Biochar Production in Distributed and Small Scale Projects

The inclusion of distributed and small-scale projects allow projects 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 section outlines the specific requirements for projects that employ distributed or artisan-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.

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.

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, namely due to the lack of chimney or stack. 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 total project on the carbon removal potential of a project is likely to be considerable, and may even render a Project net-emitting.

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 Measurement, 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 and 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 and 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 and prompt for all required data points.
• 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.

Each distributed unit must be equipped with sensors and have an established monitoring framework to ensure accurate quantification of carbon removal, including:

• 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.

• Real time monitoring of both the flue gas flow and composition is recommended. 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.
  • The most conservative scenario for CO₂e emissions (i.e. highest emissions) and flue gas flow (i.e., highest flow rate) from emissions tests across The Project shall be used to calculate CO₂e losses per batch, and this value must be applied for all batches produced.

• If a project contains more than 100 distributed kilns the most conservative 5% results may be removed from the calculation, providing they are classified as outliers using the Tukey method (i.e., > third quartile + 1.5 x the interquartile range).

• The mass of both the feedstock input and the resulting biochar must be measured and recorded for each batch using calibrated scales of an appropriate accuracy. These records, along with the kiln sensor data, must be submitted to the dMRV system.

• Only feedstock types from a pre-approved list are eligible for use in these projects. This list shall be submitted alongside the Project Design Document PDD by The Project Proponent. Biomass feedstocks must comply with the eligibility criteria of the Biomass Feedstock Accounting Module.
• Each feedstock batch must be documented, including its source, type, and weight. The Project Proponent should limit the number of approved feedstock types to simplify traceability. For on-farm circular models, a detailed map and description of the feedstock source area and previous cropping patterns are required.

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:

• Ensure that participating producers have a system for homogenous drying of feedstock.

• Ensure the moisture of a feedstock is quantified, using a digital moisture meter, ideally integrated into the dMRV application, immediately before starting biochar production.
  • Measure a specified number of moisture be randomly taken per production run to ensure moisture homogeneity. 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.
  • Ensure production does not start if the average 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 15% moisture will be ineligible for crediting.

A "batch" of biochar for a distributed unit in a single location may be grouped from multiple production batches if they meet the following criteria:

• Production Parameters:
  • A batch consists of biochar produced under consistent pyrolysis conditions and single feedstock, as evidenced by minimal variation (less than 5 % variance) in logged temperature and duration (i.e., operating time) data.
• Temporal Limit:
  • A batch cannot continue for more than a maximum of one month consecutive days of production from a single unit. This temporal limit is to simplify data aggregation and verification and guarantee a minimum sampling frequency.

If Project Proponents wish to operate a model whereby the operators receive money for the biochar produced then Project Proponents must clearly evidence how this does not incentivize biochar production volume, but instead the outcome of the production, e.g., the quality and durability of the biochar created, for example only being paid for certified carbon removal.

To ensure the safe, efficient, and standardized production of biochar, all kiln operators and supervisors 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.

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.

• Operators:

  • Responsible for the production of biochar according to defined procedures.
  • Record operational notes (e.g., start/stop times, anomalies) in a local logbook for internal use only.
  • Do not directly input data into the digital Monitoring, Reporting, and Verification (dMRV) system.

• Supervisors:

  • Responsible for reviewing operators’ logbooks and verifying completeness.
  • Enter operational data into the dMRV system, ensuring accuracy and consistency with physical records, if applicable.
  • Approve and sign off on all data before submission.

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

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.

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 ↩