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Direct air carbon capture and storage (DACCS) is an emerging carbon dioxide removal technology, which has the potential to remove large amounts of CO2 from the atmosphere. We present a comprehensive life cycle assessment of different DACCS systems with low-carbon electricity and heat sources required for the CO2 capture process, both stand-alone and grid-connected system configurations. The results demonstrate negative greenhouse gas (GHG) emissions for all eight selected locations and five system layouts, with the highest GHG removal potential in countries with low-carbon electricity supply and waste heat usage (up to 97%). Autonomous system layouts prove to be a promising alternative, with a GHG removal efficiency of 79-91%, at locations with high solar irradiation to avoid the consumption of fossil fuel-based grid electricity and heat. The analysis of environmental burdens other than GHG emissions shows some trade-offs associated with CO2 removal, especially land transformation for system layouts with photovoltaics (PV) electricity supply. The sensitivity analysis reveals the importance of selecting appropriate locations for grid-coupled system layouts since the deployment of DACCS at geographic locations with CO2-intensive grid electricity mixes leads to net GHG emissions instead of GHG removal today.
Terlouw et al. (Thu,) studied this question.