Grid-Constrained Online Scheduling of Flexible Electric Vehicle Charging

Abstract

The rapid growth of Electric Vehicles (EVs) risks causing grid congestion. Smart charging strategies can help to prevent overload while ensuring timely charging, thereby reducing the need for costly infrastructure upgrades. We study EV charging from a scheduling perspective, assuming an aggregator manages charging while respecting network cable capacities. In our model, vehicles depart only after charging is complete, so delays are possible. Our aim is to minimize these delays. We consider a network of parking lots, some of which are equipped with solar panels, where the demand that can be served is limited by the cables connecting them to the grid. We propose novel scheduling strategies that combine an online variant of well-known schedule generation schemes with a destroy-and-repair heuristic. We evaluate their effectiveness in a case study with data from the city of Utrecht. Without control, network cables would be overloaded 60–70% of the time. Our strategies completely eliminate overload, introducing an average delay of just over 1.5 min per EV in high-occupancy scenarios. This demonstrates that scheduling can significantly increase the number of EVs charged without compromising grid safety at the cost of a rather small delay. We also highlight the importance of accounting for grid topology and show the benefits of using flexible charging rates.