Method for starting a stationary gas turbine

The method involves rotating a rotor by an external rotary drive with drive torque, and igniting fuel within a stationary gas turbine at a rotor rotational speed, where gas-turbine torque is dependent on flow of hot-gas in a turbine unit. The rotor is driven by an electrical generator. The rotary drive is switched-off at a predefined rotor rotational speed such that the rotor is still driven only by the hot gas produced during combustion, where the predefined speed is greater than 0. 8 times of nominal rotational speed of the rotor.