Even Higher Cost for Direct Air Capture

Earlier this year the American Physical Society (APS) released a report estimating the cost of direct air capture (DAC) at $600 per metric ton of CO2, compared to $80 per ton for conventional, point-source CCS systems (see Bright Spots for Direct Air Capture, 6/24). Now a second study has been published in the Proceedings of the National Academy of Sciences, which advances a much higher cost estimate, even relative to the APS report. Based on observed separation cost trends and energy penalty analyses, the authors estimate the cost of DAC at $1,000/tCO2. Although this estimate is generic and not specific to any particular DAC technology, and individual DAC processes could conceivably capture carbon for much less in the event of technological breakthroughs, nevertheless the overall analysis appears sound and its implications are troubling for supporters of DAC. Despite this, as David Keith notes, "To really know what it costs, someone actually has to build it."