A method for siting adsorption-based direct air carbon capture and storage plants for maximum CO2 removal

Abstract Adsorption-based direct air carbon capture and storage (DACCS) is an emerging approach to mitigate climate change by removing CO 2 from the atmosphere. Recent studies show separately that thermodynamic and environmental performance strongly depend on regional ambient conditions and energy supply but neglect regional CO 2 storage potentials. To assess DACCS performance holistically, a detailed global analysis is needed that accounts for the interplay of regional ambient conditions, energy supply, and CO 2 storage potential. Hence, we present a novel method for the optimal siting of DACCS plants derived from optimising a dynamic process model that uses global hourly weather data and regionalised data on electricity supply and CO 2 storage potential. The carbon removal rate (CRR) measures the climate benefit and describes the speed at which a DACCS plant generates net negative emissions. First, we assume that CO 2 storage is possible everywhere. For four electricity supply scenarios, we show that the optimal siting of DACCS significantly increases the CRR when comparing the best and worst locations in each scenario: For a DACCS plant with a nameplate capture capacity of 4 kt CO 2 y −1 , the CRR can be increased by 63% from 2.16 to 3.53 kt CO 2 y ‑1 when using photovoltaic, and by 39% from 2.95 to 4.1 kt CO 2 y ‑1 when using wind power. Assuming a carbon-free electricity supply, the CRR varies between 3.17 and 4.17 kt CO 2 y ‑1 (32%). Second, we significantly narrow down optimal locations for DACCS considering regional CO 2 storage potential through CO 2 mineralisation. Overall, accounting for the interplay of regional DAC performance, energy supply, and CO 2 storage potential can significantly improve DACCS siting.