Green hydrogen from curtailment: Real data analysis

As renewable energy capacity has expanded worldwide, curtailment has emerged as a critical issue owing to transmission constraints and mismatches between generation and demand, resulting in significant energy losses. This study assesses the techno-economic potential of green hydrogen production by utilizing real data of curtailed electricity from wind and photovoltaic sources distributed over more than 2000 km and belonging to a single electrical system. Based on real curtailment data from 100 projects over one year of operation, it characterizes the temporal curtailment patterns and estimates the levelized cost of hydrogen (LCOH) under curtailed-only operation. The results reveal consistent curtailment features across all projects, such as the 25% overall occurrence of curtailment events and a larger concentration of curtailed electricity at 5% of the net effective power. A cost model incorporating electrolyzer scale effects enables the identification of the optimal electrolyzer sizes. The top ten performing parks, which are dominated by photovoltaic parks, achieve LCOH values between 5.58 and 6.97 USD/kg, with optimal electrolyzer sizes ranging from 5% to 13% of the net effective power. Sensitivity analysis shows that moderate deviations from the optimal electrolyzer size have a limited impact on LCOH, with a maximum increase of 3.8% for ± 50% deviations. Among the techno-economic parameters, LCOH is most sensitive to factors governing annual hydrogen production, namely available energy, capacity factor, and electrolyzer efficiency, followed by CAPEX, whereas OPEX, REPEX, discount rate, and degradation rate have a comparatively lower influence.