Limberg II & Kopswerk II

Limberg II und Kopswerk II, Austria

Hydropower from the Austrian Alps

With the help of pumped storage power plants like Austria's Kopswerk II and Limberg II, electricity from wind and solar plants can be reliably used in the power grids.

These power plants store excess energy in times of low consumption and give it back again when needed. Pumped storage power stations are, in a sense, the backbone of renewable energy. Kopswerk II in Austria's Vorarlberg sets new standards. It can deliver up to 525 megawatts of peak energy into the power network in seconds, or receive up to 450 megawatts of unused energy from the network.

The power house orchestra

The pumped storage power station Kopswerk II was officially opened in a ceremony on 15 May 2009. Around 1 000 guests listened to the sounds of Vorarlberg's Symphony Orchestra who had brought their violins and cellos to the giant power house caverns. In the main building, there is sufficient space to be able to house Vienna's St. Stephen's cathedral. On the surface, however, little can be seen of the gigantic proportions, other than an entrance to the underground power house.

Hydropower in Austria

Water can be used to generate electricity without causing harmful emissions. About 60 percent of Austria's electricity is produced using hydroelectric power, with 37 percent coming from burning fossil fuels. The remaining three percent is produced by renewable energy sources such as the wind, sun and biomass.

Hydraulic short-circuit and torque converter

For Kopswerk II, Voith supplied three complete sets of equipment consisting of storage pumps, each with 150 MW of pumping power and spherical valves. The sets of equipment are specially designed for use in the so-called hydraulic short-circuit mode. This means that the storage pumps and turbines are separate and can therefore work simultaneously. When there is excess power from the electricity grid, but this is not sufficient to drive the pumps, the turbines can be used at the same time so that the power can still be stored.

Kopswerk II is also fitted with three hydraulic torque converters. These allow the plant to be switched from non-operation into pump or turbine operation within seconds.

Pump turbines: economical and space-saving

Voith delivered and installed two 240 megawatt pump turbines in the pumped storage plant Limberg II, which was brought into operation in 2011. They provide a sensible alternative to the use of separate sets of machines. Limberg II is completely built into the Austrian Hohen Tauern mountain range. Due to their extremely compact measurements, both machine sets are fitted with reversible pump turbines. These can work in both directions and, depending on the direction of rotation, function as either a pump or a turbine. Not only is this technology space-saving, but pump turbines are also an economically attractive solution.