Ownership: 100 %
Production: 1698 GWh
Power: 250 MW (350 MW after rehabilitation and upgrading)
The Røssåga power plants are located in Hemnes Municipality in Nordland County. Øvre Røssåga uses the height of fall between Lake Røssvatnet and Lake Stormyrbassenget, while Nedre Røssåga uses the height of fall between Lake Stormyrbassenget and the village of Korgen.
Lake Røssvatnet has a reservoir capacity of 2.35 billion cubic metres and is Norway's second largest lake, measured in surface area.
The development of the Røssåga power plants involves the municipalities of Hemnes, Hattfjelldal and Grane. The development, which occurred during the 1950s and 1960s, was linked to operating the ironworks in Mo i Rana, providing power for domestic supply to 19 municipalities in Midt-Helgeland, and electrification of the Nordland railway line. In the 1960s, Elkem's aluminium plant in Mosjoen arrived as a major consumer of power.
Nedre Røssåga has six generating units with a total installed capacity of 250 MW. Øvre Røssåga power plant has three generating units with a total installed capacity of 160 MW. Øvre and Nedre Røssåga together currently produce about 2.6 TWh annually.
A major rehabilitation and upgrading programme has been initiated at the Røssåga power plants. In Nedre Røssåga, three of the generating units have been rehabilitated, and an additional unit of 225 MW will be built in a new cavern next to the existing power plants, and commissioned in the summer of 2016. At the same time, three of the six existing units will be decommissioned, giving Nedre Røssåga a new total capacity of 370 MW. In the period 2016-2018, the three units in Øvre Røssåga will be rehabilitated. Total installed capacity of the two power plants will be 550 MW after rehabilitation and upgrading.
The rehabilitation of Øvre and Nedre Røssåga, which both have Francis turbines, will increase annual production by 200 GWh, resulting in a total production from the new Røssåga power plants of about 2.8 TWh.
Architect Hans Grinde drew the plans for and participated in the planning of both Røssåga power plants. Parts of Nedre Røssåga power plant will be preserved as they are, in accordance with a conservation plan drawn up by Statkraft in cooperation with the Norwegian Directorate for Cultural Heritage.