NOVELTY - The energy management system has an electric power generating apparatus (30) provided with a storage tank (20) to supply electric power with respect to the load in a plant (10). The heat generated by electric power generation of the electric power generating apparatus is collected. An energy-management apparatus (200) has a heat recovery equipment that makes the refrigerant with collected heat stored in the storage tank. An excessive heat amount calculation part (211) computes excessive heat amount of electric power generating apparatus based on the heat demanding amount of storage tank.    USE - Energy management system, such as a plant energy management system, town energy management system, community energy management system for performing power management of a consumer and a home energy management system, and for managing the energy exploited in a plant, residence, commercial establishment, industrial installation and a public facility.    ADVANTAGE - The energy management system has an electric power generating apparatus provided with a storage tank to supply electric power with respect to the load in a plant, and thus appropriately performs the control of the electric power generating apparatus corresponding to heat remainder, improves the efficiency of the exploitation of energy in the energy-management area, restrains the use of fuel in the commercial power source and energy-management area, and also reduces the use of cooperative energy.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the followings:    (1) an energy-management method for managing the energy exploited in a plant, such as a residence; and    (2) a program for managing energy exploited in a plant.    DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of a plant energy-management apparatus. (Drawing includes non-English language text).    Plant (10)    Storage tank (20)    Electric power generating apparatus (30)    Energy-management apparatus (200)    Excessive heat amount calculation part (211)