Title: The perspective of direct air capture of atmospheric carbon dioxide

Authors: Alberto Boretti

Addresses: Chancellor Avenue, 3083 Bundoora VIC, Australia

Abstract: Removing CO₂ from the atmosphere by DAC, and then geologically storing it, or recycling it to renewable hydrogen-based fuels, is here discussed. The energy inputs for the capture of the atmospheric CO₂ at the present concentration is ~45 GJ t⁻¹ of C, 4.28 times the energy produced by burning the best coal generating the captured CO₂. Accounting for non-uniformities of atmospheric CO₂ concentration and pointwise capture, the energy cost is larger, as the atmospheric CO₂ concentration close to the DAC machines will reach values below the preindustrial level when the global average will be above. DAC as a way to control global concentrations of atmospheric CO₂ is questionable, making this solution unattractive.

Keywords: global warming; direct air capture; atmospheric CO₂.

DOI: 10.1504/IJGW.2022.123281

International Journal of Global Warming, 2022 Vol.27 No.2, pp.193 - 201

Received: 14 Apr 2021
Accepted: 20 Nov 2021
Published online: 07 Jun 2022 *

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