Back in time

Hydroelectric power is environmentally friendly and efficient. Along with wind power, it is currently undergoing a renaissance in Germany. Bilfinger Berger is involved in a project for Eon, one of Europe’s largest energy providers.

Eon is modernizing the seventy-year-old pumped storage power plant “Waldeck I” by Lake Edersee in Hesse. The output of the “Waldeck I” is 140 megawatts—not much compared to a large-scale power station. However, the pumped storage technology is excellently suited to provide fast and effective compensation for short-term fluctuations in the power grid. When demand increases, water flows from the higher reservoir into the power station 300 meters below, driving turbines to generate electrical power. When demand recedes, at night for example, the surplus power is used to pump the water back into the upper reservoir. Pumped storage power plants are of particular interest in conjunction with wind power: if there is a calm period and the wind facilities are not able to feed sufficient power into the grid, the pump turbine can be powered up to full output within minutes to compensate for the deficit. With the growing number of wind parks in Germany, it might be worthwhile even for large-scale energy providers to invest in the straightforward and sustainable technology of pumped storage.

Two of the four old turbines in Waldeck will be replaced by a new, state-of-the-art pump turbine. Bilfinger Berger is currently digging a 40-meter shaft into the rock at the edge of the lower reservoir to house this turbine. The water will drop an additional 40 meters, further enhancing the turbine’s energy efficiency. Bilfinger Berger will also construct the machinery hall and renew large sections of the old facility. The new pump turbine is due to go into operation in January 2009: “Waldeck I” will then feed 600 megawatts of environmentally friendly power into the power grid, along with the second pumped storage power plant by Lake Edersee,“Waldeck II”. (si)