Cleuson-Dixence

Before the construction of the Cleuson-Dixence power plant complex was built, it took approximately 2,200 hours to empty the Grande Dixence dam. In other words, the turbines had to operate at full capacity 11 hours a day, every day from October to April.

The new Cleuson-Dixence hydropower complex enables production to be concentrated over just 1,000 hours, thus multiplying Grande Dixence’s generating capacity by 2.5. This enables the output of a large nuclear power plant to be fed into the very high voltage grid in just three minutes. Cleuson-Dixence is operated by HYDRO Exploitation SA.

Built entirely underground between 1993 and 2000 by EOS SA (now Alpiq Suisse SA) and Grande Dixence SA with total investments of CHF 1.3 billion, the power plant complex comprises:

• a new water catchment drilled into the Grande Dixence dam

• a 15.8 km long feed tunnel

• a surge tank dug into the Dent-de-Nendaz mountainside

• a 4.3 km steel-lined pressure shaft

• the Bieudron underground power station

• 3 Pelton turbines – total capacity: 1,269 MW (1,395 MVA)

• Gross head: 1883 m

• 380 kV grid connection

The operation of the Cleuson-Dixence complex is closely linked to the Grande Dixence SA facility.
The Cleuson-Dixence complex was out of service for nine years. Following completion of the repair work, it was put back into operation in January 2010. It is operated by HYDRO Exploitation SA.