Optimal capacity configuration of the wind-photovoltaic-storage hybrid power system based on gravity energy storage system

Reasonable capacity configuration of wind farm, photovoltaic power station and energy storage system is the premise to ensure the economy of wind-photovoltaic-storage hybrid power system. We propose a unique energy storage way that combines the wind, solar and gravity energy storage together. And we establish an optimal capacity configuration model to optimize the capacity of the on-grid wind-photovoltaic-storage hybrid power system. The model takes the total cost of the system as the objective. Moreover, three evaluation indexes are put forward to evaluate the system, which are the complementary characteristics of wind and solar, the loss rate of power supply and the contribution rate of wind-photovoltaic-storage hybrid power system. Under the two scenarios of constant electricity price and lime-of-use electricity price, the Cat Swarm Optimization is applied in this study to solve the model. In addition, we compare the gravity energy storage way with battery energy storage and compressed air energy storage. By comparing the three optimal results, it can be identified that the costs and evaluation index values of wind-photovoltaic-storage hybrid power system with gravity energy storage system are optimal and the gravity energy storage system is economically viable. Meanwhile, the gravity energy storage system has the natural advantage in the mountainous areas, which can be promoted in renewable energy generation.