Sign In

Error
Error
Create an account

Create a free IEA account to download our reports or subcribe to a paid service.

Join for freeJoin for free

Direct Air Capture

More efforts needed
Shutterstock 1031551243

About this report

There are currently 18 direct air capture plants operating worldwide, capturing almost 0.01 Mt CO2/year, and a 1 Mt CO2/year capture plant is in advanced development in the United States. In the Net Zero Emissions by 2050 Scenario, direct air capture is scaled up to capture almost 60 Mt CO2/year by 2030. This level of deployment is within reach, but will require several more large-scale demonstration plants to refine the technology and reduce capture costs. 

CO2 capture

Direct air capture (DAC) technologies extract CO2 directly from the atmosphere. The CO2 can be permanently stored in deep geological formations, thereby achieving carbon dioxide removal (CDR). Benefits of DAC as a CDR option include high storage permanence when associated with geological storage and a limited land and water footprint. The captured CO2 can also be used, for example in food processing or combined with hydrogen to produce synthetic fuels. In a transition to net zero emissions, the CO2 used to produce synthetic fuels would increasingly need to be captured from sustainable bioenergy sources or from the atmosphere to avoid delayed emissions from fossil-based CO2 when the fuel is combusted. DAC is therefore one option to achieve this.  

CO2 capture by direct air capture, planned projects and in the Net Zero Scenario, 2020-2030

Openexpand

Eighteen DAC plants are currently operational in Europe, the United States and Canada. All of these plants are small scale, and the large majority of them capture CO2 for utilisation – for drinks carbonation, for instance – with only two plants storing the captured CO2 in geological formations for removal. Only a few commercial agreements are in place to sell or store the captured CO2, while the remaining plants are operated for testing and demonstration purposes. 

The first large-scale DAC plant of up to 1 Mt CO2/year is in advanced development and is expected to be operating in the United States by the mid-2020s.  

An improved investment environment led to announcements of several new DAC projects in 2021, including the Storegga Dreamcatcher Project (United Kingdom; aimed at carbon removal) and the HIF Haru Oni eFuels Pilot Plant (Chile; producing synthetic fuels from electrolysis-based hydrogen and air-captured CO2). Synthetic fuels (up to 3 million litres) are also set to be produced by the Norsk e-Fuel AS consortium in Norway by 2024, including (but not using exclusively) CO2 captured from DAC. In June 2022 1PointFive and Carbon Engineering announced plans to deploy 70 large-scale DAC facilities by 2035 (each with a capture capacity of up to 1 million tonnes per year) under current policy and voluntary and compliance market conditions, while Climeworks announced the construction of their largest plant to date, Mammoth (capture capacity up to 36 000 t CO2/year), which should become operational by 2024. 

Plans for a total of eleven DAC facilities are now in advanced development. If all of these planned projects were to go ahead, DAC deployment would reach around 5.5 Mt CO2 by 2030; this is more than 700 times today’s capture rate, but less than 10% of the level of deployment needed to get on track with the Net Zero Scenario. 

Energy

Two technological approaches are currently being used to capture CO2 from the air: solid and liquid DAC. Solid DAC (S-DAC) is based on solid adsorbents operating at ambient to low pressure (i.e. under a vacuum) and medium temperature (80-120°C). Liquid DAC (L-DAC) relies on an aqueous basic solution (such as potassium hydroxide), which releases the captured CO2 through a series of units operating at high temperature (between 300°C and 900°C).

Capturing CO2 from the air is more energy intensive and therefore expensive than capturing it from a point source. This is because the CO2 in the atmosphere is much more dilute than, for example, in the flue gas of a power station or a cement plant. This contributes to the higher energy need and cost of DAC relative to other CO2 capture technologies and applications. 

Energy needs of DACS and DAC with CO2 use by technology and CO2 destination, 2022

Openexpand

Capturing CO2 from the air is more energy intensive and therefore expensive than capturing it from a point source. This is because the CO2 in the atmosphere is much more dilute than, for example, in the flue gas of a power station or a cement plant. This contributes to the higher energy need and cost of DAC relative to other CO2 capture technologies and applications. 

In current DAC plant configurations, the proportion of heat in the total energy needed is influenced by the operating temperature of the technologies. Both S-DAC and L-DAC were initially designed to operate using heat and electricity, with flexible configurations allowing for heat-only operation.

Innovation

While S-DAC and L-DAC innovation efforts are mostly focused on innovative sorbents and solvents, and optimised processes and layouts, emerging DAC technologies (at a technology readiness level [TRL] below 6) include electro-swing adsorption (ESA) and membrane-based DAC (m-DAC). ESA is based on an electrochemical cell where a solid electrode adsorbs CO2 when negatively charged and releases it when a positive charge is applied (swinging therefore the electric charge, rather than the operating temperature or pressure as happens in other physical separation techniques). m-DAC has been proposed as another feasible option for capturing CO2 from the air; however, it is still in its infancy and major challenges are yet to be overcome (including the need for the expensive compression of a very large amount of ambient air to separate CO2 efficiently).

While S-DAC could be powered by a variety of low-carbon energy sources (e.g. heat pumps, geothermal, solar thermal and biomass-based fuels), the current high-temperature needs of today’s L-DAC configuration does not allow that level of flexibility and could at best operate using low-carbon fuels such as biomethane or renewables-based electrolytic hydrogen. In the future L-DAC could shift to fully electric operation (currently only available for small-scale calcination). Large-scale L-DAC plants have been designed to use natural gas for heat and to co-capture the CO2 produced during combustion of the gas without the need for additional capture equipment. This integration substantially reduces the L-DAC plant’s overall emissions and can still enable carbon removal. However, any future ability of renewable energy to supply high-temperature heat could reduce the process emissions to near zero, maximising the potential for carbon removal and associated revenue streams. Accelerating the commercial availability of large-scale electric calcination technology is considered a high priority to enable L-DAC plants to operate purely on renewable energy. 

A major advantage of DAC is its flexibility in siting: in theory, a DAC plant can be situated in any location that has low-carbon energy and a CO2 storage resource or CO2 use opportunity. Yet there may be limits to this siting flexibility. To date, DAC plants have been successfully operated in a range of climatic conditions in Europe and North America, but further testing is still needed in locations characterised, for instance, by extremely dry or humid climates, or polluted air.

The choice of location also needs to be based on the energy source needed to run the DAC plant. The energy used to capture the CO2 will determine how net-negative the system is and can also be a significant determinant of the cost per tonne of CO2 captured. For instance, both S-DAC and L-DAC technologies could be fuelled by renewable energy sources, while recovered low-grade waste heat could power an S-DAC system. 

Carbon removal requires the CO2 to be permanently stored. While the overall technical capacity for storing CO2 underground worldwide is understood to be vast, detailed site characterisation and assessment are still needed in many regions. An operating CO2 storage site can take three to ten years to develop from project conception to CO2 injection. This could become a bottleneck for DAC deployment (and CCUS deployment in general) without accelerated efforts to identify and develop CO2 storage sites.

Supporting infrastructure

The choice of location also needs to be based on the energy source needed to run the DAC plant. The energy used to capture the CO2 will determine if and how net-negative the system is and can also be a significant determinant of the cost per tonne of CO2 captured. For instance, both S-DAC and L-DAC technologies could be fuelled by renewable energy sources, while recovered low-grade waste heat could power an S-DAC system. 

Carbon removal requires the CO2 to be permanently stored. While the overall technical capacity for storing CO2 underground worldwide is understood to be vast, detailed site characterisation and assessment to render potential storage sites operational are still needed in many regions. An operating CO2 storage site can take three to ten years to develop from project conception to CO2 injection. This could become a bottleneck for DAC deployment (and CCUS deployment in general) without accelerated efforts to identify and develop CO2 storage sites.

Policy

Countries and regions that have taken an early lead in supporting DAC research, development, demonstration and deployment include the United States, the European Union, the United Kingdom, Canada and Japan.

The United States has established a number of policies and programmes to support DAC RD&D, including the 45Q tax credit (providing USD 35 per tonne of CO2 used in enhanced oil recovery and USD 50 per tonne of CO2 stored) and the California Low Carbon Fuel Standard credit (providing the DAC project meets the requirements of the Carbon Capture and Sequestration Protocol). Meanwhile, the Investment and Jobs Act (signed into law in November 2021) includes funding (USD 3.5 billion) to establish four large-scale DAC hubs and related transport and storage infrastructure. 

The European Commission has been supporting DAC through various research and innovation programmes (including the Horizon Europe programme and through the Innovation Fund, launched in 2020 for the decade 2020-2030 with an initial budget of around USD 11.8 billion) and more broadly carbon dioxide removal through its first Communication on Sustainable Carbon Cycles (published in December 2021), which suggests that 5 Mt of CO2 should be removed annually by 2030 from the atmosphere through land- and technology-based approaches such as DAC. 

Policies

Policy
Country
Year
Status
Jurisdiction
Investment

Private investors are also increasingly supporting DAC. It is one of four technologies being targeted for up to USD 1.5 billion in investment by Breakthrough Energy Catalyst, established by Bill Gates and a coalition of private investors, and it is an eligible technology for the USD 100 million Carbon Removal XPRIZE. 

Support for DAC has come from programmes such as X-Prize (offering up to USD 100 million for as many as four promising carbon removal proposals, including DAC) and Breakthrough Energy’s Catalyst Program (which raises money from philanthropists, governments and companies to invest in critical decarbonisation technologies, including DAC). Additionally, in April 2022 two investment funds amounting to more than USD 1 billion were announced. Both the Lowercarbon Capital Fund and the Frontier Fund will invest in start-ups developing technology-based CDR solutions.  

Private investment rounds have also been successful: in 2022 Climeworks raised the largest-ever DAC investment, equivalent to USD 650 million. 

International collaboration

The development of agreed methodologies and accounting frameworks based on life cycle assessment (LCA) for DAC – alongside other CDR approaches – will be important to support its inclusion in regulated carbon markets and national inventories. Notably, the latest IPCC Guidelines for National Greenhouse Gas Inventories do not include an accounting methodology for DAC, meaning that CDR associated with DAC cannot be counted towards meeting international mitigation targets under the United Nations Framework Convention on Climate Change. 

Efforts to develop carbon removal certification, including for DAC-based CDR, have commenced in Europe and the United States, as well as through initiatives such as the Mission Innovation CDR Mission. These efforts should be coordinated with the aim of establishing internationally consistent approaches.

Private-sector strategies

The voluntary market for DAC-based CO2 removal has expanded, with companies such as Microsoft, Stripe, Shopify, Swiss Re and Airbus purchasing future DAC removal to offset their CO2 emissions.  

Some of these agreements are hybrid, wherein the company purchasing the offsets is effectively supporting the capital investment to build the DAC plant that is eventually going to capture CO2 from the atmosphere. For instance, United Airlines is directly investing in DAC in line with its commitment to become carbon neutral by 2050, while Microsoft is purchasing DAC removal from Climeworks and, through its climate innovation fund, has also invested in Orca, the largest operating DAC plant for carbon removal. 

On a smaller scale, some DAC companies are currently offering commercial offset services, to individuals as well as companies willing to pay a recurring subscription to have CO2 removed from the atmosphere and stored underground on their behalf. The price of the subscription varies (depending on the amount of removal purchased) from USD 600/t CO2 to USD 1 000/t CO2

Recommendations for policy makers

Carbon removal technologies such as DAC are not an alternative to cutting emissions or an excuse for delayed action, but they can be an important part of the suite of technology options used to achieve climate goals. 

For this reason, DAC needs to be demonstrated at scale, sooner rather than later, to reduce uncertainties regarding future deployment potential and costs, and to ensure that these technologies can be available to support the transition to net zero emissions and beyond. 

In the near term, large-scale demonstration of DAC technologies will require targeted government support, including through grants, tax credits and public procurement of CO2 removal. 

Technology deployment is currently benefiting from corporate-sector initiatives and pledges to become carbon negative through the voluntary market.  

However, longer-term deployment opportunities will be closely linked to robust CO2 pricing mechanisms and accounting frameworks that recognise and value the negative emissions associated with storing CO2 captured from the atmosphere. 

As an increasing number of countries make net zero pledges, the focus of decision makers has shifted to how to turn these pledges into clear and credible policy actions and strategies. To date, very few countries and companies have developed detailed strategies or pathways to achieve their net zero goals, but a critical question for all will be the extent to which these strategies will need to rely on CDR approaches alongside direct emission reductions. DAC and other CDR approaches are part of the portfolio of technologies and measures needed in a comprehensive response to climate change. Promoting transparency and planning for the anticipated role of CDR in net zero strategies can support the identification of technology, policy and market needs within countries and regions while supporting public understanding of these approaches. 

Recommendations for the private sector

Innovation will be central to reducing the cost of DAC technologies and supporting accelerated commercialisation. Priority innovation needs for DAC include: 

  • Reducing the energy consumption needed to separate CO2 through emerging separation technologies and innovative approaches able to regenerate the solvent at low to medium temperatures. 
  • Advancing engineering maturity and market conditions to support the availability of renewables-based high-temperature heat to maximise the carbon removal potential and provide an alternative to current designs based on capture of CO2 from natural gas. 
  • Reducing the cost of large-scale opportunities to use air-captured CO2, particularly for synthetic fuels. 

Increased RD&D spending to drive innovation in DAC technologies at a national and global level will be essential in the near term. 

For DAC technologies, international co-operation can drive faster deployment and accelerated cost reductions through shared knowledge and reduced duplication of research efforts. International co-operation can also support the development and harmonisation of LCA methodologies for DAC technologies. International organisations and initiatives such as the IEA, Mission Innovation CDR Mission, the Clean Energy Ministerial CCUS Initiative, and the Technology Collaboration Programme on Greenhouse Gas R&D (GHG TCP/IEAGHG) can provide important platforms for knowledge-sharing and collaboration.  

Acknowledgements
  • Geoff Holmes, Carbon Engineering 
  • Miles Sakwa-Novak, Global Thermostat 
  • Louis Uzor, Climeworks