Server, building energy management system, and building energy management method

A server for managing energy in a building provided with:

• a natural energy supply which generates power that varies depending on meteorological conditions;
• and a plurality of energy storage facilities each storing energy in a form of electricity or heat, the server comprising
• a processor which performs a computation process to determine, among the plurality of energy storage facilities, an energy storage facility to store the power, generated by the natural energy supply, to, wherein
• when the power generated by the natural energy supply is greater than power consumed by the building and surplus power is produced, the processor
• extracts one or more energy storage facilities, among the plurality of energy storage facilities, whose periods requiring continued energy storage depending on facility specifications are less than a duration during which the surplus power is greater than a predetermined amount, and
• calculates, for each of the one or more energy storage facilities, an amount of reduction of electricity cost if the energy storage facility stores the surplus power, to determine an energy storage facility to store the surplus power to, based on the amount of reduction.