The pumped-storage plant is expected to reduce peak load deficits and to provide a minute reserve for losses of larger power station blocks in the Vattenfall grid. These features make a significant contribution to the safe operation of the grid. The pump turbines, each rated at 265 MW, were supplied in a consortium, in which Voith Hydro was primarily responsible for the hydraulic design and the entire control system, including the technology of variable-speed turbine control in two of four machines.

By means of the variable-speed control, power input during pumping can be controlled continuously. Also, efficiency especially in turbine part load ranges is improved remarkably. Start-up of the turbine is only considerably faster and provides much smoother operation for the complete unit compared to fixed-speed units.

Variable-speed is, therefore, an advantage for overall unit performance, and also for flexibility of operation within grid regulation.

Two of four pump-turbines, as well as a large share of automation and control systems. The two units are equipped with variable-speed technology.