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

Abstract

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.