Techno-Economic Assessment of Renewably Powered Electrocatalytic Nitrate Reduction for a Sustainable Nitrogen Cycle

Electrocatalytic nitrate reduction (eNO3RR) exhibits substantial potential in eliminating waste NO3– by selectively converting it into N2 or valuable resources NH3. Since eNO3RR has made rapid progress recently, it is vital to conduct a systematic evaluation of its feasibility. Herein, we provide a comprehensive techno-economic assessment (TEA) and life cycle assessment (LCA) of eNO3RR and propose economically and environmentally favorable thresholds to systematically guide its industrial-scale implementation. Sensitivity analysis suggests that current density is the most crucial factor for N2, showing an even greater impact than electricity price, while voltage ranks second only to electricity price for NH3, highlighting optimization priorities. The profitability of eNO3RR-to-NH3 at $0.03/kWh depends on the progression of performance: the full-cell energy efficiency exceeds 50% at a current density >500 mA/cm². Through continuous technological optimization, the levelized cost of ammonia (LCOA) is projected to decrease from $0.92/kg to $0.14/kg, substantially below current NH3 market prices. LCA reveals that renewable-electricity-powered eNO3RR achieves near-zero global warming potential (GWP, <0.4 kg CO2e/kg NO3–-N), offering superior decarbonization compared to conventional wastewater treatment (WWTP) and Haber-Bosch (H–B) processes.