Biogenic Carbon Capture and Storage

1.0 Summary

This Protocol (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.) provides the requirements and procedures for the calculation of net CO₂ equivalent (CO₂e) (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.)removals (The term used to represent the CO₂ taken out of the atmosphere as a result of a CDR process.) from the atmosphere via Industrial Process Biogenic Carbon Capture and Storage (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”.) (Bio-CCS). This Protocol is developed for application to Bio-CCS processes or combinations of processes (e.g., solid sorption,¹ liquid solvent,² membrane processes,³ electrochemistry,⁴ etc.) in which a cradle-to-grave (​​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.)GHG Statement (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.) can be accurately applied and in which the CO₂ captured is stored via physical⁵ or chemical⁶ trapping mechanisms for > 1000 years.

The Protocol ensures:

• Consistent, accurate procedures are used to measure and monitor all aspects of the process required to enable accurate accounting of net CO₂e removal;
• Consistent system boundaries (GHG sources, sinks and reservoirs (SSRs) associated with the project boundary and included in the GHG Statement.) and calculations are utilized to quantify net CO₂e removal;
• Requirements are met to ensure the CO₂ removals are additional; and
• Evidence is provided and verified by independent third parties to support all net CO₂e removal claims.

2.0 Sources and Reference Standards and Methodologies

Specific standards and Protocols which are utilized as the foundation of this Protocol and for which this Protocol is intended to be fully compliant with are as follows:

• Isometric Standard
• ISO 14064-2: 2019 – Greenhouse Gases – Part 2: Specification with guidance at the Project (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.) level for quantification, monitoring, and reporting of greenhouse gas emission reductions (Lowering future GHG releases from a specific entity.) or removal enhancements

Additional reference standards that inform the requirements and overall practices incorporated in this Protocol include:

• ISO 14064-3: 2019 – Greenhouse Gases – Part 3: Specification with Guidance for the verification (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).) and validation (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).) of greenhouse gas statements
• ISO 14040: 2006 - Environmental Management - Life Cycle Assessment - Principles & Framework
• ISO 14044: 2006 - Environmental Management - Life Cycle Assessment - Requirements & Guidelines

3.0 Future Versions

This Protocol was developed based on the current state of the art and publicly available science regarding Bio-CCS^7,8,9. As Bio-CCS is still a developing approach to carbon dioxide removal (CDR) (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.) with ever-expanding published literature, this Protocol incorporates requirements that may be more stringent than other available regulations or Protocols. The approach taken here may be altered in future versions of the Protocol in-line with advancements in the available technology and published research.

4.0 Applicability

4.1 Co-Firing With Fossil Fuels

Whether emitted fossil CO₂ is considered a Project emission is dependent on the baseline (A set of data describing pre-intervention or control conditions to be used as a reference scenario for comparison.) scenario according to the guidelines in Section 7: System Boundary and Project Baseline, Appendix A1: Guidance for Handling Fossil CO₂ and Appendix B2: Baselines.

5.0 Environmental and Social Safeguarding

The Project Proponent must consider environmental and social impacts from processes that comprise part of the Project. The Project Proponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) must provide evidence that the Project will do no net environmental or social harm by complying with Sectionthe 3.7Environmental and Social Impacts section of the Isometric Standard as well as the following requirements:

• Project Proponents must comply with all health and safety procedures as required by the authority of the geography where the Project is located, and must demonstrate a risk assessment and mitigation plan for safeguarding working conditions, addressing any specific hazards associated with the use of the proposed sorbent or solvent and the operations of the capture and storage facility.

• Project Proponents must demonstrate that a social risk assessment has been conducted. This must consider environmental and social justice issues for the selected storage site, including a robust Stakeholder (Any person or entity who can potentially affect or be affected by Isometric or an individual Project activity.) engagement program and considerations of any direct or indirect impacts on local communities or indigenous people, including livelihoods, ancestral knowledge and cultural heritage in line with the applicable human rights laws and United Nations declarations.

5.1 Combustion Residues

Certain waste feedstocks may carry a higher risk of pollution due to contamination with hazardous components, such as chemical solvents or trace metals. The incineration of municipal solid waste (MSW) can also carry a higher risk of pollution because heterogeneous feedstocks vary in composition and may contain trace contaminants. As a result, proper handling of waste and by-product (Materials of value that are produced incidentally or as a residual of the production process.) outputs is essential.

5.1.1 Bottom Ash

5.1.2 Fly Ash and Flue Gas Scrubber Residues

5.1.3 Flue Gases

5.1.4 Persistent Organic Pollutants

6.0 Relation to the Isometric Standard

The following topics are covered briefly in this Protocol due to their inclusion in the Isometric Standard, which governs all Isometric Protocols. See in-text references to the Isometric Standard for further guidance.

6.1 Project Design Document

6.2 Validation and Verification

Projects must be validated and project net CO₂e removals verified by an independent third party consistent with the requirements described in this Protocol as well as in the Sectionrelevant 4section of the Isometric Standard.

The Validation and Verification Body (VVB) (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.) must consider following requisite components:

1. Verify that storage sites adhere to the requirements listed in the relevant storage module.
2. Verify that the quantification approach and monitoring plan adheres to requirements of Section 8, including demonstration of required records.
3. Verify that the Environmental & Social Safeguards outlined in Section 5 are met.
4. Verify that the Project is compliant with requirements outlined in the Isometric Standard.

6.2.1 Verification Materiality

The threshold for Materiality (An acceptable difference between reported Removals/emissions or Reductions/emissions and what an auditor determines is the actual Removal/emissions or Reduction/emissions.), considering the totality of all omissions, errors and mis-statements, is 5%,outlined in accordance withthe SectionMaterialiaty 4.3Threshold section of the Isometric Standard.

Verifiers should also verify the documentation of uncertainty (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.) of the GHG Statement as required by Sectionthe 2.5.7relevant section of the Isometric Standard. Qualitative Materiality issues may also be identified and documented, such as:¹²

• Data and document control issues that erode the verifier’s confidence in the reported data;
• Poorly managed documented information;
• Difficulty in locating requested information; and
• Noncompliance with regulations indirectly related to GHG emissions, removals or storage.

6.2.2 Site Visits

Project Validation and Verification must incorporate site visits to project facilities in accordance with the requirements of ISO 14064-3, 6.1.4.2, including, at minimum, site visits during the first Validation or Verification of a Project, to the capture and (if applicable) storage site. Verifiers should whenever possible observe operation of the capture and storage processes to ensure full documentation of process inputs and outputs through visual observation and validation of instrumentation, measurements, and required data quality measures.

A site visit must occur at least once during each Project Validation. Additional site visits may be required if there are substantial changes to field operations over the course of a Project's Validation period, or if deemed necessary by Isometric or the VVB. Site visit plans are to be determined according to the VVB's internal assessment, in consultation with Isometric.

6.2.3 Verifier Qualifications and Requirements

VVBs must comply with the requirements defined in Sectionthe 4Validation and Verification Requirements section of the Isometric Standard. In addition, teams should maintain and demonstrate expertise associated with the specific technologies of interest, including solvent/sorbent chemistry, electricity procurement and heat/power generation and the relevant CO₂ storage technology.

Competency must be demonstrated in accordance with Isometric's VVB policy, for example based on the relevant sectoral scope accreditations in IAF MD 14, or another demonstration of relevant expertise for this Protocol and the selected storage module(s).

6.3 Ownership

6.4 Additionality

The Project Proponent must be able to demonstrate additionality through compliance with Sectionthe 2.5.3Additionality section of the Isometric Standard. The baseline scenario and counterfactual (An assessment of what would have happened in the absence of a particular intervention – i.e., assuming the Baseline scenario.) utilized to assess additionality must be project-specific, and are described in Section 7.2 of this Protocol.

Additionality determinations should be reviewed and completed every five years (aligned with the Crediting Period, at a minimum, or whenever project operating conditions change significantly, such as the following:

• Regulatory requirements or other legal obligations for project implementation change or new requirements are implemented; or
• Project financials indicate Carbon Finance (Resources provided to projects that are generating, or are expected to generate, greenhouse gas (GHG) Emission Reductions or Removals.) is no longer required, potentially due to, for example:
  • Sale of co-products that make the business viable without Carbon Finance; or
  • Reduced rates for capital access.

Any review and change in the determination of additionality should not affect the availability of Carbon Finance and Verified Credits for the current or past Crediting Periods, but if the review indicates the Project has become non-additional, this will make the Project ineligible for future Credits.¹³

6.5 Uncertainty

The uncertainty in the overall estimate of the net CO₂e removal as a result of the Project must be calculated and transparently presented. The total net CO₂e removed over a Reporting Period ([math: RP]; see Section 8) for a Project, [math: CO_2e_{Removal,\ RP}], must be conservatively determined, based on the requirements outlined in Sectionthe 2.5.7relevant section of the Isometric Standard.

6.5.1 Reporting of Uncertainty

Projects must report a list of all input variables used in the net CO₂e removal calculation and their uncertainties, including:

• Emission factors utilized, as published in public and other databases used;
• Values of measured parameters from process instrumentation, such as metered heat and electricity usage, sorbent/solvent replacement periods and other equipment considerations;
• Laboratory analyses, including that required by selected storage module(s), which could include analysis of carbon content and purity of injected CO₂, CO₂-containing injectants or carbonated minerals; and
• Summary of data handling, processing, and error propagation approach.

The uncertainty information should at least include the minimum and maximum values of a variable. More detailed uncertainty information should be provided if available, as outlined in Sectionthe 2.5.7relevant section of the Isometric Standard.

In addition, a sensitivity analysis (An analysis of how much different components in a Model contribute to the overall Uncertainty.) that demonstrates the impact of each input parameter’s uncertainty on the final net CO₂e uncertainty must be provided. Details of the sensitivity analysis method must be provided so that the results can be re-created. Parameters may be omitted from a full uncertainty analysis if a Sensitivity Analysis can demonstrate that the parameter contributes to <1% change in removal. For all other parameters, information about uncertainty must be specified.

6.6 Data Sharing

In accordance with Sectionthe 3.8Data Sharing section of the Isometric Standard, all evidence and data related to the underlying quantification of the net CO₂e removal will be available to the public through Isometric's platform. This includes:

• Project Design Document
• GHG Statement
• Measurements taken
• Emission factors used
• Scientific literature used

The Project Proponent can request certain information to be restricted (only available to authorized Buyers (An entity that purchases Removals or Reductions, often with the purpose of Retiring Credits to make a Removal or Reduction claim.), the Registry (A database that holds information on Verified Removals and Reductions based on Protocols. Registries Issue Credits, and track their ownership and Retirement.), and VVB) where it is subject to confidentiality. This includes emission factors from licensed databases. However, all other numerical data produced or used as part of the quantification of net CO₂e removal will be made available.

7.0 System Boundary and Project Baseline

7.1 System Boundary and GHG Emission Scope

The scope of this Protocol includes GHG sources, sinks (Any process, activity, or mechanism that removes a greenhouse gas, a precursor to a greenhouse gas, or an aerosol from the atmosphere.) and reservoirs (SSRs (Sources, Sinks and Reservoirs)) associated with a Bio-CCS Project (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.).

A cradle-to-grave GHG Statement must be prepared encompassing the GHG emissions relating to the activities outlined within the system boundary.

GHG emissions and removals associated with the Project may be direct emissions (Emissions that are produced by a specific CDR process and are directly controllable.) from a process or storage system, or indirect emissions from combustion of fuels, electricity generation, or other sources. Emissions must include all GHG SSRs within the system boundary, from the construction or manufacturing of each physical site and associated equipment, closure and disposal of each site and associated equipment, and operation of each process (CO₂ capture process, CO₂ transportation, storage, and monitoring), including embodied emissions (Life cycle GHG emissions associated with production of materials, transportation, and construction or other processes for goods or buildings.) of equipment and consumables used in the Project. The Project Proponent is responsible for identifying all sources of emissions directly or indirectly related to project activities.

Any emissions from sub-processes or process changes that would not have taken place without the CDR Project must be fully considered in the system boundary. Any activity that ultimately leads to the issuance (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.) of Credits should be included in the system boundary. Biomass feedstock emissions must be calculated as outlined in Section 3 of the Biomass Feedstock Accounting Module v1.3. This allows for accurate consideration of additional, incremental emissions induced by the carbon removal process.

The GHG Statement boundary (The Controlled, Related and Affected GHG Sources, Sinks and Reservoirs to be considered in the GHG Statement.) must include all relevant GHG SSRs controlled, related and affected by the Project, including but not limited to the SSRs set out in Figure 1 and Table 1. If any GHG SSRs within Table 1 are deemed not appropriate to include in the system boundary, they may be excluded provided that robust justification and appropriate evidence is provided in the PDD.

Figure 1. Process flow diagram showing system boundary for Bio-CCS projects

[Image: FigureSystem 1boundary diagrams]

Table 1. Scope of activities to be included in the system boundary for Bio-CCS projects

Miscellaneous GHG emissions are those that cannot be categorized by the GHG SSR categories provided in Table 1. The Project Proponent is responsible for identifying all sources of emissions directly or indirectly related to project activities and must report any outside of the SSR categories identified as miscellaneous emissions.

Emissions associated with The Project's impact on activities that fall outside of the system boundary of The Project must also be considered. This is covered under Leakage in Section 8.2.35.4.

In line with the GHG Accounting Module v1.01, the Project must:

• Consider all GHGs associated with SSRs, in alignment with the United States Environmental Protection Agency’s definition of GHGs which includes: carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O) and fluorinated gasses such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF₆) and nitrogen trifluoride (NF₃). For CO₂ stored, only CO₂ shall be included as part of the quantification. For all other activities all GHGs must be considered. For example, the release of CO₂, CH₄, and N₂O is expected during diesel consumption;
• Quantify emissions in tonnes CO₂ equivalent (t CO₂e) using the 100-year Global Warming Potential (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.) (GWP) for the GHG of interest, based on the most recent volume of the IPCC Assessment Report (currently the Sixth Assessment Report); and
• Consider Materiality of SSRs in line with Isometric requirements.

Bio

7.2 Baseline

See Appendix B2: Baselines for further guidance on constructing a Project baseline.

• Biomass counterfactual: If the CO₂ would have remained stored in the biomass in the absence of the CDR Project, it is considered ineligible biomass, and is therefore not eligible to count towards Crediting. The Biomass Feedstock Accounting Module v1.3 sets out requirements for establishing ineligible biomass as part of the Counterfactual Storage Eligibility Criteria, and includes details for quantification of [math: CO_2e_{Counterfactual}].
• Storage counterfactual: The storage counterfactual of qualifying projects is considered to be zero unless a counterfactual scenario is required in the applicable Storage Module. For example, geological sequestration of fluidic CO₂ typically has zero counterfactual, but mineralisation of CO₂ must consider the counterfactual scenario of any mineralisation of CO₂ that would occur in the absence of the Project.

8.0 Net CDR Calculation

8.1 Calculation Approach and Reporting Period

Bio-CCS systems are typically operated continuously, with captured CO₂ being transported and durably stored using a variety of potential processes. Due to the continuous nature of Bio-CCS systems, the equations used to calculate removals will pertain to all net emissions occurring over an interval of time. This unit of time is defined as the Reporting Period, [math: RP], which is the time period during which net CO₂e removals are claimed by the Project Proponent and submitted for verification. The total net CO₂e removal is written hereafter as [math: CO_2e_{Removal}].

The following sections outline the process for calculating the net CO₂e removed for each Reporting Period based on total mass stored during that period, written hereafter as [math: CO_2e_{Removal,\ RP}].

8.2 Calculation of CO₂eRemovaleRemoval ,RP

Net CO₂e removal for a process utilizing Bio-CCS must be calculated as follows for a Reporting Period, [math: RP]:

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

(Equation 1)

Where;

• [math: CO_2e_{Removal,\ RP}] = total net CO₂e removed from the atmosphere over a given [math: RP], in tonnes CO₂e.
• [math: CO_2e_{Stored,\ RP}] = the total biogenic CO₂ removed from the atmosphere and durably stored over the [math: RP], in tonnes CO₂e. See Section 8.2.13.
• [math: CO_2e_{Counterfactual,\ RP}] = the total counterfactual CO₂ removed from the atmosphere and durably stored in the absence of the Project over the [math: RP], in tonnes CO₂e. See Section 8.2.24.
• [math: CO_2e_{Emissions,\ RP}] = the total GHG emissions associated with the [math: RP], in tonnes of CO₂e. See Section 8.2.35.

It should be noted that any potential 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.) of CO₂ storage in the final storage location occur after Credits have been issued so are not included in this equation. See Sectionthe 5.6Reversals and Buffer Pools section of the Isometric Standard for further information. Risk of reversal information is given in Appendix D4: Risk of Reversal Questionnaire, with further information provided within the relevant Storage Module.

8.2.13 Calculation of CO₂eeStored, RP

[math: CO_2e_{Stored

CO2eStored,\ RP}] represents the cumulative total CO₂ sequestered in all durable storage reservoirs over a Reporting Period. It is calculated as:

[math: CO_{2}e_CO_2e_{Stored,\ RP} = F_{B} \times \sum_{i}^{N} CO_{2}e_{Storage,i}]

(Equation 2)

• [math: F_{B}] is the biogenic fraction that is eligible for Crediting. If all captured [math: CO_{2}] is biogenic, [math: F_{B} = 1]. Otherwise, see Section 8.2.13.1.
• [math: CO_{2}e_{Storage,i}] is the total amount of [math: CO_{2}] sequestered in a durable storage reservoir, i, following an applicable storage Module, over the Reporting Period, RP (Reporting Period), in tonnes [math: CO_{2}e]. This term must be measured following the requirements in the respective storage Module.
• [math: N] is the total number of durable storage reservoirs used for storage of captured [math: CO_{2}].

Quantification of [math: CO_{2}e_{Storage}], measurements, and monitoring requirements for the different conversion and storage options are detailed within the respective Modules.

8.2.13.1 Determination of Biogenic Fraction F_B

Once [math: F_{B}] is determined in accordance with Section 8.2.13.1.1 or Section 8.2.13.1.2, the [math: CO_{2}e_{Storage}] as determined by the appropriate storage Module(s) must be converted to eligible biogenic [math: CO_{2}e_{Storage}] using Equation 2.

8.2.13.1.1 Method A: Radiocarbon Measurement of Flue Gas

[math: F_{B}] must be determined by

• Flue sampling location according to ISO 10396/EN 15259 or ASTM D7459.
  • Flue gas sampling may be on the pre-capture or post-capture CO₂ stream.
• Flue sampling according to EN 14181 or ASTM D7459.
• Representative flue gas samples must be taken continuously, integrated over a maximum of a 3 months of operations, by an extractive CEMS.
• Flue gas samples must be demonstrated to be proportionally matched to the flue stack gas mass flow during collection. From these samples, the biogenic fraction ([math: F_{B}]) must be determined by radiocarbon sampling and determination using ISO 13833:2013 or ASTM D6866-21.

8.2.13.1.2 Method B: Mass Balance Determination per Feedstock

[math: F_{B}] must be conservatively determined using a carbon mass balance approach detailed by Equation 3.

[math: F_B = \frac{\sum_{i}^{N_B}(m_{Biomass,i} \cdot C_{Biomass,i})}{\sum_{i}^{N_B}(m_{Biomass,i} \cdot C_{Biomass,i}) + \sum_{i}^{N_{FF}}(m_{FF,i} \cdot C_{FF,i})}]

(Equation 3)

where

• [math: m_{Biomass,i}] is the measured dry mass of biomass feedstock, i, used by the Project within a Reporting Period.
• [math: C_{Biomass,i}] is the CO₂e of biomass feedstock, i.
• [math: N_B] is the total number of biomass feedstocks used in a Reporting Period.
• [math: m_{FF,i}] is the measured mass of fossil fuel, i, used by the Project within a Reporting Period.
• [math: C_{FF,i}] is the CO₂e of fossil fuel, i.
• [math: N_{FF}] is the total number of fossil fuel feedstocks used in a Reporting Period.

8.2.13.2 Initial Estimation of Biogenic and Fossil Fractions of CO₂

8.2.24 Calculation of CO₂eCounterfactual

Type:eCounterfactual, Counterfactual

8.2.35 Calculation of CO₂eEmissions

Type:eEmissions, Emissions

[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}^{}]

8.2.35.1 Calculation of CO₂eEstablishment

8.2.35.2 Calculation of CO₂eOperations

8.5.3 Calculation of CO₂eEnd-of-Life, RP

[math: CO_2e_{End-of-Life,\ RP}] includes all emissions associated with activities that are anticipated to occur after the Crediting Period until the end of the Project Commitment Period. This includes activities related to ongoing monitoring for Reversals.

[math: CO_2e_{End-of-Life,\ RP}] must be estimated upfront and allocated in the same way as set out for calculation of [math: CO_{2}e_{Establishment,\ RP}].

Given the uncertain nature of [math: CO_2e_{End-of-Life,\ RP}] emissions, assumptions must be revisited at each Reporting Period and any necessary adjustments made.

8.5.4 Calculation of CO₂eLeakage, RP

[math: CO_2e_{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.

[math: CO_2e_{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.

8.5.5 Procedure for Handling Missing Data

The Project Proponent must identify, highlight and justify any data gaps and missing calibration data should they occur. Isometric and the VVB must be notified of data gaps and missing calibration data as soon as they become evident. Documentation that explains the approach taken and details the missing data must be provided to Isometric and the VVB and included in the GHG Statement.

For parameters that require sub-hourly measurements (such as direct GHG emission concentrations and flow rates), the Project Proponent must adhere to the following procedure for handling missing data events.

Where data gaps in measurements are 30 minutes or less in duration, the Project Proponent must use an average measurement utilising measurements taken 30 minutes prior to and following the data gap.

Where data gaps in measurements are longer than 30 minutes in duration, the Project Proponent must apply the above approach for up to a 30 minute period within the duration of the data gap only. For the remaining duration of the data gap the Project Proponent must assume a conservative stance in consultation with Isometric, depending on the nature of the data loss as detailed below:

• If the data loss pertains to the capture of biogenic CO₂, no carbon dioxide removal can be claimed due to the lack of data.
• If the data loss pertains to GHG emissions, for example, from the flue stack to the atmosphere, the Project Proponent must assume a maximum value for the release of GHG emissions identified from the 24 hours prior to, and the 24 hours following the data gap.
• If the data loss pertains to [math: F_{B}], the Project Proponent may justify the use of an averaged [math: F_{B}] based on comparable historic data for the feedstock type and time period. This justification will require evidence of low variability in [math: F_{B}] over comparable periods to the data gap, and must be a conservative estimation by subtracting the standard deviation of the averaged or historical data.

In addition, data gaps must account for less than 5% of the data used for both the calculation of removals and the calculation of emissions within a given Reporting Period, any data missing above this threshold will also be subject to the conservative rules outlined above.

Where calibrations are missed, one must be completed as soon as this becomes evident. For data collected between when the calibration was required and when it took place, a conservative estimate should be agreed between the VVB, Project Proponent and Isometric.

8.5.6 Emissions Accounting requirements

GHG emissions accounting must be undertaken in alignment with the GHG Accounting Module v1.1, which ensures a consistently rigorous standard in how GHG emissions are quantified and reported between different CDR Projects and approaches. This includes:

• Requirements for data quality, including a detailed data quality hierarchy for activity data and emission factors;
• Consideration of Materiality in emissions accounting;
• Emissions amortization requirements;
• By-product accounting relating to inputs to the process that are by-products; and
• Waste input accounting relating to inputs to the process that are wastes,

8.5.6.1 Co-Product Allocation

The Bio-CCS process may result in the production of co-products, such as electricity and heat. Projects must follow the co-product allocation procedures described in Section 6.1 of the GHG Accounting Module v1.1. This includes provisions for a narrow system boundary in instances where the facility is a retrofit and provisions for applying the substitution method.

Table 2. Additional eligibility criteria for dividing the process into sub-processes

8.5.6.1.1 Emissions Allocation for Mixed Biogenic and Fossil Feedstocks

Table 3. Eligibility criteria for mass balance emissions allocation

If eligible, Projects may allocate Project emissions to the biogenic fraction by multiplying relevant Project emissions by [math: F_B] in line with Equation 10. Relevant Project emissions are those where the same processes are shared between fossil and biogenic CO₂ capture and storage. [math: CO_{2}^{}e_{Leakage}] emissions must not be allocated.

[math: {CO}_{2}^{}e_{Emissions,\ RP}^{}\ = \ F_B\ *\ ({CO}_{2}^{}e_{Establishment,\ RP}^{}\ + \ {CO}_{2}^{}e_{Operations,\ RP}^{} + \ {CO}_{2}^{}e_{End-of-Life,\ RP}^{}) \ + \ {CO}_{2}^{}e_{Leakage,\ RP}^{}]

(Equation 10)

Where

• [math: CO_2e_{Emissions,\ RP}] = the total GHG emissions for a Reporting Period, [math: RP], in tonnes of CO₂e.
• [math: F_B] = is the biogenic fraction that is eligible for Crediting. If all captured CO₂ is biogenic, [math: F_B] = 1. See Section 8.3.1.
• [math: CO_2e_{Establishment,\ RP}] = the total GHG emissions associated with project establishment, for the Reporting Period, [math: RP], in tonnes of CO₂e, see Section 8.5.1.
• [math: CO_2e_{Operations,\ RP}] = the total GHG emissions associated with operational processes for the [math: RP], in tonnes of CO₂e, see Section 8.5.2.
• [math: CO_2e_{End-of-Life,\ RP}] = the total GHG emissions that occur after the [math: RP] and are allocated to the [math: RP], in tonnes of CO₂e, see Section 8.5.3.
• [math: CO_2e_{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 [math: RP], in tonnes of CO₂e, see Section 8.5.4.

8.5.6.2 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:

• Capture Process:
  • Electricity used in process operations, including renewable energy, such as:
    • Sorbent/solvent or other regeneration process (electrically heated, electrochemical, or other).
    • Electricity for pumps, motors, drives, etc.
    • Electricity for instrumentation and controls; and
    • Electricity for building operation and management for capture buildings and direct support buildings.
      • Research and development and administrative facilities are not included.
  • Fuel combustion for thermal energy generation (heat/steam) such as:
    • Sorbent/solvent or other regeneration process (thermal); and
    • Heat for capture process buildings and operations.
  • Heat utilization for thermal processes;¹⁴ and
  • Cryogenic processes for CO₂ purification or liquefaction.
• CO₂ Transportation:
  • Electricity or fuel used for operation of a pipeline or similar non-mobile CO₂ transportation process.
• CO₂ Storage:
  • Electricity used for operation of any CO₂ conversion processes, such as ex-situ carbonate production and handling;
  • Electricity used for injection operations, including any pumps, compressors (including for compression into supercritical CO₂), or related equipment inside the injection facility gate; and
  • Fuel used for heat generation or other purposes at the conversion or injection sites.

Energy Use Measurement

Electricity:

• Total electricity use for the CDR process. This may be measured at a single metering point that includes all electricity consumption within the CDR process, or at multiple sub-meters that, in total, account for all electricity use by the CDR process;
• Total electricity production for the bioenergy system (gross generation);
• Total electricity exported to the grid or customers.

When the electricity is provided to the CCS processes via the output of a Bio-CCS facility which produces electricity, the cradle-to-grave emissions factor for the bioenergy facility shall be used as the primary emissions factor for calculation of electricity related emissions for the CDR process.

Electricity metering and record keeping must be performed in accordance with the Energy Use Accounting Module v1.3.

Thermal Energy

Any thermal energy used by the CDR process must be monitored, including steam use, direct combustion of fuels within the CDR process to provide heat, and use of waste heat.

In the case of steam, waste heat, or other thermal inputs to the CDR Process, measurements must be made of the total thermal energy supplied to the CDR Process. Total thermal energy must be measured using the following methods:

• Mass flow meter (coriolis, multivariable vortex meter, or similar) calibrated for steam measurement with accuracy specification of +/- 2% of reading or better on supply or return;
• Volumetric flow meter (differential pressure, turbine, or other) in conjunction with temperature and pressure measurement using calibrated instrumentation, providing a combined accuracy of total steam flow of +/- 2% or better on supply or return;
• Temperature and pressure measurement on both supply and return;
• Specifications of gas or thermal fluid (i.e. heat transfer fluid), including density and specific heat.

Emissions associated with thermal energy and its production, and record keeping, must be performed in accordance with the Energy Use Accounting Module v1.3.

8.5.6.3 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.

The Project Proponent must identify all equipment and consumables used in the biomass conversion and storage process, identify appropriate cradle to grave emission factors, and allocate the emissions to removals appropriately.

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

• Equipment, including:
  • Equipment and infrastructure for processes relating to the wider facility, for example energy generation or product manufacturing.
  • CO₂ capture process:
    • Process equipment, including process units for capture and sorbent regeneration;
    • Sorbent, solvent, or other material handling systems, such as pumps, conveyors, augers, feed bins, and related equipment;
    • Heat transfer equipment;
    • CO₂ purification equipment;
    • CO₂ compression and storage equipment (on-site); and
    • Preparation or mixing equipment for sorbents, solvents, or other materials.
  • CO₂ transportation:
    • Equipment used for transportation of CO₂, including pipelines, and any pumps or compressors.
  • CO₂ storage:
    • Ex-situ CO₂ conversion or reaction equipment (i.e. for carbonate production), including all vessels, pumps, storage, and other process equipment;
    • Closed-system temporary holding of CO₂ at the injection site; and
    • CO₂ injection equipment, including compressors, pumps, and all wellbore equipment and materials.
  • Monitoring:
    • Monitoring wells and all associated materials (steel casing, concrete (A composite material composed of aggregate, cement, sand and water that cures to a solid over time.), etc.);
    • On-line analyzers, measurement equipment, or other such devices; and
    • Buildings and associated equipment utilized for monitoring purposes(e.g., on-site laboratories).
  • Universal equipment for all processes:
    • Pumps, piping, and related equipment;
    • Storage tanks;
    • All support structures, facilities, and infrastructure, including steel platforms, framing, supports, concrete footings, building structures, offshore rigs where applicable etc.; and
    • All instrumentation, controls, and other process management equipment.
• Consumables, including:
  • Consumables for processes relating to the wider facility, for example energy generation or product manufacturing.
  • Capture Process:
    • Sorbents or solvents, including emissions associated with:
      • Sorbent production including any CO₂ emissions released directly from sorbent production, such as emissions of CO₂ from calcination of limestone; and
      • Proper disposal of used sorbents
    • Heat transfer fluids such as thermal oils or refrigerants.
  • CO₂ storage:
    • Feedstocks or reactants used in the conversion of CO₂ to other products for storage; and
    • dilutants or additives used to support or improve injection of CO₂ or CO₂-containing product.
  • Monitoring:
    • Gases, reagents, or other materials used for operation of monitoring equipment, analytical testing, calibration of monitoring equipment and on-site analyzers; and
    • Consumable sampling equipment or supplies that are used in significant quantities.
  • Universal consumables for all processes:
    • Gases such as nitrogen used for process operations, instrumentation, purges, or other operations;
    • Water, including full cradle-to-grave emissions associated with:
      • Delivery of process water (including cooling water), including embodied emissions associated with water production equipment, such as new wellbores, pumps, and piping, and all energy usage for delivery.
      • Disposal or treatment of used or waste process water (including cooling water), including emissions associated with wastewater treatment.
    • Water treatment chemicals used in cooling or process water.

Section 4.1 of the GHG Accounting Module v1.1 sets out the calculation approach to be followed including allocation of embodied emissions, life cycle stages to be considered, data sources and emission factors.

8.5.6.4 Transport Emissions Accounting

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

Emissions associated with transportation should include transportation of products as part of a batch [math: n]’s process, including the following:

• Transport of biomass feedstock;
• Transport of compressed gaseous or liquid CO₂ or CO₂ containing fluid or carbonated minerals;
• Transport and shipping related to collection and analysis of samples for environmental monitoring or lab analysis.

Section 4.2 of the GHG Accounting Module v1.1 provides requirements on how transportation-related emissions must be calculated so that they can be subtracted in the net CO₂e removal calculation. It sets out the calculation scope, approach to be followed, and acceptable emissions factors.

8.5.7 Direct Emissions (Pre-Capture)

Bio-CCS processes can generate direct emissions of non-biogenic CO₂ and/or other GHGs due to:

• process leaks
• fugitive emissions
• releases
• GHG-containing tailgas from:
  • conversion processes
  • degradation of sorbents or solvents

Direct emissions reported under this section include non-biogenic CO₂ and other GHGs. Biogenic CO₂ released is reflected in reductions to the measured value of stored CO₂ ([math: CO_{2eStored,RP}]), which determines net CO₂e removal and creditingCrediting.

Additionally, Projects that comply with EC1 in the GHG Accounting Module v1.01, or EC1 in Table 2 may exclude direct emissions, provided these emissions were occuringoccurring and would continue to occur in the baseline scenario. This means direct emissions from additional feedstock sourced because of the CDR Project must be accounted for.

8.25.37.2.21 Calculation of CO₂eDirecteDirect Emissions

[math: CO_{2}e_{Direct\ Emissions,RP} = \sum_{n=1}^{nv} \sum_{i=1}^{N} V_{i} \cdot W_{n,i} \cdot GWP_{n} \cdot \Delta t_{i}]

8.25.37.2.3 Required Records and Documentation for Direct Emissions

The Project Proponent must maintain the following records as evidence supporting calculation of direct emissions:

• All raw data and data processing or calculation records for measurements and calculations of emissions;
• Results of any emissions tests used to determine emission rates of GHGs from process streams or flow measurements of gas flow from Bio-CCS or related processes, including signed report from accredited emissions testing entity;
• Flow rate data from flow meters (including pitot tubes) for each period of interest, including flow meter data recorded in data acquisition systems, manual operation logs, or other records indicating date, time, and flow rate, as well as meter identification number or ID;
• Documentation of any known evidence of releases, such as:
  • Pressure relief valve activation (open/close position, or safety valve failure and replacement record);
  • Observed change in weight of storage vessels, and
  • Visual observation of release records with followup measurements and documentation of release.

Records of all data and analyses must be maintained by the Project Proponent and provided for verification purposes for a periodminimum of five years after the end of the monitoring period.

8.25.7.3.2.4 Post-Capture Emissions

In order to conservatively determine the fossil CO₂ emitted due to the Project between capture and storage, the quantity of fossil CO₂ captured must be quantified and the quantity of fossil CO₂ proven to be durably stored by the Project must be deducted.

8.25.37.2.54 Method A: Calculate Using Measured CO₂e_Captured

[math: CO_{2}e{_{{Post-Capture\text{ }Emissions}}} = CO_{2}e{_{Captured}} \cdot (1-F_B) - \left(\sum CO_{2}e{_{Storage}} \cdot (1-F_B)\right)]

(Equation 6)

Where:

• [math: CO_{2}e{_{Post-Capture\text{ }Emissions}}] is the total GHG emissions between capture and storage for a Reporting Period, RP, in tonnes of CO₂e.
• [math: CO_{2}e_{{Captured}}] is the mass of CO₂ measured at the point of capture, according to Section 8.25.37.2.65.
• [math: F_{B}] is the biogenic fraction that is eligible for Crediting. If all captured [math: CO_{2}] is biogenic, [math: F_{B} = 1]. See Section 8.2.13.1.

8.25.37.2.65 Calculation of CO₂eCaptured

[math: CO_2e_{Captured,\ RP} = \sum_{t=1}^{T}  C_{mean,cap,t} \cdot m_{cap,t}]

[math: m_{cap,t} = V_{cap,t} \cdot \rho_{cap,t} ]

8.2.3.25.7.6 Measurement of Concentration in CO₂ Streams

The concentration of CO₂ in the captured fluid stream must be:

• Measured after the capture process and before the fluid leaves the capture facility or is mixed with other CO₂ streams. and
• Measured using a continuous inline analyzer for CO₂ concentration, such as NDIR, TDL, or similar, which satisfies the below requirements:
  • Must have an accuracy of 2% of full scale or better;
  • Recorded at a frequency of 1-minute intervals at minimum;
  • Must be calibrated in accordance with and at a frequency which meets or exceeds manufacturer calibration requirements, but which in any case must be no less than annual;
  • Calibration gasses must be traceable to national standards and a certificate of analysis indicating so; and
  • Raw data must be made available upon request.

8.25.37.2.87 Measurement of Mass of CO₂ Captured

The mass of captured fluid ([math: m_{cap}]) is measured via use of a calibrated mass flow meter or volumetric flow meter and density measurements over a defined time interval (Δt). Preference is for high-accuracy flow meters such as coriolis or thermal mass flow meters, although other metering solutions are allowable. Flow metering must meet the following requirements:

• Provided with a factory calibration for the specific gas composition range expected;
• Meter accuracy specification of 2% full scale;
• Must be calibrated in accordance with and at a frequency which meets or exceeds manufacturer calibration requirements, but which in any case must be no less than annual;
• Calibration traceable to national standards;
• Meters are selected and installed for the expected and observed operating range of the captured fluid;
• Meters are installed in accordance with manufacture installation guidelines, including, for example, minimum distances up or downstream of piping disturbances required to ensure accurate flow measurement; and
• Raw data must be made available upon request

Alternative methods of measuring the mass of CO₂ captured on a batch basis may be accepted on a case-by-case basis in agreement with Isometric.

8.25.37.2.98 Method B: Calculate by Mass of Fossil Fuel Feedstocks

[math: CO_{2}e_{{Post-Capture\text{ }Emissions}} = \sum_{i}^{N_{FF}}(m_{FF} \cdot C_{FF}) - \left(\sum_{j}^{N} CO_{2}e_{{Storage,j}} \cdot (1-F_B)\right)]

(Equation 9)

Where:

• [math: CO_{2}e{_{{Post-Capture\text{ }Emissions}}}] is the total GHG emissions between capture and storage for a Reporting Period, RP, in tonnes of CO₂e.
• [math: m_{FF,i}] is the measured mass of fossil fuel, i, used by the Project within a Reporting Period.
• [math: C_{FF,i}] is the CO₂e of fossil fuel, i.
• [math: N_{FF}] is the total number of fossil fuel feedstocks used in a Reporting Period.
• [math: F_{B}] is the biogenic fraction that is eligible for Crediting. If all captured [math: CO_{2}] is biogenic, [math: F_{B} = 1]. Otherwise, see Section 8.2.13.1.
• [math: CO_{2}e_{Storage,j}] is the total amount of [math: CO_{2}] sequestered in a durable storage reservoir, j, following an applicable storage Module, over the Reporting Period, RP, in tonnes [math: CO_{2}e]. This term must be measured following the requirements in the respective storage Module.
• [math: N] is the total number of durable storage reservoirs used for storage of captured [math: CO_{2}].

8.2.3.3 Calculation of CO2eEnd-of-Life

[math: CO_2e_{End-of-Life,\ RP}] includes all emissions associated with activities that are anticipated to occur after the Reporting Period, but are directly or indirectly related to the Reporting Period. For example, this could include ongoing sampling activities for MRV for the specific deployment (directly related), or end-of-life emissions for the Project facility (indirectly related to all deployments).

GHG emissions associated with [math: CO_2e_{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 quantified as part of that Reporting Period. GHG emissions associated with activities that are indirectly related to all deployments may be allocated in the same ways as set out in [math: CO_2e_{Establishment,\ RP}].

Given the uncertain nature of [math: CO_2e_{End-of-Life,\ RP}] emissions, assumptions must be revisited at each Crediting Period and any necessary adjustments made. Furthermore, if there are unexpected [math: CO_2e_{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.

8.2.3.4 Calculation of CO2eLeakage

[math: CO_2e_{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.

[math: CO_2e_{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.

8.2.3.5 Procedure for Handling Missing Data

The Project Proponent must identify, highlight and justify any data gaps and missing calibration data should they occur. Isometric and the VVB must be notified of data gaps and missing calibration data as soon as they become evident. Documentation that explains the approach taken and details the missing data must be provided to Isometric and the VVB and included in the GHG Statement.

For parameters that require sub-hourly measurements (such as direct GHG emission concentrations and flow rates), the Project Proponent must adhere to the following procedure for handling missing data events.

Where data gaps in measurements are 30 minutes or less in duration, the Project Proponent must use an average measurement utilising measurements taken 30 minutes prior to and following the data gap.

Where data gaps in measurements are longer than 30 minutes in duration, the Project Proponent must apply the above approach for up to a 30 minute period within the duration of the data gap only. For the remaining duration of the data gap the Project Proponent must assume a conservative stance in consultation with Isometric, depending on the nature of the data loss as detailed below:

• If the data loss pertains to the capture of biogenic CO2, no carbon dioxide removal can be claimed due to the lack of data.
• If the data loss pertains to GHG emissions, for example, from the flue stack to the atmosphere, the Project Proponent must assume a maximum value for the release of GHG emissions identified from the 24 hours prior to, and the 24 hours following the data gap.
• If the data loss pertains to [math: F_{B}], the Project Proponent may justify the use of an averaged [math: F_{B}] based on comparable historic data for the feedstock type and time period. This justification will require evidence of low variability in [math: F_{B}] over comparable periods to the data gap, and must be a conservative estimation by subtracting the standard deviation of the averaged or historical data.

In addition, data gaps must account for less than 5% of the data used for both the calculation of removals and the calculation of emissions within a given Reporting Period, any data missing above this threshold will also be subject to the conservative rules outlined above.

Where calibrations are missed, one must be completed as soon as this becomes evident. For data collected between when the calibration was required and when it took place, a conservative estimate should be agreed between the VVB, Project Proponent and Isometric.

8.2.4 Emissions Accounting

8.2.4.1 General

GHG emissions accounting must be undertaken in alignment with the GHG Accounting Module v1.0, which ensures a consistently rigorous standard in how GHG emissions are quantified and reported between different CDR Projects and approaches. This includes:

• Requirements for data quality, including a detailed data quality hierarchy for activity data and emission factors;
• Consideration of Materiality in emissions accounting;
• Emissions amortization requirements; and
• By-product accounting relating to inputs to the process that are by-products.

8.2.4.2 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 v1.3.

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 the GHG Accounting Module v1.0.

8.2.4.3 Co-Product Allocation

The Bio-CCS process may result in the production of co-products, such as electricity and heat. Projects must follow the co-product allocation procedures described in Section 6.1 of the GHG Accounting Module v1.0. This includes provisions for a narrow system boundary in instances where the facility is a retrofit and provisions for applying the substitution method.

Table 2. Additional eligibility criteria for dividing the process into sub-processes

8.2.4.4 Emissions Allocation for Mixed Biogenic and Fossil Feedstocks

Table 3. Eligibility criteria for mass balance emissions allocation

If eligible, Projects may allocate Project emissions to the biogenic fraction by multiplying relevant Project emissions by [math: F_B] in line with Equation 10. Relevant Project emissions are those where the same processes are shared between fossil and biogenic CO2 capture and storage. [math: CO_{2}^{}e_{Leakage}] emissions must not be allocated.

[math: {CO}_{2}^{}e_{Emissions,\ RP}^{}\ = \ F_B\ *\ ({CO}_{2}^{}e_{Establishment,\ RP}^{}\ + \ {CO}_{2}^{}e_{Operations,\ RP}^{} + \ {CO}_{2}^{}e_{End-of-Life,\ RP}^{}) \ + \ {CO}_{2}^{}e_{Leakage,\ RP}^{}]

(Equation 10)

Where

• [math: CO_2e_{Emissions,\ RP}] = the total GHG emissions for a Reporting Period, [math: RP], in tonnes of CO2e.
• [math: F_B] = is the biogenic fraction that is eligible for Crediting. If all captured CO2 is biogenic, [math: F_B] = 1. See Section 8.2.1.1.
• [math: CO_2e_{Establishment,\ RP}] = the total GHG emissions associated with project establishment, for the Reporting Period, [math: RP], in tonnes of CO2e, see Section 8.2.3.1.
• [math: CO_2e_{Operations,\ RP}] = the total GHG emissions associated with operational processes for the [math: RP], in tonnes of CO2e, see Section 8.2.3.2.
• [math: CO_2e_{End-of-Life,\ RP}] = the total GHG emissions that occur after the [math: RP] and are allocated to the [math: RP], in tonnes of CO2e, see Section 8.2.3.3.
• [math: CO_2e_{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 [math: RP], in tonnes of CO2e, see Section 8.2.3.4.

8.2.4.5 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:

• Capture Process:
  • Electricity used in process operations, including renewable energy, such as:
    • Sorbent/solvent or other regeneration process (electrically heated, electrochemical, or other).
    • Electricity for pumps, motors, drives, etc.
    • Electricity for instrumentation and controls; and
    • Electricity for building operation and management for capture buildings and direct support buildings.
      • Research and development and administrative facilities are not included.
  • Fuel combustion for thermal energy generation (heat/steam) such as:
    • Sorbent/solvent or other regeneration process (thermal); and
    • Heat for capture process buildings and operations.
  • Heat utilization for thermal processes;17 and
  • Cryogenic processes for CO2 purification or liquefaction.
• CO2 Transportation:
  • Electricity or fuel used for operation of a pipeline or similar non-mobile CO2 transportation process.
• CO2 Storage:
  • Electricity used for operation of any CO2 conversion processes, such as ex-situ carbonate production and handling;
  • Electricity used for injection operations, including any pumps, compressors (including for compression into supercritical CO2), or related equipment inside the injection facility gate; and
  • Fuel used for heat generation or other purposes at the conversion or injection sites.

8.2.4.5.1 Energy Use Measurement

Electricity:

• Total electricity use for the CDR process. This may be measured at a single metering point that includes all electricity consumption within the CDR process, or at multiple sub-meters that, in total, account for all electricity use by the CDR process;
• Total electricity production for the bioenergy system (gross generation);
• Total electricity exported to the grid or customers.

When the electricity is provided to the CCS processes via the output of a Bio-CCS facility which produces electricity, the cradle-to-grave emissions factor for the bioenergy facility shall be used as the primary emissions factor for calculation of electricity related emissions for the CDR process.

Electricity metering and record keeping must be performed in accordance with the Energy Use Accounting Module v1.3.

Thermal Energy

Any thermal energy used by the CDR process must be monitored, including steam use, direct combustion of fuels within the CDR process to provide heat, and use of waste heat.

In the case of steam, waste heat, or other thermal inputs to the CDR Process, measurements must be made of the total thermal energy supplied to the CDR Process. Total thermal energy must be measured using the following methods:

• Mass flow meter (coriolis, multivariable vortex meter, or similar) calibrated for steam measurement with accuracy specification of +/- 2% of reading or better on supply or return;
• Volumetric flow meter (differential pressure, turbine, or other) in conjunction with temperature and pressure measurement using calibrated instrumentation, providing a combined accuracy of total steam flow of +/- 2% or better on supply or return;
• Temperature and pressure measurement on both supply and return;
• Specifications of gas or thermal fluid (i.e. heat transfer fluid), including density and specific heat.

Emissions associated with thermal energy and its production, and record keeping, must be performed in accordance with the Energy Use Accounting Module v1.3.

The Energy Use Accounting Module v1.3 provides requirements on how energy-related emissions must be calculated 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 emissions factors.

8.2.4.6 Transport Emissions Accounting

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

Emissions associated with transportation should include transportation of products as part of a batch [math: n]’s process, including the following:

• Transport of biomass feedstock;
• Transport of compressed gaseous or liquid CO2 or CO2 containing fluid or carbonated minerals;
• Transport and shipping related to collection and analysis of samples for environmental monitoring or lab analysis.

Section 4.2 of the GHG Accounting Module v1.0 provides requirements on how transportation-related emissions must be calculated so that they can be subtracted in the net CO2e removal calculation. It sets out the calculation scope, approach to be followed, and acceptable emissions factors.

8.2.4.7 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.

The Project Proponent must identify all equipment and consumables used in the biomass conversion and storage process, identify appropriate cradle to grave emission factors, and allocate the emissions to removals appropriately.

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

• Equipment, including:

  • Equipment and infrastructure for processes relating to the wider facility, for example energy generation or product manufacturing.

  • CO2 capture process:

    • Process equipment, including process units for capture and sorbent regeneration;
    • Sorbent, solvent, or other material handling systems, such as pumps, conveyors, augers, feed bins, and related equipment;
    • Heat transfer equipment;
    • CO2 purification equipment;
    • CO2 compression and storage equipment (on-site); and
    • Preparation or mixing equipment for sorbents, solvents, or other materials.

  • CO2 transportation:

    • Equipment used for transportation of CO2, including pipelines, and any pumps or compressors.

  • CO2 storage:

    • Ex-situ CO2 conversion or reaction equipment (i.e. for carbonate production), including all vessels, pumps, storage, and other process equipment;
    • Closed-system temporary holding of CO2 at the injection site; and
    • CO2 injection equipment, including compressors, pumps, and all wellbore equipment and materials.

  • Monitoring:

    • Monitoring wells and all associated materials (steel casing, concrete (A composite material composed of aggregate, cement, sand and water that cures to a solid over time.), etc.);
    • On-line analyzers, measurement equipment, or other such devices; and
    • Buildings and associated equipment utilized for monitoring purposes(e.g., on-site laboratories).

  • Universal equipment for all processes:

    • Pumps, piping, and related equipment;
    • Storage tanks;
    • All support structures, facilities, and infrastructure, including steel platforms, framing, supports, concrete footings, building structures, offshore rigs where applicable etc.; and
    • All instrumentation, controls, and other process management equipment.

• Consumables, including:

  • Consumables for processes relating to the wider facility, for example energy generation or product manufacturing.

  • Capture Process:

    • Sorbents or solvents, including emissions associated with:
      • Sorbent production including any CO2 emissions released directly from sorbent production, such as emissions of CO2 from calcination of limestone; and
      • Proper disposal of used sorbents
    • Heat transfer fluids such as thermal oils or refrigerants.

  • CO2 storage:

    • Feedstocks or reactants used in the conversion of CO2 to other products for storage; and
    • dilutants or additives used to support or improve injection of CO2 or CO2-containing product.

  • Monitoring:

    • Gases, reagents, or other materials used for operation of monitoring equipment, analytical testing, calibration of monitoring equipment and on-site analyzers; and
    • Consumable sampling equipment or supplies that are used in significant quantities.

  • Universal consumables for all processes:

    • Gases such as nitrogen used for process operations, instrumentation, purges, or other operations;
    • Water, including full cradle-to-grave emissions associated with:
      • Delivery of process water (including cooling water), including embodied emissions associated with water production equipment, such as new wellbores, pumps, and piping, and all energy usage for delivery.
      • Disposal or treatment of used or waste process water (including cooling water), including emissions associated with wastewater treatment.
    • Water treatment chemicals used in cooling or process water.

Section 4.1 of the GHG Accounting Module v1.0 sets out the calculation approach to be followed including allocation of embodied emissions, life cycle stages to be considered, data sources and emission factors.

9.0 Storage

This Protocol provides multiple options for conversion and durable storage of CO₂. The Project Proponent can choose from available options when submitting their Project for verification:

10.0 Acknowledgements

Isometric would like to thank following contributors to previous versions this Protocol and relevant Modules:

• Tim Hansen (350 Solutions); Biogenic Carbon Capture and Storage Protocol and Energy Use Accounting Modules.
• Danny Cullenward (University of Pennsylvania); Biogenic Carbon Capture and Storage Protocol and Biomass Feedstock Accounting Module.
• Kevin Fingerman (California State Polytechnic University-- Humboldt); Biogenic Carbon Capture and Storage Protocol and Biomass Feedstock Accounting Module.
• Chris Holdsworth (University of Edinburgh); CO₂ Storage in Saline Aquifers and CO₂ Storage via In-Situ Mineralization in Mafic and Ultramafic Formations Modules.
• Wilson Ricks (Princeton University); Energy Use Accounting Module.

11.0 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”.

​​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.

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.

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

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.

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).

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.

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.

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

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

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

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

A location where carbon is stored. This can be via physical barriers (such as geological formations) or through partitioning based on chemical or biological processes (such as mineralization or photosynthesis).

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

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.

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.

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

The area surrounding an injection well described according to the criteria set forth in the U.S. Code of Federal Regulations § 40 CFR.146.06, which, in some cases, such as Class II wells, the project area plus a circumscribing area the width of which is either 1⁄4 of a mile or a number calculated according to the criteria set forth in § 146.06.

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

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

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

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.

Materials of value that are produced incidentally or as a residual of the production process.

The document that clearly outlines how a Project will generate rigorously quantifiable Additional high-quality Removals or Reductions.

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.

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

The defined temporal and geographical boundary of a Project.

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).

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 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.

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.

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

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.

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.

The Controlled, Related and Affected GHG Sources, Sinks and Reservoirs to be considered in the GHG Statement.

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.

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.

The introduction of new materials, products or technologies to an existing process or facility.

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.

Reporting Period

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.

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

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.

12.0 Appendix A1: Guidance for Handling Fossil CO₂

This section provides guidance for Projects which capture fossil CO₂, whether through mixed feedstocks or co-firing with fossil fuels.

Note that for the purposes of this Protocol, geologic CO₂ liberated from minerals is considered fossil CO₂ unless it can be demonstrated that the CO₂ is of biogenic origin and mineralized by the Project (for example, as a sorbent).

12.1 Direct Emissions and Leaks

For CO₂ leaks prior to the point of quantification of [math: CO_{2}e_{Storage}] (according to the storage Module), for eligible biogenic CO₂ there is no penalty for emitting CO₂, as in the counterfactual scenario this CO₂ would have entered the atmosphere.

However, whether emitted fossil CO₂ is considered within the system boundary is dependent on The Project type:

• For retrofit projects where the fossil emissions are present in the baseline scenario, these emissions are not considered an emissions source.
• For retrofit projects where the use of fossil fuels (or waste feedstocks where biogenic and fossil carbon is inseparable) is above the baseline usage rate (see Appendix B2: Baselines, these emissions must be accounted for according to Section 8.2.35.2, as these emissions of fossil CO₂ to the atmosphere would not have occurred in the absence of the Project.
• For all other Projects, fossil direct emissions and leaks must be accounted for according to Section 8.2.35.

12.2 Reversals

Once fossil CO₂ is durably stored by the Project, any emission of CO₂ from the storage reservoir attributable to the Project is considered a reversal, regardless of [math: F_{B}], excluding fossil CO₂ that can be robustly demonstrated to be part of the baseline scenario (see Appendix B2: Baselines), in agreement with Isometric and the VVB.

12.3 Quantification of Miscellaneous Fossil CO₂ Emissions

For quantification of the fossil component of any mixed CO₂ emission from the Project, use Equation A1.

[math: CO_{2}e_{{Misc, Fossil}} = (1-F_B) \cdot CO_{2}e_{Misc}]

(Equation A1)

Where

• [math: CO_{2}e] is the total amount of CO₂e, in tonnes.

13.0 Appendix B2: Baselines

For guidance on the construction of a baseline for a Project that is drawing a narrow system boundary, see Appendix D4 of the Biomass Feedstock Accounting Module v1.3. The concept of Baseline Feedstock Consumption rate can be applied to drawing a baseline fossil fuel usage. Usage of fossil fuels above this rate must be within the system boundary.

14.0 Appendix C3: Guidance on Cap-and-Trade Schemes

Factors that characterize a robust cap-and-trade policy include:

• emission limits that are stringent in relation to emissions, inclusive of any banked compliance instruments,
• effective border adjustment policies that minimize carbon leakage, especially in the electricity sector,
• the legal authority and apparent political commitment to operate the market over long time horizons, and
• any other major factors that illustrate a high likelihood of credible, binding emission limits for covered facilities.

Currently the EU Emissions Trading Scheme, which covers the 27 EU member nations as well as Iceland, Norway, and Liechtenstein; and the UK Emissions Trading Scheme are the only cap-and-trade jurisdiction approved as sufficiently rigorous under this Protocol.

15.0 Appendix D4: Risk of Reversal Questionnaire

This risk assessment identifies the pathway (A collection of Removal or Reduction processes that have mechanisms in common.) 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 the Projectproject, with details included in the Project 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.

Projects using this Protocol have the option of a number of storage modules. The typical buffer pool contributions and the rationale are indicated in the relevant storage module: typically, geologic storage is considered Very Low Risk Level (leading to a 1% buffer pool).

If Reversals are not directly observable (i.e., all storage is as carbonated materials in the built environment and/or DIC in an open system), the Project's Risk of Reversal is automatically "No observable risk." Such Projects do not need to complete this questionnaire, but must still maintain a monitoring plan in accordance with the requirements of the relevant Protocol. Please note storage as carbonated materials in the built environment also requires a Project-specific calculation of reversal risk and uncertainty discount.

The risk score, as determined by the Risk of Reversal Questionnaire, will determine a project’s 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.) 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. In any event, projects should reassess their reversal risk at a minimum every 5 years.

The Risk of Reversal Questionnaire questions that pertain to this Protocolprotocol, 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 inorganic carbon, the presence the following risk factors must be reflected in the risk score corresponding to question 10:

• Acidic fluid
• Alkaline fluid (if stored as dissolved inorganic carbon)
• Temperatures in excess of 800 degrees celsius

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

California Air Resources Board. (2022). Carbon Sequestration: Carbon Capture, Removal, Utilization, and Storage. https://ww2.arb.ca.gov/our-work/programs/carbon-sequestration-carbon-capture-removal-utilization-and-storage

Environment and Climate Change Canada. Clean Fuel Regulations: Quantification Method for CO₂ Capture and Permanent Storage Version 1.0. (2022) https://publications.gc.ca/collections/collection_2022/eccc/En4-474-2022-eng.pdf

Intergovernmental Panel on Climate Change. (2005). IPCC Special Report on CO₂ Capture and Storagehttps://www.ipcc.ch/site/assets/uploads/2018/03/srccs_wholereport-1.pdf

International Organization for Standardization. (2008). Evaluation of measurement data — Guide to the expression of uncertainty in measurement (ISO JGCM GUM). https://www.iso.org/sites/JCGM/GUM/JCGM100/C045315e-html/C045315e.html?csnumber=50461

International Organization for Standardization. (2006). ISO 14040:2006 Environmental management — Life cycle assessment — Principles and framework. https://www.iso.org/standard/37456.html

International Organization for Standardization. (2006). ISO 14044:2006 Environmental management — Life cycle assessment — Requirements and guidelines. https://www.iso.org/standard/38498.html

International Organization for Standardization. (2011). ISO 14066:2011 Greenhouse gases — Competence requirements for greenhouse gas validation teams and verification teams. https://www.iso.org/standard/43277.html

International Organization for Standardization. (2017). ISO/IEC 17025:2017 General requirements for the competence of testing and calibration laboratories. https://www.iso.org/standard/66912.html

International Organization for Standardization. (2019). ISO 14064-2:2019. Greenhouse Gases - Part 2: Specification With Guidance At the Project Level For Quantification, Monitoring And Reporting Of Greenhouse Gas Emission s Or Removal Enhancements. ISO. https://www.iso.org/standard/66454.html

International Organization for Standardization. (2019). ISO 14064-3:2019. Greenhouse gases — Part 3: Specification with guidance for the verification and validation of greenhouse gas statements. ISO. https://www.iso.org/standard/66455.html

International Organization for Standardization. (2022). ISO 9300:2022 Measurement of gas flow by means of critical flow nozzles. https://www.iso.org/standard/77401.html

Matthews, J.B.R. (Ed.). (2018). IPCC, 2018: Annex I: Glossary [Matthews, J.B.R. (ed.)]. In: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of... Cambridge University Press. https://doi.org/10.1017/9781009157940.008

Methodology for assessing the quality of carbon Credits, Version 3.0. (2022, May). https://carbonCreditquality.org/methodology.html

NIST (2015, April 20). Overview of ASTM D7036: A Quality Management Standard for Emission Testing. https://www.nist.gov/system/files/documents/2017/10/31/overview-astm-d7036.pdf

NIST. (2023). Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices - 2023 Edition. NIST. https://www.nist.gov/pml/owm/publications/nist-handbooks/handbook-44-current-edition

US Department of Energy. (2022) Best Practices for Life Cycle Assessment (LCA) of Direct Air Capture with Storage (DACS). https://www.energy.gov/sites/default/files/2022-06/FECM%20DACS%20LCA%20Best%20Practices.pdf

U.S. Environmental Protection Agency. (2023, April 18). Understanding Global Warming Potentials | US EPA. Environmental Protection Agency. Retrieved June 14, 2023, from https://www.epa.gov/ghgemissions/understanding-global-warming-potentials

California Air Resources Board (2018). CCS Protocol under the Low Carbon Fuel Standard (LCFS). https://ww2.arb.ca.gov/sites/default/files/2020-03/CCS_Protocol_Under_LCFS_8-13-18_ada.pdf

Terlouw, T., Bauer, C., Rosa, L., Mazzotti, M. (2021). Life cycle assessment of CO₂ removal technologies: a critical review. Energy & Environmental Science. https://doi.org/10.1039/D0EE03757E