What is Direct Air Capture?

What is Direct Air Capture?

Direct air capture (DAC) is a technology that chemically extracts CO2 directly from ambient air, producing a concentrated stream of CO2 for permanent geological storage or utilization. Unlike point-source carbon capture, which intercepts emissions at industrial facilities, DAC can remove historical emissions already dispersed in the atmosphere. It is one of the few scalable approaches to achieving net-negative emissions.

Why It Matters

Even aggressive emissions reduction efforts cannot undo past emissions: humans released about 2,400 billion tonnes of CO2 between 1850 and 2019, according to the IPCC, much of which remains in the atmosphere. The highest-ambition 1.5°C scenario in the 2026 State of Carbon Dioxide Removal report needs about 8.8 billion tonnes of removal a year by mid-century, against about 2.2 billion tonnes removed today, almost all through conventional methods such as forests. Nature-based removal approaches—reforestation, soil carbon sequestration—face permanence and scalability constraints. DAC offers a technologically precise, verifiable, and permanent removal pathway that complements biological methods.

The DAC industry is nascent. The IEA counted 27 DAC plants worldwide in early 2025, capturing almost 10,000 tonnes a year in total. Climeworks' Mammoth plant in Iceland, designed to capture up to 36,000 tonnes a year, captured 105 tonnes in its first ten months, according to the Icelandic outlet Heimildin (2025), and Occidental's larger Stratos plant in Texas is now expected to start operating in 2027. Congress authorized $3.5 billion for the U.S. Department of Energy's Regional DAC Hubs program in 2021; the two hubs selected in 2023 share up to $1.2 billion, and after a long review DOE told Congress in April 2026 that it would keep both. The DOE's 2021 "Carbon Negative Shot" set a goal of removal below $100 per net tonne within a decade, far below the IEA's current estimate of $500 to $1,900 per tonne.

For corporate climate strategy, DAC-based carbon removal occupies a unique position. It offers the highest-quality carbon credits available—fully additional, precisely measured, and geologically permanent—making it the preferred removal pathway for organizations seeking credible net-zero claims. Buyers including Microsoft and the Frontier coalition, whose members include Stripe, JPMorgan Chase, and Shopify and which has committed to buy $1.8 billion of permanent carbon removal by 2040, have signed advance purchase agreements, creating a demand signal that de-risks investment in capacity expansion.

The energy requirements of DAC are substantial and shape its deployment geography. Capturing one tonne of CO2 takes roughly 5.5 to 9.5 gigajoules of energy (about 1,500 to 2,600 kWh), mostly as heat, according to the IEA. Siting DAC facilities alongside abundant low-carbon energy—geothermal in Iceland, solar in the American Southwest, wind in Patagonia—is essential to ensuring the process removes more carbon than it generates.

How It Works / Key Components

Two primary technology approaches dominate the DAC landscape. Solid sorbent systems (used by Climeworks and by Global Thermostat, now owned by Zero Carbon Systems) pass air over solid materials that chemically bind CO2 at ambient conditions, then heat the sorbents to approximately 100°C to release the captured CO2. Liquid solvent systems (developed by Carbon Engineering, which Occidental Petroleum acquired in 2023 and whose technology Occidental's 1PointFive subsidiary is deploying) bubble air through a potassium hydroxide solution that absorbs CO2, then process the resulting carbonate through a series of chemical reactions at up to 900°C to regenerate the solvent and release pure CO2.

Each approach has distinct trade-offs. Solid sorbent systems operate at lower temperatures, enabling the use of low-grade waste heat or geothermal energy, but current sorbent materials degrade over time and require periodic replacement. Liquid solvent systems achieve higher capture rates per unit of equipment and use well-understood industrial chemistry, but their high-temperature regeneration step demands significant energy—typically natural gas with CCS, though electrification pathways are under development.

Once captured, the concentrated CO2 stream follows the same pathways as point-source CCS: pipeline or ship transport to geological storage sites, or utilization in products like synthetic fuels, building materials, or chemicals. The combination of DAC with permanent geological storage is termed DACCS (Direct Air Carbon Capture and Storage), and this is the configuration that qualifies as carbon dioxide removal under most frameworks.

Cost reduction depends on industrial learning and scale. The IEA estimates that current DAC projects cost $500 to $1,900 per tonne; advances in capture materials and scale effects could bring costs to around $300 per tonne by mid-century, and some next-generation designs target $100. Public procurement programs, advance market commitments, and the 45Q tax credit of $180 per tonne for DAC with geological storage, which the July 2025 budget law kept, support early projects.

Council Fire's Approach

Council Fire helps clients evaluate DAC-based carbon removal as a component of credible net-zero strategies. We assess the quality and pricing of DAC credit offerings, structure advance purchase agreements, and advise on portfolio approaches that balance cost, quality, and delivery risk across removal pathways. Our guidance is rooted in the principle that high-quality removal should complement—never substitute for—aggressive emissions reduction.

Frequently Asked Questions

How does DAC compare to planting trees for carbon removal?

Both are valid removal pathways with different characteristics. Afforestation and reforestation are cheaper (the IPCC puts their cost at $0 to $240 per tonne) but face permanence risks from fire, disease, and land-use change, and verification is complex. DAC is expensive (about $500 to $1,900 per tonne for current projects, according to the IEA) but offers precise measurement, geological permanence, and no land competition. A credible removal portfolio typically includes both—nature-based solutions for near-term volume and engineered removal for permanence and scalability.

Is DAC just an excuse to keep burning fossil fuels?

This critique misunderstands the application. DAC addresses residual emissions from genuinely hard-to-abate sectors (aviation, agriculture, certain industrial processes) and historical atmospheric CO2 accumulation. Every credible net-zero scenario—including those from the IPCC, IEA, and major climate research institutions—includes carbon dioxide removal alongside radical emissions cuts. The concern is valid when DAC is invoked to justify inaction on emissions reduction; the technology itself is a necessary tool when deployed responsibly.

When will DAC be affordable enough for widespread deployment?

The IEA expects advances in capture materials and scale to bring costs down to around $300 per tonne by mid-century, while some next-generation designs target $100. The 45Q tax credit of $180 per tonne for DAC with geological storage, which the July 2025 budget law kept, covers only part of today's costs, so projects also depend on buyers. Advance purchase commitments from the Frontier coalition (founded by Stripe, Alphabet, Meta, Shopify, and McKinsey) are de-risking investment in current-generation plants while funding development of next-generation technologies.