Leirfossene power plant is located on the lower part of the Neavassdraget watercourse (Nidelva River) in Trondheim Municipality in Sør-Trøndelag County.
Ownership: 100 %
Production: 150 GWh
Power: 45 MW
The power plant has an installed capacity of 49 MW and an annual average production of 150 GWh. The power plant is equipped with two Francis turbines with a capacity of 29 and 16 MW.
The power plant uses a gross height of fall of 61 metres. The water is transferred by shaft and tunnel from the intake reservoir Lake Øvre Leirfoss and down to the power plant. From there the water goes through an approximately 1.5 km-long outlet tunnel that discharges downstream in Lake Nedre Leirfoss.
Leirfossene power plant was commissioned in October 2008 after two years of construction. It is built inside the mountain under the Sjetnemarka district of the municipality and replaced the Øvre Leirfoss and Nedre Leirfoss power plants from 1901 and 1910 respectively.
The two old plants were not demolished, but converted into small power plants that utilize the minimum water discharge that flows in the Nidelva riverbed parallel to the tunnel system for the new Leirfossene plant.