E.ON has planned to expand the capacity of Waldeck pumped-storage hydroelectric station on Lake Eder in the federal state of Hesse in central Germany by building a new 300MW pumped-storage plant next to the existing Waldeck 2 facility.

Construction on the project will begin in 2012 following the approval from the Hesse state government in Kassel in late2011, and is expected to take four years, with the new capacity entering service in 2016.

The new plant, including the penstock pipes, turbine room and other generating equipments, will be built completely underground directly next to Waldeck pumped-storage hydro station and will use the same access tunnel.

The volume of Waldeck 2’s upper reservoir will be increased by about 10% by raising its retaining walls for the new plant, which will use Waldeck’s existing, on-site switching yard to deliver power onto the network.

Once the EUR250m project becomes operational in 2016, it will bring Waldeck’s total capacity for generating power and for storing power that is not needed when it is produced to 920MW, which is equivalent to about 15% of Germany’s total pumped-storage capacity.