Natural Gas vs. Electricity for Solvent-Based Direct Air Capture

Removing CO 2 from the air with chemicals (Direct Air Capture, DAC) requires a significant amount of energy. Here, we evaluate cost co-constructing solvent DAC process its energy system. We compare eight systems paired two alternative designs for liquid-solvent system capturing 1 MtCO /year, which roughly 240 to 300 megawatts steady power equivalent, 80% thermal and 20% electric. Two burn natural gas onsite heat electricity, nearly all released during combustion, six are all-electric non-fossil systems. The facility alone contributes $310/tCO conventional process-based design $150/tCO more novel design. When decomposition calcium carbonate occurs within natural-gas-heated calciner, adds only $80/tCO these costs, assuming $3.25/GJ ($3.43/MMBtu) gas. However, leakage in supply chain increases net capture dramatically: 2.3% (U.S. national average) 20-year Global Warming Potential 86, costs about 50% higher. For systems, total depends on electricity cost: each $/MWh levelized by $2/tCO . Continuous is required, because high-temperature calciner cannot be cycled off, so solar wind must supplemented storage. Our representative $250–$440/tCO geothermal energy, $370–$620/tCO nuclear (two variants–a light water reactor small modular nuclear), $360–$570/tCO wind, $430–$690/tCO photovoltaics variants different daily capacities), $300–$490/tCO hybrid natural-gas-powered electric calciner.