Alta power plant

The power plant is situated 40 kilometres from the mouth of the Alta River, which has a large part of the Finnmarksvidda plateau as its catchment area. The lower 40 km of the river is used by salmon to migrate. The power plant makes use of a height of fall of 185 metres from the 18 kilometre-long Lake Virdnejávri reservoir. Most of the reservoir is located in Kautokeino Municipality.

From the 110-metre-high concrete arch dam, Norway's highest, to the outlet of the power plant, the river is dry for a stretch of two kilometres. To ensure that the temperature of the operating water through the power plant best matches that of the water in the river below the plant, two intakes have been established at different depths. Water from the power plant is discharged back to the river through an outlet tunnel. Alta power plant has two generating units with Francis turbines.

The power plant is one of the most controversial hydropower developments in Norwegian history. The protests partly arose from concerns about reindeer herding in the area and salmon migration in the Alta River. Read more about the Alta development from 1980 to 1987 here.