Sizing of interoperable EV charging stations on highways with a coordinated charging scheduling strategy

Electric vehicle charging station (EVCS) sizing on highways poses unique challenges compared to urban areas due to the “charge-and-go” tendency of drivers, fewer and more distant stations, and higher charging demand. Unlike urban areas, where prolonged parking enables temporal load management, highways require dynamic spatial load distribution. Special strategies, such as coordinated charging and interoperability, enable efficient and cost-effective EVCS sizing for highways. Therefore, this study proposes a coordinated charging strategy for highway EVCS sizing, incorporating interoperability principles. Charging demand is managed through spatial load shifting and communication between interoperable EVCSs, efficiently utilizing available fast-charging sockets. If no sockets are available, EVs are directed to neighboring stations based on their remaining battery energy. Indirectly, this intelligent redistribution of demand minimizes grid overloads, enhancing system reliability. The method which is applied to Türkiye's busiest highway reduces charging equipment requirements by 15.2%, significantly lowering initial investment costs. Moreover, spatially distributed charging reduces annual peak power demand by 22.2%, mitigating grid stress by balancing the load across the network. These results highlight the potential of incorporating coordinated charging in EVCS sizing to improve sustainability, feasibility, and scalability of EV infrastructure. This approach offers a replicable framework for tackling EVCS challenges on highways worldwide.