What is direct air capture?

 Recommendations

What is direct air capture?

Direct air capture (DAC) technologies extract CO2 directly from the atmosphere at any location, unlike carbon capture which is generally carried out at the point of emissions, such as a steel plant. The CO2 can be permanently stored in deep geological formations or used for a variety of applications.

What are the challenges?

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.

Where do we need to go?

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 in the sector.

Recommendations

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.  

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 benefitting from corporate-sector initiatives and pledges to become net zero or even 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. 

Governments should continue to support the development of high-integrity mechanisms to monitor, report, and certify units of CO2 removal generated by DAC facilities. This also needs to be incorporated within larger efforts to evaluate, certify, and incentivise other forms of CDR commensurate with their prospective climate impacts. 

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. One example is California (United States), which in November 2022 updated its carbon neutrality plan to include targets for carbon removal, prompting the introduction of new legislation aiming to expand California’s carbon removal capacity. In addition, at the national level, the United States launched a USD 35 million CDR purchase pilot prize, the first initiative by the federal government to directly purchase CDR from domestic providers.

A critical question for all countries is the extent to which net zero 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.

Additionally, more work is required to differentiate emissions reductions and avoided emissions from carbon removals to align with scientific recommendations. This should be incorporated in climate targets and policy, and reflected in the establishment of different credit categories for carbon markets for effective climate action.

The speed at which the clean energy grid is built out in locations suitable for geologic carbon storage will be a significant determinant of DAC deployment across all areas of the globe. Currently, the United States is discussing expedited permitting for certain clean energy transmission projects, as well as other ways to streamline interagency permitting for delivering low-emissions electricity to the grid. Lengthy grid permitting processes could become an important obstacle to the scale-up of DAC.

Priority innovation needs for DAC include:  

Reducing the energy needed to separate CO2 through emerging separation technologies and approaches able to regenerate the solvent at low to medium temperatures. Innovation in separation solvents and sorbents with lower heat requirements is occurring all around the globe in universities, national labs, and corporate providers, but even for the most promising and commercially available new sorbents, a well established and diverse supply chain is currently lacking. 

Advancing engineering maturity and market conditions to support the availability of renewables-based high-temperature heat to maximise the carbon removal potential of L-DAC 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 and for construction materials.  

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