Capacity optimization of a large-scale photovoltaic power generation system coupled with hydrogen production and storage based on economic analysis

The renewable energy system coupled with hydrogen storage has proven to be a suitable method to reduce the variability of output power and meet stable hydrogen supply demand. However, the excessive cost of hydrogen through water electrolysis using renewable energy restricts its application, and the capacity configuration of electrolyzers and gaseous hydrogen storage tanks is affected by the immoderate reliance on engineering experience, leading to the unbalance of generation side and hydrogen demand side. In this study, a 300 MW photovoltaic power generation system has been proposed to fit the raw material demand of a synthetic ammonia plant, i.e., around 1000 kg/h hydrogen. A simplified mathematical model including an electrolyzer and a hydrogen tank is proposed to get the best capacity configuration. The levelized cost of hydrogen (LCOH) is chosen as an optimization function, and a particle swarm optimization algorithm is adopted to get the optimal results. The simulation results indicate that the optimal capacity configuration is 176.36 MW for the electrolyzer and 14644.2 Nm3 for the hydrogen tank, and the LCOH is 30.31 Yuan/kg. Compared with the empirical model, the LCOH based on the optimization model is 8.87% lower than that of the empirical model, indicating better economic benefits of the optimization model.