Integrative techno-economic and environmental assessment for green H₂ production by alkaline water electrolysis based on experimental data

Alkaline water electrolysis has been in the spotlight for green H₂ production using electricity generated from renewable energy because of its high technology readiness level and low investment. However, commercialization of alkaline water electrolysis is challenging because of the low current density. Therefore, a techno-economic and environmental assessment was conducted for green H₂ production by alkaline water electrolysis with experimental data from the advanced alkaline water electrolysis system of the Korea Institute of Energy Research (KIER) to identify the potential of this technology. Based on techno-economic analysis results, the stack cost and unit electricity price must be below 0.035 $ kWh⁻¹ and 406 $ kW⁻¹, respectively, to make this technology cost-competitive compared to the conventional H₂ production method (< 2 $ kgH₂⁻¹). Furthermore, CO₂ emissions of 30.7, 17.4, 7.04, and 3.12 kgCO_2-eq kgH₂⁻¹ were obtained for the current, 2030, 2050, and renewable Korean electricity mix scenarios, respectively, indicating that both scenarios (Korean electricity mix in 2050 and renewable) have lower CO₂ emissions than the conventional H₂ production method (11.5 kgCO_2-eq kgH₂⁻¹). In addition, environmental impact reductions of 89.8%, 83.6%, 65.9%, and 91.0% for CO₂ emissions, stratospheric ozone depletion, fine particulate matter formation, and fossil resource scarcity, respectively, were obtained for the renewable scenario compared to the current Korean electricity mix. Therefore, the electricity source has significant effects on the economic feasibility and environmental impacts for green H₂ production.