Direct Air Capture Machines Have Their First Commercial Customers , Now They Need to Get Cheap Enough to Matter

The Machine That Captures Carbon From Thin Air

Direct air capture technology uses chemical processes to extract carbon dioxide from ambient air at concentrations of approximately 420 parts per million, concentrating it to a pure CO2 stream that can be permanently stored underground or used as a feedstock for synthetic fuels and materials. The engineering challenge of DAC is the thermodynamic unfavourability of capturing CO2 at such low atmospheric concentration. Capturing a tonne of CO2 from ambient air requires substantially more energy than capturing the same quantity from a concentrated industrial point source like a power plant or cement kiln, because the energy cost of the separation process increases as the concentration of the target molecule decreases. This thermodynamic reality is the fundamental reason why DAC is expensive and why the gap between the cost of DAC carbon removal and the price that voluntary carbon markets and regulatory compliance frameworks pay for carbon removal has limited DAC deployment to demonstration and small commercial scale despite a decade of development investment.

The commercial customers that DAC has attracted despite its high cost are purchasing carbon removal for reasons that go beyond the immediate price-per-tonne comparison with alternative carbon offsets. The permanence of geological CO2 storage, which sequesters the captured carbon in rock formations over geological timescales rather than the decades of forest-based carbon sequestration whose reversibility climate advocates and corporate sustainability teams increasingly flag as a credit quality limitation, commands a premium from buyers whose corporate net-zero commitments require the durable carbon removal that DAC can verify. Microsoft, Stripe, Shopify, and several other technology companies have made advanced market commitments for DAC carbon removal at prices that would be commercially indefensible for conventional fossil fuel offset purchases but that the buyers justify as investment in the scaling of the technology whose cost reduction requires the early commercial demand that de-risks manufacturing scale-up.

Climeworks Mammoth and the Scale-Up Reality

Climeworks operates the two largest direct air capture plants in the world. Its Orca plant in Iceland, opened in 2021 with a capture capacity of four thousand tonnes of CO2 per year, was the first commercial-scale DAC plant and provided the operational data whose learning informed the design of the Mammoth plant that Climeworks opened in Iceland in 2024. Mammoth's design capacity of 36,000 tonnes per year of CO2 represents a tenfold scale-up from Orca and is the most significant single step in DAC capacity expansion attempted to date. The Mammoth plant uses modular collector units, each consisting of fans that draw air through a solid sorbent material that binds CO2, and a regeneration cycle that releases the captured CO2 by heating the sorbent. The CO2 is then mixed with water and injected deep into basalt rock formations where it mineralises into carbonate minerals within two years, providing the geological permanence that Climeworks's corporate customers are paying for.

The cost of CO2 capture at the Mammoth plant has not been publicly disclosed in precise terms, but Climeworks's commercial pricing for the carbon removal credits sold from its plants has been in the range of several hundred to over one thousand US dollars per tonne, reflecting the actual cost of DAC carbon removal at current scale. The cost reduction pathway that Climeworks and other DAC developers have committed to involves the combination of learning curve improvements as manufacturing scale increases, energy cost reduction through co-location with cheap renewable electricity, and engineering optimisation of the capture and regeneration cycle that increases the CO2 captured per unit of energy and capital invested. The DOE's target of reducing DAC cost to one hundred dollars per tonne, established through the DAC Earthshots programme, represents the economic threshold at which DAC becomes competitive with a wider range of climate policy mechanisms and at which the demand for DAC carbon removal could expand from voluntary corporate purchasers to compliance-driven industrial buyers.

Heirloom and the Mineralisation Approach

Heirloom Carbon Technologies uses an approach to direct air capture that differs fundamentally from Climeworks's solid sorbent technology. Its process uses calcium oxide, produced by heating limestone, whose natural affinity for CO2 causes it to absorb atmospheric CO2 when spread in thin layers and exposed to air. The calcium carbonate produced by this absorption is then heated to release the CO2 for geological storage and regenerate the calcium oxide for reuse. The commercial appeal of Heirloom's mineralisation approach is its use of calcium oxide, an extremely abundant and inexpensive material, rather than the engineered solid sorbents that Climeworks uses whose cost and durability over many regeneration cycles is a significant component of the operating cost of solid sorbent DAC. Heirloom's first commercial plant in Tracy, California commenced operation in 2023 and is providing the operational data on calcium oxide-based DAC at commercial scale that the company's scale-up plans require.

Top 10 Companies in Direct Air Capture Globally

1. Climeworks: Largest commercial DAC operator with the Orca and Mammoth plants in Iceland; its geological storage partnership with Carbfix and its corporate customer base including Microsoft and Stripe represent the most commercially validated DAC business model, though its cost per tonne of CO2 removed remains substantially above the levels required for mainstream climate policy deployment.
2. Carbon Engineering (Oxy): Canadian DAC technology company acquired by Occidental Petroleum; its liquid solvent DAC approach and its 1PointFive subsidiary's Stratos plant in Texas, which targets one million tonnes per year of CO2 capacity at full scale, represent the largest planned DAC deployment and the first to integrate DAC with enhanced oil recovery as a commercial revenue stream.
3. Heirloom Carbon: US startup using accelerated mineralisation of calcium oxide for direct air capture; its low-cost sorbent material and its first commercial plant in California are the commercial milestones that validate the mineralisation approach as a lower-cost alternative to the engineered solid sorbents that dominate current DAC deployments.
4. Global Thermostat: US DAC company using amine-based solid sorbents on monolith structures; its technology's ability to use low-grade waste heat rather than high-temperature electricity for sorbent regeneration creates the energy cost advantage that is most commercially significant in locations where electricity costs are high and industrial waste heat is available.
5. Verdox: MIT spin-out developing electrochemical DAC using electrically-driven carbon capture rather than thermal regeneration; its electrochemical approach theoretically reduces the energy required for CO2 capture and release relative to thermal regeneration systems and could improve the economics of DAC in locations where renewable electricity is cheap but heat is expensive to generate.
6. Sustaera: US DAC startup using granular solid sorbents in a fluidised bed reactor configuration; its sorbent engineering focus and its DOE funding create the technology development pathway for a DAC approach that addresses the sorbent degradation and reactor design challenges that limit the current generation of solid sorbent DAC systems.
7. Carbfix: Icelandic company providing the geological CO2 storage service that Climeworks and other DAC operators use for permanent CO2 sequestration; its basalt mineralisation process and its expansion from Iceland to other basalt-rich geological formations internationally create the permanent storage infrastructure that DAC carbon removal permanence claims depend on.
8. Skytree: Dutch DAC company developing modular small-scale DAC units for distributed deployment; its compact system design and its focus on CO2 utilisation rather than geological storage creates the commercial market for DAC-captured CO2 in controlled environment agriculture, carbonated beverages, and synthetic fuel production whose economics differ from the geological storage pathway.
9. Carbon Management Canada: Research and commercialisation organisation supporting Canadian DAC development; its role in developing the regulatory framework and support programmes for DAC in Canada creates the policy infrastructure that the commercial DAC projects targeting Canadian geological storage formations require.
10. Frontier (Stripe/Alphabet/McKinsey): Advance market commitment fund purchasing DAC carbon removal to accelerate cost reduction; its aggregated demand from corporate buyers provides the offtake certainty that enables DAC developers to raise the capital for commercial plant construction that individual project finance cannot support at current credit prices.