This is a Carbon Storage Module and covers Marine sub-sediment burial. This module is part of the Riverse BiCRS methodology, which allows Project Developers to choose the relevant modules for their project, and shall be used with the necessary accompanying modules.

See more details on how modules are organized in the BiCRS home page.

Eligible technologies

Project type

This module covers marine sub-sediment burial projects that inject waste and residual biomass feedstock inputs directly into the anoxic layer of marine sub-sediments. Projects shall meet all of the following criteria:

• Demonstrate capability to perform MRV as agreed upon in the validated project documentation

• Demonstrate a net-negative project carbon footprint based on initial LCA estimates of induced emissions and initial CDR estimates based on modeling

• Projects that sink biomass to the seafloor but do not bury and embed it into marine sub-sediments are not eligible.

• The cand entity eligible for receiving carbon finance is the operator performing storage at the sub-sediment burial site. Biomass producers and sub-sediment burial machinery manufacturers are not eligible Project Developers.

Project scope

A project is defined as all burial activities that take place from one port over the project lifetime (by default a maximum of 5 years, renewable), and all removal that occurs as a result of that burial, plus the upstream/downstream activities associated with that burial (e.g. GHG emissions from feedstock sourcing, transport...).

See the Storage batch section for more details on how a project is organized into different burial areas and burial events.

Eligible sites

Storage must be done in anoxic conditions.

Storage must be done in existing accessible marine sub-sediment. Projects that drill, dredge or build wells for the sole purpose of accessing sub-sediments or creating sub-sediment conditions are not eligible, due to the associated environmental risks.

See the Site characterization section for more specific requirements.

Eligible feedstock

See the BiCRS Biomass Feedstock module for more specific feedstock requirements.

Crediting timeline and process

Storage batches

Measurements and reporting are performed for storage batches. Verification and credit issuance is done at the reporting period scale (by default, annually), grouping results for all storage batches concerned during that reporting period. The organization of a project into storage batches, sites and points is described below, and depicted in Figure 1.

Sedimentary conditions for storage points within one storage site must be within the following ranges (data requirements are outlined in the Data Sources section):

• Grain size: the majority grain size at the burial sediment depth must be either defined as either clay (0.002-0.05 mm) or sand (0.05-2 mm) for all storage points within a storage site, indicated by >50% of sediment grain size. Defined by recommendations of USGS.

• Water depth at storage point: At water depths 1-20 m, water depths must be within 0.5 m. At water depths 20-200 m, water depths must be within 5 m.

• Sub-sediment depth of storage: At sub-sediment depths 2-3 m, storage depths must be within 0.5 m. At sub-sediment depths >3 m, storage depths must be within 1 m.

Ongoing burial into the sub-sediment shall last no longer than 31 days per storage batch, to standardize sampling timescales. If burial continues after 31 days, it shall be considered a separate storage batch.

One project may work with different storage batches simultaneously. Each storage batch shall be monitored and reported separately within the same Monitoring Report. Storage batch information shall be monitored and reported at least once per calendar year.

Information about storage batches may be monitored continuously by Project Developers by uploading claim information to the Riverse MRV platform. All claims from one calendar year are audited together annually by a third party VVB for verification and issuance of credits.

Feedstock mixture

A feedstock mixture is defined as one biomass feedstock or uniform mixtures of feedstocks. One feedstock mixture may be used across several storage batches, but any time the feedstock mixture of one storage batch changes, a new storage batch shall be started.

The feedstock mixture composition may vary by no more than 20% to be considered the same homogeneous feedstock mixture, where the composition is made of feedstocks of a specific type from a specific supplier.

See the Pre-burial sampling section for requirements on feedstock sampling.

Storage site and storage point requirements

Storage points must meet the criteria outlined in Table 1 to be eligible. The criteria are set to ensure storage points are suitable for permanent carbon storage and have low reversal risks.

All criteria shall be outlined in the Site Characterization Report, prepared before any burial events occur and submitted with the PDD for the validation audit. In addition, the Site Characterization Report shall provide GPS coordinates of each planned storage point, and a GIS-generated map showing each storage point and the delineation of the associated storage site.

Data sources characterizing storage points must be, in the following order of preference, 1) primary data from a pilot survey e.g. site surveys, in situ measurements and measurements on samples collected at the project site, delivered by the Project Developer, or 2) secondary data from the specific area concerned (e.g. published peer-reviewed literature or database measurements) or 3) secondary data from an area that is proven to be sufficiently representative and similar to the project area in the appropriate factors that relate to permanent storage.

Table 1 The required measurements and information for a storage site that must be presented in the Site Characterization Report, before any burial occurs, to justify that the storage site is appropriate for permanent CDR via marine sub-sediment burial.

Sampling requirements

Sampling occurs at two stages of the project: sampling of the feedstock mixture before burial to establish organic carbon buried, and sampling the feedstock mixture after burial to check for any reversals (i.e. carbon degradation or diffusion. At both stages of sampling, laboratory testing shall provide the following measurements of the feedstock mixture:

• % organic content of the solid biomass

• % moisture content of the feedstock mixture

• density of the feedstock mixture

Pre-burial sampling

Two representative samples of the feedstock mixture shall be prepared and sent for laboratory testing per storage batch: one at the beginning (day one) and one at the end of the storage batch (day 31 or an earlier date when the storage batch is complete).

Post-burial monitoring and sampling

Post-burial monitoring and sampling shall occur:

• at least 12 months after the burial event, and

• optionally, may also be performed within 1-3 months after the burial event if the Project Developer chooses the 50/50 credit issuance approach.

See the Crediting timeline and process section for more details.

Post-burial monitoring and sampling should be completed using sediment coring, to access the buried biomass, extract samples, and send them to a laboratory to measure the organic content of the solid biomass. Alternative approaches may be considered on a case by case basis, and approved by the VVB, the Riverse Certification team and, if deemed necessary by the Riverse Certification team, an expert peer reviewer.

Sampling and laboratory testing shall be done separately for each storage point. At least three sub-samples shall be taken from each storage point and mixed together to obtain one composite sample for the storage point. Samples can not be mixed from all storage points in one storage site to perform laboratory tests on a composite sample.

Sampling plan

Project Developers shall prepare a Sampling Plan before any burial events occur, and submit it with the PDD for the validation audit. The Sampling Plan shall describe:

• how representative samples will be taken of the feedstock mixture in pre-burial sampling

• how to preserve moisture content of feedstock mixture while sending it to the lab

• number of samples used for post-burial sampling

• strategy for ensuring random/representative/unbiased sampling locations for post-burial sampling

Eligibility criteria

The eligibility criteria requirements specific to this module are detailed in the sections below. Other eligibility criteria requirements shall be taken from the accompanying modules and methodologies:

Permanence

Removal Riverse Carbon Credits (RCCs) issued from marine sub-sediment burial have a permanence horizon of 1000 years.

Permanence is assessed at two points during project certification:

• at ex-ante validation it is estimated using literature data and models

• during verification it is demonstrated using direct measurements.

Requirements for each stage are detailed below.

Estimating permanence at validation

To demonstrate that carbon in sub-sediment burial will remain permanently stable, indicators from the Storage site and storage point requirements section must be provided at validation, in the Site Characterization Report, demonstrating compliance with the requirements.

These indicators are suitable proof that a substantial fraction of the buried carbon is permanently stable. The amount of permanently stored carbon is determined using the models and equations detailed in the GHG reduction quantification section.

Demonstrating permanence at verification

At verification, it is assumed that any organic carbon still remaining in the feedstock mixture 12 months after burial will remain permanently stored over 1000 years.

For each storage batch, the organic carbon content in the buried feedstock mixture is measured via sampling at 1-3 months (optional) and 12 months (mandatory) to determine the carbon permanently stored.

The actual amount of permanently stored carbon is measured as described in the GHG quantification section, replacing the modeled amounts used during validation to issue ex-post Riverse Carbon Credits.

Risk of reversal

Project Developers shall fill in the Riverse Marine sub-sediment burial risk evaluation to evaluate the risk of carbon storage reversal, based on social, economic, natural, and delivery risks.

Co-benefits

Project Developers shall prove that their project provides at least 2 co-benefits from the UN Sustainable Development Goals (SDGs) framework (and no more than 4).

Common co-benefits of Marine sub-sediment burial, and their sources of proof, are detailed in Table 2. Project Developers may suggest and prove other co-benefits not mentioned here.

Table 2 Summary of common co-benefits provided by Marine sub-sediment burial projects. Co-benefits are organized under the United Nation Sustainable Development Goals (UN SDGs) framework.

Environmental and social do no harm

Project Developers shall prove that the project does not contribute to substantial environmental and social harms.

Projects must follow all national, local, and European (if located in Europe) environmental regulations related to the project activities.

Feedstock sustainability risks shall be taken from the Biomass feedstock module.

ESDNH risk evaluation

Project Developers shall fill in the Riverse Marine sub-sediment burial risk evaluation to evaluate the environmental and social risks of their project.

Permitting

Project Developers must follow all relevant laws and legal requirements for reporting operations to local, federal and international governing bodies. Project Developers must follow the requirements outlined in their permit relating to the amount of tonnes injected if specified, and geographic area permitted for operations .

Permits are typically required for accessing coastal marine sediments and performing sub-sediment burial. The Project Developer must provide written authorization by either 1) the permit granting regulatory authority or 2) by the partner providing the permit demonstrating freedom to operate and perform sub-sediment burial in the geographic area defined in the PDD.

Environmental Impacts Assessment (EIA)

Typically, the EIA should be completed in advance of obtaining permitting for credit generation, and will be completed over the course of operations and reported to Riverse.

EIA may not be required for all permits for storage. When EIA is not required for permitting (e.g. for a research permit or permit exemption), the Project Developer shall demonstrate that a baseline environmental survey has been completed, assessing the elements listed below, and that the potential impacts have been considered to be within regulatory guidelines. This justification shall be evaluated by both the VVB and the Riverse Certification Team. Project Developers shall provide the same information as they would in a full EIA to Riverse for project validation, and cover aspects including:

• Marine protected areas

• Benthic habitat

• Fishing grounds

• Shipping lanes

• Subsea infrastructure

• Materials of historical significance

Baseline environmental survey and/or EIA must address how the project adheres to regulatory requirements such as limitations on sediment resuspension and habitat destruction due to seabed intervention.

GHG quantification

The system boundary of this quantification section starts after burial of feedstock mixture and covers carbon storage through end of life after 1000 years, and accounts for potential re-emission and decay modeled for 1000+ years. Sources of GHG emissions covered in this module include only permanent carbon storage modeling. Other GHG emissions shall be taken from the accompanying modules.

Data sources

The required primary data for GHG reduction calculations from projects are presented in Table 3. These data shall be included in the project’s PDD and made publicly available.

Table 3 Summary of primary data needed from projects and their source for project validation and verification. See the Monitoring Plan section for more details on monitoring and verification requirements. Asterisks (*) indicate which data shall be updated for each storage batch.

Secondary data taken from the literature are used to define default values for the parameters outlined in Table 4. These values are only used for ex-ante validation models, and will be replaced by project measurements during verification.

Table 4 Values from scientific literature that may be used instead of primary data, for validation stage ex-ante carbon degradation modeling.

Carbon storage modeling

Carbon storage is calculated by subtracting the amount of organic carbon degraded over 1000 years from the amount of initially buried organic carbon.

• Carbon burial is measured using the amount of feedstock mixture buried, and its measured organic carbon content.

• Carbon degradation is subtracted from this carbon burial. It is modeled at validation and measured at verification.

Carbon degradation

Carbon degradation is conservatively modeled during validation using a multi-G kinetic model (see Appendix A and Example 1), and measured during verification.

Example 1: GHG quantification validation modeling

Assumptions

1. The entirety of buried biomass will be securely located in the seabed, allowing point-source monitoring of organic carbon degradation via measurement of organic carbon content.

2. Organic carbon degradation is front-loaded and logarithmic. 12 months is an appropriate and sufficiently long timeframe to determine how much carbon degradation (if any) will occur over 1000 years.

   1. Biomass degradation will either begin after embedding in the sub-sediment following a logarithmic relationship (Keil et al., 2010), or it will not occur at all.

3. The rate of organic carbon degradation under oxic conditions is greater than the rate under anoxic conditions.

4. Biomass degradation can be measured by tracking organic carbon content of samples of the buried feedstock mixture over time.

5. Storage points will not experience re-suspension or re-working such that burial biomass is exposed to the water column over 1000 years.

6. The site characteristics and requirements detailed in Table 1 are suitable to identify sub-sediment areas that are anoxic.

Uncertainty assessment

See general instructions for uncertainty assessment in the Riverse Standard Rules. The outcome of the assessment shall be used to determine the percent of RCCs to eliminate with the discount factor.

The uncertainty in this module is assessed below for each component.

The uncertainty at the module level is estimated to be low. This translates to an expected discount factor of at least 3% for projects under this module.

Risk evaluation template

Monitoring plan

The following information shall be provided for verification of each storage batch:

Appendix

Appendix A: Scientific Basis of Sub-Sediment Biomass Storage

This appendix outlines the scientific foundation for sub-sediment biomass storage, summarizing key research on organic carbon degradation and preservation in marine sediments. While no studies directly replicate the conditions described in this module, relevant literature on similar processes is compiled.

Introduction

Marine sediments serve as the final carbon sink, storing 150–200 billion tons of organic carbon in their upper layers (Hedges & Keil, 1995; Hedges, Keil & Benner, 1997; Atwood et al., 2020). The biological pump transfers oceanic carbon to sediments via microbial fixation, food chain dynamics, and sinking particulate matter. Despite its inefficiency—only ~1% of sinking carbon reaches sediments, and just 0.1% is buried long-term (Burdige, 2007; LaRowe et al., 2012)—this process significantly influences atmospheric CO₂ levels.

Biomass degrades rapidly in oxygenated sediments, but in anoxic environments, it can persist for millennia. Oxygen exposure time (OET) controls degradation: prolonged exposure breaks macromolecules into labile forms, accelerating conversion to CO₂. Reducing OET preserves biomass, as seen in bog bodies and historic wooden structures preserved in compacted, oxygen-deprived sediments (Ceccato et al., 2014; Macchioni et al., 2016).

Organic Carbon Preservation in Marine Sediments

Decades of research (Hedges & Keil, 1995; Arndt et al., 2013; LaRowe et al., 2020) indicate that organic carbon degrades slowly in anoxic sediments due to low substrate availability, microbial competition, mineral protection, and biochemical inaccessibility (Kristensen & Holmer, 2001; LaRowe et al., 2022).

Biomass preservation for over 1,000 years is common in coastal zones with high sedimentation rates and low OET. For example, rapid burial in the Bay of Bengal (30 cm/yr sedimentation) protects wood from microbial degradation, preserving organic material for millions of years (Lee et al., 2019). Similarly, wood fragments up to 11,900 years old have been recovered from the Gulf of Mexico (Schwab et al., 1996), and entire ancient forests remain buried off the Alabama coast (Delong et al., 2021; Moran et al., 2024).

Studies show organic carbon degradation slows exponentially over time, with rates up to 1,000× lower in anoxic sediments than in oxic environments (Kristensen & Holmer, 2001; Keil et al., 2010; LaRowe et al., 2012; Arndt et al., 2013). This supports the assumption that degradation rates in oxic conditions (Keil et al., 2010) represent a worst-case scenario for anoxic sub-sediment burial.

Biomass Degradation in Marine Sediments

Biomass degradation begins with extracellular enzymatic hydrolysis, where aerobic microbes break down macromolecules into small organic compounds. These are further processed via anaerobic fermentation into substrates for redox reactions. However, without sufficient OET, enzymatic hydrolysis cannot begin, preventing degradation (Hartnett et al., 1998; Hedges et al., 1999). Ligno-cellulosic biomass requires longer OET than algal biomass to initiate breakdown.

In deep sediments, sulfate reduction is the dominant degradation process, accounting for 50% of total biomass decomposition globally (Jorgensen et al., 2019). This slow, energy-limited process produces CO₂ and hydrogen sulfide (HS). CO₂ diffuses upward, where it may be fixed by microbes or released at the sediment-water interface. Worst-case CO₂ diffusion rates align with modern dissolved inorganic carbon (DIC) fluxes (Krumins et al., 2013). CO₂ accumulates due to compaction, it can form hydrates at depths >10 m in cold marine sediments (Eccles & Pratson, 2012; Velaga et al., 2011).

Hydrogen sulfide, though toxic, is rapidly oxidized in oxygenated environments, preventing marine toxicity. Additionally, 10–20% of HS reacts with iron hydrates to form pyrite (FeS), further stabilizing organic matter (Barber et al., 2017; Baumgartner et al., 2023).

Methanogenesis, consuming 15% of CO₂ from sulfate oxidation, contributes to organic carbon degradation (Regnier et al., 2011). Over time, sediment compaction reduces porosity, slowing diffusion and promoting FeS formation. This further limits CO₂ and methane movement, allowing microbial utilization.

Conclusion

Long-term biomass preservation in marine sediments is driven by low OET, rapid burial, and anoxic conditions. Anoxic degradation is significantly slower than oxic processes, enhancing the stability of buried carbon. Existing research supports the feasibility of sub-sediment biomass storage as a durable carbon sequestration strategy.

Appendix B Additional optional ESDNH indicators to monitor

ESDNH indicators may be measured by the Project Developer within the validation stage to reduce project risk, and suggested monitoring during the verification stage.

• Hydrogen sulfide is toxic to benthic life, and excessive production may exceed oxidation rates, increasing ecological risk.

• Methane, a potent greenhouse gas, can also impact benthic organisms if released.

Suggested monitoring plan additions to monitor environmental harms

Appendix C Reasoning for 2 m burial depth

In addition to reaching below the maximum oxygen penetration depth at any season, there is a required sub-sediment depth of at least 2 m depth into the sediment is required due to risk of reversal, due to maximum 2m sediment scouring during tropical zones, and infilling of previously scoured areas due to resuspension due to storms (Morton, 1979; Sherwood et al., 1994), fluid-mud flows (Wheatcroft, 2000), and erosion (Morton, 1979, Harris & Wiberg, 2001).

On the continental shelf, seafloor sediments are eroded and reworked by bottom currents and wave action, a process known as “scouring” (Flood et al. 1983). This creates linear or lobate depressions shaped by dominant environmental forces. Channel-shaped scours, or furrows, range from 10–100 meters wide and 100–1000 meters long, with coarse sand or gravel floors. Larger lobate deposits (100–500 meters wide) are often filled with mega-rippled coarse sand, forming "Rippled Scour Depressions" (Davis et al. 2013). Major storms can also transport large amounts of sediment to the deep sea without leaving scours (Teague et al. 2006).

Scouring and sediment resuspension pose risks to carbon storage in shelf sediments, as buried biomass must remain covered to prevent oxygen exposure. To assess this risk, we reviewed 29 studies on sediment furrows and ripple scour depressions across various depths and oceanographic settings (Figure 4, Table 5). Reported scour depths, including those from extreme events (e.g., Hurricanes Katrina, Ivan, Sandy), inform our recommendation of a >2-meter burial depth for carbon storage. While regional variation is significant, findings from Ferinni et al (2005) suggest that wider continental shelves may offer greater protection from erosion.

Table 5: Summary of observation of furrowing and rippled scour depressions in literature

Version history

This page describes the changes in the Marine sub-sediment burial module.

This is a Carbon Storage Module and covers the biochar application to soils. This module is part of the Riverse BiCRS methodology, which allows Project Developers to choose the relevant modules for their project, and shall be used with the necessary accompanying modules.

See more details on how modules are organized in the BiCRS home page.

Scope of the module

This module covers industrial biochar projects that meet all of the following criteria:

Biochar may be applied directly to soils or incorporated into soil-related products, such as soil additives, horticultural substrates, potting soils, fertilizer mixes, or compost.

Projects may be designed to prioritize bio-oil or bioenergy production, where biochar is the co-product. Such projects may still be eligible for removal Riverse Carbon Credits under this module, if they meet all criteria outlined herein.

This module also covers any potential avoided horticultural products from the use of biochar.

This module issues removal RCCs on the basis of biochar use/delivery, i.e. application to soils and permanent storage, not on the basis of biochar production.

Eligible Project Developers

The Project Developer and entity eligible for receiving carbon finance may be either:

• the operator of the biochar production site, or

• land owners or managers who purchase biochar and apply it to their soil.

Pyrolyzer and gasification equipment manufacturers are not eligible Project Developers.

Production batches

Measurements and reporting are performed for production batches, and credit issuance is done at the reporting period scale (by default, annually). A production batch is the biochar produced under the same conditions regarding production temperature and feedstock mix. It is assumed that all biochar from the same production batch has similar characteristics (i.e. $H/C_{\text{org}}$, moisture content…).

Specifically, the definition of a production batch follows the European Biochar Certificate Guidelines definition, where pyrolysis temperature and biomass feedstock composition must not change by more than 20%.

A production batch has a maximum validity of 365 days, after which biochar shall be considered part of a different production batch even if conditions are unchanged.

Information about production batches may be monitored continuously by Project Developers by uploading claim information to the Riverse MRV platform. All claims from one calendar year are audited together annually by a third party VVB for verification and issuance of credits. See the Continuous issuance section of the Riverse Procedures Manual for more details.

Eligibility criteria

The eligibility criteria requirements specific to this module are detailed in the sections below. Other eligibility criteria requirements shall be taken from the accompanying modules and methodologies:

Permanence

Estimating permanent carbon fraction

Projects issuing removal RCCs from biochar application to soil may claim one of two different permanence horizons, depending on their GHG reduction quantification method: a permanence horizon of 100 years or 1000 years.

Permanence is ensured by measuring one of the following characteristics of biochar that are known indicators of carbon stability:

• 100 year pathway: Hydrogen and organic carbon content ($H/C_{\text{org}}$). $H/C_{\text{org}}$ must be less than 0.7 to be considered eligible for 100-year permanent removals.

• 1000 year pathway: Random reflectance. The fraction of the biochar that has a random reflectance of 2% or higher can be considered inertinite, which is an extremely stable, permanent storage of mineral carbon.

The distinction between the two permanence horizons is supplementary, qualitative information that 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 reduction quantification section.

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

Risk of reversal

Project Developers shall fill in the Riverse Biochar application to soils risk evaluation to evaluate the risk of carbon storage reversal, based on social, economic, natural, and delivery risks.

Project Developers shall assign a likelihood and severity score to each risk, and provide an explanation of their choices. The Riverse Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

The Project Developer, Riverse Certification team, or the third-party auditor may suggest additional risks to be considered for a specific project.

Each reversal risk with a high or very risk score is subject to:

• risk mitigation plan, developed by the Project Developer, that details the long-term strategies and investments for preventing, monitoring, reporting and compensating carbon removal reversal, or

• additional contributions to the buffer pool, at a rate of 3% of verified removal Riverse Carbon Credits for each high or very high risk

No double counting

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 only one party intends to issue carbon credits, this must be proven through signed agreements, minimizing the risk of double counting.

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.

Co-benefits

Project Developers shall prove that their project provides at least 2 co-benefits from the UN Sustainable Development Goals (SDGs) framework (and no more than 4).

Common co-benefits of biochar application to soil, and their sources of proof, are detailed in Table 1. 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 Summary of common co-benefits provided by biochar application to soils projects. Co-benefits are organized under the United Nation Sustainable Development Goals (UN SDGs) framework.

Substitution

If Project Developers can prove that their biochar product replaces a specific and known amount of a specific product, (e.g. a known fraction of a horticultural substrate mix), then the product may be considered as replaced and avoided. The Project Developer shall justify the amount of material actually replaced by biochar, and may not simply use a 1:1 mass replacement ratio. A non-exhaustive list of possible replaced products include:

• Horticultural peat/peat moss

• Lime

• Perlite and vermiculite

• Synthetic mineral fertilizers (only when biochar is used as an ingredient in fertilizer mixes, not when it is directly applied to soils)

By default, it shall be assumed that biochar application to soils does not replace any measurable, verifiable product.

If only removal RCCs are issued, then this eligibility criteria is not applicable.

Note that avoidance from energy co-products is covered in a a separate module.

Environmental and social do no harm

Project Developers shall prove that the project does not contribute to substantial environmental and social harms.

Projects must follow all national, local, and European (if located in Europe) environmental regulations related to, for example, pyrolysis, gasification, waste feedstock management, and biochar spreading on soils.

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 European Biochar Certificate Guidelines (for EBC-Agro). This shall be measured for each production batch.

Table 2 The thresholds for pollutant concentrations allowed in biochar, as detailed in the European Biochar Certificate Guidelines.

ESDNH risk evaluation

Project Developers shall fill in the Riverse Biochar application to soils risk evaluation, 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

GHG quantification

The GHG reduction quantification instructions from all other modules used by the project must be used in conjunction with the present module in order to obtain full life-cycle GHG reduction quantifications.

The system boundary of this quantification section starts at the arrival of biochar at the site of permanent incorporation/application (i.e. field for spreading, mixing into potting soil...) and ends at the biochar end of life, after accounting for decay and re-emission in its end use application.

Quantification shall be done at a minimum for each biochar production batch, and may be done more frequently for Continuous issuance. Verification shall be done annually by summing the GHG reduction quantifications for each production batch produced in the calendar year.

GHG emissions covered in this module include:

• Permanent carbon storage modeling

• Production of avoided baseline scenario materials

Data sources

The required primary data for GHG reduction calculations from projects are presented in Table 2. These data shall be provided for each production batch and made publicly available.

Table 2 Summary of primary data needed from projects and their source for initial project certification and validation. Asterisks (*) indicate which data are required to be updated annually during verification (see Monitoring Plan section).

The ecoinvent database version 3.10 (hereafter referred to as ecoinvent) shall be the main source of emission factors unless otherwise specified. Ecoinvent is preferred because it is traceable, reliable, and well-recognized. The ecoinvent processes selected are detailed in Appendix 1.

No other secondary data sources are used in this module.

Co-product allocation

The rules outlined at the methodology-level in the BiCRS methodology document shall be applied for allocating GHG emissions between co-products.

Assumptions

1. By default, biochar application to soils does not replace any product.

2. The fraction of biochar with an $R_o$ below 2% does not contribute to any permanent carbon storage. This fraction, classified as semi-inertinite rather than inertinite, likely plays a role in long-term carbon storage. However, due to limited research on its quantification, it is conservatively excluded from this analysis.

3. All biochar from the same production batch has the same characteristics (e.g. M_{\text{%}}, $H/C_{\text{org}}$, $R_o$).

Baseline scenario

The baseline scenario for the purpose of Removal vs Avoidance RCCs issuance is detailed below.

Project scenario

Project Developers must choose between one of two approaches to quantify the total carbon removals from their biochar product, as described in the Permanence section. A single approach must be used consistently throughout each reporting period, though a different approach may be chosen for subsequent reporting periods.

1. Modeling 100-year removals using bulk measurements of $H/C_{\text{org}}$, or

2. Estimating 1000-year removals using random reflectance measurements as proxies for inertinite.

Approach 1: Modeling 100-year removals with $H/C_{\text{org}}$

This approach is based on research from Woolf et al., 2021, and the IPCC modeling method. It is rooted in soil ecology and soil biochemistry disciplines. The permanent fraction of biochar carbon remaining after 100 years ( $F_{\text{perm 100}}$) is modeled using the average soil temperature of 15°C.

For verification, Project Developers shall provide primary project data in the form of laboratory measurements for $H/C_{\text{org}}$ and M_{\text{%}} following the Sampling requirements.

Approach 2: Estimating 1000-year removals using random reflectance

This approach is based on research from Sanei et al., 2024, and is rooted in organic petrology and geochemistry disciplines. This approach is built upon research showing that fractions of inertinite in biochar samples are:

• inert and permanent and will not re-release their carbon for at least 1000 years.

• represented by the fraction of the sample with a Random Reflectance ($R_o$) of 2% or higher.

For verification, Project Developers shall provide primary project data in the form of laboratory measurements for $R_o$ distribution and M_{\text{%}} per production batch following the Sampling requirements.

$R_o$ distribution shall be calculated on at least 500 measurements, yielding a distribution diagram similar to the examples in Figure 1.

The fraction of the distribution with an $R_o$ above 2% shall be assumed to equal the fraction of the biochar carbon that is stored permanently for 1000 years. The fraction

The fraction of the distribution with an $R_o$ below 2% shall represent the fraction of biochar carbon that is not permanently stored, and for which no removal RCCs are issued.

Future Approach 3: Using H/C as a proxy for inertinite

Riverse is actively monitoring ongoing research and seeking expert advice on the potential development of a third approach that uses $H/C_{\text{org}}$ measurements as proxies for inertinite content. For example, if the $H/C_{\text{org}}$ value is less than 0.2, it could be interpreted as indicating that 95% of the biochar is inertinite. While this simplification has been suggested by experts and holds promise, it is currently considered insufficiently rigorous due to a lack of supporting evidence and clear guidance.

Uncertainty assessment

See general instructions for uncertainty assessment in the Riverse Standard Rules. The outcome of the assessment shall be used to determine the percent of RCCs to eliminate with the discount factor.

The three assumptions presented in the Assumptions section have moderate uncertainty, but the most conservative approach is taken in the quantifications.

The baseline scenario selection (if applicable) has low uncertainty, because the specific circumstances, amount and type of baseline material must be proven by the Project Developer.

The equations and models have low to moderate uncertainty. The model for 100-year permanence from Woolf et al., 2021 has moderate uncertainty because it is a model fitted to experimental data, which always introduces variability. The equations for 1000-year permanence from Sanei et al., 2024 have low uncertainty because they are basic conversion equations.

The assumption that biochar characteristics are the same throughout the production batch is low, thanks to the strict definition of a production batch ensuring low-variability, and the exhaustive sampling requirements ensuring a representative sample.

The uncertainty at the module level is estimated to be low. This translates to an expected discount factor of at least 3% for projects using this module.

Sampling requirements

The following indicators shall be measured for each production batch:

• $H/C_{\text{org}}$

• Carbon content (organic and/or total)

• moisture content

• random reflectance (only if applying for 1000-year permanence)

Measurements shall be performed by laboratories with at least one quality assurance accreditation, such as:

• ISO/IEC 17025

• CEN/TS 17225-1

• ISO 10694

Unaccredited laboratories from academic settings shall be evaluated on a case by case basis by the VVB and the Riverse Certification team.

The sampling procedure detailed in sections below and summarized in Figure 1 is the recommended approach for representative sampling. However, Project Developers may implement their own approach if it is detailed in the PDD and in Sampling Records; ensures one representative sample per production batch; addresses samples and composite samples amount and frequency; and ensures homogenization. The VVB and the Riverse Certification team must validate the rigor and representativeness of the proposed sampling approach.

The recommended approach sampling requirements are based on the following sources:

• EU Fertilizing Products Regulation (EU) 2019/1009

• European Biochar Certificate Guidelines Annex 4 Representative Sampling

Representative sampling

One representative sample per Production Batch shall be created and sent for laboratory testing. This sample ensures that any within-batch variability is captured in the measurements.

Table 1 details the number of composite samples that should be taken per Production Batch to obtain one representative sample, based on the EU Fertilizing Products Regulation (EU) 2019/1009.

The representative sample size should be be 24 liters * the n number of composite samples per Production Batch detailed in Table 1.

Table 1

The European Biochar Certificate Guidelines Annex 4 Representative Sampling should be followed for taking composite samples. Those requirements are summarized below.

Homogenization

The representative sample shall be homogenized by the Project Developer or by the laboratory that performs testing. The biochar shall be ground to a size of <3 mm.

The ground sample is mixed by shoveling the pile three times from one pile to another.

A sub-sample of 1.5 liters shall be taken from 15 spots in the mixed pile.

The 15 sub-samples are re-combined, and then mixed by shoveling the pile three times from one pile to another.

From the mixed pile of the combined sub-samples, 15 subsamples of 150 ml each should be taken at 15 different spots in the pile and combined. This combined homogenized representative cross sample is used for laboratory testing.

Retention samples

A one-liter retention sample shall be collected each day that biochar is produced. These samples should be combined for storage over the calendar month. Retention samples must be stored for a minimum of two years.

Sampling records

For each Production Batch, Project Developers shall submit a Sampling Record for verification to prove their adherence to the requirements above. Sampling Records shall include the following information for each sample taken:

• Date of sampling

• Amount of biochar sampled

• Description of representative sampling process (either followed the recommended approach, or describe the individual approach)

• Sample ID

• Visual description and observation of biochar

• Description of any potential anomalies

• Proof of retention sampling

• Photos showing the date, sample ID, and amount of biochar that is included in the present Sampling Record

Validation and verification requirements

Ex-ante validation data requirements

Biochar projects often use carbon financing to launch new projects, and validation is done ex-ante before the project begins operations. In this case, provisional RCCs are estimated using reasonable project data estimates. These provisional credit estimates are converted to verified issued credits upon verification using real project data. Required project data estimates are detailed below.

A project may use one quantification approach for ex-ante estimation, and use a different approach for verification.

Ex-ante validation delivery risk

When validation is conducted on non-operating projects that are in the planning stage, Project Developers shall prove during validation that the biochar is reasonably expected with strong certainty to end up in its intended use (application to soil). This shall be provided by either:

• Option 1: Signed agreements with the end-buyers that they intend to purchase the agreed upon quantity of biochar annually (preferable).

• Option 2: If the project is in planning stages and has not yet secured a buyer, a signed agreement from the Project Developer of their intended buyer/user of biochar. Note that the delivery risk is higher for this option, so Option 1 is preferable. An increased discount factor may be applied.

Verification of biochar end use

Upon verification, once the project has started operating, Project Developers shall prove that biochar has been used in the intended application for each Production Batch, (e.g. incorporated into soils, added to fertilizer mixes…). This shall be done in Biochar Application Verification Reports that shall 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.

Monitoring plan

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

• Description of the pyrolysis conditions (temperature and residence time) and any variability in the process

• Amount of biochar produced, in tonnes of fresh biochar

• Moisture content of biochar

• Organic carbon content

• $H/C_{\text{org}}$ (only for Approach 1: Modeling 100-year removals with H/C org)

• Random reflectance ( $R_o$) mean and distribution (only for Approach 2: Estimating 1000-year removals using random reflectance)

• ESDNH pollutant measurements

• Biochar Application Verification Reports

• Sampling records

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

• Number of Production Batches

• Total amount of biochar produced per year, in tonnes of fresh biochar

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

Appendix

The table below presents a non-exhaustive selection of Ecoinvent activities that may be used in the GHG reduction calculations for this module. Additional activities may be used for any project, if the following selection does not cover all relevant activities.

Table A1 List of ecoinvent 3.10 processes used in the GHG reduction quantification model, all processes are from the cutoff database

Risk evaluation template

Version history

This page describes the changes in the Biochar application to soils module.

Because this module is considered the V2.0 of the Riverse BECCS and Biochar V1.0 methodology, the table below also includes changes from the Riverse BECCS and Biochar V1.0 methodology that are covered in other modules (e.g. Biomass feedstock).