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. 

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. 

DAC technologies require significant amounts of energy. The two leading DAC technologies – solid DAC (S-DAC) and liquid DAC (L-DAC) – were initially designed to operate using both heat and electricity. The lower temperature heat needs of S-DAC mean it can be fuelled by renewable energy sources (including heat pumps and geothermal). The high temperature heat needs of L-DAC (up to 900°C) underpin current plant designs that rely on natural gas for heat, although the CO₂ from the use of this gas is inherently captured within the process and not emitted. Innovation to support renewable energy options for high-temperature industrial heat would maximise the carbon removal potential of L-DAC plants.

DAC still needs to be demonstrated in different conditions. 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. It can also be located near existing or planned CO₂ transport and storage infrastructure. 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.

Innovation in CO₂ use opportunities, including synthetic fuels, could drive down costs and provide a market for DAC. Early commercial efforts to develop synthetic aviation fuels using air-captured CO₂ and hydrogen have started, reflecting the important role that these fuels could play – alongside biofuels – in the sector. In the Net Zero Emissions by 2050 Scenario, around one-third of aviation fuel demand in 2050 is met by these synthetic fuels, but currently their cost can be more than five times conventional fossil-based options. Further innovation is needed to support cost reductions and faster commercialisation, and build a potentially large market for air-captured CO₂. 

Business models for DAC are linked to high-quality carbon removal services and CO₂ use opportunities. DAC companies are offering commercial CO₂ removal services to individuals and companies. Although DAC with CO₂ storage is among the most expensive options to balance emissions, it is attracting interest from companies seeking high-quality CDR that offers additionality, durability and measurability. The purchase of DAC-based carbon removal is currently limited to voluntary carbon markets.

Internationally agreed approaches to the certification and accounting of DAC are needed. 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 (UNFCCC). 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 co‑ordinated with the aim of establishing internationally consistent approaches. 

DAC deployment must be accelerated for net zero. The Net Zero Scenario requires the immediate and accelerated scale-up of DAC, calling for an average of 32 large-scale plants (1 MtCO₂/year each) to be built each year between now and 2050. This will require increased public and private support to reduce costs, improve technologies and build the market for DAC technologies. The IEA has identified six near-term priorities for DAC deployment aligned with net zero goals:

1. Demonstrate DAC at scale as a priority. Targeted policies and programmes are needed for near-term demonstration and deployment. Governments should ensure that planned projects are able to progress to operation and provide essential learnings for DAC technologies and supply chains.
2. Foster innovation across the DAC value chain. Innovation will be critical to: reducing manufacturing and operational costs, as well as the energy needs for DAC plants; supporting the availability of low-emission energy sources for high-temperature heat; and developing and reducing the cost of CO₂ use applications including synthetic aviation fuels.
3. Identify and develop CO₂ storage. The potential for DAC to remove CO₂ from the atmosphere in large quantities rests on the development of suitable geological CO₂ storage. Although the storage potential is vast, the time to develop these resources can be as long as ten years and could act as a brake on the scale-up of DAC in some regions.
4. Develop internationally agreed approaches to DAC certification and accounting. Robust, transparent and standardised international certification and accounting methodologies for DAC are needed to facilitate its recognition in carbon markets and IPCC greenhouse gas inventory reporting.
5. Assess the role of DAC and other CDR approaches in net zero strategies. Improved understanding and communication of the anticipated role of DAC and other CDR approaches in net zero strategies will help identify the technology, policy and market needs within countries and regions. For example, the United Kingdom’s Net Zero Strategy identifies a need for around 80 MtCO₂ of technology-based carbon removals by 2050.
6. Build international co‑operation for accelerated deployment. Collaboration through international organisations and initiatives such as the IEA, Clean Energy Ministerial, Mission Innovation, and Technology Collaboration Programme on Greenhouse Gas R&D (GHG TCP/IEAGHG) can play an important role in promoting knowledge sharing, reducing duplication in research efforts, and harmonising approaches to LCA and accounting methodologies for DAC technologies.