Greater efficiency thanks to modern technology. Thanks to new generators, Alpiq has increased the capacity of both groups in Miéville power station from 60 to 70 MW. The renovations took five years and cost CHF 25.8 million. The average annual production of 110 million kWh corresponds to the average annual electricity consumption of around 30,000 households. Capacity and efficiency were increased without changing the water intake.
This upgrade was prompted by the decision to feed in electricity from Miéville power station, with a voltage of 65 kV, to the Force Motrices Valaisannes substation in Vernayaz. Until then the power station had been connected to the regional 65-/125-kV grid. The new feed-in was implemented in 2007/2008. Between 2009 and 2011, Alpiq replaced the generators of both turbine generator groups, including the control system. At 35 MW per machine, the capacity of the new generators is 5 MW higher than that of the old machines. In the wake of this upgrade, Alpiq was able to dismantle the 1100-meter long 65-kV overhead line with its six pylons and lay the new cables underground. This measure has in particular enhanced the landscape surrounding the Pissevache waterfall, a popular attraction in Vernayaz.
The Salanfe unit of the power complex is situated in Miéville in the municipality of Vernayaz, between Martigny and St. Maurice. The plant is fed from Lac de Salanfe reservoir, located at an altitude of 1925 meters. The power station went into operation in 1950. Salanfe SA is a fully-owned subsidiary of Alpiq Suisse SA. The renovations were realised by Hydro Exploitation SA.