Optimal charging of electric vehicle fleets: Minimizing battery degradation and grid congestion using Battery Storage Systems

The electrification of the transport industry is rapidly becoming a solution to mitigate the greenhouse emissions problem. However, this electrification faces multiple challenges related to higher operational cost and limited charging capacity. To cope with these challenges, within the European project URBANIZED, an optimization algorithm has been developed to determine charging schedules (i.e., charging current vs time) for electric vehicle fleets. The optimization algorithm exploits the benefits of adding a Battery Storage System (BSS) to the charging infrastructure. The algorithm minimizes the economical costs associated to charging a vehicle, such as battery degradation, grid connection and BSS costs, while taking into account vehicle-related and grid-related constraints. Simulation results show that charging the vehicle fleet as late as possible is the best way to reduce the total operation costs, due to the lower battery degradation. Likewise, the usage of a BSS allows to further increase the battery lifetime at an extra-cost of investing in a BSS system.