To provide an operation management method and an arrangement of private owner electric power facilities which can easily purchase demanded power, without introducing the privately owned electrical power facilities with the cost saving capable of being expected by a customer.

A service enterpriser 30 installs the private owner electric power facilities 10, 11 which are the properties in a customer 1 purchasing power, and the service enterpriser 30 fetches the operating data of the private owner electric power facilities 10, 11 to an arithmetic processing unit 19 via a network 18 remotely supervised, to carry out operation maintenance including supply of fuel. The service enterpriser 30 sells generated power of the private owner electric power facilities 10, 11 to the customer 1 and receives charge.