A method for operating a first energy generator in an electric power supply system to which a plurality of electric consumers and at least the first energy generator, which is embodied as a regenerative energy generator, are connected via respectively one grid connection point each assigned thereto, wherein at least the first energy generator has an inverter of predetermined power rating, the AC voltage output of which is electrically connected to a first grid connection point assigned thereto, and wherein the operating control of the inverter regarding its reactive power feed and/or its reactive power draw into or out of the electric power supply system takes place depending on a continuously measured mains voltage value. The reactive power control in the energy grid is improved in that the mains voltage value is measured at a second grid connection point, which is different from the first grid connection point of the energy generator.