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Direct Air Capture
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This protocolProtocol provides the requirements and procedures for the calculation of net carbon dioxide equivalent (CO2e) removals 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-gravegreenhouse gas (GHG) Statement 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 emissions associated with DAC processes. Additionally, the protocolProtocol ensures:
Specific standards and protocols which are utilized as the foundation of this protocolProtocol, and for 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 was developed based on the current state of the art and publicly available science regarding DAC and CO2storage. Because DAC is still a developing approach to carbon dioxide removal (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 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 associated with this Protocol (see CO2Section Storage Module8). A cradle-to-grave GHG Statement must also be able to be accurately applied to all processes within the scope of the project.
To ensure long-term durability, CO2 characteristics and the conditions within the storage reservoir must be well defined, modeledProject 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 asthe generation of claimedCredits removalsunder this Protocol, as this constitutes an avoided emissions project,- not aemissions removal. DAC projects that are co-located with industrial point sources of CO2, defined here as being within 1km distance, with major emissions sources originating from the development or combustion of fossil fuels or petrochemicals, are only eligible if the projectProject proponentappropriately usesdiscounts isotopemeasured 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 capturedgross CO2 mayremovals providein supportan foramount 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. In practice, this evaluationshould be achieved by measuring the concentration of CO2 in the ambient air at the inlet to the DAC process, and discounting gross removals by an amount corresponding to the relative excess of this measurement 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 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 must consider environmental and social impacts, and the projectProject proponentProponent 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 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 to be evaluated under this protocolProtocol, the projectProject proponentProponent must document project characteristics in a Project Design Document (PDD), as outlined in Section 3.2 of the Isometric Standard. The PDD will form the basis for projectProject verificationVerification and evaluation in accordance with this protocolProtocol, and must include consideration of processes unique to DAC, for example:
Projects must be validated and projectProject net CO2e removals verified by an independent third party, consistent with the requirements described in this Protocol, as well as in Section 4 of the Isometric Standard.
The Validation and Verification Body (VVB) must consider following requisite components:
The threshold for Materiality, considering the totality of all omissions, errors, and mis-statements, is 5%, in accordance with Section 4.3 of the Isometric Standard.
Verifiers should also verify the documentation of uncertainty of the GHG Statement, as required by Section 2.5.7 of the Isometric Standard. Qualitative materialityMateriality issues may also be identified and documented, such as:1314:
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 validation and initial verification to the DAC projectProject and storage site. ValidatorsVerifiers 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.
Verifiers and validatorsVVBs 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 via DAC and subsequent storage 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 of net CO2e removals, a single Project Proponent must be specified contractually as the sole owner of the Credits. Contracts must comply with all requirements defined in Section 3.1 of the Isometric Standard.
The Project Proponent must be able to demonstrate additionality through compliance with Section 2.5.3 of the Isometric Standard. The baseline scenario and counterfactual 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 creditingCrediting periodPeriod), at a minimum, or whenever project operating conditions change significantly, such as the following:
Any review and change in the determination of additionality should not affect the availability of carbonCarbon financeFinance and Verified Credits for the current or past creditingCrediting periodsPeriods, but if the review indicates theThe projectProject has become non-additional, this should make theThe projectProject ineligible for future creditsCredits.1615.
The uncertainty in the overall estimate of the net CO2e removal as a result of the projectProject 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 determined, based on the requirements outlined in Section 2.5.7 of the Isometric Standard.
Projects 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 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. 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. ThatThis includes:
The projectProject proponentProponent can request certain information to be restricted (only available to authorized buyersBuyers, the Registry, and VVB) 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 includes the GHG sources, sinks, and reservoirs (SSRs) associated with a DAC projectProject.
A cradle-to-grave GHG Statement must be prepared encompassing the GHG emissions relating to the activities associated with a DAC and storage projectProject for net CO2e removal, as summarized in Figure 1 and described below:
Emissions for processes within the system boundary should include all GHG SSRs from the construction or manufacturing of each projectProject 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 of Credits can be excluded from the system boundary.
GHG 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 must consider all GHGs associated with the relevant SSRs, in alignment with the United States Environmental Protection AgencyEPA’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).
All GHGs must be quantified and converted to CO2e in the GHG Statement using the 100-yr Global Warming Potential (GWP) 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 (e.g., CH4, and N2O) via use of appropriate emission factors 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 emissions are expected from these types of sources.
The baselinesbaseline scenario for a DAC projectProject assumes the activities associated with theThe projectProject do not take place and any associated infrastructure is not built.
The counterfactual 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. 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 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.
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 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 Reversalsshould be noted that any potential reversals of CO2 storage in the final storage location occur after Credits 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 amount of CO2 present in the CO2-containing injectant that is injected and stored in the geologic or engineered storage formation in a givendifferent [math: RP]. This is the gross 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 ([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 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 must identify all equipment and consumables used in the DAC process, identify appropriate cradle -to -grave 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 emissions that cannot be categorized by [math: CO_2e_{Energy}], [math: CO_2e_{Transportation}], or [math: CO_2e_{Embodied}]. The Project Proponent 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 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 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 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 provides multiple options for durable storage of CO2. The Project Proponent can choose from available options when submitting their Project for verification:
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 must monitor, document and report all metrics identified within this Protocol. Following this guidance will ensure the Project Proponent measures and confirms carbon removed and long-term storage compliance, and will enable quantification of the emissions removal resulting from the Project activity during theThe Project Crediting Period, prior to each Verificationverification.
This methodology utilizes a comprehensive monitoring and documentation framework that captures the GHG impact in each stage of a Project. Monitoring and detailed accounting practices must be conducted throughout to ensure the continuous integrity of 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 emissions and CO2 removals.
The Modulesstorage modules associated with this Protocol 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 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:
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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 ↩
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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. ↩
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