There is provided a method of operating a pump turbine plant including a turbine with a turbine impeller and a turbine spiral casing having a first pressure pipe, and a pump with a pump impeller and a pump spiral casing having a second pressure pipe; an electrical machine dynamically in a drive connection with a shaft, the pump turbine plant further including a hydraulic short-circuit that can be created between the turbine and the pump, wherein the turbine has a greater rated power than the pump, and wherein the turbine and the pump operate under partial load at least temporarily in the hydraulic short-circuit. The method further includes operating the turbine or the pump in the hydraulic short-circuit when a degree of efficiency of the pump and of the turbine in the hydraulic short-circuit is greater than a degree of efficiency of the turbine on its own.