Direct air capture (DAC), a process consisting of capturing CO2 from ambient air, holds one of the keys to sustainable aviation. Among the ways to use DAC CO2 to decarbonise aviation, two are being held up as offering competing possibilities:
On the one hand, DAC CO2 combined with carbon capture and storage (DACCS), which means that CO2 would be collected then buried underground while aviation continues to use fossil kerosene.
On the other hand, DAC CO2 and green hydrogen can be used to produce e-kerosene, a near-zero emission alternative fuel to displace the sector’s use of fossil jet fuel.
At first, the “bury it” scenario may appear more achievable, as the alternative “use it” scenario requires additional, and more costly, production processes such as green hydrogen production. However, the report finds that the “use it” scenario comes with additional benefits which, if they are taken into account in the cost analysis, mean that e-kerosene can come out cheaper than using fossil kerosene and DACCS.
Price, furthermore, is not everything. Indeed, the report explains that the DACCS option might result in carbon lock-in and may make the transition to a non-fossil approach even more expensive at a later stage. This briefing summarizes that report, provides additional arguments in favour of “use it,” and outlines recommendations for policy-makers.