Method and apparatus for operation of a power station

A power station comprises a power-consuming shaft run on which a motor and a compressor are arranged, as well as a power-emitting shaft run on which a generator and an expansion machine are arranged. The compressor feeds a compressed fluid into a storage volume. The compressed storage fluid is expanded in the expansion machine, producing work. The generator and the motor are connected to the electrical grid system via frequency converters. This makes it possible to operate the electrical machines at a rotation speed which is asynchronous with respect to the grid system. A method and apparatus is disclosed that allows the net power output of the power station to be matched to the demands of the electrical grid system by varying the rotation speed of at least one of the shaft runs.