochar on the same farm

Stationary

Shared Pyrolysis Hubs

Kiln at a fixed and shared location.
Central operator manages the kiln.
Biomass comes from several sources, biochar distributed to users who may or may not have provided the biomass.

On-Farm Producers

Kiln at a fixed location, at an individual's farm.
Farmers pyrolyze their own biomass and use the biochar on their own land.

## 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.md#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.md#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.md#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:

Project Size	Annual audit rate	Annual audit minimum number of sites	Indicative 5-Year Cumulative Coverage
<10 sites	2 sites per year	2	100% of all sites visited at least once
11–200 sites	10% of sites per year	2	~50% of all sites visited at least once
201–500 sites	5% of sites per year	15	~25–50% of all sites visited at least once
500+ sites	5% of sites per year	10, maximum 40 per year	~25% of all sites, maximum 200 unique sites over 5 years

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.md#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.md#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.
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. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.rainbowstandard.io/methodologies/distributed-closed-kiln-biochar/eligibility-and-scope.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.