Co-location of air capture, subseafloor CO₂ sequestration, and energy production on the Kerguelen plateau

Reducing atmospheric CO₂ using a combination of air capture and offshore geological storage can address technical and policy concerns with climate mitigation. Because CO₂ mixes rapidly in the atmosphere, air capture could operate anywhere and in principle reduce CO₂ to preindustrial levels. We investigate the Kerguelen plateau in the Indian Ocean, which offers steady wind resources, vast subseafloor storage capacities, and minimal risk of economic damages or human inconvenience and harm. The efficiency of humidity swing driven air capture under humid and windy conditions is tested in the laboratory. Powered by wind, we estimate ∼75 Mt CO₂/yr could be collected using air capture and sequestered below seafloor or partially used for synfuel. Our analysis suggests that Kerguelen offers a remote and environmentally secure location for CO₂ sequestration using renewable energy. Regional reservoirs could hold over 1500 Gt CO₂, sequestering a large fraction of 21st century emissions.