Introduction to Direct Air Capture

What is Direct Air Capture?

Diagram of a solid DAC system with thermal regeneration. Image adapted from Long International.

Direct air capture (DAC) describes a group of technologies that are engineered to selectively remove CO2 from ambient air when it is flown through a device. Related methods of removing CO2 from industrial waste streams like power plant and cement production flue gases are well-developed and widely adopted, however, capturing CO2 from air directly is a distinct challenge due to its low concentration in the atmosphere (approx. 430 parts per million or 0.04%). Carbon dioxide removal (CDR) approaches like DAC are critical. Whereas point source CO2 capture from industry seeks to reduce ongoing emissions, CDR tackles emissions from all sources, including diffuse emissions that must be removed to meet our climate goals. The IPCC AR6 report (2022) established that CDR will need to scale to 27.0 gigatons annually by 2100 to sustain net zero emissions and limit further temperature rise if average global warming exceeds 1.5 °C, as occurred in 2024. If warming is contained to under 1.5 °C, CDR will need to scale to 17.6 GtCO2/y by 2100.

Step 1: Capture. A growing number of chemical reactions utilizing specially-designed sorbents have been optimized to capture CO2 by reacting with the gas selectively and changing its chemical structure, or by causing CO2 to stick to the surface of a material while other molecules in air are unaffected. DAC systems are broadly characterized as solid, liquid, membrane, or cryogenic DAC based on the characteristics of the sorbent used or the capture mechanism. View a breakdown of the current DAC industry based on technical approach here.

Step 2: Release. Once CO2 is captured, it is released as a concentrated stream for geological storage or subsequent utilization. Generally, release occurs by applying energy to reverse the chemical reaction that captured the CO2. Most commonly, DAC systems are heated to release CO2, which occurs at approximately 90–120 °C or as high as 900 °C, depending on the DAC system. A growing number of companies are also pursuing electrochemical and photochemical methods of DAC, which release CO2 using electricity or light, respectively. View a breakdown of the current DAC industry based on technical approach here.

Step 3: Storage and Utilization. Geological storage is currently the dominant method to ensure permanent and durable carbon removal using DAC. Geological storage in sub-surface saline aquifers and in porous rock formations are well developed, effective practices widely used in point source CO2 capture. On the other hand, opportunities to utilize captured CO2 directly – for example, in greenhouses or as a feedstock to create products like fuels – are growing. Utilization can offer a path to create a profitable carbon removal cycle and also provides distinct advantages. In hard-to-abate industries like aviation, which is broadly limited to using jet fuel, CO2-derived fuels are promising alternatives to lower their climate impact. Explore current CO2 utilization in the DAC industry here.

Additional resources: 6 Things to Know About Direct Air Capture (2025), Direct Air Capture: Process Technology, Techno-Economic and Socio-Political Challenges (2022), The Applied Innovation Roadmap for CDR (2023), CDR Primer (2021).

Scalable DAC will depend on energy efficiency.

DAC systems today consume a substantial amount of energy, roughly 5–11 GJ/tCO2 removal in most cases. In the capture step, separating such a small concentration of CO2 from air requires huge volumes of air to pass through DAC systems. Typically, large fans consume electricity to draw in air and push it through the systems. This accounts for a significant portion of DAC energy consumption in many cases, but by in large, the greatest amount of energy required for DAC is needed to release captured CO2 and regenerate the sorbents.

Energy-efficiency is the most consequential factor of DAC success at scale. Low-carbon electricity generates about 40 EJ/y currently with the ability to rise to about 200 EJ/y by 2050. Thus, at a targeted capacity of 1.2 gigatons of CO2 removed per year in 2050, DAC systems* would consume about 6% of global low-carbon energy at an efficiency of 10 GJ/tCO2 removed, but only about 0.6% at 1 GJ/tCO2. Likewise, energy requirements affect the operating cost of DAC systems. As a result, many DAC companies are targeting industrial waste heat, geothermal energy, and other indirect heat sources to power their regeneration steps, or are otherwise optimizing their processes to be more energy-efficient. DAC is a technologically-varied industry, but companies share the common goal of reducing energy consumption to remain competitive.

Scaling DAC to meet our climate goals will require substantial energy, and for productive carbon removal this energy must be from low-carbon sources like solar, wind, and nuclear. Besides optimizing energy-efficiency, new purpose-built renewable energy sources will be required beyond what is currently needed to decarbonize power production. In addition, DAC should integrate with growing industries like data centers that produce significant waste heat to avoid competition for low-carbon energy.

While DAC units are typically compact and modular and don't require significant land use, the land area required to site new-carbon energy sources to power DAC is a relevant consideration. At a scale of 1 GtCO2/y (requiring up to approx. 10,000 km² for DAC facilities), nuclear power (up to approx. 17,000 km²) requires less land than solar and wind (up to approx. 55,000 and 90,000 km², respectively) to supply the requisite energy.

Other resources besides energy and land, such as water consumption, should be considered when assessing the feasibility of DAC projects. For a more complete evaluation of resource requirements and other associated risks, explore DAC methods and related risk assessments based on technological approach here.

*These estimates also include CDR via indirect water capture, but are dominated (approx. 80%) by DAC.

Source: The Applied Innovation Roadmap for CDR (2023).

The cost of DAC requires supportive policy to grow.

Construction of the STRATOS plant in March 2025, Texas, USA. Image source: 1PointFive.

Deep Sky Alpha test site, Alberta, Canada. Image source: GE Vernova.

The cost of DAC is a current barrier to its large-scale implementation. Among disclosed sales, the price of carbon credits from DAC in the voluntary carbon market in 2024 ranged widely from $100–2000/tCO2 removed, with an average of $490 over several years. Many estimates place the near-term cost of DAC at approximately $600–1000/tCO2, although lower estimates are reported. While current costs are high, large-scale DAC projects are expected to learn through deployment and reduce their energy and cost requirements as real-world insights drive improvements. The US Department of Energy Carbon Negative Shot Strategy has identified an ambitious goal of 1 Gt CO2 removal per year by 2050 at a price of $100/tCO2, including storage. Independent analysis of several leading DAC approaches has estimated that prices can feasibly fall to $100–600/tCO2 with storage. Meanwhile, the authors of the study note that the estimated global economic damages of CO2 emissions (social cost of carbon) range between $177–805/tCO2 emitted.

Policy support for DAC is critical. Large-scale DAC deployments amounting to megaton- and gigaton-scale carbon removal at today's cost estimates are unrealistic for all but the largest companies involved. As context, Oxy/1PointFive's STRATOS plant with an nameplate capacity of 0.5 MtCO2/y cost approximately $1–1.3 billion, with BlackRock investing $550 million. 1PointFive's next project, the South Texas DAC Hub, with a proposed capacity of 1 MtCO2/y has been awarded up to $650 million from the US DOE, and ADNOC's XRG is considering a $500 million investment.

From 2021–2024 the United State led in global support for DAC programs at all stages of development, most notably in its $3.5 billion dollar federal investment in four regional DAC hubs each capable of capturing 1 MtCO2/y. As of October 2025, much of this funding was placed under review or cancelled, including for two DAC hubs. Separately, the 45Q tax credit reimburses up to $180/t for CO2 captured and stored using DAC. Besides federal support, US states have an opportunity to lead in DAC development where it aligns with their stated climate goals and resources. For example, California offers abundant geothermal and solar resources, and has a strong climate policy framework. Texas offers abundant renewable energy generation, largely from wind power, and has a well-developed CO2 transport and storage infrastructure.

Globally, support for DAC is growing. Canada provides an investment tax credit of up to 60% for DAC and has a purchasing program for carbon removal. Canada also hosts the Deep Sky Alpha test site in Innisfail, Alberta, a growing test bed of pilot-scale DAC systems incorporating geological storage. The EU has allocated approximately EUR $660 million to support CDR methods, including DAC, through Horizon Europe and other programs, and is considering a purchasing program for carbon removal. The UK supports DAC through the Direct Air Capture and Greenhouse Gas Removal Innovation Programme. Kenya's electrical grid is over 90% renewable, primarily from geothermal sources, and the Great Rift Valley contains ideal rock formations for geological storage. Great Valley Carbon is a Kenya-based system integrator and project developer that has formed partnerships with many leading DAC technology producers to pursue pilot projects in the area. Naturally, the locations of DAC companies and deployments are concentrated in areas where supportive funding and policy exists.