A control system includes a computer that controls each of multiple power balancing resources. The computer selects one or more control targets to be used for power balancing of an external electric power source from the power balancing resources, and controls each of the one or more control targets so as to cause the power storage device to charge or discharge for the power balancing. The computer preferentially selects the power balancing resource provided with a small-capacity power storage device as the control target for the power balancing of which duration is shorter than a predetermined time, and preferentially selects the power balancing resource provided with a large-capacity power storage device as the control target for the power balancing of which the duration is longer than the predetermined time.