Insights from Techno-Economic Analysis Can Guide the Design of Low-Temperature CO2 Electrolyzers toward Industrial Scaleup

Abstract

The field of CO₂ reduction has identified several challenges that must be overcome to realize its immense potential to simultaneously close the carbon cycle, replace fossil-based chemical feedstocks, and store renewable electricity. However, frequently cited research targets were set without quantitatively analyzing their impact on economic viability. Through a physics-informed techno-economic assessment, we offer guidance on top priorities for CO₂ reduction. Although separations dominate capital cost, increasing single-pass conversion is unnecessary because it leads to selectivity loss in current membrane electrode assemblies. Decoupling selectivity and single-pass conversion by moving away from a plug flow reactor design would reduce the base case levelized cost from $1.22/kg_CO to $0.97/kg_CO, as impactful as eliminating CO₂R overpotential. Operating at high current densities (>500 mA/cm²) is undesirable unless cell voltages can be lowered. We confirm that levelized product cost is dominated by the cost of electricity to drive electrolysis. Although wholesale wind and solar electricity are cheaper than retail electricity, their capacity factors are too low for economical operation. Adding energy storage to increase the capacity factor of solar electricity triples the capital cost of the process. By updating research priorities based on fundamental electrolyzer behavior, we hope this work accelerates the practical application of CO₂ reduction.