Its lower reservoir is located on the Our River, bordering Germany, and the upper is elevated above on the nearby Saint Nicholas Mountain.

Construction on an eleventh pump-generator began in 2010 and it is expected to be commissioned in 2013, which will bring the plant's installed capacity to 1,296 megawatts (1,738,000 hp).

Planning for the project began in 1925[2] but the idea failed due to a lack of funding and political pressure.

On 10 July 1958, a treaty was signed between Luxembourg and the German state of Rhineland-Palatinate, which also shares the Our River, allowing construction.

[2] Planning for a 200 megawatts (270,000 hp) eleventh unit began in 2006 and the designs were completed in 2009 by Lahmeyer International.

On 15 June 2010, Upper Reservoir I was drained to install a new intake structure, which was completed in November 2010.

To supply water to the generators and to serve as a discharge for the pumps, both Upper Reservoirs I & II have combined intakes/outlets.

[7] Water from Upper Reservoir I is sent to the main power house, which contains nine Francis pump-turbine-generators, via a system of tunnels and penstocks.

Upper Reservoir II's intake/outlet sends water down to the secondary powerhouse which contains one Francis turbine-pump-generator.

After electricity is generated, both power stations discharge water into the lower reservoir which is created on the Our River by the 30 metres (98 ft) tall and 130 metres (430 ft) long gravity dam, Vianden Dam.