Alta power plant is situated in Sautso in Alta Municipality in Finnmark County.
Ownership: 100 %
Production: 655 GWh
Power: 150 MW
The power plant has two generating units of 100 and 50 MW respectively, and an annual mean production of about 655 GWh.
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 watershed. The lower 40 km of the river is used by salmon to migrate. The power plant uses a height of fall of 185 metres from the 18 kilometre-long Lake Vird'nejav'ri 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.
The power plant was commissioned in 1987 and is one of the most controversial hydropower developments in Norway's history. The protests were partly due to concerns about reindeer herding in the area and salmon migration in the Alta River.