Techno-economic analysis of integrated offshore wind–solar energy systems for green hydrogen production

‘Green’ hydrogen, produced by the electrolysis of water using renewable energy sources, is expected to become a versatile energy carrier in the future. This study examined the techno-economic performance of combined offshore wind-solar energy systems for hydrogen production in Choshi, Chiba Prefecture, Japan, a region with high average wind speeds. Hourly wind speed and solar radiation data were used to simulate hydrogen production under two system configurations: unlimited power cuts without batteries and no power cuts with battery storage. In the no-power-cut case, battery integration increased the nominal hydrogen cost by 43.8 %, 17.7 %, and 19.8 % in 2025, 2030, and 2050, respectively. However, sensitivity analysis considering higher electrolyzer OPEX due to degradation revealed that the unlimited power-cut system can become more expensive, making battery-supported systems economically favorable over the long term. These findings highlight the importance of integrating battery storage to enhance technical reliability and economical pathways for offshore wind–solar hydrogen production systems. • Off-grid offshore wind and solar energy systems are designed to power alkaline electrolyzers. • The hydrogen cost generated by the systems is minimized with the optimal equipment capacities. • Electrolyzer operation with unlimited and no power-cut cases is simulated. • Wind power can minimize hydrogen cost in the no-power-cut case by reducing backup battery capacity.