Optimizing Charging Station Locations for Electric Car-Sharing Systems.

This paper is about strategic decisions required for running an urban station-based electric car-sharing system. In such a system, users can rent and return publicly available electric cars from charging stations. We approach the problem of deciding on the location and size of these stations and on the total number of cars in such a system using a bi-level model. The first level of the model identifies the number of rental stations, the number of slots at each station, and the total number of cars to be acquired. Then, such a generated solution is evaluated by computing which trips can be accepted by the system using a path-based heuristic on a time-expanded location network. This path-based heuristic iteratively finds paths for the cars through this network. We compare three different pathfinder methods, which are all based on the concept of tree search using a greedy criterion. The algorithm is evaluated on a set of benchmark instances which are based on real-world data from Vienna, Austria using a demand model derived from taxi data of about 3500 taxis operating in Vienna. Computational tests show that for smaller instances the algorithm is able to find near optimal solutions and that it scales well for larger instances.