Energy management system and power interchange method

An energy management system to allow for efficient power interchange through a reduction of communication congestion, the energy management system being provided in one power consumer in a case where the energy management system is provided in each of a plurality of power consumers to manage a power interchange between said plurality of power consumers that each include a distributed power supply and load equipment and that are connected to each other by a power path and an information path, said energy management system comprising:

• an information transmitter to transmit information to said information path;
• an information receiver to receive information from said information path;
• and
• a region information manager to manage at least part of information about a plurality of small regions that each include said plurality of power consumers,
• wherein each of said plurality of small regions overlaps at least any of the other small regions of said plurality of small regions, and
• said region information manager manages
• information about at least one belonging region of said plurality of small regions, said one power consumer belonging to said at least one belonging region, and
• information specifying, in addition to said one power consumer, at least one other power consumer of said plurality of power consumers, said other power consumer belonging to said at least one belonging region.