Integrated hydrogen production and liquefaction via alkaline electrolysis: Conceptual design and life cycle assessment under geothermal and hybrid renewable energy scenarios

The viability of a hydrogen economy depends on efficient liquefaction for long-distance transport and storage. This study evaluates an integrated system combining alkaline water electrolysis, continuous ortho -to-para catalytic conversion, and reverse-Brayton/Organic Rankine Cycle (ORC) cooling. Aspen HYSYS V14 simulations yield 15.07 kg/h of liquid hydrogen (97.98% para -hydrogen) at −236.9 °C and 2100 kPa. Two power-supply options are assessed: a 1008.2-kW geothermal dual-flash/ORC system in Meshkinshahr, Iran, and a HOMER Pro-optimized hybrid microgrid (8 MW PV, 1.98 MW wind, 500 kW biogas, 29,500 kWh battery) in Arsanjan, Iran. Through comprehensive exergy, exergoenvironmental, sensitivity, and techno-economic analyses, the geothermal scenario demonstrates a 38.5% overall exergy efficiency with 944 kW of exergy destruction. The electrolyzer and evaporator EV-1 are the main irreversibility sources, destroying 308.4 kW (74.08% efficiency) and 192.3 kW (40.73%), respectively. Environmentally, the electrolyzer bears the highest burden due to stack materials (exergoenvironmental factor ≈ 76%), while EV-1′s impact is dominated by exergy destruction (factor ≈ 1.5%, relative impact difference ≈ 145%). Economically, the hybrid system outperforms the geothermal pathway, achieving a lower net present cost ($19.97 M), levelized cost of electricity ($0.115/kWh), and levelized cost of hydrogen ($8.31/kg), representing reductions of 13.4%, 19%, and 13.4%, respectively.