Nedre Leirfoss power plant is located on the Nidelven River in Trondheim Municipality in Sør-Trøndelag County.
Ownership: 100 %
Production: 21 GWh
Power: 2.4 MW
The plant uses a height of fall of 27 metres and is a river power plant. The installed capacity is 2.4 MW.
The power plant was commissioned in 1910 with two generating units. In 1921, 1943 and 1958, new generating units were added. There were five installed in total, although plans called for six.
The power plant was partially replaced by Leirfossene power plant in 2008. However, to exploit the minimum water discharge of 10 cubic metres per second between Øvre and Nedre Leirfoss, a new generating unit with a vertical Francis turbine was installed in 2014. Only two of the original generating units remain in the plant.
Nedre Leirfoss power plant is now designated as a special preservation area by Trondheim Municipality under the Planning and Building Act of 1985.
Plans for the plant were originally drawn by architect Axel Guldahl and the plant has a distinctive architecture. The building is rectangular with rounded corners and has clear allusions to a medieval castle with a cornice rising above the flat roof. The building is also equipped with "gun ports" and tower-like constructions on each corner. The power plant building is constructed of concrete and faced with stone.