Techno-economic evaluation of solar-driven PEM water electrolysis systems for hydrogen production: Comparison and regional insights

Solar-driven proton exchange membrane (PEM) water electrolysis represents a promising pathway for green hydrogen production. However, current research is largely site-specific and leaves the performance and economic trade-offs of various solar integration strategies underexplored. This work develops an integrated TRNSYS-MATLAB model to evaluate three configurations of photovoltaic (PV)-PEM, photovoltaic/thermal (PV/T)-PEM, and photovoltaic plus solar thermal (PV-ST)-PEM across various temporal and spatial scales, which encompassed typical-day, annual, and multi-regional analyses across eight representative cities. A generalised approach based on peak sun hours (PSH) is introduced, representing a key innovation by transforming location-specific results into a framework applicable worldwide. Results show that the PV/T-PEM configuration achieves the highest technical performance with a peak solar-to-hydrogen (STH) efficiency of 6.8% and an annual hydrogen production of 455 kg. Although this production is a 27% improvement over the base PV-PEM system, it remains the most capital-intensive option with levelised cost of hydrogen (LCOH) generally exceeding 15 $/kg. Conversely, PV-PEM is more cost-effective, reaching a minimum LCOH of 5.6 $/kg despite its lower annual yield of 359 kg. PV-ST-PEM performs intermediately. The PSH framework confirms that as solar availability increases from 1 to 8 h, annual hydrogen production rises from below 60 kg to a peak of 455 kg for PV/T-PEM system. The LCOH for the most economical PV-PEM configuration declines from over 75 $/kg to a minimum of 5.6 $/kg. Overall, this work demonstrates that technical superiority does not inherently guarantee economic feasibility. It provides a robust and generalised framework to guide global investment and policy for solar-hydrogen infrastructure.