A depleted EV transmits first information including a current location of the depleted EV to a server. Each of the other vehicles transmits second information including a current location of the vehicle to the server. When the server receives from the depleted EV a help signal requesting power supply from another vehicle to the depleted EV, the server selects, from among the other vehicles, a rescue EV to supply electric power to the depleted EV, using the first information and the second information.