Scenario-based assessment of green hydrogen and ammonia production and levelized costs from a hybrid offshore wind–floating photovoltaic system, 2026–2050

This study develops an integrated framework for assessing green hydrogen and ammonia production from a hybrid offshore wind farm (OWF) and floating photovoltaic (FPV) system over 2026–2050. The framework integrates reduced-order hourly power reconstruction, machine-learning-assisted long-term projection using synthetic European Centre for Medium-Range Weather Forecasts Reanalysis v5 (ERA5)-based weather realizations, specific electricity consumption (SEC)-consistent fuel conversion, electrolyzer sizing, and commissioning-year-indexed techno-economic assessment. Under the adopted site and engineering assumptions, the 20% FPV configuration is retained as a smoothing-oriented reference, providing the maximum baseline power-smoothing index of 11.13%. Across 23 sensitivity cases, this configuration maximizes smoothing performance in 73.9% of the cases, while the 10% and 20% FPV cases remain Pareto-efficient throughout the analysis. Under the average scenario, monthly hydrogen production increases from 1408.1 to 3089.7 t month −1 in 2026 to 1905.2–4220.7 t month −1 in 2050. The average levelized cost of hydrogen (LCOH) declines from 6.21 to 3.39 € kg −1 , while the levelized cost of ammonia (LCOA) decreases from 1487.94 to 803.28 € t −1 . The principal contribution is an internally consistent workflow linking offshore hybrid-power variability, electrolyzer sizing, SEC-based fuel conversion, and commissioning-year-specific cost evolution.