ELECTRICITY CONTROL SYSTEM

According to one embodiment, an electricity control system includes a power plant (1), a customer (5) and a central device (100) connected to each other via a power line (6). The customer (5) includes an electricity generator (209, 210) that generates electricity. The central device (100) provides the customer (5) with feedback of an incentive indicated by a value obtained by multiplying an electricity amount injected into a grid within an electricity amount generated in the electricity generator (209, 210) by a first incentive coefficient L used when the power plant (1) has surplus electricity to supply.