Biomass Feedstock Accounting

This Module establishes the requirements associated with the use of feedstocks as a part of carbon dioxide removal Projects. This includes setting out criteria for feedstocks in relation to sustainability, counterfactual storage and market leakage. This Module also provides methods for the quantification of counterfactual storage and market leakage to determine eligible feedstocks. This Module is currently applicable to the following feedstocks:

• Forestry residues¹ and downstream wood processing residues²
• Agricultural residues
• Industrial residues
• Municipal wastes
• Invasive species

Every Project Proponent must consider specific alternative uses of feedstocks that would have occured in the absence of the Project. The baseline scenario must be considered relative to each feedstock used if the Project utilizes multiple feedstock types, in line with Section 2.5.2 of the Isometric Standard. If a Project uses any feedstock that is deemed ineligible by this Module, this feedstock will not count towards Crediting. If a Project utilizes ineligible biomass for alternative uses in excess of 25% of the feedstock mass in a given Reporting Period, removals within the Reporting Period will not be Credited by Isometric.

The current approach outlined in this Module provides:

• Sustainable sourcing criteria that aim to ensure feedstocks are sourced without threatening the sustainability of the upstream resource.
• Counterfactual storage criteria that aim to ensure removals provide near-term climate benefits.
• Market leakage criteria that aim to assess the full emissions impact and additionality of feedstock use while accounting for limited data availability in some feedstock sourcing scenarios.

This Module was developed based on the current state of the art and publicly available science regarding sourcing biomass for Biomass Carbon Removal and Storage (BiCRS) Projects. This Module is based in part on the most up-to-date literature and models at the time of publication. This Module will continue to be updated as scientific and economic understanding develops.

Future work to include additional feedstocks, such as purpose-grown BiCRS feedstocks, will be undertaken as necessitated by demand, and as enabled by improved research and modeling.

This Module will be reviewed on an annual cadence in line with the Isometric Standard.

The framework outlined in this Module sets out sourcing criteria that qualify feedstocks as eligible for use in BiCRS Projects in a way that ensures sustainable sourcing and accounts for the emissions impacts that result from market leakage. These considerations vary based on the characteristics and sourcing activities of the feedstock.

Feedstock eligibility requires the Project Proponent to demonstrate that the feedstock complies with the Sustainability Criteria (Section 2.1) and the Prohibited Feedstock Criteria (Section 4.1) to establish eligibility. Eligible feedstocks must then undergo further evaluation to assess their counterfactual storage (Section 3) and market leakage (Section 4.2) values. Guidance of how to use this document can be seen in Figure 1 below.

• Sustainability Criteria: Requirements to ensure that feedstock sourcing is sustainable. These criteria are reviewed every Reporting Period. See Section 2.1 for details.
• Counterfactual Storage: Counterfactual storage considers the CO₂e stored in the feedstock that would have remained durably stored in absence of the Project activities. This feedstock fraction does not count towards Crediting. Counterfactual storage assessments are valid for 10 years. See Section 3 for details.
• Prohibited Feedstocks: Some feedstocks are deemend ineligible for crediting under this Module. This is due to the significant risk of market leakage associated with sourcing these feedstocks. This applies to feedstocks that meet the other criteria outlined within this module. Feedstocks such as food/feed crops and purpose grown BiCRS feedstocks are not detailed here as they have no path through the Module. Feedstocks must meet one of the criteria within this section to establish the feedstock as eligible. See Section 4 for details.
• Market Leakage: Increased demand for a feedstock driven by sourcing by a Project Proponent may cause market changes that increase GHG emissions through additional activities to replace feedstock services, or changes in market supply leading to land-use change or other market shifts. Market leakage assessments are valid for 10 years. See Section 4 for details.

For use by a Project Proponent for Crediting, feedstock sourcing must be deemed sustainable. The following section outlines how a Project Proponent is required to assess whether their feedstock sourcing is sustainable and provide evidence of sustainability for their feedstock type. In some instances, sustainability criteria also include an evaluation of market leakage (e.g., SC5.1).

The following information must be submitted as part of the verification for each Reporting Period:

• The Project Proponent must establish sustainable sourcing practices for the Sustainability Criteria relevant to their feedstock type. A feedstock must satisfy all criteria associated with the feedstock type (e.g., SC1.1 and SC1.2 and SC1.3 for forestry residues). Sustainability Criteria must be determined for each Reporting Period. This means that for each claimed removal the Project Proponent must either produce new evidence that the relevant Sustainability Criteria are met or ensure existing evidence is up-to-date.

When feedstocks are used for BiCRS Projects, each eligible unit of stored carbon will be Credited as CO₂e. However, not all removed and stored carbon is considered environmentally additional from a climate impact perspective. To accurately determine a Project's climate impact, the Project Proponent must assess if the feedstock's biogenic carbon would have been released into the atmosphere in the near term (e.g., through burning or rapid decay), termed $CO_2e_{CounterfactualEmissions}$, or if this carbon would have remained stored longer, termed $CO_2e_{Counterfactual}$. Only the fraction that would have been emitted in the absence of the Project activities will be Credited as an environmentally additional removal.

Accounting for counterfactual storage ensures Credits accurately reflect the Project's actual climate impact, preventing overstatement of removals by accounting for carbon that would have stayed out of the atmosphere for long periods regardless of the Project's intervention. This is also to ensure Project activities have a measurable impact in mitigating near-term climate change and to incentivize the use of feedstocks with the most near-term impacts.

Project Proponents must demonstrate that the counterfactual fate has been properly assessed and the counterfactual storage has been appropriately quantified. Once a feedstock's counterfactual fate has been established, it's determined fate is valid for 10 years provided the feedstock sourcing does not change. Under exceptional circumstances where Isometric identifies a significant change to the understood counterfactual fate, Isometric reserves the right to conduct an audit to ensure feedstocks continue to meet the criteria laid out in this Module. Typically the historical fate of the feedstock is a good indicator of the future counterfactual fate of the feedstock absent the Project activities. To assess the counterfactual fate of the feedstock, at least one of the following pieces of evidence must be provided by the Project Proponent:

• Historical evidence of the counterfactual fate of the feedstock over the last 5 years provided by the feedstock supplier.
• Purchase records or a contractual clause in purchase records confirming the counterfactual fate of the feedstock over the last 5 years.
• An assessment of the expected fate over the last 5 years of the feedstock given the most economically viable option in a given sourcing area, including all data, documentation and assumptions used.
• Retrofits using feedstocks at or below the Baseline Feedstock Consumption Rate can evidence the counterfactual as the pre-retrofit scenario over the last 5 years (e.g., combustion with emissions released for bioenergy projects). See Appendix 4 for more details.
• In some cases, an affidavit from the feedstock supplier confirming the counterfactual fate of the feedstock may be considered.

All feedstocks eligible for crediting must meet one of the criteria listed in Table 2 to evaluate counterfactual storage.

Feedstocks that do not meet CC1 or CC2 within Table 2 must quantify counterfactual storage. Biogenic carbon that would likely be stored in the biomass for the next 15 years in the counterfactual is considered counterfactually stored.

Counterfactual storage is a quantified measurement of stored biogenic carbon, and takes into account the amount of biogenic carbon within the feedstock and the emissions associated with the release of the biogenic carbon.

Biomass decay that would lead to additional carbon storage in the landscape is taken into account (e.g., soil organic carbon gains from biomass decay). This effect may be nonlinear and Project Proponents can provide evidence of its negligibility at the feedstock removal rates.

Counterfactual storage is reported in CO₂e units. Counterfactual emissions are evaluated as the CO₂e using the 100-year Global Warming Potential (GWP), GWP₁₀₀, of all released GHGs within 15 years. The most recent volume of the IPCC Assessment Report should be used (currently the Sixth Assessment Report) to represent the GWP₁₀₀ of GHGs.

If all stored biogenic carbon within the feedstock would be emitted within 15 years in the counterfactual, then $CO_2e_{Counterfactual}$ = 0. If CO₂e emissions within 15 years exceed the equivalent stored biogenic carbon within the feedstock at 15 years, counterfactual storage can be quantified by the amount of biogenic CO₂e that is stored after 50 years. This is to increase the eligibility of feedstocks that have a disproportionately large near-term release of GHGs with a GWP₁₀₀ >1 in the counterfactual. Example calculations can be found in Appendix 6.

Equation 1 and equation 2 must be used to quantify the total CO₂e that is ineligible for Crediting.

$$CO_2e_{Counterfactual,\  x}\ \  = \ \ CO_2e_{Feedstock} \ \ - \ \ CO_2e_{CounterfactualEmissions}$$

(Equation 1)

$$CO_2e_{CounterfactualEmissions} \ \ = \ \ min(CO_2e_{CounterfactualEmissions15}, \ \  CO_2e_{Feedstock}\ \ - \ \ CO_2e_{CounterfactualStorage50})$$

(Equation 2)

Where:

• $CO_2e_{Counterfactual,\ x}$ - The mass of biogenic carbon that is ineligible for crediting, in tonnes of CO₂e, for batch $x$.
• $CO_2e_{Feedstock}$ - The mass of biogenic carbon within the feedstock, in tonnes of CO₂e, for batch $x$.
• $CO_2e_{CounterfactualEmissions}$ - The mass of biogenic carbon eligible to count towards gross removals, in tonnes of CO₂e, for batch $x$.
• $CO_2e_{CounterfactualEmissions15}$ - The mass of CO₂e emissions that would be emitted from the feedstock in the counterfactual within 15 years, for batch $x$.
• $CO_2e_{CounterfactualStorage50}$ - The mass of biogenic carbon within the feedstock that would remained stored in the counterfactual after 50 years, in tonnes of CO₂e, for batch $x$.

For each Reporting Period, $CO_2e_{Counterfactual}$ must be aggregated across all feedstock batches, where $n$ is the total number of batches:

$$CO_2e_{Counterfactual}\ \  =\ \  \sum_{x=1}^{n}\ CO_2e_{Counterfactual,\  x}$$

(Equation 3)

Where:

• $CO_2e_{Counterfactual}$ - The total mass of biogenic carbon that is ineligible for crediting, in tonnes of CO₂e.

Sourcing feedstocks for the purpose of BiCRS Projects can lead to an increase in GHG emissions resulting from changes to the supply and demand equilibrium, also called market leakage. For example, the sourcing of a feedstock above the Baseline Feedstock Generation Rate could lead to increased feedstock production (e.g., land use change). This can also occur when removed feedstocks exceed the Sustainable Usage Rate, leading to demand for a replacement product (e.g., fertilizer). Feedstocks that do not meet the criteria established in Table 3 are deemed ineligible under the current Module due to high risks of significant market leakage. Market leakage must be evaluated in all cases using the criteria within Table 4.

Once a Project's feedstock is identified as eligible, it maintains it's eligibility for a period of 10 years provided the feedstock sourcing does not change. Under exceptional circumstances where Isometric identifies a significant risk of substantial market leakage, Isometric reserves the right to conduct an audit to ensure feedstocks continue to meet the criteria laid out in this Module.

The following information must be submitted every 10 years:

• Project Proponents must demonstrate that feedstocks adhere to one of the criteria within Table 3 to be eligible under this Module.
• Project Proponents must demonstrate that feedstocks adhere to one of the criteria within Table 4, to evidence that market leakage has been evaluated. In cases where the feedstock is not considered to generate market leakage, evidence must be provided against the relevant criteria to demonstrate 0 market leakage emissions.

Certain feedstocks are deemed ineligible by this Module due to the associated high risk of significant market leakage. These include cases where the feedstock was cultivated for the purpose of food, feed, energy or use in BiCRS as well as materials used in long-lived wood products such as construction materials and furniture. There are exceptions under specific circumstances. To establish feedstock eligibility, the feedstock must meet the relevant criterion outlined in Table 3.

All feedstocks must select a market leakage assessment and meet all criteria within the selected assessment as laid out in Table 4 (e.g., ML5.1 and ML5.2) for the evaluation of market leakage emissions, termed $CO_2e_{Leakage}$.

If the Project's feedstock only qualifies for ML1 within Table 4 the emissions associated with market leakage must be calculated.

$CO_2e_{Leakage}$ is part of the calculation of $CO_2e_{Emissions}$ as set out by the relevant Protocol. $CO_2e_{Leakage}$ must be quantified and aggregated across all feedstock batches, $x$, within that removal, where $n$ is the total number of batches.

$CO_2e_{Leakage}$ attributed to feedstocks for a Reporting Period is quantified with the following equation:

$$CO_2e_{Leakage}\ \  =\ \  \sum_{x=1}^{n}\ CO_2e_{Leakage,\ x}$$

(Equation 5)

Where:

• $CO_2e_{Leakage}$ - The total GHG emissions associated with the Project's impact on activities that fall outside the system boundary of a Project, over a given Reporting Period, in tonnes of CO₂e.

The calculation of $CO_2e_{Leakage}$ is informed by:

• The type and source of the feedstock.
• Whether some, or all of the feedstock sourced serves an economic purpose.
• Whether some, or all of the feedstock sourced falls over the Sustainable Usage Rate.
• Whether some, or all of the feedstock sourced falls over the Baseline Feedstock Consumption Rate for a retrofit.
• The alternative use of the feedstock and the replacement material or process.
• Whether information is available regarding the direct counterfactual use of the feedstock, or whether market-level information must be used.
• The contribution of upstream revenue.

The Project Proponent must undertake an appropriate assessment based on the available information regarding the feedstock. The assessment must consider the market leakage impact of the feedstock use for the Project, including all relevant emissions.

If the Project Proponent contributes more than 5% of revenue to the feedstock supplier, the Project Proponent must assess their upstream attributional emissions (See Section 6.4 of the GHG Accounting Module for guidance).

To quantify the impact of market leakage, Projects must identify the alternative use of the feedstock and the marginal impact associated with the diversion of feedstock from this alternative use. This will typically involve identifying the unconstrained marginal product and applying a conversion rate to understand the quantity of the replacement product required.

1. The Project Proponent must identify the quantity of the feedstock that had an alternative use.
2. The default assumption will be that the highest-value potential alternative use for the feedstock represents the alternative use. Project Proponents can demonstrate the actual alternative use through:
• An affidavit or other credible documentation from the feedstock supplier detailing the historical use of the feedstock over the past 5 years.
• Market data or reporting showing the typical uses of the feedstock in the region where the feedstock supplier operates.
• A justification for excluding the highest value alternative use. This can involve providing evidence of historical supplier behavior and demonstrating that such behavior is not applicable in the current case due to a specific geographical or market condition (e.g. because the historical purchaser is no longer in operation). For example, bioenergy may be identified as the highest-value alternative use for a given feedstock. However, if the Project Proponent can show that the feedstock is not typically transported beyond a certain distance to bioenergy facilities, and that no such facilities exist within that distance from the feedstock source, this would constitute sufficient evidence to rule out bioenergy as a viable alternative use.
3. The replacement product for the use case must be identified. This is the most likely replacement material for the prior use of the feedstock. This must be an unconstrained marginal product, meaning the market it operates in can respond to supply/demand dynamics.
4. A conversion factor will be applied to understand the quantity required to replace the original feedstock function.
5. An emission factor will be sourced that represents the production of the replacement material.
6. The quantity of replacement product required will be multiplied by the emissions factor for the replacement material.
7. Any additional activities likely to occur as a result of using the replacement material that are not considered in the emissions factor selected, such as additional transportation to the use site and application activities will also be considered.

Examples of the calculation of $CO_2e_{Leakage}$ for different cases are set out below.

A Project Proponent may source wood products that were otherwise used for bioenergy production. Therefore, by sourcing the wood for the Project, the wood has been diverted from its alternative use for energy production. If wood suitable for bioenergy is a constrained resource, diverting wood from bioenergy plants may lead to an increased use of fossil power sources. The market leakage emissions are the emissions associated with the generation of energy based on the remaining grid mix⁸. The Project calculates the quantity of forgone energy production associated with the feedstock used for the Project. The forgone energy production (kWh) is multiplied by the average emissions intensity of the grid in the region.

A Project Proponent may source manure that is partially over the Sustainable Usage Rate. The Project causes some displacement to the manure that would have been used for nutrient replenishment. Manure is a constrained resource (as a residue from the dairy or livestock industry), so it is generally assumed that the replacement material is synthetic fertilizer. The Project Proponent must calculate the quantity of manure over the Sustainable Usage Rate, apply a conversion factor for the requisite fertilizer required to fulfill the same function as the manure, and source an emission factor for fertilizer use (see Appendix 4 for more details). The market leakage emissions are the quantity of fertilizer required multiplied by the emission factor for the fertilizer production.

A Project Proponent may source feedstock that otherwise would have been used for animal bedding. The biomass product is constrained as it is a residue from an industrial process, and the unconstrained marginal product is identified as hay. The Project Proponent quantifies the amount of feedstock that would have been used for animal bedding and applies a conversion factor to identify the quantity of hay that must be sourced as a replacement material. The market leakage emissions are the quantity of hay required multiplied by the emission factor for hay.

Isometric would like to thank the following contributors to this Module:

Matthew Gammans, Ph.D. (North Dakota State University)
Kevin Fingerman, Ph.D. (Cal Poly Humboldt)
Tim Hansen (350 Solutions)

This appendix details how the Project Proponent must monitor, document and report all metrics identified within this Module to calculate counterfactual emissions. Following this guidance will ensure the Project Proponent measures and confirms removals and long-term storage compliance, and will enable quantification of the emissions removal resulting from the Project activity during the Project Reporting Period, prior to each Verification.

This methodology utilizes a comprehensive monitoring and documentation framework that captures the GHG impact in each stage of a Project. Monitoring and detailed accounting practices must be conducted throughout to ensure the continuous integrity of the removals and Crediting.

The Project Proponent must develop and apply a monitoring plan according to ISO 14064-2 principles of transparency and accuracy that allows the quantification and proof of GHG emissions removals.

For replacement of fertilizer function provided by the feedstock, the mass of fertilizer accounted for in emission calculations must account for the equivalent amount of service that the feedstock provided. See Section 8.2 for a worked example using manure.

The total fertilizer capacity previously provided by the feedstock must be calculated based on the feedstock's NPK content. Feedstock NPK content must be determined by sampling of the feedstock for each production batch x, or from available scientific literature.

The amount of fertilizer replacement in the counterfactual scenario must account for replacing the same amount of NPK as in the feedstock, using the most limiting factor (either N, P, K) to determine the mass of fertilizer required. This is likely to be a very conservative estimate, since not all nutrition will be able to be utilized. As better data & evidence is built, a lower estimate can be used when well evidenced with scientific literature.

This section outlines how to calculate the GHG emissions associated with the replacement of manure as a fertilizer, $CO_2e_{Replacement}$, for a specific quantity of sourced manure from a single location. The actual emissions associated with the replacement material depend on various variables related to the nutrient composition of the sourced manure and the nutrient requirements of the cropland surrounding the manure source location.

If the quantity of manure procured does not exceed the Sustainable Usage Rate then $CO_2e_{Replacement},\ x\ =\ 0$. Guidance on calculating the Sustainable Usage Rate can be found in Appendix 4.

The following equation can be used to calculate $CO_2e_{Replacement,\ x}$.

$$CO_2e_{Replacement,\ x}\ \ =\ \ max(0,\ Rr\ -\ SUR) \cdot (CO_2e_{EmbodiedReplacement}\ +\ CO_2e_{EnergyReplacement}\ +\ CO_2e_{TransportationReplacement})$$

(Equation 6)

Where:

• $Rr$ - The removed residue mass in tonnes over the sourcing region.
• $SUR$ - The Sustainable Usage Rate of the residue, expressed in tonnes over the sourcing region.
• $CO_2e_{Replacement,\ x}$ - The total GHG emissions associated with the replacement fertilizer, in tonnes of CO₂e, for batch $x$.
• $CO_2e_{EnergyReplacement}$ - The total GHG emissions associated with the energy consumption related to replacement activities for a tonne of fertilizer production and application, in tonnes of CO₂e.
• $CO_2e_{EmbodiedReplacement}$ - The total GHG emissions associated with the production and use of a tonne of fertilizer to replace the nutrient services of the manure, in tonnes of CO₂e.
• $CO_2e_{TransportationReplacement}$ - The total GHG emissions associated with the transportation of a tonne of fertilizer, in tonnes of CO₂e.

Unsustainable forest management is a major concern within the BiCRS industry as rates of deforestation continue to exceed regeneration in many areas. While carbon stocks are an important consideration for the validity of removal Credits, additional factors must be considered to protect global forests. This is why, in addition to our requirements for carbon stock and primary forest considerations, we have the additional requirement that feedstock sourcing adhere with the principles laid out by leading forest sustainability organizations. Relying on the principles and expertise of these programs allows us to be confident that feedstocks sourced for removals credited by Isometric are vetted against the highest standards to provide ecosystem, cultural and forest sustainability. This includes the maintenance of habitats, the preservation of biodiversity and ecosystem services, as well as respecting local communities and workforces.

Pre-approved forestry certification/management programs are listed in Table 6. Feedstocks sourced from these programs are satisfy the requirements of SC1.1 and SC2.1, for use in any BioCCS or BiCRS project, including retrofit projects, subject to the other criteria outlined in this Module.

For retrofit Projects, feedstock sourcing has a broader range of eligible certification/management programs for the feedstock sourced at or under the Baseline Feedstock Consumption Rate (See Appendix 4 for details). The establishment of baseline feedstock sourcing and quantity provides confidence that the feedstock would be sourced regardless of the BiCRS project. These additional programs, that satisfy the requirements of SC2.1 only, are listed in Table 7.

Project activities necessitates the requirement of defining the baseline activities to inform all three of the themes within this Module, sustainable sourcing, counterfactual storage and market leakage. Below are some specific baseline definitions defined to demonstrate how the baseline scenario of a given Project is determined.

• Baseline Feedstock Consumption Rate can be used by Projects that retrofit existing facilities/processes, making use of residues that are generated through the production of primary products. This allows the Project to demonstrate what feedstock would be sourced over a given time frame, regardless of the Project activities, and what feedstock is sourced due to the Project activities. For more information, see Section 10.1.
• Baseline Emissions Rate and Maximum Biogenic Carbon Utilization Rate can be used in conjunction to decouple the demand by the baseline facility for increased feedstock sourcing driven by an increased demand for the primary product(s), from the increase in feedstock sourcing due to incentives around carbon crediting. This allows for a Project to demonstrate that they are having no affect on feedstock sourcing despite retrofitting a facility. For more information, see Section 10.2.
• Parasitic load is defined as the energy requirements that retrofit infrastructure demands from a baseline facility. This often necessitates an increase in feedstock sourcing, an increase in energy drawn from the grid, or a drop in primary product(s) from the baseline facility. For more information, see Section 10.4.

• Baseline Feedstock Generation Rate is defined as the rate of which a residue is generated over a given time frame, absent the Project activities. This is an important consideration for informing the market leakage assessment for a feedstock. Increases in the feedstock generation rate due to a Project's activities will likely result in market leakage, this could be due to an increase in upstream material sourcing by the feedstock supplier, or by a decrease in feedstock supplier primary outputs given the increased revenue incentives. For example, a sawmill may expand operations due to the revenue contributions of the Project, or be less diligent about using residues for long-lived materials such as fiberboard. For more information see Section 10.5.

• Sustainable Usage Rate can be used to demonstrate an amount of feedstock over a given time frame that can be sourced with no impact to the upstream service the feedstock supplies. This is typically used to demonstrate an amount of agricultural residue that can be removed from in-field retention without affecting services such as erosion control, nutrient replenishment and water retention. This enables Projects to use a feedstock where no clear excess of supply, such as a stockpile, is evident. For more information see Section 10.6.

The Baseline Feedstock Consumption Rate can be used by Projects that retrofit existing facilities/processes, making use of residues that are generated through the production of primary products. This allows the Project to demonstrate what feedstock would be sourced over a given time frame, regardless of the Project activities, and what feedstock is sourced due to the Project activities. To establish the Baseline Feedstock Consumption Rate Project Proponents must use facility-level data on average feedstock consumption for each feedstock from the 5 years prior to the Project's first procurement date. This is usually calculated from operational data or prior purchase agreements. If such data is unavailable, the value can be calculated using feedstock-to-output ratios. The value will be a rolling average of feedstock consumption over a defined time horizon, typically 5 years for industrial facilities, though other selections may be necessary due to highly variable feedstock consumption or data limitations. The variability of the feedstock consumption must also be characterized for the 5-year baseline period. This can be achieved by calculating the variance of feedstock consumption on both a reporting-period-length and annual level. Normal deviations from the mean versus induced changes can be evaluated using statistical tests such as a statistical process control assessment (SPC) or a similar test with appropriate justification.

If a perceived change in feedstock consumption is detected, the Project Proponent has three options:

1. The Project Proponent may justify this variability with evidence that the increase comes from increased demand for their primary products, not facility profitability associated with CDR production. If this increase in demand is determined to be a permanent shift, the baseline can be revised upward as deemed appropriate by a review of the available evidence. If the increase in demand is determined to be transitory in nature, these reporting periods should be omitted from future calculations updating the baseline.
2. The Project Proponent may provide sufficient evidence to demonstrate that all biomass sourced in excess of normal baseline operations remains eligible under the Biomass Feedstock Accounting Module.
3. The Project Proponent may proportionally credit the fraction of CDR that originates from biomass within their normal operating level, typically defined as three standard deviations above the baseline mean.

Calculated baselines must be representative of historical data, and a seasonal baseline may be appropriate in markets with high-seasonal variability such as energy production facilities.

To utilize the expanded list of criteria options available (e.g., SC2, ML2) by establishing a Baseline Feedstock Consumption Rate, the volume and source of feedstock must be consistent before and after the retrofit.

Should the 5 year baseline period include facility downtime due to exceptional circumstances, these observations will not be included in the average calculation. Baseline periods of shorter or longer durations than 5 years will be considered on a case-by-case basis. Isometric is open to the necessity of some adjustments being made in cases where a facility underwent significant upgrades or efficiency improvements within the baseline period. The adjustments will be made conservatively and justified based on comparisons to other analogous facilities. After the Project start date, the Baseline Feedstock Consumption Rate must be recalculated annually using a rolling average. However, in order to be eligible to revise the baseline upwards, the Project Proponent must demonstrate that the total biomass claimed as falling within baseline operations did not exceed 110% of the Baseline Feedstock Consumption Rate in the prior year In cases where feedstock use by a Project is in excess of the Baseline Feedstock Consumption Rate, the Project Proponent must assess this excess feedstock separately.

For CCS retrofit Projects, Project Proponents may be eligible to use ML2 to quantify market leakage, if their Baseline Emission Rate is greater than the Maximum Biogenic Carbon Utilization Rate of their capture process. The Baseline Emission Rate is the annual mass of biogenic carbon that is released as flue gas from the facility pre-retrofit. Like the Baseline Feedstock Consumption Rate, this value will be based on the average annual value over the 5 years prior to the Project start. Ideally, this is calculated from operational data or prior purchase agreements. If such data is unavailable, the value can be calculated using feedstock-to-output ratios.

The Maximum Biogenic Carbon Utilisation Rate, termed $\phi _{Bio}$, is the maximum quantity of input biogenic carbon that can be utilized by the capture process. The following calculation will be used to calculate the $\phi _{Bio}$:

$$\phi_{Bio}\ =\ Capture_{Capacity}\ \cdot\ ( \dfrac{1}{Capture_{Efficiency}})$$

(Equation 7)

Where:

• $\phi_{Bio}$ - The Maximum Biogenic Carbon Utilization Rate
• $Capture_{Capacity}$ - The maximum CDR the retrofit is capable of generating annually.
• $Capture_{Efficiency}$ - The estimated fraction of input biogenic carbon that is captured by the CDR process.

For example, if a facility has a $Capture_{Capacity}$ of 100 gross tonnes of CO₂ annually, and a $Capture_{Efficiency}$ of 0.8, the $\phi_{Bio}$ is 1,250 tonnes of biogenic CO₂.

The portion of a facility’s on-site biomass energy output (electric and/or thermal) that is consumed by or diverted to equipment, within the Project system boundary thereby reducing net energy available for other uses. Only the share supplied for biomass combustion within the facility is counted as parasitic load. Projects must quantify this energy and convert it to an equivalent feedstock mass using documented fuel properties and conversion efficiencies.

The Baseline Feedstock Generation Rate is the rate at which a feedstock supplier produces or generates feedstock material. For example, it could be the rate of manure production at a dairy, or forest residue generation at a forestry operation. Project Proponents calculate this by using facility, farm, or operation-level data on the average annual feedstock generated prior to the Project start date. This Module does not specify a general time horizon, but highly-capitalized industrial facilities or industries with substantial year-to-year variation in feedstock production will select a longer time horizon than farms or forestry operations.

For animal agriculture residues, the Baseline Feedstock Generation Rate is set at the levels of total output 2 years before the Project Proponent sources a batch of feedstock, as outlined in SC4. The Project Proponent must demonstrate that the total annual amount of feedstock the Project Proponent contracts for the current year will be at or below the Baseline Feedstock Generation Rate. Similar methods to those outlined in the Baseline Feedstock Consumption Rate can be used in evaluating the Baseline Feedstock Generation Rate. By linking eligibility to past production, we ensure that increasing production for the purposes of receiving additional payments would incur losses for at least 2 years. Given the low margins in agricultural production and current costs of capital, this delay period likely makes these decisions economically infeasible.

Some feedstocks may play important economic or ecological roles even if they are not typically sold in markets. For example, farmers may depend on locally available corn stover or manure for fertilization. The Sustainable Usage Rate refers to the maximum amount of a feedstock that can be removed from a region without compromising the region’s ability to meet a specific economic or ecological need. In the case of manure, for instance, the Sustainable Usage Rate would represent the highest annual quantity that can be exported while still leaving enough for farmers who rely on it to meet their fertilization requirements.

The following calculation is an example of how to calculate the Sustainable Usage Rate for manure when there is no observable counterfactual. Other calculations may be appropriate, particularly for other feedstocks, and must be evidenced when submitting the PDD.

$$Manure_{SUR}\ =\ Manure_{Gross}\ -\ Manure_{Demand}$$

(Equation 8)

Where:

• $Manure_{SUR}$ - The Sustainable Usage Rate of the manure mass in tonnes that can be obtained from a feedstock supplier
• $Manure_{Gross}$ - The average annual manure mass in tonnes generated within 5 miles of the source feedlot.
• $Manure_{Demand}$ - The maximum manure mass in tonnes required to satisfy the limiting nutrient requirements of the primary crop within a 15 mile radius.

$$Manure_{Gross}\ =\ Livestock_{Output}\ \cdot\ Livestock_n$$

(Equation 9)

Where:

• $Livestock_{Output}$ - The average manure mass in tonnes generated by a livestock animal per year.
• $Livestock_n$ - The livestock headcount within 5 miles of the manure source.

$$Manure_{Demand}\ =\ Crop_{Area}\ \cdot\ Crop_{Req}$$

(Equation 10)

Where:

• $Crop_{Area}$ - The total number of cropland acres within a 15 miles radius of the manure source. This can be multiplied by the fraction of farmers that use fertilizer within the country or equivalent. If a Project Proponent can demonstrate that no manure has left the property of the feedstock supplier over the previous 2 years, using a manure management plan or signed affidavit, then the CropArea can be constrained to property operated by the feedstock supplier.
• $Crop_{Req}$ - The maximum potential annual requirement for manure mass in tonnes to satisfy replenishment of the limiting nutrient of an acre of cropland. This limiting nutrient could be nitrogen, phosphorus or potassium. As nutrient requirements vary across crops, Project Proponents must either compute a acreage-weighted average for the $Crop_{Req}$ value across all major crops in the region or use the value relevant for the the Primary Crop in the region. The Primary Crop is defined as the crop with the highest average annual devoted acreage within the 15-mile radius circle.

If a Project Proponent can demonstrate that all produced manure can be accounted for using a manure management plan or a signed affidavit from the feedstock supplier, the equation can be simplified to:

$$Manure_{SUR}\ =\ Manure_{Gross}\ -\ Observed_{Counterfactual}$$

(Equation 11)

Where:

• $Manure_{Gross}$ - The annual mass of manure produced by the source feedlot.
• $Observed_{Counterfactual}$ - The mass of manure in tonnes from a supplier that is currently used as a nutrient source.

The following list is to be used as guidance for which industry residues are considered by Isometric to have a sufficiently low risk of market leakage to be eligible to use the Sustainability Criteria outlined in SC5. This list, while not exhaustive, is aimed to highlight appropriate industry residues that are likely to be deemed eligible within this Module. Additional feedstocks will be considered on a case-by-case basis.

A Project Proponent identifies an excess supply of corn stover over the SUR. The corn stover contains 30t of biogenic carbon. The counterfactual fate of the excess stover is combustion in piles and therefore all biogenic carbon would be released as emissions much earlier than 15 years.

Convert the carbon to CO₂e

$$CO_2e_{Feedstock}\ \ = \ \ 30 \cdot \dfrac{44}{12}\ \ = 110$$

Calculate $CO_2e_{CounterfactualEmissions}$ by applying equation 2

$$CO_2e_{CounterfactualEmissions}\ \ =\ \ min(CO_2e_{CounterfactualEmissions15},\ \ CO_2e_{Feedstock}\ \ -\ \ CO_2e_{CounterfactualStorage50})\\\ \\\ 
110\ \ =\ \ min(110,\ \ 110\ \ -\ \ 0)$$

Apply equation 1

$$CO_2e_{Counterfactual}\ \ =\ \ CO_2e_{Feedstock}\ \ -\ \ CO_2e_{CounterfactualEmissions}\\\ \\\ 
0\ \ =\ \ 110\ \ -\ \ 110$$

A Project Proponent sources excess slash residue from an FSC certified forestry project. The wood contains 30t of biogenic carbon. The decay rate of the wood residue is slow due to recalcitrant components such as lignin. The counterfactual fate of the slash material is piled up and left to decay. 25% of the biogenic carbon remains after 15 years. 5% of the biogenic carbon remains after 50 years. 1% of the emissions from decaying C are released as CH₄ in the first 15 years. The 100-year GWP of CH₄ is 27.

Convert the carbon to CO₂e

$$CO_2e_{Feedstock}\ \ =\ \ 30\ \ \cdot\ \ \dfrac{44}{12}\ \ =\ \ 110$$

Calculate $CO_2e_{CounterfactualEmissions15}$ by combining CO₂ and CH₄ emissions as CO₂e

$$CO_2e_{CounterfactualEmissions15}\ (CO_2)\ =\ (30\ \cdot\ (1\ -\ 0.25))\ \cdot\ 0.99\ \cdot\ \dfrac{44}{12}\ =\ 81.7\\\ \\\ CO_2e_{CounterfactualEmissions15}\ (CH_4)\ =\ (30\ \cdot\ (1-0.25))\ \cdot\ 0.01\ \cdot\ \dfrac{16}{12}\ \cdot\ 27\ =\ 8.1\\\ \\\ CO_2e_{CounterfactualEmissions15}\ =\ 81.7\ +\ 8.1\ =\ 89.8$$

Calculate $CO_2e_{CounterfactualStorage50}$

$$CO_2e_{CounterfactualStorage50}\ =\ 110\ \cdot\ 0.05\ =\ 5.5$$

Calculate $CO_2e_{CounterfactualEmissions}$ by applying equation 2

$$CO_2e_{CounterfactualEmissions15}\ =\ min(CO_2e_{CounterfactualEmissions15},\ CO_2e_{Feedstock}\ -\ CO_2e_{CounterfactualStorage50})\\\ \\\ 89.8\ =\ min(89.8,\ 110\ -\ 5.5)$$

Apply equation 1

$$CO_2e_{Counterfactual}\ =\ CO_2e_{Feedstock}\ -\ CO_2e_{CounterfactualEmissions}\\\ \\\ 20.2\ =\ 110\ -\ 89.8$$

A Project Proponent sources excess oat shells from a hulling facility. The oat hulls contain 30t of biogenic carbon. The current counterfactual fate of the oat shells is that they are left to decay in large piles. The decay rate of the oat shells is fairly slow given the recalcitrant components such as lignin. 25% of the biogenic carbon remains after 25 years. 1% of the biogenic carbon remains after 50 years. 4% of the emissions from decaying carbon are released as CH₄ within the first 15 years. The GWP of CH₄ is 27.

Convert the carbon to CO₂e

$$CO_2e_{Feedstock}\ =\ 30\ \cdot\ \dfrac{44}{12}\ =\ 110$$

Calculate $CO_2e_{CounterfactualEmissions15}$ by combining CO₂ and CH₄ emissions as CO₂e

$$CO_2e_{CounterfactualEmissions15}\ (CO_2)\ =\ (30\ \cdot\ (1\ -\ 0.25))\ \cdot\ 0.96\ \cdot\ \dfrac{44}{12}\ =\ 79.2\\\ \\\ CO_2e_{CounterfactualEmissions15}\ (CH_4)\ =\ (30\ \cdot\ (1\ -\ 0.25))\ \cdot\ 0.04\ \cdot\ \dfrac{16}{12}\ \cdot\ 27)\ =\ 32.4\\\ \\\ CO_2e_{CounterfactualEmissions15}\ =\ 79.2\ +\ 32.4\ =\ 111.6$$

Calculate $CO_2e_{CounterfactualStorage50}$

$$CO_2e_{CounterfactualStorage50}\ =\ 110\ \cdot\ 0.01\ =\ 1.1$$

Calculate $CO_2e_{CounterfactualEmissions}$ by applying equation 2

$$CO_2e_{CounterfactualEmissions}\ =\ min(CO_2e_{CounterfactualEmissions15},\ CO_2e_{Feedstock}\ -\ CO_2e_{CounterfactualStorage50})\\\ \\\ 108.9\ =\  min(111.6,\ 110\ -\ 1.1)$$

Apply equation 1

$$CO_2e_{Counterfactual}\ =\ CO_2e_{Feedstock}\ -\ CO_2e_{CounterfactualEmissions}\\\ \\\ 1.1\ =\ 110\ -\ 108.9$$

1. Such as slash material, defined in 40 CFR 80.1401 as "A residue, including treetops, branches and bark, left on the ground after logging or accumulating as a result of a storm, fire, delimbing or other similar disturbance". ↩

2. Downstream wood processing is defined as wood processing that converts raw wood material into products such as sawn timber, plywood, furniture or other goods. ↩

3. The sourcing region is defined as a region of similar ecological characteristics, such as biodiversity, as defined by relevant regional authorities (Carbon Direct 2025). ↩

4. A primary forest as defined by the UN FAO is a naturally regenerated forest of native tree species, where there are no clearly visible indication of human activities and the ecological processes are not significantly disturbed. For more information visit:
   https://openknowledge.fao.org/server/api/core/bitstreams/531a9e1b-596d-4b07-b9fd-3103fb4d0e72/content.
   Resources to demonstrate the sourcing region is not a primary forest:
   

   • https://www.nature.com/articles/s41597-021-00988-7
   • https://www.globalforestwatch.org/map/?map=eyJjZW50ZXIiOnsibGF0Ijo1LjQxODg2NzA4ODYxOTUzMywibG5nIjotNjIuNjU0MTYwMDg2MzYzNjQ2fSwiZGF0YXNldHMiOlt7ImRhdGFzZXQiOiJwcmltYXJ5LWZvcmVzdHMiLCJvcGFjaXR5IjoxLCJ2aXNpYmlsaXR5Ijp0cnVlLCJsYXllcnMiOlsicHJpbWFyeS1mb3Jlc3RzLTIwMDEiXX0seyJkYXRhc2V0IjoicG9saXRpY2FsLWJvdW5kYXJpZXMiLCJsYXllcnMiOlsiZGlzcHV0ZWQtcG9saXRpY2FsLWJvdW5kYXJpZXMiLCJwb2xpdGljYWwtYm91bmRhcmllcyJdLCJvcGFjaXR5IjoxLCJ2aXNpYmlsaXR5Ijp0cnVlfV19&mapMenu=eyJkYXRhc2V0Q2F0ZWdvcnkiOiJsYW5kQ292ZXIifQ%3D%3D
   • https://www.researchgate.net/publication/351464479_A_Review_of_Definitions_Data_and_Methods_for_Country-level_Assessment_and_Reporting_of_Primary_Forest
   ↩

5. Such as MSW, waste water treatment sludge, expired food waste, hospital/commercial waste, biogas from the digestion of waste treatment sludge and municipal woody waste. ↩

6. Recovery, transportation and replacement costs include but are not limited to the following:
   

   • Harvesting costs for the feedstock, such as the removal of corn stover residue from fields or the chipping of forestry residues.
   • Transportation costs of the feedstock supplier to provide the feedstock to the Project Proponent.
   • Replacement costs of the feedstock supplier necessary to accommodate the diversion of feedstock, such as the use of fertilizer, including the cost to source these fertilizers and the cost of spreading these fertilizers.
   This must be evidenced by the provision of invoices/purchase records, scientific literature and/or regional data. ↩

7. An economic purpose is one providing market recognized economic value through revenue generation or cost reductions for an operation. This could include the sale of good(s) for economic profit, or the use of the feedstock for an environmental service such as soil nutrient enhancement that would otherwise require a costly intervention. ↩

8. The use of marginal emissions rates would be the most conceptually aligned approach with a consequential emissions accounting framework, however currently available data and methodologies for their calculation are not sufficient to permit confident real-world usage. ↩