In the period 2016-2018, the three generating units at Øvre Røssåga will be rehabilitated and a new parallel tailrace tunnel put into use. Increased power, new tunnels and rehabilitation will increase production by 200 GWh at Øvre and Nedre Røssåga power plants, which together will be able to produce around 2.8 TWh per year.
Øvre Røssåga power plant uses the height of fall between Lake Røssvatnet and Lake Stormyrbassenget, The gross height of fall is 136 metres. Lake Røssvatnet has a reservoir capacity of 2.35 billion cubic metres and is Norway’s second largest lake, measured on surface area.
Øvre Røssåga power plant has three generating units with Francis turbines and a total installed capacity of 160 MW. Head loss in the water system or loss of energy due to friction of the water against the uneven surface of the tunnel and other obstacles, has meant that full power levels have not been achieved. The planned upgrade will make it possible to utilise this missing capacity.
Øvre Røssåga currently produces about 800 GWh a year. After the planned upgrade production will be around 900 GWh.
NLI Elektrosystemer was responsible for installation of regulators and equipment related to de-magnetizing.