A plurality of distributed power generation systems are connected via the Internet to a managing apparatus in a managing company. A power company communicates with the managing apparatus via another line. At peak times of power consumption in the midsummer and so forth, the power company requests the managing company to supply the power. The managing company controls to remotely set generation capacity of the distributed generation systems at maximum so as to reverse surplus power therefrom to a power system. A normal power rate is discounted for a user of the distributed generation system for his/her cooperation with the power company. The managing company charges the power company based on the surplus electric energy supplied to the power company.