Provincial-level prediction of full-chain carbon removal cost and efficiency of direct air carbon capture and storage (DACCS) in China

Direct air capture (DAC) removes CO₂ directly from air and achieves net CO₂ removal when coupled with transport and geological storage, thus becoming indispensable in global net-zero emissions pathways. This study proposes to identify demonstration regions and methods for cost reduction and performance improvement of direct air carbon capture and storage (DACCS) in China. We coupled life-cycle assessment (LCA) with DAC learning curves to evaluate and project the net removal efficiency and cost of liquid-solvent absorption and solid-sorbent adsorption. The results show that the national average net removal efficiencies for liquid-based DACCS vary across scenarios, ranging from 17.0% to 69.8%, whereas solid-based technology demonstrates relative stability (77.9% ~89.0%). National average net removal costs of DACCS decline with higher learning rates and larger deployment scales. By 2060, the costs are projected to be 1336~1970 RMB/t for liquid-based technology and 394~1184 RMB/t for solid-based route. There are significant provincial disparities in net removal efficiency for liquid-based technology in 2035, with only Sichuan and Yunnan provinces exceeding 70%, theoretically qualifying them as pilot demonstration. The solid-based technology, in contrast, maintains a steady efficiency of 78.6% ~84.1% across all provinces. Declining energy-related carbon emissions improve the net removal efficiency of DACCS. From 2035 to 2060, the proportion of energy-related carbon emissions drops from 77.3% to 45.7% for the liquid-based technology, and from 68.3% to 22.9% for the solid-based route, indicating that the dominant contribution of the energy supply stage to full-chain carbon emissions gradually weakens. The cost structure of the liquid route is generally energy-dominated, whereas the dominant cost component of the solid route shifts from capture-side capital expenditure to CO₂ transport and storage. This study thus suggests that DACCS demonstration projects be implemented in provinces with abundant non-fossil energy supply, and deployment should be expanded through scale effects and technological improvements to steadily reduce costs and expand adoption.