A hydropower plant for regulating the frequency of an electric grid has an upper water reservoir; a lower water reservoir; a waterway that connects the upper water reservoir with the lower water reservoir. A turbine that is arranged in the waterway includes a runner, a guide vane apparatus and a device for blowing out the runner space. An electric synchronous machine is mechanically connected to the turbine and a frequency converter is electrically connected to the synchronous machine. A mains transformer is electrically connected to the frequency converter and the mains grid. A resistor is connected in a DC intermediate circuit of the frequency converter in such a way that it may connect the line sections of the DC intermediate circuit to one another. The assembly also includes a device for cooling the resistor.