Optimal design and sizing of hybrid multi-electrolyzer systems for renewable energy driven green hydrogen in P2H systems

The efficient conversion of renewable energy into hydrogen is essential for addressing future energy challenges and enabling sustainable energy systems. Multi-electrolyzer systems present a promising avenue for extensive green hydrogen production. This paper presents an optimal capacity configuration and operational optimization model to perform a comparative techno-economic analysis of three electrolyzer configurations: proton exchange membrane (PEM)-only, solid oxide electrolyzer cell (SOEC)-only, and a hybrid electrolyzer configuration (HEC), powered by variable wind energy. A co-optimized framework for capacity sizing and dispatch is developed to capture the dynamic response and efficiency characteristics of each technology. The results show that the SOEC-only configuration achieves the highest hydrogen output per unit capacity due to its superior conversion efficiency, producing 20–25% more hydrogen than PEM at comparable scales. However, its limited flexibility results in lower renewable energy utilization (86.95%) and reduced economic performance. In contrast, the PEM-only configuration achieves nearly complete renewable utilization (97.98%) due to its fast dynamic response and lower cost, although it produces less hydrogen per unit capacity. The hybrid electrolyzer configuration combines the advantages of both technologies, as SOEC is more suitable for base-load operation, while PEM effectively responds to fluctuations in wind energy due to its rapid dynamic response. At its optimal capacity (40 MW), the HEC achieves 97.98% renewable utilization, produces 6068 t of hydrogen annually, and yields the highest economic return (13.95 M). The results further show that the HEC improves profit by 12.77% compared to the PEM optimum and by 19.95% compared to the SOEC optimum. These findings demonstrate that hybrid electrolyzer systems provide a balanced and economically effective solution for large-scale renewable hydrogen production.