Where to Site Direct Air Capture? Optimal Global Supply Chains from Capture to Storage

The cost and net removal efficiency of direct air capture with CO2 storage (DACCS) depend strongly on siting, power supply, and how captured CO2 reaches storage. Here, we present a globally resolved (1° × 1°) assessment of solid-sorbent DACCS supply chains for near-term and mid-century scenarios, coupling hourly techno-economic optimization, (prospective) life-cycle assessment, and multimodal CO2 transport to storage to estimate net levelized costs of carbon dioxide removal that account for cradle-to-grave greenhouse gas emissions. In the near-term, the cheapest sites require ∼1,100–1,200 USD/tCO2 in the central United States and western Australia; cost is governed less by CO2 capture than by access to CO2 transport and storage and the regional cost of capital, while local wind resources enable the cheapest sites. A siting hierarchy emerges: proximity to geological storage is preferred, and a well-connected port is a near-equivalent substitute where storage is distant. By 2050, a lower-carbon global economy, cheaper CO2 transport, and technological learning broaden low-cost deployment, with ∼98% of sites below 1,000 USD/tCO2 (cheapest ∼370) at a median ∼93% removal efficiency. Near-term first-mover regions remain the lowest in cost, indicating low risk of stranded assets.