[Problem] To provide an electricity supply system that efficiently utilizes electricity. [Solution] An electricity supply system includes: a power generation unit (10) for supplying electricity; a load unit (11) for consuming at least one of the electricity supplied from the power generation unit (10) and system electricity supplied from an electricity system; and a control unit (12) for controlling operations of the power generation unit (10) and the load unit (11). The power generation unit (10) supplies electricity to the electricity system, and the control unit (12) controls the power generation unit (10) and the load unit (11) on the basis of values of a plurality of types of electricity handled by the electricity supply system.