Biomass Feedstock Accounting

This module, and the framework provided in Section 2.5.2. of the Isometric Standard, enables project proponents to establish their GHG baseline through determining what the most likely counterfactual scenarios would have been in the absence of a project for a given biomass feedstock. This module is applicable to projects utilizing the following biomass feedstocks:

• Agricultural residues
• Forestry thinnings or other byproducts of forestry operations
• Industrial biomass residues

Every project must determine their GHG baseline and consider specific alternative uses of biomass that would have occurred in the absence of the project. The GHG baseline must also consider the baseline relative to each feedstock used if the project utilizes multiple feedstock types.

This module details requirements for biomass feedstock eligibility (Section 2) and counterfactual emission calculation (Section 3).

This module was developed based on the current state of the art and publicly available science regarding the land use changes that result from payments for biomass feedstock. This module is based in part on literature and models like GREET and CCLUB for life cycle analysis developed at Argonne National Lab, and Global Trade Analysis Project (GTAP) for general equilibrium economic impacts developed at Purdue University. More specific modeling for the use case of biomass residue as a feedstock for CDR will be done in the future.

The current approach outlined in this module provides additional sustainable sourcing criteria that aim to minimize the risk of potential land use effects, whilst accounting for limited data availability when only a relatively small volume of feedstock is sourced.

To extend the functionality of this module future work will be undertaken to apply the GTAP model to scenarios involving payments made for biomass residues for use in CDR and this module will be updated accordingly.

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

The Project Proponent must consider counterfactual scenarios that may have occurred in the absence of the project. Counterfactuals may vary based on the impacts of feedstock use in a given project.

These scenarios are defined below:

Feedstock eligibility is determined by both its potential market leakage impact (see Section 2.1), its counterfactual storage scenario (see Section 2.2) and whether it’s a purpose-grown feedstock (see Section 2.3). To be eligible under protocols applicable to this module, a given feedstock must meet the requirements in all three Sections.

Creating a market for biomass feedstocks may generate new revenue in the source sector that alters producer behavior in ways that result in additional GHG emissions. For example, increased profit may lead to changes in forest treatment or agronomic management activity to increase biomass yield or changes to livestock management to consolidate waste.

The framework outlined in this module sets outsourcing criteria that qualify the feedstock as eligible for use in a way that minimizes possible land use effects. If any one of the following criteria holds true, the feedstock is eligible for use under this module:

It is recommended that, where feasible, a Project Proponent collects farm-specific information as part of their sustainable sourcing practices. However, at this moment, this information is not required for the determination of eligibility.

1. Historical land use: purchase feedstock only from acreages that have been used to grow corn either continuously or in rotation with another crop for the past 10 years.
2. Tillage practices: for crop residues sourced from row crop agriculture, collect evidence from the feedstock supplier on the intensity of cultivation practices on the acreage from which the corn stover is sourced. Project Proponents are recommended to maintain records on whether fields engage in conventional tillage, reduced tillage, or no tillage.
3. Sustainable feedstock harvest: collect evidence from the feedstock supplier that the rate of biomass harvest on the acreage from which the feedstock is sourced does not exceed the sustainable rate of removal.

Accounting for counterfactual loss in carbon storage, for example in soils, through the use of certain feedstocks can be difficult and many approaches lead to the use of a form of tonne year accounting.

Instead of this, this framework requires the feedstock to meet the following eligibility criteria:

If only a portion of the feedstock is expected to be stably maintained for longer than this threshold, the percentage of biomass that would not have decayed before the 15 year threshold is not eligible under this framework and the carbon content of this biomass must be subtracted from the LCA (see Equation 2).

$$CO_2e_{DecayCounterfactual,\ p} =
 CO_2e_{Feedstock} \times
 δ_{StorageCounterfactualDiscount}$$

(Equation 1)

Where:

• $CO_{2}e_{DecayCounterfactual,\ p}$ = the total quantity of CO₂e that is ineligible due to the decay rate of the feedstock as laid out in EC10
• $CO_2e_{Feedstock}$ = the CO₂e content of the biomass feedstock used
• $δ_{StorageCounterfactualDiscount}$ = the discount applied to the carbon content of the biomass feedstock. For example, if 95% of the biomass was shown to have likely decayed before the threshold value in EC10 then $δ_{StorageCounterfactualDiscount}$ = 0.05

This discount can arise through two different mechanisms:

• Biomass that wouldn't have decayed until after the threshold time is ineligible and must be discounted;
• Biomass that would have decayed before the threshold time may still lead to a discount if a portion of the decayed biomass would have led to durable storage, such as corn stover decay leading to increases in soil organic carbon. This effect may be nonlinear and the Project Proponent may provide evidence that at the removal rates they have sourced feedstock from this effect is negligible.

The intent of this criterion is to avoid situations in which the biomass could have been used for energy production instead of carbon removal.

The feedstock must meet the following eligibility criteria in order to be eligible for use under this module:

Specific emission calculations associated with a project’s counterfactual scenario(s), as required in Section 7.2 of protocols applicable to this module, are determined as described below.

As biomass sourcing typically operates on a batch basis; the total counterfactual GHG emissions associated with a removal are calculated from the sum of all counterfactual GHG emissions across all feedstock production batches, $p$, within that removal, where $N$ is the total number of batches:

$$CO_2e_{Counterfactual,\ R} = \sum_{p=1}^{N}CO_{2}e_{Counterfactual,\ p}$$

(Equation 2)

Where:

• $CO_2e_{Counterfactual,\ R}$ = the total quantity of counterfactual GHG emissions over a 15-year time horizon, as total net greenhouse gas emissions for a removal $R$, in tonnes of CO₂e
• $CO_{2}e_{Counterfactual,\ p}$ = the total quantity of counterfactual GHG emissions over a 15-year time horizon, as total net greenhouse gas emissions for a production batch $p$, in tonnes of CO₂e, see Equation (3)

Counterfactual emissions associated with an individual production batch, $p$, can be calculated as follows:

$$CO_2e_{Counterfactual,\ p} = CO_2e_{Energy\ Counterfactual,\ p} + \\ CO_2e_{Replacement,\ p}+ CO_2e_{DecayCounterfactual,\ p}$$

(Equation 3)

Where:

• $CO_2e_{Energy Counterfactual,p}$ = the net change in GHG emissions associated with energy consumption from baseline to project for a production batch $p$, in tonnes of CO₂e, see Section 3.1.
• $CO_2e_{Replacement,p}$ = the net change in GHG emissions associated with replacing the function of the feedstock removed for a production batch $p$, in tonnes of CO₂e, see Section 3.2, Equation (4).
• $CO_{2}e_{Decay Counterfactual,\ p}$ = the net amount of GHG storage ineligible due to the decay rate of the feedstock for a production batch $p$, in tonnes of CO₂e, see EC10 Equation (1). Note that feedstocks that have an energy counterfactual have a decay counterfactual of zero.

Emissions associated with energy usage for processes including but not limited to the growth, harvest, and collection of the biomass feedstock must be accounted for by all feedstocks.

The emissions of interest are the net change in energy emissions from baseline to project, which may be calculated in one of two ways, depending on the Project Proponent preference and available data sources:

• Determination and accounting of full baseline emissions associated with energy usage for feedstock sourcing deducted from full project emissions associated with energy use for feedstock sourcing;
• Determination and accounting for energy usage only for the project activities that occur which are in addition to any sourcing activities that would occur in the counterfactual scenario (e.g., additional fuel usage for equipment used to collect biomass that would normally be left in field, electricity use for shredding and bailing equipment, fuel use for loading biomass onto a truck)

Emissions may originate from, but are not limited to, the following sources:

• Emissions from electricity usage, CO₂e_{Feedstock Electricity} for all feedstock used in each production batch $p$
• Emissions from fuel combustion to produce heat or thermal energy in primarily non-road mobile equipment, such as forklifts and other material handling equipment or any other fuel used in the growth, harvest, and collection process, CO₂e_{FeedstockFuel} for all feedstock used in each production batch $p$.

Energy related emissions must be measured, calculated and documented in accordance with Energy Use Accounting Module.

Where feedstock may be diverted from an alternate use, emissions associated with replacing the function of the feedstock removed for use in the project must be accounted for. Exemptions are listed in Section 3.2.2.

The emissions associated with the replacement material, as determined by the feedstock framework and the counterfactual definition, must include full cradle-to-grave emissions accounting for the life cycle of the replacement product. For example emissions for the production, transportation and use of the material.

$CO_{2}e_{Replacement,\ f}$ can be calculated as follows:

$$CO_2e_{Replacement,\ f} = m_{Replacement,\ f} \times EF_{Embodied\  Replacement} + \\ CO_{2}e_{Transportation\ Replacement,\ f}$$

(Equation 4)

Where:

• $m_{Replacement,\ f}$ = the mass of the replacement product required to provide the equivalent service as the mass of the project feedstock for a function
• $EF_{Embodied\ Replacement}$ = the embodied emissions factor for the production and use of the replacement product, see Embodied Emissions Accounting Module for calculation approach details and emission factor requirements
• $CO_{2}e_{Transportation\ Replacement,\ f}$ = the CO₂ equivalent emissions associated with transportation and delivery of the replacement product for a function $f$. See Transportation Emissions Accounting Module for calculation approach details

If the replacement product is performing an environmental service, such as fertilizing, the amount of replacement product used must account for the equivalent amount of service that the Project feedstock provided. See Section 3.2.3.1 for further calculation details.

The replacement counterfactual for the Project Proponent feedstock is determined to be the economically highest value use of the feedstock in a given state.

The Project Proponent may be able to provide evidence leading to a different counterfactual being used. This can be done by demonstrating:

• An affidavit, or other credible records, from the feedstock supplier outlining the past use of their biomass over the last 5 years
• Evidence that the highest value use is not representative of the feedstock end uses for the source region. This can be done by presenting evidence of the historical behaviors of feedstock suppliers and justifying that these do not apply in the case of the feedstock in question. For example, it may be determined that bioenergy is the highest value alternative use for a feedstock, however, if a Project Proponent can demonstrate that feedstocks are not typically moved over a certain distance to bioenergy facilities and there are no bioenergy facilities within this radius of the feedstock source this would be satisfactory evidence that this alternative use is not applicable.

Replacement emissions can be considered 0 where any of the following conditions are met:

Calculation of $CO_{2}e_{Replacement, p}$ requires, but is not limited to, the following measurements:

• $m_{Replacement,\ p}$ (mass of replacement material)

For replacement of fertilizer function provided by the Project feedstock, the mass of fertilizer accounted for in emission calculations, $m_{Replacement,\ p}$, must account for the equivalent amount of service that the Project feedstock provided.

The total fertilizer capacity previously provided by the Project feedstock must be calculated based on the feedstock(s) nitrogen, phosphorus and potassium (NPK) content. Feedstock NPK content must be determined by sampling of the feedstock(s) for each production batch $p$, 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 project 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.

The project proponent must maintain the following records as evidence of CO₂e_{Replacement, p} calculations:

• If the feedstock provided an environmental service either: (1) documentation on how N, P, K values were determined from relevant literature, (2) for new or unique feedstocks, a per-feedstock lab analysis of N, P and K values, or (3) for highly variable feedstocks a per-batch lab analysis of N, P and K values.
• Feedstock weigh scale tickets for each production batch, $p$, or other equivalent records to support calculation of $m_{Replacement,\ p}$

Records must be maintained and provided for verification purposes for a period of five years.

Isometric would like to thank following contributors to this module:

• Kevin Fingerman, Ph.D. (Cal Poly Humboldt)
• Tim Hansen (350 Solutions)

This section outlines how to calculate the replacement mass of fertilizer, $m_{Replacement,\ p}$, for a specific quantity of sourced manure from a single location. The actual replacement emissions 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.

• $ObservedCounterfactual$ - quantity of manure (tonnes) from a supplier that is currently used for nutrient source.
• $QuantityProcured$ - quantity of manure (tonnes) procured for CDR by the Project Proponent from within the $SupplyRegion$.
• $QuantityGenerated$ - total quantity of manure (tonnes) generated in a supply region.
• $SupplyRegion$ - the geographic area considered when calculating relevant manure supply. Typically, this will include a 5-mile radius around the manure source. Under certain circumstances, this may be limited to the manure source.
• $Acres$ - the number of relevant acres using manure. This can be estimated using the county-level share of total acres that use manure fertilizer multiplied by the total area of farmland within a 15-mile radius of the manure source.
• $PrimaryCrop$ - The largest crop by acreage included in the $Acres$ value
• $NutrientsReq_{f}$ - necessary quantity of nutrient $f$ (N or P) per cropland acre for the $PrimaryCrop$.
• $ManureNutrient_f$ - quantity of nutrient $f$ (N or P) in 1 tonne of manure.
• $FertiliserEmissions_f$ - the emissions (CO₂e) generated in the production of 1kg of nutrient $f$ (N or P) in fertilizer.

The Sustainable Use Rate (SUR) is the quantity of manure that can be taken without the need to calculate replacement emissions. There are three potential cases:

If the source can demonstrate through manure management plan records and/or an affadavit or other documentation the quantity of manure that was used for fertilization purposes either on- or off-farm, the SUR can be calculated as follows:

$SUR$ = $QuantityGenerated$-$ObservedCounterfactual$

(Equation 5)

In this case, the $SupplyRegion$ is the feedlot, thus $QuantityGenerated$ is total quantity of manure produce annually at the source feedlot

If the source can demonstrate through manure management plan records and/or through a signed affadavit that no manure has left the property of the feedlot for at least the prior two years, the SUR can be calculated at the feedlot level. In this case, variables are calculated in the following manner:

Then the SUR is provided by the following calculation:

$$SUR = \max\left[\frac{{Acres \cdot NutrientsReq_{cN}}}{{ManureNutrient_{N}}}, \frac{{Acres \cdot NutrientsReq_{cP}}}{{ManureNutrient_{P}}}\right]$$

(Equation 6)

If there does not exist an observed counterfactual and the source farm can not demonstrate that no manure has left the farm within the past 2 years, a regional estimate of the SUR can be computed using Equation 6 above, but with variables are calculated in the following manner:

Replacement mass is calculated as follows:

If

$$QuantityProcured \leq SUR$$

then:

$$m_{Replacement,\ p}=0$$

Otherwise, the appropriate replacement emissions value is:

$$\begin{align*}
m_{Replacement,\ p} &= \left(QuantityProcured-SUR\right) \\
&\quad \times \left(ManureNutrient_{N} \cdot FertiliserEmissions_{N} + ManureNutrient_{P} \cdot FertiliserEmissions_{P}\right)
\end{align*}$$

(Equation 7)

Potential additional data sources:

• $NutrientsReq_{cf}$ - N, P needs per farmland acre from AESL at UGA (K is assumed to not be limiting).
• $ManureNutrient_{f}$ - N, P generated from cow manure in the county from Utah State University Extension.

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 carbon removed and long-term storage compliance, and will enable quantification of the emissions removal resulting from the Project activity during the Project Crediting 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 carbon 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.

1. A forest residue is defined as non-marketable wood, for example, beetle kill, sticks and twigs, mill residues, etc. ↩

2. Allowed State level alternative programs are outlined here ↩

3. Such as wood removal from areas affected by windfall, fires, insect, or disease attacks, or where wood is removed for widely-recognized ecological reasons (e.g., to reduce wildfire hazard). ↩

4. Criterion 1.1, Sustainable Biomass Sourcing for Carbon Dioxide Removal, Version 1.1, October 2023 ↩

5. Criterion 3.4, Sustainable Biomass Sourcing for Carbon Dioxide Removal, Version 1.1, October 2023 ↩

6. Criterion 1.1, Sustainable Biomass Sourcing for Carbon Dioxide Removal, Version 1.1, October 2023 ↩

7. Criterion 3.4, Sustainable Biomass Sourcing for Carbon Dioxide Removal, Version 1.1, October 2023 ↩

8. Criterion 4.2, Sustainable Biomass Sourcing for Carbon Dioxide Removal, Version 1.1, October 2023 ↩

9. Criterion 4.1, Sustainable Biomass Sourcing for Carbon Dioxide Removal, Version 1.1, October 2023 ↩

10. Cellulosic biorefinery locations and capacities can be obtained from the Renewable Fuels Association: https://ethanolrfa.org/resources/ethanol-biorefinery-locations. If the feedstock is listed as “Cellulosic Biomass”, then we assume 100% of harvested-for-sale corn stover within 50 km has an alternative fate of an ethanol production use. At present, given the small total production of cellulosic biofuel, facilities where “Cellulosic Biomass” is listed as only one potential feedstock among multiple (e.g., “Corn/Cellulosic Biomass”) will be assumed to be primarily corn and stover procured from these areas will be assumed to not have an alternative use as an energy crop. ↩

11. The verifier may provide third party verification during the verification site visits via on-site review of feedstock practices, utilization, and records, including observation of feedstock stockpiles, deliveries, applications, or other uses. ↩