IEA (2022), Direct Air Capture 2022, IEA, Paris https://www.iea.org/reports/direct-air-capture-2022, License: CC BY 4.0
Direct air capture (DAC) plays an important and growing role in net zero pathways. Capturing CO2 directly from the air and permanently storing it removes the CO2 from the atmosphere, providing a way to balance emissions that are difficult to avoid, including from long-distance transport and heavy industry, as well as offering a solution for legacy emissions. In the IEA Net Zero Emissions by 2050 Scenario, DAC technologies capture more than 85 Mt of CO2 in 2030 and around 980 MtCO2 in 2050, requiring a large and accelerated scale-up from almost 0.01 MtCO2 today.
DAC is a key part of the carbon removal portfolio. Carbon dioxide removal (CDR) is not an alternative to cutting emissions or an excuse for delaying action, but is part of a comprehensive strategy for “net” zero – where emissions being released are ultimately balanced with emissions removed. CDR approaches range from nature-based solutions such as afforestation to technology-based approaches underpinned by carbon capture and storage. DAC with geological CO2 storage has several advantages as a CDR approach, including a relatively small land and water footprint, and high degree of assurance in both the permanence of the storage and the quantification of CO2 removed.
The contribution of DAC goes beyond carbon removal. Air-captured CO2 can be used as a climate-neutral feedstock for a range of products that require a source of carbon, from beverages to chemicals and synthetic aviation fuels. In the Net Zero Emissions by 2050 Scenario around 350 Mt of air-captured CO2 is used to produce synthetic fuels in 2050, including for aviation, supporting one of the few options available to reduce emissions in the sector.
DAC plants currently operate at a small scale, but with plans to grow. Currently 18 DAC facilities are operating in Canada, Europe and the United States. All but two of these facilities sell their CO2 for use, and the largest such plant – commissioned in Iceland in September 2021 – is capturing 4 000 tCO2/year for storage (via mineralisation). The first large-scale DAC plant of up to 1 MtCO2/year is in advanced development and is expected to be operating in the United States by the mid-2020s.
Governments and industry are getting behind DAC. Since the start of 2020, governments have committed almost USD 4 billion in funding specifically for DAC development and deployment. This includes USD 3.5 billion to develop four DAC hubs and a USD 115 million DAC Prize programme in the United States. New R&D funding is forthcoming in Australia, Canada, Japan, the United Kingdom and elsewhere. The United States also launched a Carbon Negative Shot during COP26, identifying DAC among a portfolio of CDR approaches with potential to remove CO2 and durably store it, at scale, for under USD 100/tCO2. Private and philanthropic investment is also growing: leading DAC companies have raised around USD 125 million in capital since the start of 2020 and companies ranging from Microsoft to United Airlines are investing in early projects. DAC is one of four technologies that Breakthrough Energy Catalyst is targeting for up to USD 1.5 billion in investment, and it is also an eligible technology for the USD 100 million Carbon Removal XPRIZE announced in 2021.
Capturing CO2 from the air is the most expensive application of carbon capture. The CO2 in the atmosphere is much more dilute than in, for example, flue gas from a power station or a cement plant. This contributes to DAC’s higher energy needs and costs relative to these applications. But DAC also plays a different role in net zero pathways, including as a CDR solution. Future capture cost estimates for DAC are wide-ranging and uncertain, reflecting the early stage of technology development, but are estimated at between USD 125 and USD 335 per tonne of CO2 for a large-scale plant built today.
With deployment and innovation, capture costs could fall to under USD 100/tCO2. DAC costs are dependent on the capture technology (solid- or liquid-based technologies), energy costs (price of heat and electricity), specific plant configuration and financial assumptions. In locations with high renewable energy potential and using best available technologies for electricity and heat generation, DAC costs could fall below USD 100/tCO2 by 2030. The Middle East and the People’s Republic of China (hereafter “China”) could be among the least-cost locations for DAC deployment, together with Europe, North Africa and the United States. However, the potential for costs to fall to these levels will be strongly dependent on increased public and private support for innovation and deployment.