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Direct Air Capture
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This protocol (A document that describes how to quantitatively assess the net amount of CO₂ removed by a process. To Isometric, a Protocol is specific to a Project Proponent's process and comprised of Modules representing the Carbon Fluxes involved in the CDR process. A Protocol measures the full carbon impact of a process against the Baseline of it not occurring.) provides the requirements and procedures for the calculation of net 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 from the atmosphere via Direct Air Capture (DAC). This protocol is developed for application to DAC processes or combinations of processes (e.g., solid sorption1, liquid solvent2, membrane processes3, electrochemistry4, etc.) in which a cradle-to-grave (Considering impacts at each stage of a product's life cycle, from the time natural resources are extracted from the ground and processed through each subsequent stage of manufacturing, transportation, product use, and ultimately, disposal.)GHGgreenhouse Assessmentgas (AnGHG) analysisStatement of(A document submitted alongside Claimed Removals and/or Reductions that details the balance of positive and negative emissionscalculations associated with a certainRemoval processor Reduction, which includes all ofincluding the flowsProject's emissions, Removals, Reductions and Leakages, presented together in net metric tonnes of CO₂e andper other GHGs, along with other environmentalRemoval or social impacts of concernReduction.) can be accurately applied and in which the CO2 captured is stored geologicallyvia (physical5 or viachemical6 atrapping method demonstrated to be equivalent)mechanisms for >1000 years.
The protocol was developed in line with latest scientific understanding789 and industry best-practices1011 which inform the quantification of gross CO2 removeddurably captured and stored via DAC as well as the accounting of GHG emissions associated with DAC processes. Additionally, the protocol ensures:
Specific standards and protocols which are utilized as the foundation of this protocol and for which this protocol is intended to be fully compliant with are as follows:
Additional reference standards that inform the requirements and overall practices incorporated in this protocol include:
This protocol 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 (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 protocol 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 protocol as DAC and CO2 storage technology and research advance.
This protocol applies to projects anywhere that capture CO2 from ambient air and store captured CO2 geologically for >1000 years via processesphysical (suchor aschemical injectiontrapping intomechanisms salinelaid aquifers andout in-situ/ex-situ mineralization)the torelevant whichCO2 Storage Module. A cradle-to-grave GHG assessmentStatement canmust 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, modeled (A calculation, series of calculations or simulations that use input variables in order to generate values for variables of interest that are not directly measured.) 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 may not be accounted for as claimed removals (A Removal which has been submitted by a Project Proponent, but which has not yet been Verified.), as theythis areconstitutes an avoided emissions project, not additional (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.)removal. DAC projects shouldthat not beare co-located, defined here as being within 1km distance, with major emissions sources which resultoriginating from the development, use, processing, or combustion of fossil fuels or petrochemicals. Co-located facilities, are classifiedonly aseligible thoseif onthe contiguousproject orproponent adjacentuses properties.isotope Intracing extenuatingof circumstances,the captured CO2 to enable accounting of only non-fossil CO2 in such aslocations. thoseAtmospheric allowingdispersion modeling12 and biogenic carbon monitoring of the captured CO2 may provide support for substantialthis gains in efficiency (e.g., via waste heat utilization) with little risk of non-additionality, co-location of facilities may be evaluatedevaluation.
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 protocol. A project may qualify for this distinction by meeting one of the following conditions113:
The project must consider environmental and social impacts and the project proponent must provide evidence that the project will do no net environmental or social harm by complying with Section 3.7.1 of the Isometric Standard as well as the following requirements:
The following topics are covered briefly in this protocol due to their inclusion in the Isometric Standard, which governs all Isometric protocols. See in-text references to the Isometric Standard for further guidance.
For each specific project to be evaluated under this protocol, the project proponent 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 project verification (A process for evaluating and confirming the net Removals and Reductions for a Project, using data and information collected from the Project and assessing conformity with the criteria set forth in the Isometric Standard and the Protocol by which it is governed. Verification must be completed by an Isometric approved third-party (VVB).) and evaluation in accordance with this protocol, and must include consideration of processes unique to DAC, suchfor asexample:
Projects 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 project 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 VerificationValidation and ValidationVerification 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 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 materiality issues may also be identified and documented, such as213:
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 project and storage site. Validators should whenever possible observe operation of the capture and storage processes to ensure full documentation of process inputs and outputs through visual observation and validation of instrumentation, measurements, and required data quality measures.
A site visit must occur at least once every 2 years at each location.
Verifiers and validators 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.
Competency must be demonstrated through the below relevant sectoral scope accreditations listed below, orbased throughon demonstrationIAF ofMD relevant14 experience,and in accordance with Isometric's VVB policy:
CO2 removalCDR 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 process, 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., injection site operators), and to avoid double counting of net CO2e removals, a single Project Proponent must be specified contractually as the sole owner of the CO2e removalsCredits. Contracts must comply with all requirements defined in Section 3.1 of the Isometric Standard.
The Removal Project Proponent shouldmust 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 isare described in Section 7.2 of this Protocol.
Additionality determinations should be reviewed and completed every five years (aligned with the crediting period), at a minimum, or whenever project operating conditions change significantly, such as the following:
Any review and change in the determination of additionality should not affect the availability of carbon finance 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 crediting periods (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 has become non-additional, this should make the project ineligible for future credits316.
The uncertainty in the overall estimate of the net CO2e removal as a result of the project must be calculated and transparently presented. The total net CO2e removed over a reporting period ([math: RP]; see Section 7.3.1) for a project, [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., Projectsbased muston comply withthe 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 (An analysis of how much different components in a Model contribute to the overall Uncertainty.) that demonstrates the impact of each input parameter’s uncertainty on the final net CO2e uncertainty must be provided. Details of the sensitivity analysis method must be provided so that the results can be re-created. Parameters may be omitted from a full uncertainty analysis if a Sensitivity Analysis can demonstrate that the parameter contributes to <1% change in Removal. For all other parameters, information about Uncertainty must be specified.
In accordance with 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.). That includes:
The Projectproject Proponentproponent can request certain information to be restricted (only available to authorized buyers (An entity that purchases Removals or Reductions, often with the purpose of Retiring Credits to make a Removal or Reduction claim.), the Registry (A database that holds information on Verified Removals and Reductions based on Protocols. Registries Issue Credits, and track their ownership and Retirement.) and VVB) where it is subject to confidentiality. This includes emissions factors from licensed databases. However, thatall does not apply to anyother numerical data produced or used as part of the quantification of net CO₂2e removedremoval will be made available..
The scope of this protocol includes the cradle-to-grave GHG Assessment of all emissions associated with the following aspects of a DAC and storage project for CO2e removalsources, as summarized in Figure 1. A GHG Statement must be prepared, which must account for the following activities:
Emissions for processes within the system boundary should include all GHG sinks (Any process, activity, or mechanism that removes a greenhouse gas, a precursor to a greenhouse gas, or an aerosol from the atmosphere.), and reservoirs (SSRs) associated with a DAC project.
A locationcradle-to-grave whereGHG carbonStatement is stored. This canmust be viaprepared physicalencompassing barriersthe (suchGHG emissions relating to the activities associated with a DAC and storage project for net CO2e removal, as geologicalsummarized formations)in orFigure through1 partitioningand baseddescribed onbelow:
Emissions for processes (suchwithin asthe mineralizationsystem orboundary photosynthesis).)should include all GHG SSRs from the construction or manufacturing of each project and associated equipment, closure of each project and disposal of associated equipment, and operation of each process (DAC systemprocess, CO2 transportation, CO2 storage). Projects are required to include embodied emissions of both equipment and consumablesCO2 inmonitoring).
Ancillary theactivities process,(such as summarized in Figure 1.
Note that this protocol does not require inclusion of emissions resulting from ancillary activities not directly related to project operations, such assupplementary research and development activities, and corporate administrative activities) andthat any associated facilities. It does include activitiesare associated with longa termproject assurancebut are not directly or indirectly related to the issuance of durableCredits (Thecan amountbe of time carbon removedexcluded from the atmosphere by an intervention – for example, a CDR project – is expected to reside in a given Reservoir, taking into account both physical risks and socioeconomic constructs (such as contracts) to protect the Reservoir in question.) storage, including required monitoring activities and controls.
[Image: DAC]
Figure 1
Schematic of Direct Air Capture and CO2 sequestration process, with primary processes (red boxes) and GHG sources, sinks and reservoirs considered in the system boundary. Blue boxes represent calculated emissions using appropriate emission factors and conversion to CO2e while green boxes represent emissions of potential emissions of CO2 only.
Carbon fluxes (The amount of carbon exchanged between two or more Reservoirs over a period of time.) and associated GHG emissions and removals fromassociated with the project may derive from, but are not limited to, the following sources:
All GHGs must be quantified and converted to CO2e in the GHG Statement using the 100-yr Global Warming Potential (GWP) for processesthe or transportation due to combustionGHG of fuelsinterest, electricitybased generation,on orthe similarmost sourcesrecent 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 GHGGHGs (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 baselines scenario for a DAC project assumes the activities associated with the project 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 domain in the absence of the project. As stipulated in Section 4, the baselinecounterfactual of qualifying projects is considered to be zero. The activity would not occur in a business as usual scenario, and there is no other business as usual counterfactual (An assessment of what would have happened in the absence of a particular intervention – i.e., assuming the Baseline scenario.) at this time for extraction of CO2 from ambient air and its durable storage. Therefore, deduction of baseline CO2e emissions is not included.
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 netCO2 removals and GHG emissions occurringthat occur over an interval of time. This unit of time is defined as the Reporting Period, [math: RP], andwhich isrepresents initiallyan theinterval of time betweenover injectionwhich commencingnet CO2e removals are calculated and reported for verification and then between verifications.
The following sections outline the process for calculating the net CO2e removed for each reporting period based on total mass stored during that period, written hereafter as [math: CO_2e_{Removal,\ RP}].
Total emissions reductions may be adjusted in future years for a reporting period, [math: RP], due to 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.) (see Section 8) that may occur over the duration of the long-term storage period.
Net CO2e removal for a process utilizing DAC with storage must be calculated as follows for a reporting period, [math: RP]:
[math: CO_2e_{Removal} = CO_2e_{Stored}\ –\ CO_2e_{Counterfactual}\ -\ CO_2e_{Emissions}]
(Equation 1)
Where;
TheNote: finalReversals netoccur CO2eafter quantificationCredits musthave bebeen conservativelyissued determined,so givingare highnot confidenceincluded (95%in orthis above)equation. thatSee Section 5.6 of the estimatedIsometric massStandard for further infomartion. Risk of carbonreversal wasinformation removedis provided within the relevant Storage Module.
Type: Sequestration
[math: CO_2e_{Stored}] represents the massamount of carbon as CO2e present in the CO2-containing injectant that is injected and stored in the geologic or engineered storage formation in a given [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 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:
Calculation of [math: CO_2e_{Stored}] requires two primary measurements
[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:
IfThe premixed dissolvedtotal CO2 is injected into the subsurface or during the ex-situ mineralization processes which may use a carbonate slurry, then the total carbon content must be determined viausing the analysisdifference ofin samplescarbonate ofconcentration injectantin orthe inputmineral stream,waste pre and post mineralization. This should be carried out in line with the following standard following:
TestsCarbon content analyses must be completed by an ISO 1702510694 accredited laboratory, or equivalent, with accreditation including the specific method of interest.
All samples must be collected as individual grab samples from the injectantmineralized streammaterial. AProject minimumProponents 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 threeheterogeneous materials is given in Section 4 of the Rock and Mineral Feedstock Characterization Module. At a minimum, samples must be collectedtaken fordaily each sampling event and for stable carbon mass flows, at a minimum this sampling must occur quarterly. The carbon content must then be conservatively estimated by using 1 standard error belowwhilst the meanex-situ for either the reporting period or smaller time unit (Δt) set within the PDD. The Project will also be subject to random sampling, to alleviate the risk of any substantially different carbon content at given time:
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:
ExWhere CO2 is stored via ex-situ mineralization may use carbonate slurries or other such injectants are produced, determination of weightthe mass of delivered CO2-containing injectant toof the injectionmaterial sitethat mayhad undergone ex-situ mineralisation shall be performedmeasured using a calibrated scale. TheThis totalcould massfor stored mayexample be determineddone by determining the difference in delivery truck weight measured upon arrival at the injectionfinal storage facility and at departure, after offloading of product, either into closed-system temporary holding or directly stored, or using load cells/sensors on temporary holding tanks.
Any truck scale used must have a current certification in accordance with applicable local, state, or federal regulations for legal-for-trade weights and measures. Testing and calibration of scales must utilize certified weights in accordance with local, state, or other regulations, calibration weights must meet NIST Handbook 44 specifications518, and scale testing and any calibration must be performed regularly (at minimum once annually) by a state certified entity.
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 CO2e stored in injected CO2 or CO2-containing injectant:
Records of all carbon content analyses and injections must be maintained by the injection facility or project proponent and provided for verification purposes for a periodminimum of five years.
Type: Counterfactual
For DAC with geologic sequestration, the counterfactual for eligible projects is considered to be 0zero, if all eligibility criteria are met and conditionsas outlined in Section 4 are also met.
However, there are considerations for counterfactual energy usage, which are discussed and accounted for within the Energy Use Accounting Module (see Section 7.4.3.1).
Type: Emissions
[math: CO_2e_{Emissions}] is is the total quantity of GHG emissions from operations and embodied emissions associated with thea injectionsgiven thatReporting occurred in reporting periodPeriod, [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.Project} +CO_2e_CO_{Monitoring2}e_{Leakage}]
(Equation 3)
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.
When the Project Proponent is planning to cease operations within a given storage site, they must project the calculation of monitoring emissions 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 site 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.
EmissionsGHG emissions associated with energy[math: usageCO_2e_{Energy}] throughoutshould include all phases of the process must be accounted for, whether electricity or thermal energy, typicallyemissions associated with electricity usage or fuel combustion.
Energy related emissions may include, but are not limited to:
Refer toThe Energy Use Accounting Module forprovides guidance 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 guidelinesapproach to be followed for intensive facilities and non-intensive facilities and acceptable emissions 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 reporting period must be accounted for, including the following:
The Transportation Emissions Accounting Module provides guidance 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 overto anremovals appropriateappropriately allocationin periodline with the Embodied Emissions Accounting Module.
Project Proponents must account for all embodied emissions in DAC equipment and facilities, including but not limited to the following:
DAC Process:
CO2 transportation:
CO2 sequestrationstorage:
Monitoring:
Universal equipment for all processes:
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., steam boiler) emissions consider full cradle-to-grave GHG emissions. 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, equipment and facilities, including but not limited to the following:
DAC Process:
CO2 sequestrationstorage:
Monitoring:
Universal equipmentconsumerables for all processes:
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 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.
Miscellaneous GHG emissions for emissions associated with injections[math: forCO_2e_{Misc.}] ashould giveninclude reportingall period,project 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 project 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_{MonitoringMisc.}].
Projects are responsible for identifying and quantifying such emissions.
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 sorbentsnon-CO2 orGHGs solventsrequires astwo carryoverprimary or directlymeasurements, ifthe theymeasurement haveof athe 100total yrquantity GWPof >emissions 1
Emissionsand the analysis of emissions for theCO2 aboveand examplesother areGHG content. This can be calculated as follows:
[math: CO_{2}e_{MiscProjct} = \sum_{t=1}^{T} m_{em,t} \cdot\ C_{GHG,t} \cdot\ GWP_{GHG}]
(Equation 4)
Where:
Quantification of [math: CO_2e_{Misc. Project}] in a given [math: RP], requires two primary measurements, the measurement of the total quantity of emissions and the analysis of emissions for CO2 and other GHG content.
The total quantity of direct emissions can be determinedmeasured by various acceptable methods, including:
The concentration of CO2 or other GHGs in the emissions ([math: CO_2e_{Release}]) or tail gas ([math: CO_2e_{Tailgas}]) 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 project proponent and provided for verification purposes for a period of five years.
[math: CO_2e_{Leakage,\ n}] includes emissions associated with a project's impact on activities outside the system boundary of the project. This includes instances where the 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 project, market leakage emissions associated with the replacement of consumables used must be considered as a minimum.
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.
A module for Ex-Situ Mineralization will be coming soon.
Isometric would like to thank following contributors to this Protocol and relevant modules:
Isometric would like to thank following reviewers of this Protocol and relevant modules:
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 the Project Crediting Period, prior to each Verification.
This methodology utilizes a comprehensive monitoring and documentation framework that captures the GHG impact in each stage of a Project. Monitoring and detailed accounting practices must be conducted throughout to ensure the continuous integrity of 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 Modules associated with this Protocol have their own set of required parameters that need to be monitored. Please refer to the following Sections of the Modules to see a complete list of all requirements:
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: C_{mean,\ inj,\ t}] | %wt of CO₂ within the injectate, or additonal C concentration in the carbonated minerals as a result of ex-situ mineralization | Always | Eq. 2 (Direct Air Capture) | Measured | wt% | Analytical determination of carbon content in injectate or carbonated minerals | For CO₂ measurements: Continuous inline analyzer for CO₂ such as NDIR, TDL, or equivalent. For measurement of carbon content in carbonated minerals: ISO 10694:1995, or equivalent. | Continuous for injection streams, or daily for carbonated minerals | 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 | 7.4.1 (Direct Air Capture) |
| [math: m_{Inj,\ t}] | Total mass of CO₂ containing injectate injected or of carbonated minerals stored during time [math: t] | Always | Eq. 2 (Direct Air Capture) | Measured | kg | Direct mass measurement | Calibrated mass flow meter or volumetric flow meter and density measurements over a defined time interval Δt | Continuous | Scales must be calibrated annually by certified entity | Weigh scale tickets for each injection (arrival and departure weights); Calibration records for scales | 7.4.1 (Direct Air Capture) |
| [math: kwh_{L}] | Electricity usage for DAC process | Always | Eq. 4 (Energy Use Accounting Module) | Measured | kwh | Electricity usage records |
| Each reporting period | 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 reporting period | 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 reporting period | 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 reporting period | 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 reporting period | 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 reporting period | 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 reporting period | 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 reporting period | 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 reporting period | 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 reporting period | 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 reporting period | 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 reporting period | 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 reporting period | 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. 4 (Direct Air Capture) | 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. 4 (Direct Air Capture) | 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 the project and cost based embodied emission factors | 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 the project and cost based embodied emission factors | 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 the project and cost based embodied emission factors | 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 |
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
Methodology for assessing the quality of carbon credits, Version 3.0. (2022, May). https://carboncreditquality.org/methodology.html
NIST (2015, April 20). Overview of ASTM D7036: A Quality Management Standard for Emission Testing. https://www.nist.gov/system/files/documents/2017/10/31/overview-astm-d7036.pdf
NIST. (2023). Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices - 2023 Edition. NIST. https://www.nist.gov/pml/owm/publications/nist-handbooks/handbook-44-current-edition
US Department of Energy. (2022) Best Practices for Life Cycle Assessment (LCA) of Direct Air Capture with Storage (DACS). https://www.energy.gov/sites/default/files/2022-06/FECM%20DACS%20LCA%20Best%20Practices.pdf
U.S. Environmental Protection Agency. (2023, April 18). Understanding Global Warming Potentials | US EPA. Environmental Protection Agency. Retrieved June 14, 2023, from https://www.epa.gov/ghgemissions/understanding-global-warming-potentials
U.S. DOE. (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., Mazzotti, M. (2021). Life cycle assessment of carbon dioxide removal technologies: a critical review. Energy & Environmental Science. https://doi.org/10.1039/D0EE03757E
Shi, Xiaoyang, Hang Xiao, Habib Azarabadi, Juzheng Song, Xiaolong Wu, Xi Chen, and Klaus S. Lackner. "Sorbents for the direct capture of CO2 from ambient air." Angewandte Chemie International Edition 59, no. 18 (2020): 6984-7006. ↩
Custelcean, Radu. "Direct air capture of CO2 using solvents." Annual Review of Chemical and Biomolecular Engineering 13 (2022): 217-234. ↩
Fujikawa, Shigenori, and Roman Selyanchyn. "Direct air capture by membranes." MRS Bulletin 47, no. 4 (2022): 416-423. ↩
Renfrew, Sara E., David E. Starr, and Peter Strasser. "Electrochemical approaches toward CO2 capture and concentration." ACS catalysis 10, no. 21 (2020): 13058-13074. ↩
Al Hameli, Fatima, Hadi Belhaj, and Mohammed Al Dhuhoori. "CO2 sequestration overview in geological formations: Trapping mechanisms matrix assessment." Energies 15, no. 20 (2022): 7805. ↩
Rochelle, Christopher A., I. Czernichowski-Lauriol, and A. E. Milodowski. "The impact of chemical reactions on CO2 storage in geological formations: a brief review." Geological Society, London, Special Publications 233, no. 1 (2004): 87-106. ↩
Ricks, Wilson, Qingyu Xu, and Jesse D. Jenkins. "Minimizing emissions from grid-based hydrogen production in the United States." Environmental Research Letters 18, no. 1 (2023): 014025. ↩
Goeppert, Alain, Miklos Czaun, GK Surya Prakash, and George A. Olah. "Air as the renewable carbon source of the future: an overview of CO 2 capture from the atmosphere." Energy & Environmental Science 5, no. 7 (2012): 7833-7853. ↩
Sanz-Pérez, Eloy S., Christopher R. Murdock, Stephanie A. Didas, and Christopher W. Jones. "Direct capture of CO2 from ambient air." Chemical reviews 116, no. 19 (2016): 11840-11876. ↩
Terlouw, Tom, Karin Treyer, Christian Bauer, and Marco Mazzotti. "Life cycle assessment of direct air carbon capture and storage with low-carbon energy sources." Environmental science & technology 55, no. 16 (2021): 11397-11411. ↩
Erans, María, Eloy S. Sanz-Pérez, Dawid P. Hanak, Zeynep Clulow, David M. Reiner, and Greg A. Mutch. "Direct air capture: process 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://verra.org/wp-content/uploads/2023/06/DAC-Module-Public-Consultation-Draft.pdf↩↩2
ISOFor 14064-3: 2019example, Section40CFR195 5- Transportation of Hazardous Liquids via Pipeline and 40CCF146.194 - Class VI Wells.7 ↩↩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. ↩
Adefila, Kehinde, Yong Yan, Lijun Sun, and Tao Wang. "Flow measurement of wet CO2 using an averaging pitot tube and coriolis mass flowmeters." International Journal of Greenhouse Gas Control 63 (2017): 289-295. https://doi.org/10.1016/j.ijggc.2017.06.005↩
https://www.nist.gov/pml/owm/nist-handbook-44-current-edition↩
Lyons, L., Kavvadias, K. and Carlsson, J., 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. ↩
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, Trieu-Vuong, In-Young Choi, Youn-Suk Son, and Jo-Chun Kim. "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 Stivenson, Edwing Alexander Velasco Rozo, and Víctor G. Baldovino-Medrano. "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↩