Performance analysis of a distributed renewable energy system integrating ground source heat pumps and fuel cells with controlled hybrid energy storage

Battery integrated with hydrogen storage has emerged as a potential way for improving energy utilization and reliability of solar-driven distributed energy systems. However, solar intermittency often forces electrolyzer to operate under low-load conditions, which reduces energy conversion efficiency and hydrogen production. This work develops a hybrid energy storage control method by considering the electrolyzer operational status. The short-term storage capability of the battery is used to suppress low-load operation of electrolyzer while absorbing surplus power. A distributed energy system integrating photovoltaic/thermal, ground source heat pump, electrolyzer, battery and fuel cell is developed to provide cooling, heating and power for an integrated building, which is established in TRNSYS. Furthermore, a multi-objective optimization framework is formulated, considering energy efficiency, economic performance, environmental impact and electrolyzer operational characteristics. The optimal system configuration is determined using TOPSIS–EWM decision-making method, and comparative analysis is conducted for cases with/without battery and electrolyzer control method. The results indicate that compared with the case without battery and control method, high-load operating time ratio of electrolyzer under high-load condition increases by 79.73%, accompanied by a 1.31% improvement in energy efficiency. And battery-assisted control shifts electrolyzer operation toward higher-efficiency regimes under fluctuating renewable conditions while the battery regulates short-term power fluctuations and hydrogen storage enables long-term energy balancing. The proposed hybrid energy storage control method based on electrolyzer operation status provides an effective pathway for the coordinated utilization of hydrogen storage and battery in renewable energy systems and improves the development of hydrogen-based technology in integrated parks.