Biochar Production and Storage

7.1.1 MaterialityActivities integrated into existing practices

ProjectIn Proponentssome instances, Biochar project activities may excludebe SSRsintegrated into existing activities. Activities or portions of activities that were already occurring in the baseline and would have continued to occur without the Biochar project may be omitted from the system boundary, subject to the conditions set below.

For the purpose of this provision, an "activity" may refer to an operational sub-unit, such as an individual trip leg, a single pass of field equipment, or a discrete processing step, where such sub-units can be cleanly delineated by equipment, timing, and physical scope. Where a pre-existing activity is partially modified by the project (for example, a transport trip whose route is extended to include project-specific stops, or a field operation whose pass is lengthened to include project inputs), the activity must be partitioned into:

• portions that are materially unchanged by the project, which may be excluded from the system boundary under this provision; and
• portions that are new, extended, or altered as a result of the project, which must remain within the system boundary and be quantified in the relevant sub-section of Section 8.5.

An activity, or portion of an activity, may only be excluded where the totalProject emissionsProponent forcan that SSR, anddemonstrate all excluded SSRs collectively, are expected to be negligible. Negligible SSRs are those which fall below a Materiality threshold based on environmental significance of < 1% of net CO2e removals. Project Proponents must follow the Materiality assessment requirements set out in Section 5 of the GHGfollowing:

• it Accountingwas Moduleoccurring v1as part of routine operations prior to project activities;
• it would have continued to occur in the absence of the Biochar project; and
• its scope, frequency, equipment, route, payload, and intensity are not materially altered as a result of project activities.0

Evidence supporting these conditions must be provided in the PDD. This must include either:

• Historic records documenting the activity prior to project start. Acceptable records include management logs, operational records, applicator invoices, or equivalent documentation; or
• A signed affidavit from the relevant operator (e.g., farmer, land manager, applicator, or equivalent party) confirming the activity was part of routine operations prior to the project.

And the following:

• A signed affidavit from the relevant operator (e.g., farmer, land manager, applicator, or equivalent party) confirming:
  • the equipment, route, timing, cadence, and intensity of the activity are not materially changed as a result of the Biochar project; and
  • the activity would have continued at a comparable level absent the project.

Where these conditions are met, only the emissions associated with the activity as it would have occurred in the baseline may be excluded. Any incremental emissions attributable to the project must remain within the system boundary and be accounted for in the relevant emissions sub-section.

7.2 Baseline

The baseline scenario for biochar projects assumes that the activities associated with the biochar Project do not take place and that any infrastructure associated with the biochar Project is not built.

Counterfactual storage assesses the CO₂ that would have remained durable stored as biogenic carbon in the absence of The Project. This durably stored portion is ineligible for crediting as it is not environmentally additional. The counterfactual storage of all feedstocks must be quantified according to the Biomass Feedstock Accounting Module v1.3.

8.0 Net CDR Calculation

8.1 Calculation Approach and Reporting Period

The Reporting Period, RP, for biochar projects represents the interval of time over which removals are calculated and reported for verification. The equations used to calculate net CO₂e removals will pertain to all GHG emissions and CO₂ removals occurring over a Reporting Period. In most cases, the Reporting Period represents a timeframe covering a complete cycle of activities, including biomass feedstock sourcing, pyrolysis, biochar processing, and biochar storage.

For all storage pathways (A collection of Removal or Reduction processes that have mechanisms in common.) associated with biochar, it is necessary to calculate the total carbon (as CO₂e) stored in the biochar ([math: C_{biochar}]). Guidelines for determining [math: C_{biochar}] are provided in Section 8.3.1. These calculations depend on methodologies outlined in the relevant Storage Module and therefore must be applied in conjunction with the relevant storage Module calculations.

In addition to [math: C_{biochar}] quantification, an initial characterization is required to determine the amount of CO₂ durably removed through biochar production. The specific requirements and methodologies for this assessment are provided in the relevant Storage Module.

GHG emission calculations must include all emissions related to the project activities that occur within the Reporting Period. This includes: (a) any emissions associated with project establishment allocated to the Reporting Period (See Section 8.6.1) (b) any emissions that occur within the Reporting Period (See Section 8.6.2), c any anticipated emissions that would occur after the Reporting Period that have been allocated to the Reporting Period (See Section 8.6.3) and (d) emissions that occur outside of the system boundary that are associated with the Reporting Period (See Section 8.6.4).

Total net CO₂e removal is calculated for each Reporting Period, and is written hereafter as [math: {CO}_{2}^{}e_{Removal, RP}^{}]. The final net CO₂e removal quantification must be conservatively determined, giving high confidence that at a minimum, the estimated amount of CO₂e was removed.

In line with the Isometric Standard, this Protocol requires that Removal Credits are issued ex-post (Issuance of Credits after removal or reduction took place. This is the manner in which Isometric Delivers Credits.). Credits may be issued once CO₂ has been durably stored in the identified storage reservoir.

8.2 Calculation of CO₂eRemoval, RP

Net CO₂e removal for the production of biochar and its durable storage for each Reporting Period, [math: RP], can be calculated by Equation 1.

[math: CO_2e_{Removal, RP} = CO_2e_{Stored, RP} - CO_2e_{Counterfactual, RP} - CO_2e_{Emissions, RP}]

(Equation 1)

Where:

• [math: {CO}_{2}^{}e_{Removal, RP}^{}] - the total net CO₂e removal for the Reporting Period, RP, in tonnes of CO₂e.
• [math: {CO}_{2}^{}e_{Stored, RP}^{}] - the total CO₂ removed from the atmosphere and stored as organic carbon in the biochar for the RP, in tonnes of CO₂e.
• [math: {CO}_{2}^{}e_{Counterfactual, RP}^{}] - the total counterfactual CO₂ removed from the atmosphere and stored as organic carbon in the absence of The Project for the RP, in tonnes of CO₂e.
• [math: {CO}_{2}^{}e_{Emissions, RP}^{}] - the total GHG emissions for the RP, in tonnes of CO₂e.

Reversals (The escape of CO₂ to the atmosphere after it has been stored, and after a Credit has been Issued. A Reversal is classified as avoidable if a Project Proponent has influence or control over it and it likely could have been averted through application of reasonable risk mitigation measures. Any other Reversals will be classified as unavoidable.) which occur after Credits have been issued are separately accounted for by the Buffer Pool (A common and recognized insurance mechanism among Registries allowing Credits to be set aside (in this case by Isometric) to compensate for Reversals which may occur in the future.), and are therefore not included in Equation 1. Risk of reversal information is given in Appendix A: Risk of Reversal Questionnaire, with further information provided in Section 5 of the Biocharrelevant Storage Module, and are therefore not included in AgriculturalEquation Soils Module1.

8.3 Calculation of CO₂eStored, RP

The method of calculation for [math: CO_2e_{Stored, RP}] will depend on the method of storage. Refer to the relevant storage Module for requirements (see Section 12).

8.3.1 Calculation of C_biochar

The process of biochar production can be divided into several units from which C_biochar can be calculated. These are:

• The production batch, [math: p], which typically consists of utilizing a single type of biomass feedstock, or a consistent blend of multiple feedstocks. This is subsequently converted to biochar through pyrolysis, and transported to a storage site for storage. The unique characteristics of the biomass used, the pyrolysis process, the produced biochar characteristics, transportation distances, and storage site characteristics will be the same for all of the biochar within a Production Batch. The term “Production Process” refers to the complete sequence of activities and operations that result in the creation of a “Production Batch”. The definition of a batch is project specific but must be a period of less than one month, even if the production process is consistent.
  • Once a maximum production batch duration is defined for The Project it must be consistently applied across all sampling method. Production batches may be shorter than this threshold but must not exceed it.
• The production process, this refers to the systematic and consistent sequence of steps and methods used to convert biomass feedstock into biochar through pyrolysis. It is a collective set of biochar production batches generated using the same feedstock and under consistent pyrolysis conditions producing a stable and consistent output of biochar.
• Storage batch, this refers to biochar that is stored together, this may either be constituted of a single production batch, or multiple production batches ([math: n]) blended together prior to storage.

[math: C_{biochar}] can be calculated for either at the production batch or storage batch (i.e. a blend of biochar) level

The two approaches are set out in the following sections:

8.3.1.1 At the Production Batch

Where biochar Production Batches are not blended prior to storage, is calculated as follows:

[math: CO_2e_{Stored,\ RP,\ p} = C_{biochar,\ p} \cdot m_{biochar,\ p} \cdot \frac{44.01}{12.01}]

(Equation 2)

Where:

• [math: CO_2e_{Stored,\ p}] - the total CO₂ removed for batch [math: p], in tonnes of CO₂e
• [math: C_{biochar,\ p}] - the concentration of C in the biochar stored in the production batch [math: p] as weight percent
• [math: m_{biochar,\ p}] - the total mass of biochar emplaced for storage from the production batch [math: p], in tonnes
• [math: \frac{44.01}{12.01}] - stoichiometric conversion factor from carbon mass to CO₂ equivalent mass (molecular weight ratio)

8.3.1.2 At the Storage Batch

The total amount of CO₂ contained in the stored biochar can be calculated as follows.

Where all biochar production batches are blended prior to storage:

[math: CO_2e_{Stored,\ RP,\ n} = \left(\sum_{\text{all } p \text{ in batch } n} \frac{C_{biochar,\ p} \cdot m_{biochar,\ p}}{100}\right) \times \frac{44.01}{12.01}]

(Equation 3)

Where:

• [math: n] - Storage Batch identifier
• [math: p] - Production Batch identifier
• [math: CO_2e_{Stored,\ RP,\ n}] - the total CO₂ equivalent removed for storage batch n, in tonnes of CO₂e
• [math: C_{biochar},\  p] - the concentration of carbon in the biochar from production batch p, as weight percent
• [math: m_{biochar}, p] - the total mass of biochar from production batch [math: p] included in storage batch [math: n], in tonnes
• [math: \frac{44.01}{12.01}] - stoichiometric conversion factor from carbon mass to CO₂ equivalent mass (molecular weight ratio)

8.3.2 Frequency of Measurement

This Protocol provides two alternative methods for measuring and quantifying carbon content frequency. Method A requires measuring the carbon content of every production batch. Method B involves sampling only a representative proportion of production batches and applying conservative estimates to determine the carbon content of unsampled batches.

The preferred approach to sampling is as follows:

• ≥ 3 independent samples must be collected per defined production batch to characterize variability within a production batch.
• These must be collected from points that are either spatially or temporally distributed across the batch and submitted to the laboratory as separate, independent samples.
• Each sample must be analyzed individually, providing a direct measure of between-sample heterogeneity and supporting more robust uncertainty estimation.

For example, if a project defines a production batch as a seven-day period, samples must be collected on three randomly selected days within that period, with each sample submitted to the laboratory as an independent field sample.

Any proposed alternative sampling approaches must be agreed with Isometric in advance.

8.3.2.1 Method A: Sampling Every Batch

Using this method, the organic carbon content of a Production Batch must be determined through direct measurement, using one of the following approaches:

1. Single-batch sampling

• For unblended biochar, which by definition originates from a single Production Batch, the biochar is sampled directly, and no further calculation is required.

2. Multiple-batch sampling

• Where a Storage Batch is formed by blending biochar from multiple Production Batches, samples must be collected from each constituent Production Batch.
  • The carbon content of the entire Storage Batch is then determined using a mass-weighted average of the carbon contents of the individual Production Batches, as calculated in Equation 3

8.3.2.1.1 Sampling Requirements

Refer to the section “Minimum Number of Samples per Batch” for requirements on the acceptable minimum number of samples per Production Batch.

• Multiple samples must be taken per Batch and the mean
  [math: 𝐶_{biochar}] must be used in calculations.
• All supporting data used to calculate averages must be documented and reported.

8.3.2.2 Method B: Sampling a Production Process

In exceptional cases, a different sampling frequency may be agreed upon with Isometric prior to verification, provided that the Production Process conditions can be demonstrated to remain stable throughout The Project.

For the acceptable minimum number of samples to take per Batch, see minimum number of samples per Batch below.

8.3.2.2.1 Conservative Estimation of Carbon in Unsampled Batches

For batches which are not sampled, carbon content must be conservatively estimated, as follows:

[math: C_{Biochar} = \mu_{CC} - \sigma_{\overline{CC}}]

(Equation 4)

[math: \sigma_{\overline{CC}} = \frac{\sigma_{CC}}{\sqrt{n_{samples}}}]

(Equation 5)

Where:

• [math: \sigma_{\overline{CC}}] - the standard error of the mean of carbon content, across all eligible samples for this Production Process
• [math: \sigma_{CC}] - the standard deviation of carbon content, across all eligible samples for this Production Process
• [math: n_{samples}] - the number of eligible samples for this Production Process
• [math: \mu_{CC}] - the mean carbon content of all eligible samples for this Production Process

Eligible samples are those taken in the previous 6 months before a specific Production Batch was produced. Older samples may not be used. Samples must be from a demonstrably stable production process, evidenced by consistent production temperatures and residence times or durations.

8.3.2.2.2 Treatment of Carbon Content Measurement Outliers

This process applies only when Method B is used to calculate carbon content and must be applied to all carbon content measurements used in those calculations, regardless of which production batches were sampled.

For a given Production Process, an outlier is defined as any individual carbon content measurement, [math: m], that lies more than three standard deviations ([math: \sigma_{CC}]) above or below the mean ([math: \mu]):

[math: m > \mu + 3\sigma_{CC} \quad \text{or} \quad m < \mu - 3\sigma_{CC}]

To minimize the influence of extreme measurements, all outliers must be adjusted using winsorization, defined as follows:

• If [math: m > \mu + 3\sigma_{CC}], set [math: m_w = \mu + 3\sigma_{CC}].
• If [math: m < \mu - 3\sigma_{CC}], set [math: m_w = \mu - 3\sigma_{CC}].

The winsorized measurement [math: m_w] must then be used in all carbon content calculations.

Calculation of [math: \mu] and [math: \sigma_{CC}]:

• [math: \mu] and [math: \sigma_{CC}] must be calculated from all historical carbon content measurements from the same production process taken within the six months preceding the removal date for which the carbon content is being calculated.
• When estimating carbon content for a sampled batch, only historical measurements should be used to calculate [math: \mu] and [math: \sigma_{CC}]. Samples from the batch currently being calculated must not be included.
• [math: \sigma_{CC}] must be calculated using the sample standard deviation formula.

Winsorization may only be applied after a minimum of 30 measurements have been collected for the relevant production process to ensure statistical significance.

The Project Proponent must:

• Track the frequency and distribution of outliers across Production Batches.
• Investigate if the number of outliers significantly exceeds the statistically expected frequency, as this may indicate a systematic issue with the Production Process or measurement method.
• Provide supporting evidence and corrective actions if requested during verification. Verification bodies (VVBs) may review outlier monitoring at their discretion.

8.3.2.2.3 Sampling Requirements

• Sample Eligibility
  • Only samples collected within 6 months prior to a specific Production Batch may be used for carbon content estimation. Samples older than 6 months are not eligible.
• Random Sampling Protocol
  • All batches must undergo random sampling to ensure representative carbon content measurements across production.
  • The random sampling approach requires agreement with Isometric and documented in the PDD.
• Compliance Triggers
  • A project review by Isometric will be triggered if either condition occurs within a 6-month period:
  • Project Proponent fails to conduct required sampling on 3 or more occasions
  • More than 3 measurements fall below 3 standard deviations from the mean
• Production Process Changes
  • If a new Production Process is triggered, because of a change in feedstock or pyrolysis conditions, as per the definition in Section 8.3.1
  • Or their are significant deviations in carbon content are detected (as defined in compliance triggers above)
  • When a new Production Process is established, sampling must restart from zero with no historical data carried forward.

8.3.3 Minimum Number of Samples per Batch

For all measurements, samples must be collected from a well-mixed and representative aliquot of the biochar. Unless otherwise agreed with Isometric, to account for potential variation within a single Production Batch, the following approach must be adopted:

• A minimum of three samples must be collected from each measured Production Batch.
• These samples must be representative of the full range of physical characteristics present in the batch (e.g., particle size, color, texture).

8.3.4 Ensuring Representative Sampling

Samples must accurately represent materials designated for the storage pathway that will form the basis for credit quantification. Biochar should be sampled in its final pre-storage condition, i.e., post-processing and at typical moisture levels. For storage in agricultural soils involving co-application with other substances (such as compost), sampling should occur before the blending process is performed.

8.4 Measurement of Mass of Biochar Stored

The measurement of mass stored will depend on the storage Module being used. As such, it is for Thethe Project Proponent to describe and justify their stated method of measurement in the PDD. Below are examples of accepted methods.

Preferred Method: Weighbridge Measurement

• The mass of applied biochar is determined by weighing delivery trucks using calibrated scales at the application or delivery site. This measurement serves dual purposes:
  • Proof of delivery to the storage/application site
  • Accurate mass determination via difference between loaded and unloaded truck weights
• Scale Certification Requirements
  • All truck scales must maintain current certification under applicable local, state, or federal legal-for-trade regulations. Testing and calibration must:
    • Use certified weights meeting NIST Handbook 44¹⁵ specifications
    • Be performed by state-certified entities
    • Comply with all relevant local, state, and federal regulations

Alternative Method: Documentation-Based Verification

• When truck scales are unavailable at the application or delivery site, Isometric may pre-approve alternative proof of delivery consisting of:
  • Signed delivery receipt documents
  • Bills of lading
  • Photographic evidence of delivery

When using this alternative method, the PDD must detail:

• All weight measurement procedures to be conducted at the production site
• Transportation Protocols and precautions to prevent mass loss (for open systems, biogeochemical and/or physical interactions which occur during the removal process that decrease the CO₂ removal .) during transit
• Chain of custody documentation

8.4.1 Required Documentation - CO₂eStoredeStored, RP

The Project Proponent must maintain the following records as evidence of gross CO₂e stored in applied biochar:

• Delivery Records:
  • Weigh scale tickets showing arrival and departure weights for each biochar delivery, or equivalent documentation
• Carbon Content Analysis:
  • Analytical results from ASTM (A standards organization that develops and publishes voluntary consensus international standards.) D5291 (or equivalent) carbon content analysis for each required batch
• Incident Documentation:
  • Records of any spills during application operations, including quantity estimates of material released

All carbon analysis results and application mass records (including weigh scale tickets) must be retained by Thethe Project Proponent for verification purposes for a minimum of five years after the end of the monitoring period.

8.4.1.1 Production and Storage Monitoring

Biochar production, transportation, and storage processes must be continuously monitored to identify and document:

• Process upsets or equipment failures
• Resulting biochar spills or losses
• Quantification of lost material

Any deviations should be reported to Isometric as soon as reasonably possible after discovery.

8.4.1.2 Loss Accounting

When process upsets result in biochar loss:

1. Quantify the Loss: Measure and document the amount of biochar lost from each affected batch
2. Adjust Delivery Records: Deduct the quantified loss from the delivered biochar amount recorded on delivery weigh tickets
3. Allocate to Applications: Apply loss deductions directly to the specific biochar applications affected by each batch
4. GHG Statement: Account for all documented losses in the GHG Statement for the relevant Project batch

This ensures that only successfully delivered and stored biochar is credited for carbon storage in Thethe Project's GHG accounting.

8.5 Calculation of CO₂eCounterfactualeCounterfactual, RP

Type: Counterfactual

The calculation of [math: CO_2e_{Counterfactual,\ n}], is determined by the requirements of the Biomass Feedstock Accounting Module v1.3.

8.6 Calculation of CO₂eEmissionseEmissions,RP

Type: Emissions

[math: CO_2e_{Emissions,\ RP}] is the total quantity of GHG emissions from operations and allocated embodied emissions for each Reporting Period [math: RP]. This can be calculated as:

[math: CO_{2}e_{ Emissions,\ RP} = CO_{2}e_{Establishment,\ RP} + CO_{2}e_{Operations,\ RP} \\ + CO_{2}e_{End-of-life,\ RP} + CO_{2}e_{Leakage, RP}]

(Equation 6)

Where:

• [math: CO_{2}e_{ Emissions,\ RP}] - the total GHG emissions for a Reporting Period, RP, in tonnes of CO₂e.
• [math: CO_{2}e_{Establishment,\ RP}] - the total GHG emissions associated with project establishment for a RP, in tonnes of CO₂e, , see Section 8.6.1.
• [math: CO_{2}e_{Operations,\ RP}] - the total GHG emissions associated with operational processes for a RP, in tonnes of CO₂e, see Section 8.6.2.
• [math: CO_{2}e_{End-of-life,\ RP}] - the total GHG emissions that occur after the RP and are allocated to the RP, in tonnes of CO₂e, see Section 8.6.3.
• [math: CO_{2}e_{Leakage,\ RP}] - the GHG emissions associated with The Project’s impact on activities that fall outside of the system boundary of a Project, over a given RP, in tonnes of CO₂e, see Section 8.6.4.

The following sections set out specific quantification requirements for each variable.

8.6.1 Calculation of CO₂eEstablishment, RP

GHG emissions associated with [math: CO_{2}e_{Establishment,\ RP}] should include all historic emissions incurred as a result of project establishment, including but not limited to the SSRs set out in Table 1.

Project establishment emissions occur from the point of project inception through to before the first removal activity takes place. GHG emissions associated with project establishment may be amortized over the anticipated project lifetime, or per output of product. Rules on amortization (The term used to describe allocation of Project emissions to multiple Removals or Reductions.) are outlined in Section 7 of the GHG Accounting Module v1.0.

8.6.2 Calculation of CO₂eOperations, RP

GHG emissions associated with [math: CO_{2}e_{Operations,\ RP}] should include all emissions associated with operational activities including but not limited to the SSRs set out in Table 1. This includes direct emissions from pyrolysis, [math: CO_2e_{Direct, RP}], for which calculation and measurement details are set out in Section 10.1.1.

For biochar projects, the Reporting Period begins when the activity associated with a batch of Removals begins, and ends upon application of biochar from that batch at the storage site. As an example, for Projects storing biochar in agricultural soils, the Reporting Period begins with biomass feedstock sourcing and ends with biochar application to agricultural soils. The Reporting Period may cover a set period of time, for example a one month period of activity, inclusive of biomass sourcing through to application on agricultural soils for batches of Removals that fall into that month.

[math: CO_{2}e_{Operations,\ RP}] emissions must be attributed to the Reporting Period in which they occur. Allocation may be permitted in certain instances, on a case by case basis, in agreement with Isometric.

8.6.3 Calculation of CO₂eEnd-of-life, RP

[math: CO_{2}e_{End-of-life,\ RP}] includes all emissions associated with activities that are anticipated to occur after the ReportingCrediting Period, butuntil arethe directlyend orof indirectlythe Project Commitment Period. This includes activities related to theongoing Reporting Period. For example this could include end-of-life emissionsmonitoring for project facilities (indirectly related to all deployments)Reversals.

GHG emissions associated with [math: CO_{2}e_{End-of-life,\ RP}] may occur from the end of the Reporting Period onward, and typically through to completion of project site deconstruction and any other end-of-life activities.

GHG emissions associated with activities that are directly related to each deployment must be quantifiedestimated asupfront part of that Reporting Period. GHG emissions associated with activities that are indirectly related to all deployments may beand allocated in the same waysway as set out infor calculation of [math: CO_{2}e_{End-of-lifeEstablishment,\ RP}].

Given the uncertain nature of [math: CO_{2}e_{End-of-life,\ RP}] emissions, assumptions must be revisited at each CreditingReporting Period and any necessary adjustments made. Furthermore, if there are unexpected [math: CO_{2}e_{End-of-life,\ RP}] emissions associated with a Reporting Period, or The Project as a whole, that occur after The Project has ended, then the Reversal process will be triggered to compensate for any emissions not accounted for.

8.6.4 Calculation of CO₂eLeakage, RP

[math: CO_{2}e_{Leakage,\ RP}] includes emissions associated with a Project's impact on activities that fall outside of the system boundary of a Project.

It includes increases in GHG emissions as a result of The Project displacing emissions or causing a knock on effect that increases emissions elsewhere. This includes emissions associated with activity-shifting, market leakage and ecological leakage.

It is Thethe Project Proponent's responsibility to identify potential sources of leakage emissions. At a minimum, biochar Projects must account for market leakage emissions associated with biomass feedstocks as set out in the Biomass Feedstock Accounting Module v1.3.

[math: CO_{2}e_{Leakage,\ RP}] emissions must be attributed to the Reporting Period in which they occur. Allocation may be permitted in certain instances, on a case by case basis in agreement with Isometric.

8.6.5 Emissions Accounting Requirements

8.6.5.1 General

GHG emissions accounting must be undertaken in alignment with the GHG Accounting Module v1.01, which ensures a consistently rigorous standard in how GHG emissions are quantified and reported between different CDR Projects and approaches. This includes:

8.6.5.2

• Requirements Data Collection

Project Proponents must use the most representative, accurate and plausiblefor data that is available at the time of assessment in the GHG Statement. Activity data used to inform GHG accounting may be primary data or secondary data. Project Proponents must strive to use primary data in GHG accounting, but secondary data may be used where primary data is either not available or not practical. More details on data requirementsquality, including a detailed data quality hierarchy andfor activity data qualityand principles,emission canfactors;

An example is emissions related to building the pyrolysys reactor. The Project Proponent should strive to obtain activity data such as mass and type of materials used for the reactor, as well as distanced travelled to transport the materials, and energy used during the construction process. If such data is not available, it is acceptable to use an industry average data and emission factors to estimate such emissions. Suitable emission factor sources are described in relevant Modules.

8.6.5.3 Considerations for Waste Input Emissions

Embodied emissions associated with system inputs considered to be waste products (An output of a process that has no intended value to the producer.) can be excluded from the accounting of the GHG Statement system boundary provided the appropriate eligibility criteria are met.

For waste energy inputs, for example the use of waste heat, refer to the Energy Use Accounting Module v1.23 provides requirements on how energy-related emissions must be calculated for the Project so that they can be subtracted in the net CO₂e removal calculation. It sets out the calculation approach to be followed for intensive facilities and non-intensive facilities and acceptable emission factors.

Energy emissions are those related to electricity or fuel usage. Examples of electricity usage may include, but are not limited to:

• Electricity consumption for pyrolysis activities;
• Processing equipment, motors, drives and instrumentation;
• Biomass pre-treatment, drying, densification or particle size reduction;
• Facility operations;
• Pyrolysis system start up;
• Electricity for building operation & management; and
• Electricity consumption for any biochar processing activities at the pyrolysis site or application site.

Examples of fuel consumption may include, but are not limited to:

• Pyrolysis system start up;
• Pyrolysis reactor heating;
• Emission control (e.g. propane for flare co-firing or pilot);
• Handling equipment, such as fork trucks or loaders; and
• Fuel consumption of agricultural machinery for spreading.

All biomass feedstock must be eligible and accounted for according to the Biomass Feedstock Accounting Module v1.3.

For all other waste inputs, refer to Section 6.3 of theThe GHG Accounting Module v1.01 provides requirements on how transportation and embodied emissions must be calculated for The Project so that they can be subtracted in the net CO₂e removal calculation.

Embodied emissions are those related to the life cycle impact of equipment and consumables. They may include, but are not limited to:

• Process inputs or consumables:

  • Catalysts;
  • Water (for biomass pre-treatment or reactor cooling, not to be used during pyrolysis);
  • Thermal oils used for heat transfer;
  • Coolants used for biochar quench; and
  • Gasses such as nitrogen used for process or instrumentation purges.
  • Gasses, reagents or other materials used for operation of monitoring equipment and on-site analyzers; and

• Equipment:

  • Pyrolysis reactor;
  • Feedstock conveyors, augers, feed bins, and related equipment;
  • Biochar quench or condenser units, including any heat transfer equipment, such as glycol chillers and pumps;
  • Offgas emissions control systems, such as flares or oxidizers;
  • Preparation or mixing equipment;
  • Pumps, piping, and related equipment;
  • Storage tanks;
  • All support structures, facilities, and infrastructure, including steel platforms, framing, supports, concrete (A composite material composed of aggregate, cement, sand and water that cures to a solid over time.) footings and building structures; and
  • On-line analyzers, measurement equipment, or other such devices.

Transportation emissions are those related to transportation of products and equipment. They may include, but are not limited to:

• Transportation of biomass to pyrolysis facility;
• Transportation of pyrolyzed biochar to storage site; and
• Transportation and shipping related to collecting samples for characterization.

8.6.5.41 Co-Product Allocation

The biomass pyrolysis process may result in the production of co-products, such as bio-oil, pyrolysis gas (bio-gas), electricity and heat.

Projects must follow the co-product allocation procedures described in Section 6.1 of the GHG Accounting Module v1.01. For projects where the CDR product(s) and co-products have a measurable energy content, the optional procedure outlined in Section 8.6.5.21.1 may be applied instead of the Procedures outlined in Section 6.1 of the GHG Accounting Module v1.01.

8.6.5.41.1 Emissions Allocation Based on Energy Content

Emissions allocation may be undertaken based on energy content for shared processes in instances where all co-products, including CDR products, have a measurable energy content which can be expressed in Megajoules (MJ). Shared processes are defined as processes for which the CDR product and all co-products are mutually dependent on. Where this is not the case for all co-products, no allocation should be made based on energy content. In this section Net Calorific Value is defined as the amount of energy released by complete combustion, assuming the water vapor produced during combustion is not condensed and used.

Equation 7 sets out the calculation procedure to be followed to apply emissions allocation based on energy content. When this procedure is followed, the term [math: CO_2e_{Emissions,RP}] in Equation 6 in Section 8.6 should be calculated based on Equation 7 for shared processes.

[math: CO_2e_{Emissions,RP} = (F_{Allocation,RP} \;*\; ( CO_2e_{Establishment,RP} \;+ \;CO_2e_{Operations,RP} \;+ \;CO_2e_{End-Of-Life,RP})) \;+ \;CO_2e_{Leakage,RP}]

(Equation 7)

Where:

[math: CO_2e_{Establishment,RP}], [math: CO_2e_{Operations,RP}], [math: CO_2e_{End-Of-Life,RP}] and [math: CO_2e_{Leakage,RP}] are calculated as per the relevant sections of this Protocol.

[math: F_{Allocation}] is the fraction of emissions assigned to the CDR product, represented as:

[math: F_{Allocation} = \frac {MJ_{Output, CDR}}{\qquad \sum_{p=1}^n MJ_{Output, p}}]

(Equation 8)

Where:

[math: MJ_{Output, CDR}] is the energy content of the CDR product, equal to the Net Calorific Value, expressed in MJ/kg.

[math: MJ_{Output}] is the energy content of a specific output, expressed in MJ. The sum of outputs for all co-products must be considered in Equation 8:

• For electricity outputs, this should be equal to the total quantity of electricity exported over the Reporting Period, converted to MJ;
• For heat this should be equal to the Net Useful Thermal Output exported over the Reporting Period, expressed in MJ; and
• For all other outputs, this should be equal to the Net Calorific Value multiplied by the quantity of product produced and exported over the Reporting Period, expressed in MJ.
• [math: p] represents the product

8.6.5.5 Energy Use Accounting

This section sets out specific requirements relating to quantification of energy use as part of the GHG Statement. Emissions associated with energy usage result from the consumption of electricity or fuel.

Examples of electricity usage may include, but are not limited to:

• Electricity consumption for pyrolysis activities;
• Processing equipment, motors, drives and instrumentation;
• Biomass pre-treatment, drying, densification or particle size reduction;
• Facility operations;
• Pyrolysis system start up;
• Electricity for building operation & management; and
• Electricity consumption for any biochar processing activities at the pyrolysis site or application site.

Examples of fuel consumption may include, but are not limited to:

• Pyrolysis system start up;
• Pyrolysis reactor heating;
• Emission control (e.g. propane for flare co-firing or pilot);
• Handling equipment, such as fork trucks or loaders; and
• Fuel consumption of agricultural machinery for spreading.

The Energy Use Accounting Module v1.2 provides requirements on how energy-related emissions must be calculated in a CDR Project. It sets out the calculation approach to be followed and acceptable emissions factors.

8.6.5.6 Transport Emissions Accounting

This section sets out specific requirements relating to quantification of emissions related to transportation.

Emissions associated with transportation include transportation of products and equipment as part of a Reporting Period process. Examples may include, but are not limited to:

• Transportation of biomass to pyrolysis facility;
• Transportation of pyrolyzed biochar to storage site; and
• Transportation and shipping related to collecting samples for characterization.

The Transportation Emissions Accounting Module v1.1 provides requirements on how transportation-related emissions must be calculated in a CDR Project so that they can be subtracted in the net CO2e removal calculation. It sets out the calculation approach to be followed and acceptable emissions factors.

8.6.5.7 Embodied Emissions Accounting

This section sets out specific requirements relating to quantification of embodied emissions as part of the GHG Statement. Embodied emissions are those related to the life cycle impact of equipment and consumables.

Examples of project-specific materials and equipment that must be considered as part of the embodied emission calculation include but are not limited to:

• Process inputs or consumables:
  • Catalysts;
  • Water (for biomass pre-treatment or reactor cooling, not to be used during pyrolysis);
  • Thermal oils used for heat transfer;
  • Coolants used for biochar quench; and
  • Gasses such as nitrogen used for process or instrumentation purges.
• Gasses, reagents or other materials used for operation of monitoring equipment and on-site analyzers; and
• Equipment:
  • Pyrolysis reactor;
  • Feedstock conveyors, augers, feed bins, and related equipment;
  • Biochar quench or condenser units, including any heat transfer equipment, such as glycol chillers and pumps;
  • Offgas emissions control systems, such as flares or oxidizers;
  • Preparation or mixing equipment;
  • Pumps, piping, and related equipment;
  • Storage tanks;
  • All support structures, facilities, and infrastructure, including steel platforms, framing, supports, concrete (A composite material composed of aggregate, cement, sand and water that cures to a solid over time.) footings and building structures; and
  • On-line analyzers, measurement equipment, or other such devices.

The GHG Accounting Module v1.0 sets out the approach to be followed to account for embodied emission, including life cycle stages to be considered (Section 4.1), data sources and emission factors (Section 3.4), and rules on amortization (The term used to describe allocation of Project emissions to multiple Removals or Reductions.) (Section 7).

9.0 Pyrolysis Reactor System Requirements

9.1 Acceptable Technologies

There are a wide range of technologies available for achieving pyrolysis of solid biomass. These may be characterized into "slow pyrolysis" and "fast pyrolysis" based on the heating rate and residence time of biomass in the pyrolysis chamber. Slow pyrolysis processes are ideal to maximize the yield of pyrolysis towards the solid biochar product, and minimize the production of bio-oil and pyrolysis gasses, however both "slow" and "fast" pyrolysis processes may be eligible under this Protocol. Technology may also be characterized by its technology level (low- mid or high- technology) based on the reactor design, as well as the level of automation, and application of sensors and monitoring equipment. Equally, processes may be either continuous (ongoing with a regular flow of feedstock through the system), or batch (non-continuous) based.

This Protocol does not explicitly specify the type of reactor or technology level required, Project Proponents must be able to meet the monitoring requirements set out below and reactor designs, including the reactor type, expected materials specifications and engineering design diagrams must be described in the PDD.

Biochar can be produced using a wide range of technologies that vary in scale, level of automation, and intended outputs. Some reactor systems are specifically designed to produce biochar as the primary product of the process. These tend to be more centralized, higher-technology solutions that allow for precise control of operating parameters such as temperature, residence time, and oxygen levels, resulting in consistent product quality and higher levels of process monitoring. A summary of common reactor types is found in Table 5.

Table 5: Overview of common reactor types

This Protocol recognizes the diversity of production approaches and establishes performance-based requirements to ensure that, regardless of technology type or scale, environmental safeguards, product quality, and monitoring standards are maintained.

Additional styles of project may also include those covered by the following Modules:

9.2 System Design Requirements

9.2.1 Design Diagram Requirements

The diagram must clearly show:

In instances where Project Proponents wish to expand an existing Project, or to submit a new Project for validation, where the reactor vessels used to achieve pyrolysis of biomass are manufactured according to the same design diagrams as those submitted for initial project validation, it is not necessary to resubmit a new design diagram at each subsequent validation event. In cases where the design of the reactor vessel differs to that from the original project validation, submission of updated design diagram documentation is required.

9.2.2 Construction Considerations

It is anticipated that the pyrolyzer will operate at high temperatures and may also operate at elevated pressures. Therefore, appropriate design considerations must be implemented to ensure the mechanical integrity and safe operation of the reactor to mitigate potential adverse operational conditions.

These considerations are essential to ensure the mechanical integrity and safe operation of the reactor.

9.2.3 Reactor Maintenance

10.0 Emissions Testing Requirements

This section sets out the permissible ultimate fate of requirements for the measurement and quantification of gaseous pyrolysis gas loss from the reactor and the calculation of the direct carbon emissions from pyrolysis.

10.1 Operation Emissions

The thermochemical conversion of solid biomass to produce biochar through pyrolysis also produces gaseous co-products. Depending on the pyrolysis conditions and feedstock, the gaseous phase may contain both volatile condensable components (bio-oil) and non-condensable components (pyrolysis gasses; predominantly CH₄, with N₂O, CO, CO₂ and light hydrocarbons). Depending on the specific technologies deployed by The Project, there are various options for handling the gaseous co-product eluted from the pyrolysis unit. Permissible options for the measurement and handling the gaseous product and emissions accounting requirements associated requirements are detailed in this Section.

N₂O is a potent greenhouse gas, which may be formed during pyrolysis of feedstocks with low C/N ratios. The presence of substantial reactive or labile N is a key precursor to N₂O formation in the flue gas. While there is no accepted threshold in the scientific literature below which N₂O emissions from flue gas becomes a concern, typically this is at C/N ratios under 30; examples of feedstock with this ratio may include, but are not limited to; manure, biosolids or seaweed. The Project Proponent must justify why N₂O is not a significant concern if they do not plan to monitor its concentration in the flue gas.

Project Proponents must secure and maintain all required permits and approvals related to air emissions, combustion equipment, and other applicable air quality regulations for biochar production. They shall provide supporting documentation, such as permits, inspection reports, or emissions test results, demonstrating compliance with local, regional, and national air pollution control requirements. Projects must also ensure ongoing adherence to these regulations throughout the crediting period, updating documentation as permits are renewed or amended.

10.1.1 Quantification of Emissions

This section details the two acceptable methods of quantifying the Direct Emissions [math: CO_{2}e_{Operations,\ RP}] from a pyrolysis process, either through direct continuous measurement or regular emissions testing.

10.1.1.1 Option 1 - Direct Continuous Measurement CO₂e_{, RP}

Direct measurement is the primary and preferred method for quantifying [math: CO_{2}e_{Operations,\ RP}].

Emissions should be calculated as follows:

[math: CO_{2}e_{Operations,\ RP} = \sum_{n=1}^{n_c} \sum_{i=1}^{N} m_{i} \cdot C_{n,i} \cdot GWP_n \cdot \Delta t_i]

(Equation 9)

Where:

• [math: CO_{2}e_{Operations,\ RP}] - the total amount of non-CO₂ GHG emissions associated with the release of pyrolysis gasses directly to the atmosphere, via combustion in an emissions control unit, or via combustion for the provision of thermal energy within the process, during a Reporting Period, [math: RP], in tonnes of CO₂e, measured directly.
• [math: m_i] - the total mass flow rate of gas emitted to the atmosphere during time period [math: i], in tonnes per hour. Measurement must be made immediately upstream of the point of emission to the atmosphere.
• [math: C{_n, _i}] - the concentration of species [math: n] in the emitted gas during time period [math: i], expressed as a mass fraction. Measurement must be made immediately upstream of the point of emissions to the atmosphere.
• [math: GWP_n] - the 100-year global warming potential of species [math: n].
• [math: {\Delta t_i}] - the duration of time period [math: i], in hours.
• [math: n_c] - the total number of species in the emitted gas stream.
• [math: N] - the total number of time periods comprising the Reporting Period, [math: RP].

Note: Direct emissions reported under this section include non-CO₂ greenhouse gases only, as CO₂ emissions are accounted for separately to avoid double counting. CO₂ released during pyrolysis is reflected in reductions to stored carbon ([math: CO_{2eStored,RP}]), which determines net CO₂e removal and crediting.

10.1.1.1.1 Measurement Requirements

10.1.1.1.2 Required Records

• The Project Proponent must retain for at least five years after the end of the monitoring period:
  • Raw flow and composition measurement data for the Reporting Period.
  • Calibration records for all meters and analyzers.
  • Manufacturer manuals detailing calibration and maintenance procedures.

10.1.1.2 Option 2 - Regular Emissions Testing for CO₂e_{Operations, RP}

Where direct measurement is not practically feasible (e.g., highly distributed pyrolysis reactors, remote locations), emissions testing may be used as an alternative method. This measurement will then be applied to all subsequent batches produced, until the next emissions test is performed (with the exception of distributed project, see Section 9.1.1.4).

Emissions should be calculated as follows:

[math: CO_{2}e_{Operations,\ RP} = \sum_{n=1}^{n} (C_{n,test} \cdot \dot{m}_{test} \cdot GWP_n \cdot H_{emit})]

(Equation 10)

Where:

• [math: CO_{2}e_{Operations,\ RP}] the total amount of non-CO₂ GHG emissions associated with the release of pyrolysis gasses directly to the atmosphere, via combustion in an emissions control unit, or via combustion for the provision of thermal energy within the process, during a Reporting Period, [math: RP], in tonnes of CO₂e, measured using regular emissions testing.
• [math: C_{n,test}] = measured concentration of species n from the spot test (mass fraction), corrected to the appropriate basis (dry/wet, standard temperature and pressure).
• [math: \dot{m}_{test}] = gas mass flow rate during the spot test (t/hr), corrected to the same basis.
• [math: H_{emit}] = total number of hours the reactor was emitting during the Reporting Period.

Note: Direct emissions reported under this section include non-CO₂ greenhouse gases only, as CO₂ emissions are accounted for separately to avoid double counting. CO₂ released during pyrolysis is reflected in reductions to stored carbon ([math: CO_{2eStored,RP}]), which determines net CO₂e removal and crediting.

Regular Emissions Testing should be representative of actual operations, including quenching if appropriate. Emissions testing is considered representative only if:

• Feedstock Consistency
  • Feedstock used in operations must be identical or demonstrably similar to that used in emissions testing.
  • Where the biomass feedstocks used during project operations and emissions testing are not the same, analytical testing should be used to demonstrate that they are similar. Analytical testing must follow ASTM D5291 and demonstrate that, for each measured feedstock characteristic, the biomass used in actual project operations falls within ±10% of the corresponding value from the biomass used during emissions testing.
• Process Consistency
  • Pyrolysis temperature during operations must be within ±10% of emissions test values.

Temperature must be measured using a calibrated sensor that is:

• Accurate to ±2% full scale
• Able to record at a frequency of ≥ 1-minute intervals
• Calibrated at least annually, traceable to national standards

Raw data must be retained and made available on request.

10.1.1.2.1 Required Records

The Project Proponent must retain for at least five years after the end of the monitoring period:

• Emissions testing reports from accredited entities.
• Raw temperature data for the Reporting Period.
• Calibration records for all measurement equipment.
• Manufacturer manuals detailing calibration and maintenance requirements.

10.1.2 Permissible Routes for Gaseous Emissions

All non-CO₂ emissions to the atmosphere, via any of the approaches described in the following Sections, must be converted to tonnes of CO₂e using their respective 100-year Global Warming Potential (GWP) for the relevant GHGs, based on the most recent volume of the IPCC Assessment Report (presently the Sixth Assessment Report).

These are:

10.1.2.1 Venting

• Venting of pyrolysis gasses directly to the atmosphere.
• Required measurements directly before or at point of emission:
  • Gas flow rate
  • Composition of the vented gas stream accounting for at least CH₄, N₂O, CO, and CO₂.

10.1.2.2 Venting After an Emissions Control System

• Venting of pyrolysis gasses to the atmosphere via an emissions control system, such as a thermal oxidizer, wet scrubber, electrostatic precipitator or flare stack.
• Required measurements directly before or at point of emission:
  • Flow rate
  • Composition of the vented gas stream accounting for at least CH₄, N₂O, CO, and CO₂.

10.1.2.3 Combustion of Pyrolysis Gasses for Energy Recovery

• Combustion of pyrolysis gasses within The Project gate to provide thermal energy for operation of the pyrolyzer.
• Required measurements directly before or at point of emission:
  • Flow rate
  • Composition of the vented gas stream accounting for at least CH₄, N₂O, CO, and CO₂.
• It should be noted that the flue gas from the pyrolyzer heating source may also partially result from co-firing with fuels obtained from outside sources. If the flue gas from the pyrolyzer heating source is directly monitored, it is not necessary to include fuel combustion for heating the pyrolyzer in the calculation of [math: CO_{2}e_{Energy,\ RP}], to avoid double counting. However, the emissions associated with the production and transportation of such fuels must still be accounted for. Bio-oil produced during pyrolysis may also be co-fired using this approach, and can be accounted for in the same way as for the co-firing of pyrolysis gasses.

10.1.2.4 Provision of Gasses to a Third Party Consumer

• Provision of pyrolysis gasses to a downstream consumer for third-party use.
• In this case, Thethe Project Proponent may follow emission allocation procedures (see Section 7.1.1 for allocation calculation details).

10.1.3 Other Pathways of Gaseous Loss

10.1.3.1 Leakage Monitoring Requirements

10.1.3.2 Alternative Approaches to Leakage Verification

If it is not feasible to develop a high-quality mathematical reactor model, one of the following alternative verification approaches may be used to demonstrate that there is no substantial unintended leakage of pyrolysis gases:

10.1.3.2.1 Continuous System Pressure Monitoring

10.1.3.2.2 Regular Leakage Testing

11.0 Additional Guidance on the Condensable (bio-oil) Fraction

Condensable fractions of the gaseous stream may be separated from the using a condenser, or any other suitable gas-liquid separation unit. The resulting (condensable) liquid-phase is bio-oil, and the (non-condensable) gas-phase is pyrolysis gasses. There are three permissible end-use emissions accounting approaches for the produced bio-oil:

• Storage of the produced bio-oil by injection into natural or engineered subsurface features or geologic storage formations which may include, but are not limited to, reservoirs, saline aquifers, caverns, or mines. Storage of produced bio-oil must be conducted in compliance with the requirements described in the Bio-Oil Geological Storage Protocol. In this case, Thethe Project Proponent may claim Credits for the storage of bio-oil, in addition to the Credits claimed for storage via biochar (as detailed under this Protocol). Where Isometric Credits are generated for both bio-oil injection and biochar resulting from the same thermochemical conversion process, emissions associated with the thermochemical conversion of solid biomass to produce biochar and bio-oil will be allocated proportionately to each storage pathway for the purposes of calculating net-CO₂e removal for each (see Section 7.1.1 for allocation calculation details); or
• Provision of produced bio-oil to a downstream consumer for third-party use, such as combustion for heating. In this case, Thethe Project Proponent may follow emission allocation procedures (see Section 7.1.1 of this Protocol for allocation calculation details).
• Treatment of the produced bio-oil downstream and environmental disposal as a waste stream or hazardous waste, following methods compliant to relevant local legislative frameworks. In this case, Thethe Project Proponent must account for all emissions relevant to treatment and disposal of the waste stream (see Section 7.1 of this Protocol).

12.0 Storage

For all information on what chemical and physical characterization of biochar must be carried out, and for calculation of [math: {CO}_{2}^{}e_{Stored}^{}], please refer to the relevant storage Module.

13.0 Acknowledgements

Isometric would like to thank the following external reviewers of this Protocol/Module:

• Meredith Barr, Ph.D.
• Segun Oladele, Ph.D.
• Konstantina Stamouli, Ph.D.

14.0 Definitions and Acronyms

A document that describes how to quantitatively assess the net amount of CO₂ removed by a process. To Isometric, a Protocol is specific to a Project Proponent's process and comprised of Modules representing the Carbon Fluxes involved in the CDR process. A Protocol measures the full carbon impact of a process against the Baseline of it not occurring.

The amount of CO₂ emissions that would cause the same integrated radiative forcing or temperature change, over a given time horizon, as an emitted amount of GHG or a mixture of GHGs. One common metric of CO₂e is the 100-year Global Warming Potential.

The term used to represent the CO₂ taken out of the atmosphere as a result of a CDR process.

Describes the addition of carbon dioxide removed from the atmosphere to a reservoir, which serves as its ultimate destination. This is also referred to as “sequestration”.

Raw material which is used for CO₂ Removal or GHG Reduction.

The amount of time carbon removed from the atmosphere by an intervention – for example, a CDR project – is expected to reside in a given Reservoir, taking into account both physical risks and socioeconomic constructs (such as contracts) to protect the Reservoir in question.

Purposefully erring on the side of caution under conditions of Uncertainty by choosing input parameter values that will result in a lower net CO₂ Removal or GHG Reduction than if using the median input values. This is done to increase the likelihood that a given Removal or Reduction calculation is an underestimation rather than an overestimation.

A publicly visible uniquely identifiable Credit Certificate Issued by a Registry that gives the owner of the Credit the right to account for one net metric tonne of Verified CO₂e Removal or Reduction. In the case of this Standard, the net tonne of CO₂e Removal or Reduction comes from a Project Validated against a Certified Protocol.

A measurement which correlates with but is not a direct measurement of the variable of interest.

Independent components of Isometric Certified Protocols which are transferable between and applicable to different Protocols.

​​Considering impacts at each stage of a product's life cycle, from the time natural resources are extracted from the ground and processed through each subsequent stage of manufacturing, transportation, product use, and ultimately, disposal.

Those gaseous constituents of the atmosphere, both natural and anthropogenic (human-caused), that absorb and emit radiation at specific wavelengths within the spectrum of terrestrial radiation emitted by the Earth’s surface, by the atmosphere itself, and by clouds. This property causes the greenhouse effect, whereby heat is trapped in Earth’s atmosphere (CDR Primer, 2022).

The term used to describe greenhouse gas emissions to the atmosphere as a result of Project activities.

A worldwide federation (NGO) of national standards bodies from more than 160 countries, one from each member country.

An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.

Lowering future GHG releases from a specific entity.

GHG sources, sinks and reservoirs (SSRs) associated with the project boundary and included in the GHG Statement.

A process for evaluating and confirming the net Removals and Reductions for a Project, using data and information collected from the Project and assessing conformity with the criteria set forth in the Isometric Standard and the Protocol by which it is governed. Verification must be completed by an Isometric approved third-party (VVB).

A systematic and independent process for evaluating the reasonableness of the assumptions, limitations and methods that support a Project and assessing whether the Project conforms to the criteria set forth in the Isometric Standard and the Protocol by which the Project is governed. Validation must be completed by an Isometric approved third-party (VVB).

The Isometric process which involves expert review and Public Consultation in order to arrive at an approved version of a Protocol, against which Projects will be Validated and Removals or Reductions will be Verified.

Any process, activity, or mechanism that removes a greenhouse gas, a precursor to a greenhouse gas, or an aerosol from the atmosphere.

Activities that remove carbon dioxide (CO₂) from the atmosphere and store it in products or geological, terrestrial, and oceanic Reservoirs. CDR includes the enhancement of biological or geochemical sinks and direct air capture (DAC) and storage, but excludes natural CO₂ uptake not directly caused by human intervention.

A document submitted alongside Claimed Removals and/or Reductions that details the calculations associated with a Removal or Reduction, including the Project's emissions, Removals, Reductions and Leakages, presented together in net metric tonnes of CO₂e per Removal or Reduction.

Credits are issued to the Credit Account of a Project Proponent with whom Isometric has a Validated Protocol after an Order for Verification and Credit Issuance services from a Buyer and once a Verified Removal or Reduction has taken place.

Any person or entity who can potentially affect or be affected by Isometric or an individual Project activity.

The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.

The steps of a Project Proponent’s Removal or Reduction process that result in carbon fluxes. The carbon flux associated with an activity is a component of the Project Proponent’s Protocol.

The document, written by a Project Proponent, which records key characteristics of a Project and which forms the basis for Project Validation and evaluation in accordance with the relevant Certified Protocol. (Also known as “PDD”).

The diversity of life across taxonomic and spatial scales. Biodiversity can be measured within species (i.e. genetic diversity and variations in allele frequencies across populations), between species (i.e. the total number and abundance of species within and across defined regions), within ecosystems (i.e. the variation in functional diversity, such as guilds, life-history traits, and food-webs), and between ecosystems (variation in the services of abiotic and biotic communities across large, landscape-level scales) that support ecoregions and biomes.

Any process or activity that releases a greenhouse gas, an aerosol, or a precursor of a greenhouse gas into the atmosphere.

A United States Government agency that protects human health and the environment.

A contract in which a Buyer agrees to purchase a set Removal and/or Reduction at a set price.

The defined temporal and geographical boundary of a Project.

A calculation, series of calculations or simulations that use input variables in order to generate values for variables of interest that are not directly measured.

Third-party auditing organizations that are experts in their sector and used to determine if a project conforms to the rules, regulations, and standards set out by a governing body. A VVB must be approved by Isometric prior to conducting validation and verification.

An acceptable difference between reported Removals/emissions or Reductions/emissions and what an auditor determines is the actual Removal/emissions or Reduction/emissions.

A lack of knowledge of the exact amount of CO₂ removed by a particular process, Uncertainty may be quantified using probability distributions, confidence intervals, or variance estimates.

Improperly allocating the same Removal or Reduction from a Project Proponent more than once to multiple Buyers.

An evaluation of the likelihood that an intervention—for example, a CDR Project—causes a climate benefit above and beyond what would have happened in a no-intervention Baseline scenario.

A set of data describing pre-intervention or control conditions to be used as a reference scenario for comparison.

An assessment of what would have happened in the absence of a particular intervention – i.e., assuming the Baseline scenario.

Resources provided to projects that are generating, or are expected to generate, greenhouse gas (GHG) Emission Reductions or Removals.

Products that have a significant market value and are planned for as part of production.

The period of time over which a Project Design Document is valid, and over which Removals or Reductions may be Verified, resulting in Issued Credits.

Reporting Period

An estimate of the emissions intensity per unit of an activity.

An analysis of how much different components in a Model contribute to the overall Uncertainty.

An entity that purchases Removals or Reductions, often with the purpose of Retiring Credits to make a Removal or Reduction claim.

A database that holds information on Verified Removals and Reductions based on Protocols. Registries Issue Credits, and track their ownership and Retirement.

Sources, Sinks and Reservoirs

Emissions that are produced by a specific CDR process and are directly controllable.

Life cycle GHG emissions associated with production of materials, transportation, and construction or other processes for goods or buildings.

A product that is not an economic driver of the process it is produced in.

The multi-step process to monitor the Removals or Reductions and impacts of a Project, report the findings to an accredited third party, and have this third party Verify the report so that the results can be Certified.

The increase in GHG emissions outside the geographic or temporal boundary of a project that results from that project's activities.

A measure of how much energy the emissions of 1 tonne of a GHG will absorb over a given period of time, relative to the emissions of 1 ton of CO₂.

A collection of Removal or Reduction processes that have mechanisms in common.

Issuance of Credits after removal or reduction took place. This is the manner in which Isometric Delivers Credits.

The escape of CO₂ to the atmosphere after it has been stored, and after a Credit has been Issued. A Reversal is classified as avoidable if a Project Proponent has influence or control over it and it likely could have been averted through application of reasonable risk mitigation measures. Any other Reversals will be classified as unavoidable.

A common and recognized insurance mechanism among Registries allowing Credits to be set aside (in this case by Isometric) to compensate for Reversals which may occur in the future.

for open systems, biogeochemical and/or physical interactions which occur during the removal process that decrease the CO₂ removal .

A standards organization that develops and publishes voluntary consensus international standards.

The term used to describe allocation of Project emissions to multiple Removals or Reductions.

An output of a process that has no intended value to the producer.

A composite material composed of aggregate, cement, sand and water that cures to a solid over time.

15.0 Appendix A1: Risk of Reversal Questionnaire

Projects applicable to this Protocol are generally categorized as having No Observable Risk of Reversal according to the Isometric Standard Risk Assessment Questionnaire. In Biochar Production and Storage, carbon is stored as solid biochar through recalcitrant polyaromatic structures, and if stored according to an approved storage module, durability is expected to be between hundreds of years and millennia. Where this storage constitutes an open system with no directly observable reversals, the Isometric Standard classifies Projects operating under this Protocol as “No observable risk” for the purposes of the Risk of Reversal assessment, and such Projects are not required to complete a Risk of Reversal questionnaire. This typically results in a 0% buffer pool for Projects using this Protocol and Storage Module. Some Biochar Storage Modules do have a plausible mechanism for reversals and monitoring to detect this. In those cases, Projects must complete the Risk of Reversal questionnaire based on the relevant Storage Module and Project-specific details. This reversal risk will be reassessed at the renewal of the Crediting Period (The period of time over which a Project Design Document is valid, and over which Removals or Reductions may be Verified, resulting in Issued Credits.), or when new scientific research and knowledge are produced.

However, if a Project identifies project-specific factors which impact the Risk of Reversal, they are required to complete the Risk of Reversal Questionnaire below.

This risk assessment identifies the pathway specific risk factors relevant to a carbon removal project. The relevant risk factors identified as part of a risk assessment are included in the monitoring plan requirements for Thethe Projectproject, with details included in the PDDProject Design Document. Project specific risk factors inform the required duration of monitoring along with the monitoring requirements set out in the Protocol and the requirements set out in the Monitoring Section of the Isometric Standard.

The risk score, as determined by the Risk of Reversal Questionnaire, will determine a project’s buffer pool contribution. Projects must re-assess their reversal risk at the renewal of each crediting period, or if monitoring identifies a reversal-related risk, or if an actual reversal event takes place.

For Inmore anydetails eventon Reversals, projects should reassess their reversal risk at a minimum every 5 years.

The Risk of Reversal Questionnaire questions that pertainrefer to this Protocol, drawn from the programme-level Risk of Reversal Questionnaire defined in Appendix B: Risk Reversal Questionnaire of the Isometric Standard, include the following:.

Note the Risk Score at any step cannot be negative.

Risk Score Categories:

• 0: Very Low Risk Level (21% buffer)
• 1-2: Low Risk Level (5% buffer)
• 3-4: Medium Risk Level (7% buffer)
• 5+: High Risk Level (10-20% buffer)

Project specific risk factors will depend on the form of carbon being stored (i.e., organic vs. inorganic), the method of storage (e.g., mineralization, encapsulation), the location of carbon storage (e.g., subsurface, ocean), and the proximity of that carbon to potential agents of reversal.

For projects with carbon storage as organic carbon, the presence of the following risk factors must be reflected in the risk score corresponding to question 10:

• High-potential oxidants
• Temperatures in excess of thermal stability
• Fires
• Microbial degradation

For projects with any form of subsurface carbon storage, the presence of the following risk factors must be reflected in the risk score corresponding to question 10:

• Seismicity
• Subsurface migration

16.0 Relevant Works