Direct Air Capture

Countries and regions making notable progress to advance DAC technologies include:

• The United States announced the selection of two projects for award negotiation as part of the USD 3.5 billion DAC hub programme. Based in Texas and Louisiana, these projects could capture as much as 2 Mt CO₂ per year combined. This comes after the country announced important new funding in 2022 under the Inflation Reduction Act (IRA), increasing the 45Q tax credit to USD 180/t CO₂ captured for storage via DAC, with a capture threshold of as little as 1 kt CO₂/year. The United States also launched a carbon dioxide removal (CDR) pilot purchasing programme, where the federal government will enter into offtake agreements with CDR providers, including DAC.
• The European Commission aims to store up to 50 Mt CO₂ a year by 2030, including from DAC. In February 2024, the the European Parliament and the Council of the EU reached a provisional agreement on the Carbon Removals Certification Framework.
• In the United Kingdom, the budget announced in March 2023 included funding of up to GBP 20 billion (around USD 25 billion) for carbon capture, utilisation and storage (CCUS) applications, including for DAC.
• Canada: the 2022 federal budget announced the design details of an investment tax credit for CCUS projects between 2022 and 2030, valued at around 60% for DAC projects when CO₂ is stored at an eligible permanent sequestration site. The 2023 federal budget reaffirmed the proposed tax credit, which awaits legislation.
• In January 2023 Japan set a CCUS roadmap with a target of capturing between 6 and 12 Mt CO₂ per year by 2030, including from DAC.
  

To date, 27 DAC plants have been commissioned in Europe, North America, Japan and the Middle East. Most of these plants are small scale, with only a few commercial agreements in place to sell or store the captured CO₂, while the remaining plants are operated for testing and demonstration purposes. Only three plants are capturing 1 000 tonnes of CO₂ per year or over: Climeworks Orca plant in Iceland, the Global thermostat headquarters plant in Colorado, and Heirloom’s first large-scale facility in California.

Three DAC projects are currently under construction, with the largest two expected to come online in 2024 in Iceland (36 kt CO₂/year) and in 2025 in the United States (500 kt CO₂/year, with potential to scale up to as much as 1 000 kt CO₂/year).

Fast-growing demand for air-captured CO₂, for both carbon removal and low-emission synthetic hydrocarbon fuel production, is translating into several announcements for new, larger plants. Overall, plans for at least 130 DAC facilities are now at various stages of development. Some of the largest projects under development are in the United States, (Stratos, South Texas DAC hub, and HIF eFuels Matagorda County project in Texas, Cypress DAC hub in Louisiana, and Bison in Wyoming), Norway (the Kollsnes DAC project) and Iceland (the Mammoth project). Two megatonne-scale projects have also been announced in Kenya and the UAE, but are still at early stage.

Out of the 130 DAC plants in planning, only around 15 facilities are currently in advanced development or under construction. If all these planned projects go ahead and steadily capture CO₂ at full capacity, DAC deployment would reach around 3 Mt CO₂ by 2030; this is more than 500 times today’s capture rate, but less than 5% of the 80 Mt CO₂ needed to get on track with the NZE Scenario. All the remaining projects are still at an early stage, with no funding committed, and, in certain cases, not even an identified location for deployment.

Two technological approaches are currently 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 more expensive – than capturing it from a point source. This is because CO₂ in the atmosphere is much more dilute than, for example, in the flue gas of a power station or a cement plant.

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 both heat and electricity, with flexible configurations allowing for heat-only or electricity-only operation.

A diverse portfolio of technologies exists for S-DAC, differing in energy intensity, operating temperature, and therefore cost.

Emerging DAC technologies relying on innovative separation systems, with the main goal of reducing the energy intensity of the processes, include:

• Electro swing adsorption (ESA)-DAC is based on an electrochemical cell where a solid electrode adsorbs CO₂ when negatively charged and releases it when a positive charge is applied. ESA-DAC is currently being developed in the United States and United Kingdom.
• Zeolites are now being adopted for DAC thanks to their porous structure suitable for CO₂ adsorption. The first operational DAC plant relying on zeolites was commissioned in 2022 in Norway, with plans to scale the technology up to 2 000 tCO₂/year by 2025 through the project Removr.
• Passive DAC relies on accelerating the natural process that transforms calcium hydroxide and atmospheric CO₂ into limestone. This process is being engineered in the United States by a company using renewably powered kilns to separate CO₂ from limestone.

While the most energy intensive step in DAC operation is the re-release of the CO₂ after capture, energy savings can also be obtained by targeting other operations, such as the compression of large volumes of ambient air through large fans. This process can be optimised by combining DAC with existing ventilation systems such as those already operating within buildings.

While S-DAC could be powered by a variety of low-carbon energy sources (e.g. heat pumps, geothermal, nuclear, solar thermal and biomass-based fuels), the current high temperature needs of today’s L-DAC configuration does not allow that level of flexibility. At best, L-DAC could operate using low-carbon fuels such as biomethane or renewables-based electrolytic hydrogen, but 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 further reduce the process emissions, 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, mostly 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. In the Middle East, at least eight small-scale projects are investigating or plan to investigate DAC operating performances in the region, for storage in peridotite formations. One of them, when operational, will become the first DAC-based carbon removal project relying on sea water for its operation. Several companies have also announced potential projects in Kenya, including Climeworks and Octavia Carbon.

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 around 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.

• The United States has established a number of policies and programmes to support DAC, including the 45Q tax credit and the California Low Carbon Fuels Standard. The 2022 Inflation Reduction Act expands and extends the 45Q tax credit up to USD 180/t CO₂ permanently stored. The 2021 Infrastructure Investment and Jobs Act includes USD 3.5 billion in funding to establish 4 large-scale DAC hubs, and related transport and storage infrastructure. In August 2023, the United States issued USD 1.2 billion of this funding to two large-scale DAC hubs (Project Cypress in Louisiana and the South Texas DAC Hub in Texas) and nearly 20 additional projects to support earlier stages of project development for future DAC hubs. The United States also launched a USD 35 million carbon dioxide removal (CDR) purchase pilot prize, a public procurement mechanism that will provide cash awards in the form of offtake agreements from the federal government to companies across different removal pathways (DACS, BECCS, enhanced weathering and mineralisation). As part of this effort, the government is calling on external organisations to join a voluntary CDR “challenge” that seeks to catalyse CDR credits.
• Canada released its carbon management strategy in September 2023, which includes a focus on DAC. In terms of funding, the 2022 federal budget detailed a proposed investment tax credit for CCUS projects, to be set at 60% for investment in DACS equipment from 2022 to 2030. The 2023 federal budget reaffirmed the proposed tax credit, which awaits legislation Moreover, Environment and Climate Change Canada (ECCC) has been working since 2022 on an offset protocol for DAC as part of their Greenhouse Gas Offset Credit System.
• The European Commission has been supporting DAC through various research and innovation programmes, including Horizon Europe and the Innovation Fund. In February 2024, the the European Parliament and the Council of the EU reached a provisional agreement on the Carbon Removals Certification Framework, an EU-wide voluntary framework for certifying carbon removals. The regulation establishes EU quality criteria and outlines monitoring and reporting processes in order to facilitate investment in carbon removal technologies, including DAC.
• In the United Kingdom, in October 2021 the government set out a Net Zero Strategy aimed at achieving net zero emissions by 2050. It identifies the need for around 5 Mt CO₂ of “engineered” removals, which include DAC, by 2030, increasing to around 80 Mt by 2050. Moreover, the 2023 Spring Budget included funding of up to GBP 20 billion (around USD 25 billion) for CCUS applications, including DAC.
  

Around 60% of announced DAC capacity for 2030 (currently in early development stages) has not yet been linked to a specific location, with project developers awaiting favourable regulations before finalising their expansion plans. In November 2022, 1PointFive and Carbon Engineering announced plans to deploy 100 large-scale DAC facilities (each with a capture capacity of up to 1 Mt per year) by 2035, at least 30 of which are expected to be deployed within the United States, owing to the IRA’s recent increase to the 45Q tax credit. Other regions likely to host some of these facilities include Europe, the Middle East (which has recently shown interest in DAC) and East Asia.

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 programme (which raises money from philanthropists, governments and companies to invest in critical decarbonisation technologies, including DAC). Additionally, in April 2022 Lowercarbon Capital Fund announced its intention to invest USD 350 million 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. In 2023, Fervo Energy, received support from the Chan Zuckerberg Initiative to develop a fully integrated geothermal and DAC facility. In 2024, Mission Zero closed a funding round amounting to GBP 21.8 million to scale its DAC technology.

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, and to serve as a tool to assess the benefits of subsidy schemes for DAC. 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 (UNFCCC).

Efforts to develop carbon removal certification, including for DAC-based CDR, have commenced in Europe, the United States and Canada, as well as through initiatives such as the Mission Innovation CDR Mission and the UNFCCC Article 6.4 Supervisory Body. These efforts should be co-ordinated, with the aim of establishing internationally consistent approaches.

The CDR field would also benefit from leading jurisdictions acting on transboundary projects, where financing, demand, and/or fabrication come from one jurisdiction, but the facility is hosted in another jurisdiction. It is anticipated that in the future we will need a globally integrated industry for CDR, similar to that which exists today for energy, and a few early transboundary efforts would foster this development.

The market for DAC-based CO₂ removal is expanding substantially. These carbon removal services are offered exclusively through the voluntary carbon market and are being purchased mostly by single companies (including Airbus, Shopify, Swiss Re, Microsoft, UBS) or demand aggregators such as Frontier (which committed to buy USD 1 billion of permanent carbon removals, including from DACS, recently from CarbonCapture Inc. and Heirloom) and Next Gen (who recently purchased CDR credits with the goal of reaching over one million CDRs by 2025, including but not exclusively from DACS) to meet their own climate targets. Amazon has pledge to buy 250,000 metric tonnes of carbon removal over 10 years from 1PointFive first DAC plant under construction in Texas. JP Morgan Chase has announced agreements with several players in the voluntary carbon market for the purchase of USD 200 million in high quality, durable CDR. In February 2024, Rockwell Automotive, signed an agreement to purchase DAC-based credits from the same 1PointFive plant. Online marketplaces such as Patch are also emerging to facilitate smaller companies in the purchasing of credits with the goal of accelerating the voluntary carbon market.

The popularity of these DAC-based carbon removal services stems mainly from their very high removal potential when associated with geological storage. Most of them are currently oversubscribed due to the very limited installed operating capacity available at present, despite the high price compared to other CDR solutions on the market (the price of the subscription varies, depending on the amount of removal purchased, from USD 600/t CO₂ to USD 1 000/t CO₂).

Some private organisations have recently started working on certification initiatives for DAC-based CDR, with examples including:

• Gold Standard, who opened a consultation on operationalising and scaling the voluntary carbon market in 2020 and is expected to release a full methodology over the next couple of years. Gold Standard also released a methodology on CO₂ storage in recycled concrete, mentioning DAC as an eligible CO₂ source.
• The CCS+ Initiative, which is developing various methodologies for CCUS more broadly but also on DAC more specifically under Verra’s Verified Carbon Standard (VCS).
• Climeworks, which has developed a methodology to measure the net emissions removed from the atmosphere after adjusting for emissions resulting from plant construction, operation, and disposal (in compliance with ISO 14064-2 Standards).
• Puro.earth, who has developed a series of CO₂ Removal Certificates (CORCs), including one on geologically removed carbon from DACS and BECCS.
  

• Adam Baylin-Stern, Carbon Engineering 
• Geoff Holmes, Carbon Engineering 
• Jasmin Kemper, IEAGHG 
• Patricia Loria, CarbonCapture 
• Miles Sakwa-Novak, Global Thermostat 
• Louis Uzor, Climeworks