Techno-economic analysis of ethanol/methanol oxidation in hybrid water electrolysis

Hydrogen production via water electrolysis is limited by high electricity demand because of high ohmic and kinetic resistances, which motivates the development of hybrid processes that replace the anodic reaction with one that theoretically lowers the cell voltage. While previous studies have focused almost exclusively on voltage reduction at the electrode level, a holistic assessment of the full industrial process has been lacking. This work provides an integrated techno-economic evaluation of ethanol-assisted water electrolysis, covering electrolyzer behavior, downstream separations, and overall process feasibility. Thermodynamic analysis identified acetic acid exhibiting a markedly low reversible potential (0.06V) and substantial market relevance. A continuous flowsheet was developed using a hierarchical process synthesis approach and modeled in Aspen Plus for an ethanol feed of 40,000 kg h−1, incorporating experimentally validated performance of a NiOOH–CuO anode catalyst. The downstream separation unit relied on extractive distillation, which dominated overall utility demand. Sensitivity analysis revealed the current density and cell voltage as critical economic parameters of electrolysis. Even under optimistic assumptions, ideal Faradaic efficiency, reversible operation, and elevated current density, the resulting hydrogen break-even price (12 € kg−1) significantly exceeded prevailing green hydrogen costs. The findings indicate that although ethanol oxidation reduces theoretical energy requirements at the electrolyzer level, the overall process remains economically uncompetitive due to separation energy demands and limited value from co-produced acetic acid.