Optimizing relocation operations in electric car-sharing

In this paper, we consider a station-based electric car-sharing system which allows one-way trips, and uses relocation to re-balance the vehicle distribution. We adopt the point-of-view of a service provider, whose objective is to maximize the profit associated with the trips performed by users. We introduce an exact relocation model for operating hours, and we explicitly consider the consumption and recharge process of electric vehicles batteries. In addition, the model is extended to the relocation operations to be performed at night, namely when the system is not operating. We also describe two model-based heuristics developed to solve the relocation model for operating hours on large-scale systems. The paper is concluded by a set of computational experiments on realistic data derived from an existing car-sharing system. The experiments investigate the scalability of the proposed model and highlight the circumstances under which the relocation operations can improve the system performance.