Power generation plant for obtaining electrical power from a water or air flow includes a turbine; an electrical generator, having a coaxial configuration of a rotor and a stator. The rotor is an external rotor and part of an annular support structure for the turbine. The stator is housed in a stator housing which is sealed to the ambient medium and a wall area of the sealed stator housing running in the area of the gap between rotor and stator so that the rotor is situated radially outside the sealed stator housing and the magnetic interaction between rotor and stator occurs through this wall area. A mount for the annular support structure includes the rotor. The mount is situated adjoining the gap between the rotor and stator and is supported on the external circumference of the sealed stator housing.