The invention relates to a method for operating a stationary power plant, wherein a fuel/air mixture is burned in an internal combustion engine and wherein the internal combustion engine drives an alternating current generator, which is connected to an energy supply network and provides energy to the energy supply network, wherein if the actual rotational speed of the alternating current generator or of the internal combustion engine exceeds a predefinable maximum value due to a failure of the energy supply network, the combustion in the internal combustion engine is stopped at least partially, while the connection to the energy supply network is maintained.