Solar-to-Hydrogen Production Potential Across Romania’s Hydrogen Ecosystems: Integrated PV-Electrolysis Modelling and Techno-Environmental Assessment

This study develops and applies an integrated modeling framework to assess the solar-to-hydrogen-to-power potential across Romania’s five hydrogen ecosystems defined in the National Hydrogen Strategy. The methodology couples PVGIS-based photovoltaic yield simulations, based on hourly solar irradiation data and including system losses, with MHOGA-based electrolysis simulation, enabling a quantitative-energetic-environmental (Q-E-E) system-level assessment. A 1 MW photovoltaic plant was simulated under three mounting configurations (15° fixed tilt, optimal tilt, and solar tracking) and interfaced with alkaline (AEL) and proton exchange membrane electrolysers (PEMEL). Specific photovoltaic yields reach up to 360 kWh/m2PV·year under tracking conditions, producing up to 7.5 kg/m2PV·year (AEL) and 6.8 kg/m2PV·year (PEMEL), expressed per unit of photovoltaic surface area to enable consistent comparison across the configurations considered. The modeled round-trip efficiency of the full solar–electricity–hydrogen–electricity chain is 38.32% for AEL and 34.57% for PEMEL. Life-cycle-based emission modeling yields 0.92 kg CO2/kg H2 (AEL) and 1.03 kg CO2/kg H2 (PEMEL), while avoided emissions exceed 250 g CO2/kWh relative to grid intensity. Land-use modeling indicates area requirements between 9402 and 18,804 m2/MW, depending on the Ground Coverage Ratio. Results demonstrate that system configuration exerts a stronger influence than regional solar variability in determining hydrogen yield, highlighting the need for integrated techno-environmental optimization for large-scale deployment.