an electrified vehicle equipped with a battery;

a charging station configured to be connected to the electrified vehicle;

a first server configured to manage reservations for the charging station, and including a communicator that communicates with the electrified vehicle and a processor that controls the charging station; and

a supply and demand management server configured to manage power supply and demand on a power grid, wherein

the electrified vehicle or the charging station is configured to perform balancing power control and normal charging control, the balancing power control being power control including at least one of power supply from the electrified vehicle to a power grid or charging from the power grid to the electrified vehicle according to a balancing request from the supply and demand management server, and the normal charging control being power control for charging the battery without the balancing request,

the communicator is configured to receive a reservation request signal requesting a reservation to use the charging station by the electrified vehicle, the reservation request signal including information indicating that the balancing power control is requested when the electrified vehicle wants to perform the balancing power control,

the processor is configured to set, based on the reservation request signal, a reservation time period during which the electrified vehicle uses the charging station, wherein the reservation time period is set to a longer period when the reservation request signal includes the information indicating that the balancing power control is requested than when the reservation request signal does not include the information indicating that the balancing power control is requested,

wherein based upon the supply and demand management server determining that a power consumption of power balancing resources is expected to be larger than a predetermined value, the supply and demand management server sends the balancing request to the processor, and

based upon the processor receiving the balancing request from the supply and demand management server, the processor controls the charging station to cause the electrified vehicle to supply power from the electrified vehicle to the power grid during at least a part of a time of the reservation time period.