Upscaling DAC Hubs with Wind Energy and CO<sub>2</sub> Mineral Storage: Considerations for Large-Scale Carbon Removal from the Atmosphere
David Goldberg, Sara Nawaz, James K Lavin, Angela L. Slagle
Abstract
Continued fossil fuel emissions will increase CO 2 concentrations in the atmosphere and could require removal of 10 Gt of CO 2 per year or more to reach IPCC global climate goals. Large-scale construction of direct air capture (DAC) hubs to scrub CO 2 from the atmosphere paired with geological storage is a prominent approach to potentially meet this target. We consider one location for theoretical scale-up of a DAC hub: the Kerguelen plateau in the Southern Indian Ocean which has high-potential renewable energy resources (wind) and large volumes of basalt rock for mineral storage. With consistent wind, previous studies indicate a hub in this location could collect approximately 75 Mt of CO 2 annually, with conservative storage resources for 150–300 Mt of CO 2 each year. Even with its immense wind and storage potentials, 14 Kerguelen-scale hubs would be needed to capture and store 1 Gt of CO 2 per year. This brings into focus the important social, economic, and environmental trade-offs that must be considered in finding an acceptable balance between climate solutions, renewable energy requirements, and nature. Engaging public groups on these trade-off considerations will be crucial for gigaton scale-up of CO 2 removal in just and responsible ways.