NOVELTY - A solar power generation device is connected to electric power grid, and a home gateway is provided to control the flow of electric power with respect to electric power grid. An operation-control apparatus is connected with home gateway by a communication unit. An output suppression instruction is transmitted via the communication unit with respect to home gateway of consumer determined in the suppression object decision process. According to the output suppression instruction received by the communication unit, the home gateway of the consumer has a control process.    USE - Operation-control method of solar energy power generation system.    ADVANTAGE - The variation in output suppression between each consumer which has the solar energy power generation system connected to the same system can be reduced, and it is possible for the feeling of inequality between each consumer with respect to output suppression to eliminate. The maximum use of natural energy in town can be performed. That is, compared with the case where output suppression is carried out with respect to the residence of all, natural energy can be harnessed effectively.    DETAILED DESCRIPTION - A solar power generation device is connected to electric power grid, and a home gateway is provided to control the flow of electric power with respect to the electric power grid. An operation-control apparatus is connected with home gateway by a communication unit. The suppression object decision process is conducted to determine by series the consumer that should suppress the output of reverse power-flow according to the head-tide allocation target of each consumer in town. An output suppression instruction is transmitted via the communication unit with respect to home gateway of consumer determined in the suppression object decision process. According to the output suppression instruction received by the communication unit, the home gateway of the consumer has a control process in which the reverse power-flow of generated electric power which the solar power generation device of the consumer is suppressed. An INDEPENDENT CLAIM is included for operation-control apparatus.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic diagram of solar energy power generation system (Drawing includes non-English language text).