Techno-Economic Feasibility, Uncertainty, and Scale-Up Requirements for Electrochemical CO2-to-Ethanol Production

Electrochemical CO2 reduction to ethanol can couple captured carbon with low-carbon electricity, but plant economics depend simultaneously on Faradaic efficiency (FE), current density, full-cell voltage, carbon and product retention, stack durability, downstream recovery, and electricity cost. This study develops an auditable process-based techno-economic assessment for a membrane–electrode assembly CO2-to-ethanol plant using 1 kg of saleable ethanol at the plant gate as the functional unit. The reference plant produces 10.0 million kg y−1 gross ethanol and 9.5 million kg y−1 saleable product after 5% crossover. At 64.3% ethanol FE, 0.90 A cm−2, and 33.33 kWh kg−1 gross-ethanol stack electricity, Faraday-law scaling gives 13.57 MA current, 1508 m2 active area, and 3.07 V implied average cell voltage. The revised model calculates anodic O2 from total charge, excludes unvalidated O2 revenue from the reference case, and treats the EUR/kW stack cost proxy without a second current-density area multiplier. Minimum selling prices are EUR 2.514, 3.235, and 6.120 kg−1 at electricity prices of EUR 0, 0.02, and 0.10 kWh−1, respectively. Uncertainty and Sobol analyses identify stack cost, FE, crossover, current density, discount rate, and stack lifetime as the leading economic drivers.