Capacity configuration optimization for battery electric bus charging station’s photovoltaic energy storage system

With the development of the photovoltaic industry, the use of solar energy to generate low-cost electricity is gradually being realized. However, electricity prices in the power grid fluctuate throughout the day. Therefore, it is necessary to integrate photovoltaic and energy storage systems as a valuable supplement for bus charging stations, which can reduce reliance on the grid and the total operational cost. This paper proposes three charging station expansion models, i.e., charging station with the energy storage system, charging station with the photovoltaic system, and charging station with both photovoltaic and energy storage systems. These models consider the time-of-use electricity prices, the instability of photovoltaic output power and electric bus charging demand, and equipment investment cost. Through a case study in Beijing, the optimal capacity configuration of charging stations under each type of supplementary scheme is achieved by solving these models using software Gurobi. The findings reveal that charging stations incorporating energy storage systems, photovoltaic systems, or combined photovoltaic storage systems deliver cost savings of 13.96 %, 21.44 %, and 30.85%, respectively, compared to the station without supplemental devices. Notably, the charging station integrating both photovoltaic and energy storage systems stands out as the most cost-effective option.