Optimal Sizing of Energy Storage System at Fast Charging Stations under Electricity Market Environment

The fast charging stations (FCSs) play a crucial role in plug-in electric vehicle (PEV) commercialization. However, the fast charging load of the FCS may have a tremendous impact on the power grid. An energy storage system (ESS) is considered as a potential supplement not only to reduce the impact on the power grid but also to reduce the network integration cost and charging cost for the FCSs. In this paper, an optimal sizing strategy of the ESS within the FCS is proposed, with joint consideration of the day-ahead (DA) and real-time (RT) energy and ancillary service markets. The objective is to minimize the sum of the expected investment cost of the ESS, network connection cost and the cost of the FCS in the electricity markets. Comprehensive case studies, which are based on the codes and data of PJM market, have been carried out to verify the proposed strategy.