Principles & requirements

Additionality

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

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.

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.

Durability

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 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 CO2.

  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

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 of biochar durability for each production batch. These indicators serve both as eligibility thresholds, and as inputs to quantify the permanent fraction of carbon (FpermF_{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 section. Only this fraction shall be issued as removal RCCs.

Pathway
Indicator
Threshold requirement

100-year pathway

Hydrogen-to-organic-carbon atomic ratio (H/CorgH/C_{\text{org}})

H/CorgH/C_{\text{org}} must be less than 0.7

1000-year pathway

Random reflectance distribution

  • The fraction of the biochar residual organic carbon that has a random reflectance of 2% or higher can be considered inertinite, which is an extremely stable, permanent storage of mineral-like organic carbon.

  • Must also have H/CorgH/C_{\text{org}} less than 0.7

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 section.

These durability indicators shall be monitored for each production batch according to the Rainbow Sampling Requirements.

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

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]

Project Developers shall sign the Rainbow MRV & Registry Terms & Conditions, committing to follow the requirements outlined in the 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]

See the BiCRS methodology No double counting 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.

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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).

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.

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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.

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.

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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).

Co-benefits

Projects should support at least two quantifiable and verifiable environmental or social co-benefits, aligned with the UN Sustainable Development Goalsarrow-up-right (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.

UN SDG
Example
Proof

SDG 2.4: Ensure sustainable food production systems, increase productivity, help maintain resilient ecosystems, improve land and soil quality.

Biochar application to agricultural soils can increase crop yields, therefore reducing the amount of land, pesticides, fertilizer, and other environmentally impactful resources needed to grow food

Proof of biochar use in agriculture as opposed to other applications: contract, invoices, receipts of sale of biochar to farmers.

SDG 12.2: Achieve the sustainable management and efficient use of natural resources

The project’s circularity will be measured by the Material Circularity Indicator (MCI), 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.

Type of feedstocks used, verification of end use of biochar

Environmental and social safeguards [biomass]

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 described below, Project Developers must prove the following elements.

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.

  • 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

Environmental and social risk assessment

Project Developers shall fill in the Biomass feedstock risk assessment 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]

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.

Biochar applied to soils must be below the pollutant concentration thresholds outlined in Table 2, defined by the World Biochar Certificate Guidelines (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.

Substance
Limit amount (g/tonne dry matter)

Pb

300

Cd

5

Cu

200

Ni

100

Hg

2

Zn

1000

Cr

200

As

20

8 EFSA PAH

1

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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.

Environmental and social risk assessment

Project Developers shall fill in the Rainbow Biochar application to soils risk assessment, 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, 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, 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.

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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.

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All risk assessments must also address the Minimum environmental and social risks defined in the Rainbow Standard Rules.

Leakage

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 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]

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:

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

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