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 fully address the roughly 1.7 trillion tonnes of anthropogenic CO2 already accumulated in the atmosphere. The IPCC's pathways limiting warming to 1.5°C require removing 5-16 gigatonnes of CO2 per year by mid-century. 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 but growing rapidly. Global operational capacity reached approximately 10,000 tonnes per year in 2024, with Climeworks' Mammoth plant in Iceland (36,000 tonnes/year) and the U.S. Department of Energy's Regional DAC Hubs program ($3.5 billion across multiple sites) representing the next wave of scale-up. The DOE's "Carbon Negative Shot" initiative targets costs below $100 per tonne by 2032—down from current estimates of $400-1,000.

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. Companies including Microsoft, Stripe, JPMorgan, and Shopify have made advance purchase commitments totaling billions of dollars, 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 requires 1,500-2,000 kWh of thermal energy and 300-500 kWh of electricity. 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 Global Thermostat) 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 (used by Carbon Engineering, now part of Occidental Petroleum's 1PointFive subsidiary) 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 follows predictable industrial learning curves. First-of-a-kind DAC plants operate at $600-1,000 per tonne. Engineering estimates suggest that nth-of-a-kind plants at scale could reach $150-300 per tonne with current technology, and sub-$100 with next-generation sorbents and process improvements. Public procurement programs, advance market commitments, and the IRA's $180/tonne 45Q credit for DACCS are accelerating this cost decline.

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. Trees are inexpensive ($5-50 per tonne) but face permanence risks from fire, disease, and land-use change, and verification is complex. DAC is expensive ($400-1,000 per tonne today) 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?

Cost trajectories suggest $200-300 per tonne is achievable by 2030-2035 at scale, with sub-$100 possible by 2040-2050 with continued innovation. The IRA's $180/tonne tax credit already makes DACCS economically viable for projects with favorable energy costs. Advance purchase commitments from the Frontier coalition (Stripe, Alphabet, Meta, Shopify, McKinsey) are de-risking investment in current-generation plants while funding development of next-generation technologies.