Energy, economic, and environmental (3E) analysis of hybrid water electrolysis through alternative oxidation...

As the utilization of hydrogen expands to achieve carbon neutrality, increasing attention has been directed toward technologies capable of reducing energy consumption and greenhouse gas emissions during hydrogen production. Although green hydrogen production through renewable energy-based water electrolysis is regarded as an environmentally friendly pathway, conventional water electrolysis systems still suffer from high levelized cost of hydrogen due to substantial electricity consumption. To address this challenge, this study proposes a Hybrid Water Electrolysis (HWE) system in which the conventional oxygen evolution reaction is replaced by electrochemical oxidation reactions of organic compounds. A 1 MW-scale alkaline water electrolysis system employing Urea, Glycerol, 5-Hydroxymethylfurfural (HMF), and Glucose as reactants were modeled using Aspen Plus, followed by techno-economic analysis, and life cycle assessment. The analysis results showed that all HWE systems achieved higher hydrogen production rates than conventional alkaline water electrolysis systems (18.66 kg H₂ per hr). In particular, the glucose-based system exhibited the highest hydrogen and co-product production rates. The glucose-based system achieved the levelized cost of hydrogen as low as approximately 4.74 $ per kg H₂ under high-revenue conditions considering product sales revenue. In addition, the greenhouse gas emission analysis demonstrated that the glucose-based system achieved the lowest emissions when only the HWE system boundary was considered, whereas the urea-based system exhibited the lowest overall emissions when reactant production was included. Through a simulation-based 3-E (Energy, Economy, and Environment) analysis, this study demonstrates the potential of HWE technology to improve the economic feasibility of environmentally sustainable hydrogen production.