Biochar Production in Distributed and Small Scale Projects

Distributed and small-scale projects allow for biochar production in rural and agricultural settings where biomass feedstocks are often abundant, but the infrastructure for its transport to large-scale, centralized facilities is often lacking, cost-prohibitive, or energy-intensive. Localized production of biochar facilitates the conversion of biomass residues into a stable carbon material which may also be an effective soil amendment, which can improve soil health and increase crop yields. This approach aligns with on-farm circular economy principles, where feedstock is sourced from the land and the resulting biochar is deployed back into the same soil, creating a closed-loop or short supply chain system that maximizes both carbon sequestration and local economic benefits.

This Module outlines the specific requirements for projects that employ distributed or small-scale biochar production units. These projects are characterized by a decentralized network of smaller production facilities, each with a nominal annual biochar production capacity of less than 500 metric tons, although this is not a binding definition of Projects that may qualify under this project type. The primary aim of these provisions is to ensure the same level of data integrity, verifiability, and environmental safeguards as large-scale projects, while accounting for the unique operational challenges of a distributed model. This Module assumes at least a "mid-tech" level of technology for pyrolysis (e.g., advanced retorts or improved kilns). These systems increase gas residence time and therefore exhibit substantially reduced products of incomplete combustion and increase biochar consistency compared to open-flame pits.

Due to the potential variability in biochar production operating conditions, which can lead to differences in the physicochemical properties of the resulting biochar and consequently its durability, these Projects are only eligible for crediting through the 200 year option of the Biochar Storage in Soil Environments Module.

Project Proponents must meet all the requirements set out in the Biochar Production and Storage Protocol and relevant Modules, as well as the requirements set out in the Module. Where this Module contains requirements that duplicate or conflict with those in other Modules, this Module takes precedence.

Isometric will not credit Projects using unmodified pit, flame curtain or Kon Tiki style kilns. These styles of kiln are ineligible due to the difficulty in measurement and quantification of carbon losses through gaseous emission. The quality of the biochar produced may also be influenced by the environmental conditions, such as relative humidity and rainfall. Additionally, the risk of high CH₄ emissions, particularly from the improperly prepared i.e. moist feedstock or an inefficient pyrolysis event, is increased. Although CH₄ has a GWP₁₀₀ of 28 and is a relatively short-lived GHG, it has a GWP₂₀ of ~86 CO₂e, therefore its impact on the carbon removal potential of a project is likely to be considerable, and may even render a Project net-emitting.

In addition to the requirements set out in the Isometric Standard and the Biochar Production and Storage Protocol, projects must implement a framework for Free, Prior, and Informed Consent (FPIC) to maintain high social integrity. This ensures that all stakeholders, particularly landowners and tenants, understand the long-term implications of the Project and participate voluntarily without coercion.

The Project Proponent must demonstrate that consent was obtained through a process that is:

• Free: Consent is given voluntarily, without manipulation, undue influence, or pressure.
• Prior: Consent is sought sufficiently in advance of any project activities or feedstock collection.
• Informed: Stakeholders are provided with clear, accessible information regarding the Project’s risks, benefits (including the 20% revenue share), and their right to withdraw.
• Consent Documentation: All consent agreements must be digitally archived in the dMRV system, including time-stamped signatures or, where appropriate, video-recorded verbal consent for low-literacy contexts.

Distributed projects often operate on land with complex ownership or tenancy structures. To protect the rights of those managing the land, the following requirements apply:

• Where feedstock is collected from land managed by a tenant, the Project Proponent must obtain explicit consent from both the landowner and the tenant.
• The Project must verify that the collection of biomass residues does not infringe upon the existing rights of local communities to use that biomass for traditional purposes (e.g., fuel, fodder, or mulch).
• Through the dMRV app, the feedstock for every batch of biochar produced must be linked to a land parcel where consent has been pre-verified.
• Participants must be informed of their right to refuse feedstock collection at any time.

To ensure distributed projects contribute to local economic resilience, a transparent benefit-sharing mechanism is mandatory. Project Proponents must ensure that at least 20% of gross revenue generated from the sale of Credits by the project is returned to enrolled participants throughout the Project's duration. Benefits may be delivered as direct cash payments or in-kind contributions, provided that:

• In-kind contributions are valued at independently verifiable market rates, with the valuation methodology disclosed in the Project Design Document (PDD); and
• Any in-kind contribution includes a formal transfer of ownership to the landowner.

The form of benefits must be agreed with participants at the outset and be appropriate to the local context. Compensation must be disbursed upon verified completion of biochar production and storage and must not be delayed until Credit issuance. Proponents may aggregate payments on a defined regular cadence (e.g., weekly or monthly), which must be specified in the initial participant/stakeholder agreement and disclosed in the PDD.

The PDD must:

• Include a cost and revenue allocation table disclosing the percentage of gross revenue allocated to each party (e.g., Project Proponent, enrolled participants, insurance providers), and identifying any costs deducted before the revenue share is calculated.
• Include an anticipated timeline for revenue sharing over The Project's duration, or evidence of payments already made.
• Describe the systems and documentation used to track and evidence benefit distribution. Where benefits are contingent on participant obligations (e.g., system maintenance), these conditions must be disclosed in the PDD and communicated to participants at the initial agreement stage.
• Describe what training or assistance will be provided to participants, informed by direct engagement to address identified needs or risks.

• Distribution systems must include an accessible and culturally appropriate mechanism for stakeholders to report grievances or disputes related to revenue sharing, as well as a system for tracking the response and resolution of these issues.
• At every verification, Proponents must provide proof of payments and benefit distribution, alongside a report of any grievances raised and their subsequent resolutions.
• If annually, the cumulative benefit distributions made to landowners fall more than 20% below the level projected in the PDD revenue-sharing plan — calculated against gross revenue actually received in that period — the Proponent must submit a revised distribution plan and timeline within 60 days.

A single, legally-recognized entity (an individual or organization) must be designated as the Project Proponent. This entity is responsible for all aspects of the Project, including:

• Enrollment of all participating distributed units.
• Implementation and management of the Digital Monitoring, Reporting, and Verification (dMRV) system.
• Training of kiln operators and supervisors.
• Aggregation and storage of all project data.
• Preparation and submission of all data and documentation for project validation and verification.
• Ensuring compliance with all Protocol requirements across all units.
• Maintenance of an inventory of all approved biochar producers and their units.

A robust dMRV system is required to ensure the traceability and integrity of data from each distributed unit. The system must allow secure data collection, transfer and storage accessible only by Project Proponent, a nominated dMRV provider (if applicable), accredited verifiers (i.e., the Validation and Verification Body (VVB)) and Isometric. For example, this must involve:

• A secure, cloud-based platform for data collection and storage. Each unit's data must be time-stamped upon transmission to the central database to prevent tampering (encryption recommended). Data should be transmitted from the user's device to a secure central database. Access to the raw data must be restricted to the Project Proponent, a nominated dMRV provider (if applicable), accredited VVBs and Isometric.
• An application or a simple web interface for individual producers to input data related to each biochar batch. This interface should be designed for ease of use.
• Automatically flagging data anomalies, such as sensor readings outside of expected ranges or incomplete batch records.

The Project Proponent is responsible for checking data and investigating any anomalies and or flagged instances and providing justification before data is submitted for verification, although this may be outsourced to a nominated dMRV provider.

Each distributed unit must be equipped with sensors and have an established monitoring framework to aid the verification of carbon removal, including:

• Each pyrolysis unit must be geolocated (e.g. GPS) at the start of a production run, to verify the kiln location and ensure no double counting or kiln movement.

• Each pyrolysis unit must be equipped with a reliable temperature sensor, located in the pyrolysis chamber or flue stack, able to accurately monitor the temperature of production and capable of logging data throughout the entire production run.

• A timer or similar mechanism must track the production duration of each batch.

In terms of quantification of pyrolysis emissions:

• Real time monitoring of both the flue gas flow and composition is recommended in accordance with Section 10.1.1.1 of the Biochar Production and Storage Protocol.
• In the absence of real time data, each production unit is required to undergo annual emissions testing in accordance with Section 10.1.1.2 of the Biochar Production and Storage Protocol, measuring gas flow and emissions. This emissions test should be representative of the full pyrolysis operation of the kiln, including quenching, if appropriate. Portable emissions monitoring equipment from a reputable independent instrument provider may be used, provided adequate proof of calibration (and re-calibration, as appropriate) is supplied.
  • The most conservative scenario for CO₂e emissions (i.e., the single test result yielding the highest total $CO_2e$ per batch shall set the baseline for all units across the Project) must be applied for all batches produced within the Project.
  • Until all kilns registered to the Project have completed their first emissions test, a default deduction must be applied to all biochar batches. Based on a standardised 15% feedstock moisture profile and a 17% methane slip factor, this default deduction is fixed at 51.24 kg CO₂e per dry tonne of feedstock, subtracted from the gross sequestration total to account for the GWP100 of methane emissions generated during pyrolysis. Further details of this calculation are provided in Appendix 1.
    • If a project tests only a representative kiln per facility rather than every individual unit, the default deduction must be applied to all batches indefinitely — it does not expire upon completion of representative testing.
    • If a project tests every individual kiln, the default deduction applies until all registered kilns have completed their first emissions test. From that point, only the most conservative test result (as above) applies.

Black Carbon is a potent climate-forcing aerosol produced by the incomplete combustion of biomass, characterized by a Global Warming Potential nearly a thousand times greater than $CO_2$. In mid-tech kilns, Black Carbon is a critical consideration because fugitive emissions typically occur during unstable phases like "cold starts" or quenching, even when the system is otherwise performing well. In all projects the production of black carbon should be minimized. To maintain high environmental integrity, a conservative uncertainty deduction of 68.4 kg CO₂e per tonne of dry feedstock processed to account for these particulate emissions and their significant impact on both atmospheric warming and surface albedo will be applied to all systems unless an appropriate emissions control system is present, or Black Carbon is directly quantified. Further details of this calculation can be found in Appendix 2.

The resulting mass of biochar produced must be measured and recorded for each batch using calibrated scales (e.g. crane scales or a high capacity balance) of an appropriate accuracy, these must be tared on a flat surface, where appropriate. Dry mass must be traceable for each batch. Therefore, weighing should be performed before quenching, or it can be done after quenching if the batch-level moisture content can be measured. These records, along with the kiln sensor data, must be submitted to the dMRV system.

• Biomass feedstocks must comply with the eligibility criteria of the Biomass Feedstock Accounting Module.
• Each feedstock for a batch of biochar must be documented, including its source location and type. the Project Proponent should limit the number of approved feedstock types to simplify traceability.
• Biomass feedstock sourcing must be verified through time- and location-stamped photographs captured directly through the Project interface to confirm provenance.
• To maintain data integrity, the dMRV system must enforce a "live-capture only" policy. All photos must be taken in real-time through the app; uploading images from a gallery or other photo archives must be prohibited to prevent the reuse of fraudulent or historical data.
• High nitrogen feedstocks (C/N ratios < 30) as defined in Section 10.1 of the Biochar Production and Storage Protocol are ineligible for use under this Module, due to the high risk of N₂O formation in the flue gas and difficulty of accurate measurement and quantification.

Feedstock moisture content is well documented to cause inefficient pyrolysis, leading to increases in CH₄ emissions, while feedstock moisture below 15% is shown to significantly reduce CH₄ emissions¹. Thus, to mitigate the risk of high CH₄ emissions, feedstock preparation is critical. As such the Project Proponent must:

• Project Proponents must implement a standardized system for the homogenous drying of feedstock. This may include passive methods (e.g., solar drying, covered storage, or specialized racking) or active methods, provided they are documented in the PDD.

• Ensure the moisture of a feedstock is quantified, using a digital moisture meter, ideally integrated into the dMRV application, immediately before starting biochar production.
  • A minimum ratio of 1 sample per 100 kg of feedstock must be used to account for heterogeneity, with a minimum total number of 15 measurements per batch. Measurements must be taken randomly from the feedstock batch to prove homogeneity.
  • Ensure production does not start if the mean moisture level of the feedstock for a given batch exceeds 15% (dry basis), and feedstock must be further dried to below this threshold. Batches that are produced from feedstock over a mean of 15% moisture will be ineligible for crediting.

Projects may have the moisture threshold may be extended up to 20% (dry basis) only if the production unit is equipped with a verified methane mitigation measure, such as a secondary combustion chamber (after-burner).

Project Proponents utilizing the 20% threshold must provide data-driven emissions testing for their specific technology. This must demonstrate that the combination of higher moisture and the secondary combustion unit maintains low methane slip, consistent with the environmental integrity of the 15% baseline. This must be continuously demonstrated though emissions testing detailed in Section 4.1.1.

The integrity of a distributed carbon project lies in its potential data density. As a strategic signaling mechanism for the protocol, this section outlines the aim for project maturity: a transition from manual data entry—which is inherently prone to transcription bias and operational error—toward a fully automated, IoT-driven architecture. By signaling this trajectory now, the protocol provides a clear roadmap for technology developers to align their hardware with the high-transparency requirements of the next generation of carbon removal.

A "no-hands" approach is inherently more robust because it establishes a direct, tamper-proof link between the physical pyrolysis event and the digital record. By removing the human element from the primary data chain, this will increase the confidence in the data and therefore the quality and robustness of carbon removal, ensuring that every ton of sequestered carbon is backed by a digital trail.

While the current Module accommodates supervisor-validated logs, the Project trajectory prioritizes hands off data gathering. This transition will require several key technological shifts:

• To eliminate manual weight entry, digital scales should be integrated directly with the dMRV application via Bluetooth or hardware tethering. The mass of both feedstock and resulting biochar should recorded instantly to ensure the carbon mass balance is calculated on raw, unedited data.
• Pre-production moisture checks should utilize digital meters that provide a simplified "Red/Green" light system rather than a raw numeric value that could be misinterpreted. This must be combined with app-based feedback that immediately flags a batch as ineligible if it exceeds the 15% moisture threshold, directing the operator to dry the material further before production can commence. It is also suggested that the dMRV system capture the actual numeric moisture values for every reading.
• Projects should utilize CCTV or regular photography during the production run at the site. This provides a higher quality of evidence that production is occurring correctly and offers Projects and VVBs a clear, auditable trail of the event.

To streamline the MRV process, Project Proponents may group individual distributed units into a Facility. A Facility is defined as a cluster of kilns that demonstrates high operational and geographic consistency, allowing for representative sampling rather than unit-by-unit characterization.

To qualify as a single Facility, the grouped units must meet the following proximity requirements:

• All units within the Facility must utilize the same kiln design, materials, and production scale to ensure consistent thermochemical conversion.
• Operators within a Facility must have undergone the same standardized training program and follow identical Standard Operating Procedures (SOPs).
• The Facility must draw from the same local biomass pools, ensuring that the chemical composition of the input material is uniform across the Facility cluster.
• The kilns within a Facility must be within a 50 km radius and no more than 300 m apart in altitude.
• When units are aggregated into a Facility, the biochar characterization (e.g., Carbon content, H:Corg ratios) may be conducted on a composite sample representative of the Facility's output, provided that:
  • The dMRV system shows that all batches in the composite sample stayed within the ±10% temperature (both mean and maximum) and duration variance thresholds.
  • Biochar must be sampled from all active units within the Facility for every Reporting Period to create the composite laboratory sample.

Note this section supersedes Section 8.3.1, Section 8.3.2.1 and Section 8.3.2.2 of the Biochar Production and Storage Protocol. However, all testing that must be done is in accordance with the biochar characterisation set out Section 3 of the Biochar Storage in Soil Environments Module.

This section outlines the requirements for sampling biochar in distributed production environments. To ensure statistical representativeness while maintaining operational efficiency, this Module moves from time-based triggers to mass-based composite sampling.

• Production Batch ($p$):
  • A discrete mass of biochar produced from a consistent feedstock and pyrolysis process. In distributed systems, this typically represents the output of a single kiln cycle or a single day’s production from one unit.
• Sampling Lot:
  • A defined cumulative mass of biochar (defined in Section 6.1.3.1 and Section 6.1.3.2) from which a composite sample is formed.
  • If using the Facility Aggregation model defined in Section 5, then the Sampling Lot must consist of representative samples from cumulative production from all eligible batches within the defined Facility (i.e., multiple Production Batches from sites within the Facility).
  • Only Production Batches that meet the Facility's digital MRV thresholds (±10% temperature/duration) are eligible to contribute increments to the Composite Sample.
  • The mass of any batch triggering an anomaly (e.g., temperature deviation) must not be counted toward the Sampling Lot, and no increment from that batch shall enter the composite bucket.
• Composite Sample:
  • A single analytical sample created by combining volume and homogenizing increments from every Production Batch within a Sampling Lot.
  • The Project Proponent must demonstrate a physical homogenization process (e.g., ribbon blender) that ensures the final laboratory aliquot is representative of the entire Facility’s output.

In distributed production systems, the Composite Method must be used. This ensures all biochar produced is represented in the final laboratory analysis.

For every Production Batch ($p$) produced, an appropriate sample must be collected using a randomized cross-sectional method. These increments must be stored in a moisture-proof, sealed container until the Sampling Lot mass threshold is reached. The Project should also archive an appropriate mass of sample in case re-analysis is required.

Once the cumulative mass of the Sampling Lot ($L$) is achieved:

1. Equal dry-masses of all stored samples are combined.
2. The combined material should be thoroughly homogenized.
3. A final representative sample is extracted from this mixture and sent for laboratory analysis, at minimum, in triplicate.

In all cases a minimum of three analytical replicates must be performed per composite sample to ensure that analytical uncertainty can be accounted for.

The frequency of laboratory analysis is determined by the total mass of biochar produced.

This initial high frequency sampling and analysis is required to generate sufficient data to estimate the carbon content of future biochar production with an appropriate level of statistical confidence, understand variance, and establish a stable Production Process.

For a new Production Process or feedstock, the Project Proponent must establish a baseline:

• This method must be used for the first 500 dry tonnes of production with one composite sample (a Sampling Lot) being sent for analysis every 50 dry tonnes of biochar produced per kiln or collection of kilns i.e., Facility.

Until this threshold is reached, the consistency of the Production Process has been demonstrated and agreed with Isometric, Method A must be used, this will be for a minimum of 30 samples total (10 Sampling Lots with three replicates).

Once the initial characterization threshold is met, the sampling frequency may be reduced:

• One composite analysis must be performed for every 250 tonnes of biochar produced.
• While lab analysis is periodic, the equal mass allocation (sampling every batch) remains mandatory for every batch within the Sampling Lot.

For Sampling Lots where the composite is analyzed, the resulting organic carbon ($C_{org}$) value is applied. However, to account for variance in distributed systems, the following conservative estimates are applied to the final determination of $C_{biochar}$:

$C_{Biochar} = \mu_{CC} - \sigma_{\overline{CC}}$

$\sigma_{\overline{CC}} = \frac{\sigma_{CC}}{\sqrt{n_{samples}}}$

Where:

• $\sigma_{\overline{CC}}$: The standard error of the mean of carbon content across all eligible samples.
• $\sigma_{CC}$: The standard deviation of carbon content across all eligible samples.
• $n_{samples}$: The number of eligible samples for this Production Process.
• $\mu_{CC}$: The mean carbon content of all eligible samples.

The Project Proponent must include the following in their PPD:

• Definition of the exact mass taken from each batch (e.g., 100g taken for every 500kg produced).
• Detailed description of how the composite sample is mixed to ensure representativeness.
• Procedures for tracking increments from multiple distributed sites to the central compositing location.

The mean results from analysis must be used in calculations, and all supporting data must be documented.

Where a batch is identified as an anomaly (outside the 10% temperature and duration threshold) after it has been aggregated, the following measures shall apply:

• If the specific batch mass was not recorded, the proponent must deduct a mass equivalent to the maximum capacity of the kiln for that run from the total project inventory. This ensures that no potentially "under-pyrolyzed" material contributes to the credited total.

• The dMRV system will automatically subtract the theoretical yield of the anomalous run from the aggregate mass based on the feedstock input logs, ensuring the final "issuance" matches only the verified high-performance runs.

To ensure the safe, efficient, and standardized production of biochar, all kiln operators must undergo comprehensive training before engaging in production activities. Training must be documented in the PDD and cover at minimum; safe operation of the kiln, health, safety and environmental standards, and measurement and record keeping using the dMRV system.

Additionally, to ensure the integrity, accuracy, and credibility of monitoring, reporting, and verification (MRV) data, there must be a clear separation of responsibilities between individuals involved in biochar production and those responsible for data review and reporting. This separation helps mitigate risks of conflicts of interest, intentional data manipulation, and unintentional reporting errors. Note: The Supervisor role is a verification function and does not require a physical presence at the production site during every kiln run.

Operators:

• Responsible for biochar production according to defined safety and quality procedures.
• Record the primary data operational notes (e.g., start/stop times, anomalies) into the dMRV platform.

Operators should undergo refresher training at least once during the duration of the Project, or whenever there are significant changes to kiln technology, data collection tools, or crediting methodologies.

Supervisors:

• Responsible for reviewing digital uploads against Operator logbooks (via photo upload or physical collection) to verify completeness.
• Perform the primary data entry or "locking" of operational data into the dMRV system, ensuring it aligns with physical records.
• Act as the final quality gate, approving and signing off on all data batches before they are submitted for crediting.
• This role may be fulfilled by the Project Proponent’s internal team or an external dMRV technology partner.

The decentralized nature of distributed biochar production, particularly when engaging community operators, necessitates rigorous safety standards to protect human health and the local environment. Project Proponents are responsible for ensuring that all production sites adhere to standardized safety protocols and health and safety law within the jurisdiction of operation.

The use of decentralized production units, particularly those involving manual handling and loading of kilns, introduces significant safety risks due to their nature and high operating temperatures. To mitigate risks such as heat stress, respiratory issues, and accidental injury, the following measures are required:

• Operators must be provided with, and trained in the use of, appropriate PPE, including heat-resistant gloves, eye protection, and N95 or equivalent respirators to prevent the inhalation of particulate matter (PM) and biochar fines.

• For units that present higher operational risks, such as pits, additional barriers or safety perimeters must be established to prevent falls or accidental contact with high-temperature zones.

• All production must occur in well-ventilated outdoor areas to ensure the safe dispersal of any residual gaseous emissions.

• Every production site must maintain a designated fire-safe perimeter and have functional fire suppression tools (e.g., pressurized water, sand, or extinguishers) immediately accessible during all production runs.

Project Proponents must document their safety management system in the PDD, including:

• A clear, step-by-step Standard Operating Procedures guide for the safe operation of the specific kiln technology being used, including emergency shutdown procedures must be submitted with the PDD. This should also state the maximum amount of feedstock that can be physically processed per batch.

• Site-Specific Risk Assessment: A formal evaluation identifying potential hazards (e.g., terrain, proximity to flammable structures, or water sources) and the corresponding mitigation strategies implemented for each Facility or cluster.

• Incident Reporting: A digital log within the dMRV system to record any health or safety incidents, which must be reviewed during the verification process.

To ensure the integrity of the data and project operations, the VVB will conduct on-site visits.

• A statistically valid sample of participating distributed sites must be selected for physical inspection by the VVB at validation. At minimum, this should be > 5% of sites operating.
• Additionally VVBs will inspect 10 % of net-new facilities per year
• On-site validation activities shall include:
  • Review of feedstock and biochar mass records.
  • Inspection of the production unit and monitoring equipment.
  • Oversight of a full, representative production run.
  • Cross-referencing of physical records with data in the dMRV system, if applicable.
  • Interviews with the biochar operator and supervisor to confirm operational procedures.

In distributed biochar production environments, high-precision syngas monitoring is often technically or economically infeasible. To maintain a conservative carbon removal claim, a blanket methane ($CH_4$) deduction is applied to the gross carbon sequestration of each tonne of biochar produced.

This deduction accounts for two primary factors:

• The $CH_4$ produced during the thermochemical conversion of biomass, i.e., methane generation.
• The fraction of produced methane that escapes uncombusted into the atmosphere, i.e., methane slip.

This Module assumes 15% feedstock moisture content (dry basis) as the operational standard. While low, this moisture level may still lead to methane generation and lower combustion efficiency (higher slip) in small-scale or decentralized units compared to industrial units.

The deduction is derived from the interaction of syngas methane concentration ($x_{CH4}$) and the efficiency of the system’s thermal oxidizer or flare ($f_{slip}$).

Determine the Emission Factor ($E_{CH4}$)

Based on the 15% moisture parameterization:

• Methane Fraction ($x_{CH4}$): 0.05 (5% vol)
  • Scientific literature for slow pyrolysis (the most common method for biochar) generally shows a methane volume fraction of roughly 4% when feedstock is dry (10% moisture). As moisture increases, the partial pressure of water vapor in the reactor rises. This promotes the Methanation reaction and reduces the dilution of hydrocarbons, leading to a higher concentration of $CH_4$ in the non-condensable gas. 5% represents a "high-average" concentration.
• Slip Fraction ($f_{slip}$): 0.17 (17% of methane emitted)
  • Industrial flares are often rated at 98% efficiency ($2\%$ slip). However, distributed systems (kilns, small retorts) rarely achieve industrial-grade premixing. A baseline slip of 13.25% assumes a significantly less efficient combustion environment than a regulated industrial stack. High moisture in feedstock acts as a thermal sink. It lowers the flame temperature in the combustion zone. By assuming 17%, the protocol protects the environment against cold-start periods where combustion is poor and potential fugitive methane emissions from quenching.
• Based on empirical data for woody biomass at 15% moisture, the total yield of non-condensable gas (NCG) is approximately 300 $Nm^3$ per dry tonne of feedstock ^2,3.

Calculate Methane mass flow: $300 \text{ Nm}^3 \times 0.05 = 15 \text{ Nm}^3 \text{ of } CH_4$

Convert volume to mass:

Density of methane at standard conditions = ($0.717 \text{ kg/m}^3$)

$15 \text{ Nm}^3 \times 0.717 \text{ kg/m}^3 \approx 10.76 \text{ kg } CH_4 \text{ generated per dry tonne}$

Apply the slip factor:

$10.76 \text{ kg } CH_4 \times 0.17 \approx 1.83 \text{ kg } CH_4 \text{ emitted per dry tonne}$

Total Emission: $1.83 \text{ kg } CH_4 \text{ per dry tonne feedstock}$

Conversion to ($CO_2e$)

To calculate the final deduction, the methane mass is multiplied by the Global Warming Potential ($GWP_{100}$) of 28 (IPCC AR6).

$Deduction = 1.83 \text{ kg } CH_4 \times 28 = 51.24 \text{ kg } CO_2e \text{ per dry tonne feedstock}$

This should the be divided by the average biochar yield of the Production Process (as a decimal) to calculate the deduction per tonne dry biochar.

Project Proponents must apply the following fixed deduction to their gross carbon sequestration claims for every dry tonne of feedstock processed:

Application Note: This deduction is applied to the input mass. For example, if a project processes 100 dry tonnes of feedstock, 5.1 $tCO_2e$ must be subtracted from the total carbon removal Credits generated, regardless of the biochar yield.

This Module applies a mandatory black carbon deduction to all eligible projects that lack integrated, industrial-grade Continuous Emission Monitoring Systems (CEMS). While the technologies permitted under this Module may utilize secondary combustion to mitigate particulate matter, a conservative flat-rate penalty is required to maintain environmental integrity.

This deduction accounts for three primary factors:

• Startup/Shutdown Phases: Periods of incomplete combustion before the unit reaches the steady-state temperatures required for full syngas oxidation.
• Atmospheric Forcing: The high Global Warming Potential (GWP) of black carbon (soot) over a 100-year horizon.
• Measurement Uncertainty: The inherent difficulty in quantifying particulate matter in non-industrial or decentralized settings.

This Module assumes at least a "mid-tech" level of technology for pyrolysis (e.g., advanced retorts or improved kilns). These systems exhibit substantially reduced products of incomplete combustion compared to open-flame pits. Based on a synthesis of clean-cooking literature and kiln studies (Sparrevik et al.⁴; Cornelissen et al.⁵), emission factors generally fall between $0.1$–$0.2 \text{ kg black carbon t}^{-1}$ dry feedstock. This appendix adopts a conservative value of $0.2 \text{ kg black carbon}$ per tonne dry feedstock.

The deduction is derived from the Emission Factor ($EF_{BC}$) and the 100-year Global Warming Potential ($GWP_{BC}$).

$$Deduction = 0.2 \times 342 = 68.4 \text{ kg } CO_2e \text{ per tonne dry feedstock}$$

This should then be divided by the average biochar yield of the Production Process (as a decimal) to calculate the deduction per tonne dry biochar.

Project Proponents must apply the following fixed deduction to their gross carbon sequestration claims for every dry tonne of feedstock processed:

While the 68.4 kg CO₂e deduction is the default, proponents may apply for a reduced rate of discount (34.2 kg CO₂e) if the following conditions are met:

• Provision of third-party, ISO-accredited emission testing (e.g., EPA Method 5) over at least three, representative, full operational cycles.
• Measured $EF_{BC}$ is consistently below 0.1 kg black carbon per t dry feedstock.
• Implementation of automated temperature logging for the secondary combustion zone to prove soot oxidation temperatures are maintained during all active phases.

1. Cornelissen, G., Sørmo, E., Anaya de la Rosa, R. K., & Ladd, B. (2023). Flame curtain kilns produce biochar from dry biomass with minimal methane emissions. Science of The Total Environment, 903, 166547. https://doi.org/10.1016/j.scitotenv.2023.166547 ↩

2. Efika, C. E., Onwudili, J. A., & Williams, P. T. (2018). Influence of heating rates on the products of high-temperature pyrolysis of waste wood pellets and biomass model compounds. Waste Management, 76, 497–506. https://doi.org/10.1016/j.wasman.2018.03.021 ↩

3. Vilas-Boas, A. C. M., Tarelho, L. A. C., Oliveira, H. S. M., Silva, F. G. C. S., Pio, D. T., & Matos, M. A. A. (2024). Valorisation of residual biomass by pyrolysis: influence of process conditions on products. Sustainable Energy & Fuels, 8, 379–396. https://doi.org/10.1039/D3SE01216F ↩

4. Sparrevik, M., Adam, C., Martinsen, V., Jubaedah, & Cornelissen, G. (2015). Emissions of gases and particles from charcoal/biochar production in rural areas using medium-sized traditional and improved “retort” kilns. Biomass and Bioenergy, 72, 65–73. https://doi.org/10.1016/j.biombioe.2014.11.016 ↩

5. Cornelissen, G., Pandit, N. R., Taylor, P., Pandit, B. H., Sparrevik, M., Schmidt, H. P., & Hale, S. E. (2016). Emissions and char quality of flame-curtain "Kon Tiki" kilns for farmer-scale charcoal/biochar production. PLOS ONE, 11(5), e0154617. https://doi.org/10.1371/journal.pone.0154617 ↩

6. Samset, B. H., Lund, M. T., & Aamaas, B. (2023). Climate effects of black carbon emissions: Updated GWP and GTP values after the IPCC AR6. CICERO Center for International Climate and Environmental Research - Oslo. https://hdl.handle.net/11250/3167190 ↩