Direct Air Capture
TTS v1.0 - Annex A
Direct Air Capture (DAC) uses engineered systems - solid sorbents, liquid solvents, moisture-swing membranes, or electrochemical cells - to chemically bind CO₂ directly from ambient air, independent of land, biomass, or growing season. Captured CO₂ is permanently sequestered through deep geological injection or mineral carbonation, delivering the highest-confidence, most measurable class of carbon removal credit in the Teravent system.
Submit DAC Project View TTS v1.0 Annex A →How this pathway works
Direct Air Capture is the only carbon removal pathway that draws CO₂ from ambient air anywhere on Earth, unconstrained by soil type, land tenure, or growing conditions. Engineered contactors pass large volumes of atmospheric air across a capture medium - a solid sorbent, a liquid solvent, a moisture-sensitive membrane, or an electrochemical cell - which selectively binds CO₂ before the medium is regenerated, typically through heat, pressure swing, or an electrochemical cycle, releasing a concentrated CO₂ stream for compression and permanent storage.
Under the Teravent Technology-Based Carbon Standard (TTS v1.0) Annex A, Direct Air Capture with Storage (DACCS) projects earn Teravent Technology Credits of the Removal type (TTC-R) for verified net tonnes of atmospheric CO₂ captured and permanently stored, net of full lifecycle project emissions. The project boundary must encompass the capture facility, all energy inputs, the transport and compression train, and the injection or mineralisation site.
Four methodology variants are approved under Annex A - from solid sorbent systems with geological injection through basalt mineralisation storage. Each methodology specifies its own capture chemistry, energy requirements, continuous monitoring obligations, and storage integrity protocol.
TTS v1.0 - Annex A
This pathway is governed exclusively by the Teravent Technology-Based Carbon Standard (TTS v1.0). No external registry, standard, or methodology is referenced or incorporated. All requirements - additionality, quantification, durability, safeguards, and credit issuance - are defined within TTS v1.0 and Annex A specifically.
Four approved methodology variants
TTS v1.0 Annex A approves four discrete methodology types for the Direct Air Capture pathway. Each code represents a distinct capture chemistry with its own energy requirements, monitoring frequency, storage route, and default leakage deductions. A facility may combine multiple capture trains under separate methodology codes where each is independently metered.
Solid sorbent systems draw ambient air across structured contactors coated with a CO₂-selective sorbent (typically amine-functionalised or metal-organic-framework materials). Once saturated, the sorbent is regenerated using low-grade heat (temperature-vacuum swing) or moisture, releasing a high-purity CO₂ stream for compression and geological injection. This is the most commercially mature DAC pathway, with the largest fleet of operating reference facilities.
- Continuous CO₂ capture rate (t/hr) at contactor outlet via calibrated flow metering
- Sorbent regeneration energy consumption (thermal and electrical) logged per cycle
- Grid electricity emissions factor (real-time or hourly-matched where available) per Lifecycle GHG Assessment Protocol TLP v1.0
- Injection well pressure, temperature, and CO₂ purity at wellhead
- Sorbent lifecycle records - replacement frequency, degradation rate, and disposal or regeneration pathway
Liquid solvent DAC contacts ambient air with an aqueous alkaline solution (typically potassium hydroxide) in a packed absorption tower, forming a carbonate solution. The carbonate is then causticised with lime and calcined at high temperature (the KOH/Ca(OH)₂ cycle) to release a concentrated CO₂ stream and regenerate the solvent. This methodology requires substantial high-temperature heat input and is typically paired with a dedicated low-carbon energy supply.
- Continuous CO₂ capture rate at solvent regeneration outlet via calibrated flow metering
- Calciner fuel type and consumption - natural gas, biomass, or electric calciners each carry distinct baseline factors
- Lime (CaO) make-up rate and pellet reactor efficiency
- Solvent concentration and carryover losses to atmosphere or waste stream
- Injection well integrity monitoring per Module 4 storage protocol
Moisture-swing sorbent systems exploit the humidity sensitivity of certain ion-exchange resins, which bind CO₂ when dry and release it when exposed to moisture - eliminating the need for thermal regeneration. Electrochemical variants use membrane-based cells to directly capture and concentrate CO₂ from air using an applied electric potential. Both approaches are earlier-stage than DAC-M01 and DAC-M02 and are frequently eligible for the Frontier Technology designation.
- Continuous CO₂ capture rate at outlet via calibrated flow metering
- Cell or resin cycle energy consumption per tonne CO₂ captured
- Technology Readiness Level (TRL) documentation updated at each verification for TRL-based additionality screening
- Membrane or resin degradation rate and replacement schedule
- Water balance - moisture-swing systems require humidity cycling water accounting under DNSH water stress provisions
This methodology pairs any of the DAC-M01 through DAC-M03 capture chemistries with a mineral storage route rather than conventional saline aquifer injection. Captured CO₂ is dissolved in water and injected into reactive basaltic or peridotite formations, where it reacts with calcium and magnesium silicates to form stable solid carbonate minerals - typically within months to a few years, offering a faster path to demonstrable permanence than dissolved-phase aquifer storage. Site-specific reactive transport modelling and post-injection monitoring wells are mandatory.
- Continuous CO₂ capture and dissolution rate via calibrated flow and water-injection metering
- Reactive transport model validation against monitoring well geochemistry (minimum annual)
- Mineralisation confirmation sampling - carbonate phase identification at representative depths
- Injection pressure and induced seismicity monitoring per Module 5 seismic risk protocol
- Water sourcing and consumption records for DNSH water stress compliance
Which emission sources must be counted
TTS v1.0 Module 3 requires a full lifecycle GHG emissions inventory within the project boundary, deducted from gross captured CO₂ to arrive at the Net TTC figure. A source may be excluded only where its inclusion would reduce the net carbon benefit (conservative assumption) and this is documented in the PDD. The following assessment applies to all four DAC methodology variants.
Measurement, reporting
& verification
Teravent's Science Advisory Board assesses each pathway against four MRV dimensions. Direct Air Capture carries the highest MRV confidence ratings of any pathway in the Teravent system, reflecting continuous instrumented metering and a well-defined engineering boundary.
Net TTC quantification requires continuous CO₂ mass flow metering at ±2% accuracy at both the capture outlet and the injection or mineralisation wellhead, using instrumentation independently calibrated by an accredited VVB. Storage confirmation for geological injection requires wellhead pressure and temperature monitoring, periodic pressure falloff testing, and - for larger facilities - satellite InSAR ground-deformation monitoring. For basalt mineralisation, dedicated monitoring wells with geochemical sampling confirm carbonate mineral formation. All facility energy inputs are reconciled against grid emissions factors or renewable/nuclear procurement documentation under the Lifecycle GHG Assessment Protocol (TLP v1.0), updated annually.
Demonstrating additionality
TTS v1.0 Module 2 requires all projects to pass a three-test additionality framework, with a Technology Readiness Level (TRL) screen applied ahead of the common practice test. Because DAC remains at an early commercial stage relative to conventional industrial processes, most facilities registering today qualify for a streamlined additionality pathway.
Leakage types & deductions
TTS v1.0 Module 3 defines three leakage types applicable across all engineered pathways. DAC projects are primarily subject to energy-source and upstream input leakage; market leakage is generally de minimis given DAC's independence from land and biomass feedstock markets.
Buffer pool & reversal risk
All Annex A credits carry Class III Geological or Mineral permanence (>1,000-year storage horizon), the highest durability classification in the Teravent Standards System. Buffer pool contributions protect credit buyers against reversal events - unintended CO₂ migration or seepage from the storage formation. Buffer rates are set by the project's Storage Integrity Risk Rating (SIRR).
| Methodology | SIRR Rating | Buffer Pool Rate | Primary Reversal Risks |
|---|---|---|---|
| DAC-M01 Solid Sorbent | Low | 2–8% | Wellbore integrity failure; caprock breach at injection formation |
| DAC-M02 Liquid Solvent | Low | 2–8% | Wellbore integrity failure; solvent carryover to atmosphere reducing net capture |
| DAC-M03 Moisture-Swing / Electrochemical | Low–Medium | 4–10% | Elevated technology risk at lower TRL; wellbore integrity where geological injection used |
| DAC-M04 Basalt Mineralisation | Very Low | 2–6% | Pre-mineralisation dissolved-phase migration prior to carbonate formation; induced seismicity |
Key registration criteria
Projects must meet all of the following minimum requirements to qualify for registration under TTS Annex A. Additional methodology-specific requirements are detailed in the Annex A methodology tables for each DAC-M code.
Sustainable Development
Goal alignment
All Teravent registered Direct Air Capture projects must complete an SDG impact assessment at registration and at each verification period. Three SDGs are systematically tracked for this pathway. Projects may apply for co-benefit quality labels where independently verified indicators are met.
Deployment scope: Global - DAC is not constrained by land quality, biomass availability, or growing season, and can be sited wherever low-carbon energy and suitable geological or mineral storage formations co-locate, including industrial hubs, sedimentary basins, and basaltic terrains.
Ready to register your
DAC facility?
Submit a Project Concept Note under TTS v1.0 Annex A to begin your registration. Select the DAC-M code matching your capture chemistry, install continuous CO₂ metering to ±2% accuracy, and appoint an accredited VVB to validate your PDD and storage integrity plan.