Optimal Size of Energy Storage Systems in Microgrids Under Rapid Growth of EV Charging Demands

Utilizing an energy storage system (ESS) is an effective solution for both solving the uncertainty problem of renewable energy sources and optimizing the cost of operation of the microgrid (MG). When planning for the sizing of an ESS in a longer span (e.g., a decade ahead), precise formulation of the optimization objective function relies on ESS degradation and O&M costs, and the predicted trends of variables like hourly electricity rates, load, and generation. In addition, the characteristics of the to-be-deployed control strategy significantly affect the optimal size. Thus, this paper proposes a modular solution to the sizing problem of ESS under the rapid growth of Electric vehicle charging demand while all the mentioned concerning factors are considered. The same to-be-deployed top layer of operation hierarchical control is used at the time of sizing and an innovative cost function is developed to model the complexity of the time of use plan. The results of the optimization determine the optimal size of the battery storages in each stage and the yearly savings in operation cost considering the battery cost.