Design and cost analysis of green hydrogen and ammonia production from hybrid offshore wind and floating photovoltaic systems

This study develops an integrated techno-economic framework for offshore green hydrogen and green ammonia production using a hybrid offshore wind farm (OWF) and floating photovoltaic (FPV) system. The proposed framework couples hourly renewable power generation with proton exchange membrane (PEM) electrolysis, desalination, ammonia synthesis, hydrogen pipeline transport, and ship-based ammonia export under alternative offshore–onshore production configurations. The results show that OWF–FPV hybridization improves the stability of renewable power supply and supports more continuous operation of downstream Power-to-X (PtX) processes. Among the evaluated electrolyzer capacities, the 240 MW configuration provides the most favorable cost-performance balance, achieving the minimum levelized cost of hydrogen. Ammonia synthesis efficiency further improves system performance by increasing annual ammonia output and reducing the levelized cost of ammonia. The transport assessment indicates that hydrogen pipeline economics are strongly affected by distance, throughput, pipe sizing, and compression requirements, whereas ship-based ammonia transport shows greater resilience to long-distance export. Overall, the findings demonstrate that hybrid OWF–FPV systems can provide a technically and economically promising pathway for offshore hydrogen and ammonia production, provided that renewable variability, conversion efficiency, transport distance, and infrastructure requirements are evaluated within an integrated system framework.