Optimizing green hydrogen production: Analyzing the performance of photovoltaic-driven solid oxide electrolyzers under various solar conditions

As the world progresses toward a sustainable energy future, green hydrogen emerges as an innovative solution in the global effort to achieve decarbonization. This study examines the performance of a photovoltaic (PV)-driven solid oxide electrolyzer cell (SOEC) in producing green hydrogen under dynamic and unpredictable solar energy conditions. High-temperature electrolyzers provide substantial advantages in conversion efficiency compared to their low-temperature counterparts. The study focuses on designing and analyzing the thermodynamic and electrochemical performance of an SOEC capable of generating hydrogen and oxygen from water using solar energy. The SOEC was evaluated in exothermic and endothermic modes to ensure autonomous operation without external heat sources. The heat exchanger network was optimized to enhance system performance. This approach equips the SOEC system to adapt to renewable hydrogen production, particularly within a PV system configuration. The PV system was analyzed using two modes: direct and indirect coupling. A parametric study explores the impacts of key operating conditions, such as temperature, pressure, and current density, on cell potential and overall performance. The SOEC achieved energy and exergy efficiencies of 88% and 78%, respectively. A PV system comprising eight panels in series and seven panels in parallel generates 27.72 kW of power directly supplied to the electrolyzer. With a total annual solar energy radiation of 2.36 MWh/m2, the electrolyzer produces approximately 1500 kg of hydrogen and 12 000 kg of oxygen while consuming 13 500 kg of water annually. The findings of this study highlight significant advancements in the efficiency and stability of PV-driven SOEC.