Modelling Solar Intermittency Effects on PEM Electrolyser Performance & Degradation: A Comparison of Oman and UK

The durability of Proton Exchange Membrane Water Electrolysers (PEMWEs) under intermittent renewable power is a critical challenge for scaling green hydrogen. This study investigates the influence of solar intermittency on PEMWE performance and degradation in direct-coupled photovoltaic (PV) systems by comparing two contrasting climates: Muscat, Oman (hot-arid, high irradiance) and Brighton, UK (temperate, variable irradiance). A validated physics-based model, incorporating reversible, activation, ohmic, and concentration overpotentials along with empirical degradation laws for catalyst decay, membrane thinning, and interfacial resistance growth, was applied to hourly PV-generation data. The results indicate that Muscat’s high irradiance (985 MWh year⁻¹) produced nearly double Brighton’s hydrogen yield (14,018 kg vs. 7566 kg) and longer operational hours (3269 h vs. 2244 h), but at the cost of accelerated degradation (359.8 μV h⁻¹ vs. 231.4 μV h⁻¹). In contrast, Brighton’s cooler and more humid climate preserved efficiency (65.8% vs. 59.8%) and reduced degradation, although higher daily cycling and seasonal variability constrained total output. The findings reveal a climate-dependent trade-off: hot, stable regions maximise hydrogen productivity at the expense of lifespan, whereas variable, cooler climates extend durability but limit yield. By explicitly linking intermittency to performance and ageing, this work provides a location-specific assessment of PEMWE feasibility, supporting design and operation strategies for renewable hydrogen deployment.