Optimizing Battery Energy Storage for Fast Charging Stations on Highways

This paper addresses the challenge of high peak loads on local distribution networks caused by fast charging stations (FCS) for electric vehicles (EVs) along highways, particularly in remote areas with weak networks. It presents a multi-stage, multi-objective optimization algorithm to determine the battery energy storage system (BESS) specifications required to support the infrastructure. The algorithm results in the minimum BESS capacity and power rating required, subject to the various specific constraints to comply with distribution grid power quality standards by limiting the peak grid demand whilst taking into account several factors over one day, i.e., daily traffic patterns (used to estimate charging system demand), and details of the local electricity network (demand patterns). The optimization method was demonstrated using actual data from an intercity highway and electricity distribution network in a remote highway mid-way between two cities in New South Wales, Australia. The results showed that no BESS is needed up to a critical EV penetration rate, above which both the required BESS capacity and output power capability increase rapidly with the EV penetration rate.