Power plant system

The power plant (1) has an energy conversion unit (2) comprising a wind wheel (4) and connected to an energy supply network (14) via a current power supply line (12). Another energy conversion unit (20) i.e. combined heat and power unit, has a generator (26) driven by an internal combustion engine (22) for converting energy contained in a fuel into electric current, where the generator is connected to the energy supply network. A control unit (60) adjusts the fuel inflow into the engine based on electric performance released by the former conversion unit via the supply line.