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Direct Air Capture
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This protocolProtocol (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 carbon dioxide 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 removals(The term used to represent the CO₂ taken out of the atmosphere as a result of a CDR process.) from the atmosphere via Direct Air Capture (DAC). This protocolProtocol is developed for application to DAC processes or combinations of processes (e.g., solid-sorbent sorptionprocesses,1, liquid-solvent solventprocesses,2, membrane processes,3 electro-chemical processes, electrochemistry4, etc.), or combinations of processes, 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.)greenhouse gas (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 protocolProtocol was developed in line with latest scientific understanding7,8,9 and industry best-practices10,11 which inform the quantification of gross CO2 durably captured and stored via DAC, as well as the accounting of GHG (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).) emissions associated with DAC processes. Additionally, the protocolProtocol ensures:
Specific standards (Standard physical constants as well as standard values set forth by bodies such as the National Institute of Standards and Technology (NIST) or others.) and protocols which are utilized as the foundation of this protocolProtocol (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 forcomprised 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.), and which this protocolProtocol is intended to be fully compliant with, are as follows:
Additional reference standards that inform the requirements and overall practices incorporated in this protocolProtocol include:
This protocolProtocol (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.) was developed based on the current state of the art and publicly available science regarding DAC and CO2storage (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”.). Because DAC 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.) (CDR), with ever-expanding published literature, the protocolProtocol incorporates requirements that may be more stringent than some current regulations or other protocols related to DAC and CO2 storage. The approach taken here may be altered in future versions of the protocolProtocol as DAC and CO2 storage technology and research advance.
This protocolProtocol (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.) applies to projects anywhere that capture CO2 from ambient air and store capturedit CO2durably foraccording >1000to yearsthe viarequirements physical or chemical trapping mechanisms laid outestablished in the relevantstorage Modules (Independent components of Isometric Certified Protocols which are transferable between and applicable to different Protocols.) associated with this Protocol (see CO2Section Storage Module8). 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.) must also be able to be accurately applied to all processes within the scope of the project.
ToProject ensure(An long-termactivity durability,or CO2process characteristicsor group of activities or processes that alter the condition of a Baseline and theleads conditionsto within the storage reservoir must be well defined, modeled (A calculation, series of calculationsRemovals or simulations that use input variables in order to generate values for variables of interest that are not directly measuredReductions.) and planned to be monitored in line with jurisdictional post-closure requirements. Evidence that CO2 will be trapped via the intended method and within the intended reservoir with no free phase migration after closure (as per regulating permitting requirements) is needed to support that carbon dioxide can be durably stored.
Projects that co-capture CO2 from on-site point sources maydo not be accountedqualify for the generation of 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.) under this Protocol, as this constitutes avoided emissions - not emissions removal (The term used to represent the CO₂ taken out of the atmosphere as a result of a CDR process.). DAC projects that are co-located with industrial point sources of CO2, defined here as being within 1km distance, are only eligible if the Project appropriately discounts measured gross CO2 removals in an amount corresponding to the relative difference between local atmospheric CO2 concentrations, and background atmospheric CO2 concentrations - to ensure that only the captured fraction corresponding to non-fossil emissions is included in claimed removals (A Removal which has been submitted by a Project Proponent, but which has not yet been Verified.). In practice, as this constitutesshould anbe avoidedachieved emissionsby project, not a removal. DAC projects that are co-located, defined here as being within 1km distance, with major emissions sources originating frommeasuring the development or combustionconcentration of fossil fuels or petrochemicals, are only eligible if the project proponent uses isotope tracing of the captured CO2 to enable accounting of only non-fossil CO2 in such locations. Atmospheric dispersion modeling12 and biogenic carbon monitoring of the captured CO2 mayin providethe supportambient forair at the inlet to the DAC process, and discounting gross removals by an amount corresponding to the relative excess of this evaluationmeasurement compared to a background reading at a distance greater than 1km from the co-located industrial point source.
Only DAC projects which meet a zero emissions baseline (A set of data describing pre-intervention or control conditions to be used as a reference scenario for comparison.) scenario (see Section 7.2) are eligible under this protocolProtocol. A projectProject may qualify for this distinction by meeting one of the following conditions13:
The projectProject (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.) must consider environmental and social impacts, and the projectProject proponentProponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) must provide evidence that theThe projectProject will do no net environmental or social harm by complying with Section 3.7 of the Isometric Standard as well as the following requirements:
The following topics are covered briefly in this protocolProtocol (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.) due to their inclusion in the Isometric Standard, which governs all Isometric protocolsProtocols. See in-text references to the Isometric Standard for further guidance.
For each specific projectProject (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.) to be evaluated under this protocolProtocol (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 projectProject proponentProponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) must document project characteristics in a Project Design Document (PDD) (The document, written by a Project Proponent, which records key characteristics of a Project and which forms the basis for Project Validation and evaluation in accordance with the relevant Certified Protocol. (Also known as “PDD”).), as outlined in Section 3.2 of the Isometric Standard. The PDD will form the basis for projectProject verificationVerification (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 evaluation in accordance with this protocolProtocol, and must include consideration of processes unique to DAC, for example:
Projects (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.) must be validated (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).) and projectProject net CO2e removals verified (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).) by an independent third party, consistent with the requirements described in 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.), as well as in Section 4 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:
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%, in accordance with Section 4.3 of the Isometric Standard.
Verifiers (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.) 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 (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.), as required by Section 2.5.7 of the Isometric Standard. Qualitative materialityMateriality (An acceptable difference between reported Removals/emissions or Reductions/emissions and what an auditor determines is the actual Removal/emissions or Reduction/emissions.) issues may also be identified and documented, such as:1314:
Project 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).) and 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).) 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 validation and initial verification to the DAC projectProject and storage site. ValidatorsVerifiers (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.) 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 thereafter occur at least once every 2 years at each location.
VerifiersVVBs (Third-party auditing organizations that are experts in their sector and validatorsused 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 comply with the requirements defined in Section 4 of the Isometric Standard. In addition, teams should maintain and demonstrate expertise associated with the specific technologies of interest, including solvent/sorbent chemistry, geological storage of CO2, electricity procurement and, heat/power generation and the relevant CO2 storage technology.
Competency must be demonstrated through the relevant sectoral scope accreditations listed below, based on IAF MD 14 and in accordance with Isometric's VVB policy:
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.) via DAC and subsequent 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”.) is often a result of a multi-step process (such as capture, desorption, CO2 transport, CO2 temporary holding, the CO2 injection processor reaction, etc.), with activities in each step sometimes managed and operated by different operators, companies, or owners. When there are multiple parties involved in the process (e.g., injectionif sitecapture operatorsand storage are undertaken by different entities), and to avoid double counting (Improperly allocating the same Removal or Reduction from a Project Proponent more than once to multiple Buyers.) of net CO2e removals, a single Project Proponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) must be specified contractually as the sole owner of the 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.). Contracts must comply with all requirements defined in Section 3.1 of the Isometric Standard.
The Project Proponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) must be able to demonstrate additionality (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.) through compliance with Section 2.5.3 of the Isometric Standard. The baseline (A set of data describing pre-intervention or control conditions to be used as a reference scenario for comparison.) 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 (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.).
Additionality determinations should be reviewed and completed every five years (aligned with the creditingCrediting Period (The period of time over which a Project Design Document is valid, and over which Removals or Reductions may be Verified, resulting in Issued Credits.)), at a minimum, or whenever project operating conditions change significantly, such as the following:
Any review and change in the determination of additionality (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.) should not affect the availability of carbonCarbon financeFinance and Verified 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.) for the current or past creditingCrediting periodsPeriods (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.), but if the review indicates The Project (An activity or process or group of activities or processes that alter the projectcondition of a Baseline and leads to Removals or Reductions.) has become non-additional, this should make theThe projectProject ineligible for future creditsCredits.1615.
The 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.) in the overall estimate of the net CO2e removal as a result of the projectProject (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.) must be calculated and transparently presented. The total net CO2e removed over a reportingReporting periodPeriod ([math: RP]; see Section 7.3.1) for a projectProject, [math: CO_2e_{Removal,\ RP}], must be conservatively (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.) determined, based on the requirements outlined in Section 2.5.7 of the Isometric Standard.
Projects (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.) must report a list of all input variables used in the net CO2e removal calculation and their uncertainties, including:
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 Section 2.5.7 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 Sensitivitysensitivity Analysisanalysis can demonstrate that the parameter contributes to <1% change in Removalremoval (The term used to represent the CO₂ taken out of the atmosphere as a result of a CDR process.). For all other parameters, information about Uncertainty must be specified.
In accordance with Section 3.8 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 (A community resource where Project Proponents publish and visualize their early processes, Removal and Reduction data and Protocols – enabling the scientific community to share feedback and advice.). ThatThis includes:
The projectProject proponentProponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) can request certain information to be restricted (only available to authorized buyersBuyers (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 (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.)) where it is subject to confidentiality. This includes emissionsemission 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..
The scope of this protocolProtocol (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.) includes the GHG (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).)sources (Any process or activity that releases a greenhouse gas, an aerosol, or a precursor of a greenhouse gas into the atmosphere.), 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 (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).) (SSRs) associated with a DAC projectProject.
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.) must be prepared encompassing the GHG (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).) emissions relating to the activities associated with a DAC and storage project(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”.) Project for net CO2e removal, as summarized in Figure 1 and described below:
Emissions for processes within the system boundary (GHG sources, sinks and reservoirs (SSRs) associated with the project boundary and included in the GHG Statement.) should include all GHG (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).) SSRs from the construction or manufacturing of each projectProject (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.) and associated equipment, closure of each projectProject and disposal of associated equipment, and operation of each process (DAC process, CO2 transportation, CO2 storage, and CO2 monitoring).
Ancillary activities (such as supplementary research and development activities and corporate administrative activities) that are associated with a projectProject but are not directly or indirectly related 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 (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.) can be excluded from the system boundary (GHG sources, sinks and reservoirs (SSRs) associated with the project boundary and included in the GHG Statement.).
GHG (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).) emissions and removals associated with the projectProject may be as direct emissions from a process or storage system, or as indirect emissions from combustion of fuels, electricity generation, or other sources. The Project Proponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) must consider all GHGs associated with the relevant SSRs, in alignment with the United States Environmental Protection AgencyEPA’s (A United States Government agency that protects human health and the environment.) 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).
All GHGs (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).) must be quantified and converted to CO2e in the 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.) using the 100-yr Global Warming Potential (GWP) (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.) for the GHG of interest, based on the most recent volume of the IPCC Assessment Report (currently the Sixth Assessment Report).
[Image: figure1]
Figure 1
The above greenhouse gases must be included in emission calculations for each calculation term identified in Figure 1, according to the following guidelines:
[Image: Example blue shaded term]
Calculation terms shaded in blue must account for potential emissions of CO2 and other GHGs (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).) (e.g., CH4, and N2O) via use of appropriate emission factors (An estimate of the emissions intensity per unit of an activity.) and conversion to CO2e.
[Image: Example green shaded term]
Calculation terms shaded in green must account for potential emissions of CO2 only, as no other GHG (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).) emissions are expected from these types of sources.
The baselinesbaseline (A set of data describing pre-intervention or control conditions to be used as a reference scenario for comparison.) scenario for a DAC projectProject (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.) assumes the activities associated with theThe projectProject do not take place and any associated infrastructure is not built.
The counterfactual (An assessment of what would have happened in the absence of a particular intervention – i.e., assuming the Baseline scenario.) for DAC projects considers quantification of the CO2 that would have been removed from ambient air via a DAC process and durably stored over the same domainperiod in the absence of the projectProject (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.). As stipulatedestablished in Section 4, the counterfactual of qualifying projects is typically considered to be zero, unless a counterfactual scenario is required in the applicable storage module.
DAC 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 DAC systems, the equations below used to calculate net CO2e removals will pertain to all CO2 removals and GHG (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).) emissions that occur over an interval of time. This unit of time is defined as the Reporting Period, [math: RP], which represents an interval of time over which net CO2e removals are calculated and reported for 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).).
The following sections outline the process for calculating the net CO2e removed for each reportingReporting periodPeriod, written hereafter as [math: CO_2e_{Removal,\ RP}].
Net CO2e removal (The term used to represent the CO₂ taken out of the atmosphere as a result of a CDR process.) for a process utilizing DAC must be calculated as follows for a reportingReporting periodPeriod, [math: RP]:
[math: CO_2e_{Removal} = CO_2e_{Stored}\ –\ CO_2e_{Counterfactual}\ -\ CO_2e_{Emissions}]
(Equation 1)
Where;
Note: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 (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.) have been issued so are not included in this equation. See Section 5.6 of the Isometric Standard for further infomartioninformation. Risk of reversal information is given in Appendix 2: Risk of Reversal Questionnaire, with further information provided within the relevant storage module Storagestorage Modulemodule.
Type:Quantification Sequestration
of [math: CO_2e_{Stored}], representsmeasurements, and monitoring requirements for the amountdifferent storage (Describes the addition of CO2carbon presentdioxide inremoved from the CO2-containingatmosphere injectant that is injected and stored in the geologic or engineered storage formation into a givenreservoir, [math:which RP]serves as its ultimate destination. This is thealso grossreferred mass stored and does not account for reversals of storage from the storage formation.
This can be calculated by using the mass injected and the average concentration of CO2 of a set time period, summed across the whole [math: RP]:
[math: CO_2e_{Stored,\ RP} = \sum_{t=1}^{T} C_{mean, inj,t} \cdot m_{Inj,t}]
(Equation 2)
Where:
See contentSection divided by the fraction of C in CO23.4 for dissolved CO2 or the additional carbonate concentration in the carbonated minerals
Calculationcalculation of [math: CO_2e_{Stored}] requiresin twosaline primaryaquifers.
Durability and monitoring requirements for storage in mafic and ultramafic formations.
See Section 4.2.1 for calculation of CO2 or C:
[math: {C_{inj}}] measurement can be calculated in two different ways depending on how it is being stored. CO2 streams that are being injected into wells must be measured following Section 7.4.1.2, whilst CO2 being stored by ex-situ mineralization must be calculated following Section 7.4.1.3.
The concentration of CO2 in the gaseous, dissolved or supercritical CO2 stream must be:
The total CO2 content must be determined using the difference in carbonate concentration in the mineral waste pre and post mineralization. This should be carried out in line with the following standard following:
Carbon content analyses must be completed by an ISO 10694 accredited laboratory, or equivalent, with accreditation including the specific method of interest.
All samples must be collected as individual grab samples from the mineralized material. Project Proponents must conduct sampling such that variability in carbonated materials is characterized; sampling strategies must be reported and justified in the PDD. Further guidance on sampling of heterogeneous materials is given in Section 4 of the Rock and Mineral Feedstock Characterization Module. At a minimum, samples must be taken daily whilst the ex-situ process is ongoing.
Laboratories should complete and provide documentation of standard quality assurance procedures on a schedule in accordance with their quality management plans and accreditation requirements to include:
Laboratory quality assurance data shall be used in determination of uncertainty in accordance with Section 6.5.
The mass of injectant ([math: m_{Inj}]) 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:
Where CO2 is stored via ex-situ mineralization, determinationin ofclosed theengineered masssystems.
See Section 5.2
In general, the Project Proponent must identify, notify and explain any data gaps or missing calibration data, if any occur. The Project Proponent notify Isometric and the VVB when data gaps or missing calibration data occur and must clearly explain the approach taken and document the missing data within the GHG statement.
For those parameters where frequent, sub-hourly measurements are required (notably CO2 concentration measurements in the CO2 stream, and the measurement of mass of CO2 injected), the Project Proponent must adhere to the following procedure for handling missing data.
Where there are data gaps in measurement of the relevant parameter of up to 30 minutes, the Project Proponent may claim using an average quantity, based on the measurements proceeding and following the data gap.
Where there are such data gaps of longer than 30 minutes, the Project Proponent may apply this approach for up to a 30 minute period within the duration of the data gap, but no more than this. For the remainder of the period of the data gap, i.e. in excess of 30 minutes, no carbon dioxide removal may be claimed, due to a lack of data. In addition, data gaps must account for less than 5% of the data used for the removal calculation within a given reporting period, any missing data above this is also not creditable.
Where a calibration is missed, one must be completed as soon as this is noticed. For data collected between when the calibration was required and when it actually took place, a conservative estimate should be used agreed between the VVB, project proponent and Isometric.
The project proponent must maintain the following records as evidence of gross CO2 stored in injected CO2 or CO2-containing injectant:
Records of all analyses and injections must be maintained by the injectionbuilt facility or project proponent and provided for verification purposes for a minimum of five yearsenvironment.
Type: Counterfactual
ForUnless DACotherwise withspecified geologicin sequestrationthe applicable storage module, the counterfactual (An assessment of what would have happened in the absence of a particular intervention – i.e., assuming the Baseline scenario.) ([math: CO_2e_{Counterfactual}]) for eligible projects is considered to be zero, as outlined in Section 4 and Section 7.2.
Type: Emissions
[math: CO_2e_{Emissions}] is is the total quantity of GHG emissions associated with a given Reporting Period, [math: RP]. This can be calculated as:
[math: CO_{2}e_{Emissions} = CO_{2}e_{Energy} + CO_{2}e_{Transportation} \\ + CO_{2}e_{Embodied} + CO_{2}e_{Misc.}+CO_{2}e_{Leakage}]
(Equation 32)
Where:
Emissions that occur during a Reporting Period, [math: RP], must be included directly and fully in that Reporting Period, and not allocated across multiple Reporting Periods.
Embodied emissions which relate to multiple Reporting Periods may be allocated to removals in line with the allocation rules set out in the Embodied Emissions Accounting Module v1.0.
When the Project Proponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) is planning to cease operations within a given storage site, they must project the calculation of monitoringany emissions associated with activities required for post-closure monitoring, and allocate them to the remaining removals taking place at the storage site. If that is not possible, the Project Proponent should allocate those emissions to other projects and/or storage sitesites they conduct removal operations at, in agreement with Isometric. If for any reason emissions are not appropriately allocated, the Reversal process will be triggered in accordance with Isometric Standard, to account for any remaining monitoring emissions.
In instances where monitoring activities are shared between entities, for example if multiple DAC companies use the same storage infrastructure and share monitoring activities, the emissions associated with these activities must be allocated proportionally between the entities.
GHG emissions associated with [math: CO_2e_{Energy}] should include all emissions associated with electricity usage or fuel combustion.
Energy related emissions may include, but are not limited to:
The Energy Use Accounting Module v1.2 provides guidancerequirements 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 emissionsemission factors.
Electricity usage associated with the DAC process/facility must follow the [math: CO_2e_{Electricity,\ R}] calculation approach for intensive facilities whilst all other processes may follow the calculation approach for non-intensive processes/facilities.
Refer to Energy Use Accounting Module for the calculation guidelines.
Emissions related to transportation of CO2 or injectants for all injections during a reportingReporting periodPeriod must be accounted for, including the following:
The Transportation Emissions Accounting Module v1.1 provides guidancerequirements 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 and, approach to be followed, and acceptable emissions factors.
Refer to Transportation Emissions Accounting Module for the calculation guidelines.
Embodied GHG emissions associated with the manufacturing, delivery, and installation of all equipment and consumables used in the DAC process must be accounted for in each [math: RP]. The Project Proponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) must identify all equipment and consumables used in the DAC process, identify appropriate cradle-to-grave to(Considering graveimpacts 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.) emission factors, and allocate the emissions to removals appropriately in line with the Embodied Emissions Accounting Module v1.0.
Project Proponents must account for all embodied emissions in DAC equipment and facilities, including but not limited to, the following:
Equipment, including:
DAC Process:
CO2 transportation:
CO2 storage:
Monitoring:
UniversalGeneral equipment forused allalong processesthe value chain:
Heat generation equipment and heat transfer equipment must be accounted for, but embodied emissions may already be accounted for by emission factors used for fuel combustion (i.e.,- steamwhich boiler)are emissionsoften considerreported fullfrom cradle-to-grave GHG emissionsgate. Project Proponents should evaluate whether embodied emissions from equipment such as boilers are included in the energy emissions calculations, and if not, account for the embodied emissions here.
Project Proponents must account for all embodied emissions in DAC process consumables including but not limited to the following:
DAC Process:
CO2 storage:
Monitoring:
UniversalGeneral consumerablesconsumables forused allalong processesthe value chain:
In instances where infrastructure or equipment is shared between entities, for example if multiple DAC companies use the same storage infrastructure and associated activities, the emissions associated with these activities must be allocated proportionally between the entities.
The Embodied Emissions Accounting Module v1.0 sets out the calculation approach to be followed including allocation of embodied emissions, life cycle stages to be considered, and requirements for data sources and emission factors.
Refer to Embodied Emissions Accounting Module for the calculation guidelines.
GHG emissions associated with [math: CO_2e_{Misc.}] should include all projectProject (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.) emissions that cannot be categorized by [math: CO_2e_{Energy}], [math: CO_2e_{Transportation}], or [math: CO_2e_{Embodied}]. The Project Proponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) is responsible for identifying all sources of emissions directly or indirectly related to projectProject activities, including associated with any activities additional to those set out in Section 7.1. The Project Proponent must report such emissions as [math: CO_2e_{Misc.}].
Examples include, but are not limited to:
Quantification of [math: CO_2e_{Misc. Project}] in a given [math: RP] should be undertaken in line with the requirements set out in the Energy Use Accounting Module, the Transportation Emissions Accounting Module, and the Embodied Emissions Accounting Module, where appropriate.
Quantification of emissions associated with direct emissions of non-CO2 GHGs requires two primary measurements, the measurement of the total quantity of emissions and the analysis of emissions for CO2 and other GHG content. This can be calculated as follows:
[math: CO_{2}e_{MiscProjctMiscProject} = \sum_{t=1}^{T} m_{em,t} \cdot\ C_{GHG,t} \cdot\ GWP_{GHG}]
(Equation 43)
Where:
The total quantity of direct emissions can be measured by various acceptable methods, including:
The concentration of CO2 or other GHGs in emissions must be measured directly via one of the following methods:
The Project Proponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) must maintain the following records as evidence supporting calculation of emissions from the DAC or CO2 conversion process:
Records of all data and analyses must be maintained by the projectProject proponentProponent and provided for verification purposes for a period of five years.
[math: CO_2e_{Leakage,\ n}] includes emissions associated with a projectProject's (An activity or process or group of activities or processes that alter the condition of a Baseline and leads to Removals or Reductions.) impact on activities outside the system boundary of theThe projectProject. This includes instances where theThe Project causes an increase in GHG emissions by diverting material from other uses or incentivizing increased production activity.
It is the Project Proponent's (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) responsibility to identify potential sources of leakage emissions. For a DAC projectProject, market leakage emissions associated with the replacement of consumables used must be considered as a minimum. Project Proponents may also consider the impact of project operations on potential increased use of rare-earth materials for the production of sorbents, land use change, and increased strain on existing CO2 transportation and storage infrastructure.
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 multiple options for durable 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”.) of CO2. The Project Proponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) can choose from available options when submitting their Project for 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).):
Durability and monitoring requirements for storage in saline aquifers.
Durability and monitoring requirements for storage in mafic and ultramafic formations.
ADurability moduleand monitoring requirements for Exstorage via ex-Situsitu Mineralizationmineralization willin beclosed comingengineered soonsystems.
Durability and monitoring requirements for storage via carbonation in the built environment.
Isometric would like to thank following contributors to this Protocol and relevant modulesModules:
Isometric would like to thank following reviewers of this Protocol and relevant modulesModules:
This appendix details how the Project Proponent (The organization that develops and/or has overall legal ownership or control of a Removal or Reduction Project.) must monitor, document and report all metrics identified within 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.). 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 (The term used to represent the CO₂ taken out of the atmosphere as a result of a CDR process.) resulting from 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.) activity during theThe Project Crediting Period (The period of time over which a Project Design Document is valid, and over which Removals or Reductions may be Verified, resulting in Issued Credits.), prior to each 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).).
This methodology utilizes a comprehensive monitoring and documentation framework that captures the GHG (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).) impact in each stage of a Project. Monitoring and detailed accounting practices must be conducted throughout to ensure the continuous integrity of 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 evidencing of GHG (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).) emissions and CO2 removals.
The Modulesstorage modules associated with 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.) have their own set of required parameters that need to be monitored. Please refer to the following requirements Sections of the relevant Modules to see a complete list of all requirements:
See CO₂Section Storage6 for monitoring requirements for storage in Salinesaline Aquifersaquifers.
See Section 7 for monitoring requirements for storage in mafic and ultramafic formations.
See Section 9
See Section 6 for monitoring requirements for storage via carbonation in the built environment.
These parameters must be monitored for the purpose of Carbon Emissions Calculation and Embodied Carbon Emissions Calculation.
| Parameter | Parameter Description | Required | Equation | Parameter Type | Units | Data Source | Measurement Method | Monitoring Frequency | QA/QC Procedures | Required Evidence | Reference |
|---|---|---|---|---|---|---|---|---|---|---|---|
| [math: | |||||||||||
| Electricity usage for DAC process | Always | Eq. 4 (Energy Use Accounting Module) | Measured | kwh | Electricity usage records |
| Each | Appropriate calibration and maintenance of meters | Operator logs, plant data systems, or plant records | 7.4.3.1 (Direct Air Capture); 3.2.2.2 (Energy Use Accounting Module) | |
| [math: m_{p}] | Derating factor | Always | Eq. 4 (Energy Use Accounting Module) | Measured or estimated | N/A | Electricity power output | Averaged metered A/C power output per hour, OR estimated | If measured, continuous for a | Appropriate calibration and maintenance of meters | Operator logs, plant data systems, or plant records | 7.4.3.1 (Direct Air Capture); 3.2.2.2 (Energy Use Accounting Module) |
| [math: EF_{G}] | Hourly short-run marginal emissions rate of the facility's local electricity grid | Always, unless all electricity is qualified | Eq. 4 (Energy Use Accounting Module) | Estimated | CO2e/unit (tonnes) | Short run marginal emissions data | N/A | Hourly | N/A | Choice and rationale for EF choice | 7.4.3.1 (Direct Air Capture); 3.2.2.2 (Energy Use Accounting Module) |
| [math: EF_{P}] | Hourly average electricity emission factor for a specific generator | Always | Eq. 4 (Energy Use Accounting Module) | Estimated | CO2e/unit (tonnes) | Argonne National Laboratory GREET Model, California Air Resources Board modified GREET model (CA-GREET), Ecoinvent database, US Federal Life Cycle Inventory database or LCA (An analysis of the balance of positive and negative emissions associated with a certain process, which includes all of the flows of CO₂ and other GHGs, along with other environmental or social impacts of concern.) Commons, or from similar databases used in common LCA practices or tools | N/A | Hourly | N/A | Choice and rationale for EF choice | 7.4.3.1 (Direct Air Capture); 3.2.2.2 (Energy Use Accounting Module) |
| [math: m_{Fuel,\ DAC}] | Mass of fuel used in DAC process | Always | Eq. 5 (Energy Use Accounting Module) | Measured | gal | Fuel usage records |
| Each | Appropriate calibration and maintenance of scales or meters | Operator logs, plant data systems, or plant records | 7.4.3.1 (Direct Air Capture); 3.3 (Energy Use Accounting Module) |
| [math: EF_{Fuel, DAC}] | Fuel emission factor for the DAC process | Always | Eq. 5 (Energy Use Accounting Module) | Estimated | CO2e/unit (tonnes) | Argonne National Laboratory GREET Model, California Air Resources Board modified GREET model (CA-GREET), Ecoinvent database, US Federal Life Cycle Inventory database or LCA Commons, or from similar databases used in common LCA practices or tools | N/A | Each | N/A | Choice and rationale for EF choice | 7.4.3.1 (Direct Air Capture); 3.3 (Energy Use Accounting Module) |
| [math: m_{Fuel,\ Postprocessing}] | Mass of fuel used in postprocessing | Always | Eq. 5 (Energy Use Accounting Module) | Measured | gal | Fuel usage records |
| Each | Appropriate calibration and maintenance of scales or meters | Operator logs, plant data systems, or plant records | 7.4.3.1 (Direct Air Capture); 3.3 (Energy Use Accounting Module) |
| [math: EF_{Fuel, Postprocessing}] | Fuel emission factor for postprocessing | Always | Eq. 5 (Energy Use Accounting Module) | Estimated | CO2e/unit (tonnes) | Argonne National Laboratory GREET Model, California Air Resources Board modified GREET model (CA-GREET), Ecoinvent database, US Federal Life Cycle Inventory database or LCA Commons, or from similar databases used in common LCA practices or tools | N/A | Each | N/A | Choice and rationale for EF choice | 7.4.3.1 (Direct Air Capture); 3.3 (Energy Use Accounting Module) |
| [math: m_{Fuel,\ Conversion}] | Mass of fuel used in injectate conversion process & non-mobile transportation | Always | Eq. 5 (Energy Use Accounting Module) | Measured | gal | Fuel usage records |
| Each | Appropriate calibration and maintenance of scales or meters | Operator logs, plant data systems, or plant records | 7.4.3.1 (Direct Air Capture); 3.3 (Energy Use Accounting Module) |
| [math: EF_{Fuel, Conversion}] | Fuel emission factor for injectate conversion process & non-mobile transportation | Always | Eq. 5 (Energy Use Accounting Module) | Estimated | CO2e/unit (tonnes) | Argonne National Laboratory GREET Model, California Air Resources Board modified GREET model (CA-GREET), Ecoinvent database, US Federal Life Cycle Inventory database or LCA Commons, or from similar databases used in common LCA practices or tools | N/A | Each | N/A | Choice and rationale for EF choice | 7.4.3.1 (Direct Air Capture); 3.3 (Energy Use Accounting Module) |
| [math: F_{Transportation}] | Quantity of fuel used in mobile transportation | Under certain conditions | Eq. 2 (Transportation Emissions Accounting Module) | Measured or estimated | gal | Vehicle or fleet management records | Fuel flow meters, fleet management system data, vehicle on board diagnostics, or similar | Each | Verify instrument calibrations as appropriate | Meter, management system, OBD or other data records or logs, shipping documents | 7.4.3.2 (Direct Air Capture); 3.2 (Transportation Emissions Accounting Module) |
| [math: EF_{Fuel, Transportation}] | Fuel emission factor for mobile transportation | Under certain conditions | Eq. 2 (Transportation Emissions Accounting Module) | Estimated | CO2e/unit (tonnes) | Argonne National Laboratory GREET Model, California Air Resources Board modified GREET model (CA-GREET), Ecoinvent database, US Federal Life Cycle Inventory database or LCA Commons, or from similar databases used in common LCA practices or tools | N/A | Each | N/A | Choice and rationale for EF choice | 7.4.3.2 (Direct Air Capture); 3.2 (Transportation Emissions Accounting Module) |
| [math: D_{Transportation}] | Transportation distance traveled (mobile transportation) | Under certain conditions | Eq. 2 (Transportation Emissions Accounting Module) | Measured or estimated | mi or km |
| On-line mapping systems using origin and departure from shipping documents, odometer readings | Each | Review and check of shipping records and origin/destination | Shipping records | 7.4.3.2 (Direct Air Capture); 3.2 (Transportation Emissions Accounting Module) |
| [math: W_{Transportation}] | Mass transported (mobile transportation) | Under certain conditions | Eq. 2 (Transportation Emissions Accounting Module) | Measured | kg, tonne, lb |
| Calibrated weigh scale | Each | Review weigh scale calibration certificate | Shipping records, weigh scale ticket | 7.4.3.2 (Direct Air Capture); 3.2 (Transportation Emissions Accounting Module) |
| [math: EF_{Transportation, j}] | The weight- and distance-based emission factor for mobile transportation | Under certain conditions | Eq. 2 (Transportation Emissions Accounting Module) | Estimated | CO2e/unit (tonnes) | Argonne National Laboratory GREET Model, California Air Resources Board modified GREET model (CA-GREET), Ecoinvent database, US Federal Life Cycle Inventory database or LCA Commons, or from similar databases used in common LCA practices or tools | N/A | Each | N/A | Choice and rationale for EF choice | 7.4.3.2 (Direct Air Capture); 3.3 (Transportation Emissions Accounting Module) |
| [math: m_{em,\ t}] | the mass of miscellaneous emission(s) (in tonnes) during [math: t] | Under certain conditions | Eq. | Measured | kg | Direct mass measurement or analytical determination |
| Continuous if occurring | Scales must be calibrated annually by certified entity | Weigh scale tickets for each injection (arrival and departure weights); Calibration records for scales | 7.4.3.4.1 (Direct Air Capture) |
| [math: C_{GHG,\ t}] | the measured concentration as weight percent (%wt) of the relevant GHGs in the miscellaneous emission(s) | Under certain conditions | Eq. | Measured | wt% | Analytical determination |
| Continuous if occurring | Appropriate calibration and maintenance of sensors or ISO 10694 accredited laboratory | Data logs/Data Acquisition System Output or Analytical reports from qualified laboratory for audited samples, including supporting lab QA/QC results | 7.4.3.4.1 (Direct Air Capture) |
| Product Stage Emissions | Includes raw material sourcing, transport to facility and manufacturing | Always | Measured | tonnes | Independently verified LCAs for the material or product completed; an environmental product declaration (EPD) for a material or product completed and independently verified | Number/weight of each product or material used in the project facility and a corresponding EPD-based embodied carbon emission factor, OR emission factors from LCA life cycle databases, including USLCI database, Ecoinvent, ICE Database, and other published and peer-reviewed databases of embodied emissions factors and the number or weight (depending on emission factor units) of each product or material at the facility, OR overall total cost of equipment and facilities for | Each site | ISO 14040 or similar guidelines; ISO 14025, ISO 21930, EN 15804 or equivalent standards including product EPDs as well as industry-wide EPDs | Operator logs, plant data systems, or plant records | 7.4.3.3 (Direct Air Capture); 3.0 & 3.2 (Embodied Emissions Accounting Module) | |
| Construction Stage Emissions | Includes transport to site and installation at site | Always | Measured | tonnes | Independently verified LCAs for the material or product completed; or an environmental product declaration (EPD) for a material or product completed and independently verified | Number/weight of each product or material used in the project facility and a corresponding EPD-based embodied carbon emission factor, OR emission factors from LCA life cycle databases, including USLCI database, Ecoinvent, ICE Database, and other published and peer-reviewed databases of embodied emissions factors and the number or weight (depending on emission factor units) of each product or material at the facility, OR overall total cost of equipment and facilities for | Each site | ISO 14040 or similar guidelines; ISO 14025, ISO 21930, EN 15804 or equivalent standards including product EPDs as well as industry-wide EPDs | Operator logs, plant data systems, or plant records | 7.4.3.3 (Direct Air Capture); 3.0 & 3.2 (Embodied Emissions Accounting Module) | |
| End of Life Stage Emissions | Includes demolition of building, transport to end of life, waste processing and final disposal or scenarios for these life cycle stages | Always | Measured | tonnes | Independently verified LCAs for the material or product completed; an environmental product declaration (EPD) for a material or product completed and independently verified | Number/weight of each product or material used in the project facility and a corresponding EPD-based embodied carbon emission factor, OR emission factors from LCA life cycle databases, including USLCI database, Ecoinvent, ICE Database, and other published and peer-reviewed databases of embodied emissions factors and the number or weight (depending on emission factor units) of each product or material at the facility, OR overall total cost of equipment and facilities for | Each site | ISO 14040 or similar guidelines; ISO 14025, ISO 21930, EN 15804 or equivalent standards including product EPDs as well as industry-wide EPDs | Operator logs, plant data systems, or plant records | 7.4.3.3 (Direct Air Capture); 3.0 & 3.2 (Embodied Emissions Accounting Module) | |
| Storage and Monitoring Emissions | The total quantity of GHG emissions associated with storage monitoring operations allocated to a removal | Always | Measured | tonnes | Electricity and fuel usage records; independently verified LCAs for the material or product completed; an environmental product declaration (EPD) for a material or product completed and independently verified | Electricity meters OR utility bills OR equipment time of use and power rating; fuel meters fuel container weight fuel purchases or utility bills equipment hours of operation (handling equipment only) | Each site | Appropriate calibration and maintenance of scales or meters | Operator logs, plant data systems, or plant records | 7.4.3.3 (Direct Air Capture); 3.4 of applicable Storage Modules |
This risk assessment identifies the pathway specific risk factors relevant to a carbon removal project. The relevant risk factors identified as part of a risk assessment are included in the monitoring plan requirements for the project, 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.
The risk score, as determined by the Risk of Reversal Questionnaire, will determine a project’s buffer pool contribution. Projects must re-assess their reversal risk at the renewal of each crediting period, or if monitoring identifies a reversal-related risk, or if an actual reversal event takes place. 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 protocol, drawn from the programme-level Risk of Reversal Questionnaire defined in Appendix B: Risk Reversal Questionnaire of the Isometric Standard, include the following:
| # in Isometric Standard Questionnaire | Question | If answered “Yes” | If answered “No” |
|---|---|---|---|
| 1 | Is a reversal directly observable with a physical or chemical measurement as opposed to a modeled result? | Proceed to questions 2-9 | Proceed to questions 8-9 |
| 2 | Is the carbon being stored in an impermeable geologic system? (e.g., salt cavern) | Proceed to questions 8-9 | Add 1 to Risk Score and proceed to questions 3-9 |
| 5 | Does this approach have a material risk of reversal due to natural disasters including, but not limited to, floods, storms, earthquakes, fires, etc.? | Add 1 to Risk Score | |
| 6 | Does this approach have a material risk of reversal due to human-induced events from outside actors, such as change in farming practices, change in ownership and management of project sites, or similar? | Add up to 2 to Risk Score | |
| 7 | Applicable only for subsurface storage: Is the carbon being stored with trapping mechanisms preventing reversals? (e.g., multiple confining layers, CO₂ dissolves or solidifies) | Minus 1 to Risk Score (unless 0) | |
| 8 | Is there 10+ years of monitoring and/or lab data demonstrating low project risk? | Minus up to 2 to Risk Score | |
| 9 | Does this pathway have a documented history of reversals? | Add 2 to Risk Score | |
| 10 | Is there one or more project-specific factors that merit a high risk level? | Add up to 2 to Risk Score |
Risk Score Categories
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 of the following risk factors must be reflected in the risk score corresponding to question 10:
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:
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 Carbon Dioxide 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
Isometric. (n.d.). Isometric — Glossary: Defining the terms that appear regularly in our work. Isometric. https://isometric.com/glossary
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
Carbon Credit Quality Initiative (CCQI) Methodology for assessing the quality of carbon credits, Version 3.00_. (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. Handbook 44 (20232025). Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices - 20232025 Edition. NIST. https://www.nist.gov/pml/owm/publications/nist-handbooks/handbook-44-current-edition
US Department of Energy. (DoE) (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
U.S. DOEDoE. (2022). Best Practices for Life Cycle Assessment (LCA) of Direct Air Capture with Storage (DACS). U.S. Department of Energy, Office of Fossil Energy and Carbon Management. https://www.energy.gov/fecm/best-practices-LCA-DACS
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., and Mazzotti, M. (2021). Life cycle assessment of carbon dioxide removal technologies: a critical review. Energy & Environmental Science, 14, 1701–1721. https://doi.org/10.1039/D0EE03757E
Shi, XiaoyangX., Hang Xiao, HabibH., Azarabadi, JuzhengH., Song, XiaolongJ., Wu, XiX., Chen, X., and KlausLackner, K. S. Lackner(2020). "Sorbents for the directDirect captureCapture of CO2 from ambientAmbient airAir." Angewandte Chemie International Edition, 59, no. 18 (2020): 6984-–7006. https://doi.org/10.1002/anie.201906756↩
Custelcean, RaduR. "(2022). Direct airAir captureCapture of CO2 usingUsing solventsSolvents." Annual Review of Chemical and Biomolecular Engineering, 13 (2022):, 217-–234. https://doi.org/10.1146/annurev-chembioeng-092120-023936↩
Fujikawa, ShigenoriS., and RomanSelyanchyn, SelyanchynR. "(2022). Direct air capture by membranes." MRS Bulletin, 47, no. 4 (2022): 416-–423. https://doi.org/10.1557/s43577-022-00313-6↩
Renfrew, SaraS. E., DavidStarr, D. E. Starr, and PeterStrasser, StrasserP. "(2020). Electrochemical approachesApproaches toward CO2 captureCapture and concentrationConcentration." ACS catalysisCatalysis, 10, no. 21 (2020): 13058-–13074. https://doi.org/10.1021/acscatal.0c03639↩
Al Hameli, FatimaF., Hadi Belhaj, H., and Mohammed Al Dhuhoori, M. "(2022). CO2 sequestrationSequestration overviewOverview in geologicalGeological formationsFormations: Trapping mechanismsMechanisms matrixMatrix assessmentAssessment." Energies, 15, noArticle 20. 20 (2022)https: 7805//doi. org/10.3390/en15207805↩
Rochelle, ChristopherC. A., I. Czernichowski-Lauriol, I., and Milodowski, A. E. Milodowski(2004). "The impact of chemical reactions on CO2 storage in geological formations: aA brief review." Geological Society, London, Special Publications, 233, no. 1 (2004): 87-–106. https://doi.org/10.1144/GSL.SP.2004.233.01.07↩
Ricks, WilsonW., Qingyu Xu, Q., and JesseJenkins, J. D. Jenkins(2023). "Minimizing emissions from grid-based hydrogen production in the United States." Environmental Research Letters, 18, no. 1 (2023): 014025. https://doi.org/10.1088/1748-9326/acacb5↩
Goeppert, AlainA., Miklos Czaun, GK SuryaM., Prakash, G. K. S., and GeorgeOlah, G. A. Olah(2012). "Air as the renewable carbon source of the future: anAn overview of CO 2CO2 capture from the atmosphere." Energy & Environmental Science, 5, no. 7 (2012): 7833-–7853. https://doi.org/10.1039/C2EE21586A↩
Sanz-Pérez, EloyE. S., ChristopherMurdock, C. R. Murdock, Stephanie A. Didas, S. A., and ChristopherJones, C. W. Jones(2016). "Direct captureCapture of CO2 from ambientAmbient airAir." Chemical reviewsReviews, 116, no. 19 (2016): 11840-–11876. https://doi.org/10.1021/acs.chemrev.6b00173↩
Terlouw, TomT., Karin Treyer, ChristianK., Bauer, C., and MarcoMazzotti, MazzottiM. "(2021). Life cycleCycle assessmentAssessment of directDirect airAir carbonCarbon captureCapture and storageStorage with lowLow-carbonCarbon energyEnergy sourcesSources." Environmental scienceScience & technologyTechnology, 55, no. 16 (2021): 11397-–11411. https://doi.org/10.1021/acs.est.1c03263↩
Erans, MaríaM., Eloy S. Sanz-Pérez, DawidE. PS., Hanak, ZeynepD. P., Clulow, David MZ., Reiner, D. M., and GregMutch, G. A. Mutch(2022). "Direct air capture: processProcess technology, techno-economic and socio-political challenges." Energy & Environmental Science, 15, no. 4 (2022): 1360-–1405. ↩
Turnbull, Jocelyn Christine, Elizabeth D. Keller, Margaret W. Norris, and Rachael M. Wiltshire. "Independent evaluation of point source fossil fuel CO2 emissions to better than 10%." Proceedings of the National Academy of Sciences 113, no. 37 (2016): 10287-10291. ↩
Criteria provided in Verra 2023 Draft DAC Module: https://verradoi.org/wp-content10.1039/uploads/2023/06/DAC-Module-Public-Consultation-Draft.pdfD1EE03523A↩↩2
For example, 40CFR19549 CFR §195.402 - Transportation of Hazardous Liquids via Pipeline: Procedural manual for operations, maintenance, and 40CCF146emergencies, and 40 CFR §146.94 - Class VI Wells: Emergency and remedial response. ↩↩2
Water neutrality is defined as: the total demand for water should be the same after new development is built, as it was before. That is, the new demand for water should be offset in the existing community by making existing infrastructure and homes in the area more water efficient. ↩
httpsISO 14064-3://carboncreditquality2019, Section 5.org/methodology1.html7 ↩
Adefila,Carbon Kehinde,Credit YongQuality Yan, Lijun Sun, and Tao WangInitiative. "FlowMethodology measurementfor assessing the quality of wetcarbon CO2credits, usingVersion an averaging pitot tube and coriolis mass flowmeters3." International Journal of Greenhouse Gas Control 630 (2017May 2022): 289-295. https://doicarboncreditquality.org/10methodology.1016/j.ijggc.2017.06.005↩
https://www.nist.gov/pml/owm/nist-handbook-44-current-editionhtml↩
Lyons, L., Kavvadias, K. and Carlsson, J., (2021). Defining and accounting for waste heat and cold,. EUR 30869 EN, Publications Office of the European Union, Luxembourg, 2021, ISBN 978-92-76-42588-5,. doi:10.2760/73253, JRC126383. https://publications.jrc.ec.europa.eu/repository/handle/JRC126383↩
Flow meters must be calibrated to national traceable standards by an ISO 17025 accredited metrology laboratory. Flow meters may include critical nozzle flow meters (i.e. ISO 9300:2022 compliant meters), coriolis mass flow meters, and other applicable meters for mixed gas flows, as long as properly calibrated and maintained. ↩
Dinh, TrieuT.-VuongV., In-Young Choi, YounI.-SukY., Son, Y.-S., and JoKim, J.-Chun KimC. "(2016). A review on non-dispersive infrared gas sensors: Improvement of sensor detection limit and interference correction." Sensors and Actuators B: Chemical, 231 (2016):, 529-–538. https://doi.org/10.1016/j.snb.2016.03.040↩
Sandoval-Bohorquez, Víctor. StivensonS., Edwing Alexander Velasco Rozo, E. A. V., and Baldovino-Medrano, Víctor. G. Baldovino-Medrano(2020). "A method for the highly accurate quantification of gas streams by on-line chromatography." Journal of Chromatography A, 1626 (2020):, 461355. https://doi.org/10.1016/j.chroma.2020.461355↩