Capacity Configuration and Economic Evaluation of Grid-Connected PV and Energy Storage Charging Station

With the gradual application of new energy electric vehicles to real life, whether they will be able to achieve sustainable development has become a hot research topic. Photovoltaic power generation has the characteristics of randomness, volatility and intermittence, and the introduction of energy storage to mitigate, while improving the utilization ratio of photovoltaic power generation. The energy storage capacity and types determines the ability to store photovoltaic power and energy storage costs. Because of the high energy storage costs, merging the surplus photovoltaic power into the grid can better coordinate the PV and energy storage capacity and reduce the energy storage costs. In this paper, the grid connected PV and energy storage charging station is studied. Firstly, based on the daily operation strategy proposed in this paper, setting the maximum net income of the station as the goal and the constraints of energy storage battery SOC, charge and discharge power of the energy storage batteries, charge and discharge power conservation of batteries, system power balance and power fluctuation limit of PV connected grid are considered. Configuration capacity of energy storage battery is solved by genetic algorithm. Secondly, the economic evaluation indexes of PV and energy storage charging station are established and their values are calculated when lithium iron phosphate battery(LiFePO4, LFP), vanadium redox flow battery(VRB), Valve regulated lead acid battery(VRLA) and Natrium Sulfur battery(NSB) are used as the energy storage respectively. Finally, the analytic hierarchy process is applied to evaluate the overall economy of the station. The simulation results show that when VRLA is used as the energy storage system, the grid connected PV and energy storage charging station has the best overall economic performance.