The server executes a process that includes receiving predetermined information from each terminal in a facility, if it is determined that the electric vehicle is connected to a charging/discharging station, associating a user or a user terminal with the charging/discharging station, scheduling a power demand and supply adjustment, receiving behavior information of the user, if it is determined that it is necessary to reschedule the power demand and supply adjustment, predicting a connection period, rescheduling the power demand and supply adjustment, and if the current time has reached the start time of a power supply and supply adjustment period, executing the power demand and supply adjustment.