Geothermal-solar energy system integrated with hydrogen production and utilization modules for power supply-demand balancing

The power generation of geothermal energy is severely restricted by its low grade and limited flexibility. We propose integrating geothermal and solar energy and introducing hydrogen energy modules to achieve a flexible and highly efficient renewable power supply for communities. The comprehensive thermodynamic models of the proposed combined system are established, and the daily performance of the system is simulated and analyzed based on a power supply-demand matching strategy. From the results, the switching points of hydrogen generation/consumption mode occur at 6 h and 18 h. During the day time, the system's overall energy efficiency varies between 13.28% and 14.36%, representing a significant improvement compared to the previous geothermal-solar combined system only with 5.67% energy efficiency. Then, the effects of geothermal water temperature and solar radiation intensity on the system's daily performance are analyzed, showing the daily net hydrogen production amount increases from -28.71 kg to 306.24 kg with the improved geothermal grade. Finally, the fluctuant electricity profiles of two typical communities are taken into the simulation for case analysis. The good demand-supply matching results for both cases showcase the dynamic capture ability of the models and validate the applicability of the proposed system.