Greenhouse Gas Removal Technologies
Chapter 6: Direct Air Capture
Published:22 Aug 2022
Special Collection: 2022 ebook collection , ECCC Environmental eBooks 1968-2022Series: Energy and Environment
H. Herzog, in Greenhouse Gas Removal Technologies, ed. M. Bui and N. Mac Dowell, The Royal Society of Chemistry, 2022, ch. 6, pp. 115-137.
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Direct air capture (DAC) is technically feasible today, with commercial units already in operation. However, understanding DAC's economic feasibility is required to understand whether DAC will be a significant negative emissions technology. Several start-up companies are trying to commercialise DAC using processes based on chemical absorption or adsorption. Today, there is only one DAC installation generating negative emissions, with a selling price of $1200 per metric ton of CO2 (t CO2). This chapter explores the process fundamentals that apply to all types of DAC processes, looks at the process design for the two major types of DAC processes being developed today, and assesses estimates for DAC costs going forward. The assessment suggests that the low range of cost estimates in the literature, $100–300 per t CO2, will not be reached anytime soon, if at all. Reasonable expectations for DAC costs in 2030 are in the range of $600–1000 per net t CO2 removed.