Fiskløysa power plant

The Fiskløysa power plant is a hydroelectric power plant on Murusjøen lake in Lierne municipality in Trøndelag county.

The area

The Fiskløysa power plant is located in Muru common forest, in the eastern part of Lierne municipality. The area is owned by Statskog SF and administrated by the Nordli Mountain Council who manages the rights to hunting, fishing and grazing.
The area borders Lierne National Park in the south, with a high density of game and an intriguing geology, which makes the area attractive for hunting, fishing, outdoor recreation and hiking. There is an abundance of varied and diverse species, which is unique in a regional and national context.
Here there are long traditions of utilising and harvesting natural resources in the form of forestry, pastures, hunting, trapping, fishing and berry harvesting.
Lower parts of the area consist of highly productive forest which gradually turns into a more mountainous forest landscape further up in the terrain. The upper part of the hillside consists partly of genuine primeval forest.
The Muru area is in the watershed between the Norwegian Sea and the Baltic Sea, where the Fiskløysa river drains into Lake Muru and eastward into Sweden. Murusjøen lake has diverse fish fauna, with species such as trout, char, lake trout, Arctic char, pike, whitefish, grayling, and European bullhead.

The project

The project was developed under the auspices of NGK Utbygging AS after they took over the project from NTE and Statskog Energi, which failed to find profitability in the project. The technical plans were revised to find profitable solutions, and this led to the decision to realise the project.
The development went smoothly on the whole, although some challenges were encountered that are not entirely unusual for developments in natural conditions and surroundings, both in terms of local ground conditions and varying climate conditions. This is when it is reassuring to have an experienced project team, as well as experienced and skilled contractors who are able to find good solutions and avoid major delays. This project was plagued with everything from mobile cranes that overturned on the construction road, deep slush holes that had to be drained and subsequent massive mass replacements, as well as temperatures down to -30 °C that created challenges with telecommunications in pipe trench.

Technical information

The power plant has inflow from a catchment area of 58 km2. Minimum water flow is 300 l/s in summer and 100 l/s in winter Intake is at elevation 506 and the station is at elevation 318.4, which gives a fall height of 187.6 metres. Power production is an estimated 17.9 GWh in a normal year. This corresponds with an electricity consumption for 895 households.
The Pelton turbine has a maximum flow rate of 3.25 m3/s and runs a 5632 kVA, 6600 V generator. The electromechanical equipment was supplied by Spetals verk. The building was done by Namsskogan Bygg AS.
The penstock is made of GRP pipe and has a length of 2,360 metres and pipe diameters of 1200, 1300 and 1400 mm, with 1/3 of each diameter. The pipe materials were supplied by Brødrene Dahl AS and the construction work was carried out by Kolbjørn Nilsskog AS. The intake dam is built on soil deposits such as a filling pond with a concrete core as a sealant. Fibreglass reinforcement was used for the concrete core.
The voltage is converted to 22 kV before power is delivered to the grid. In total, 2.6 km of 22 kV cable was buried up to the NTE grid. From there, NTE buried 22 kV cables to the Nordli transformer station to replace the old overhead lines.

Technical data

Rainfall field

58.0 km²

Minimum water flow

Summer: 300 l/s

Intake elevation

506 m

Power station elevation

318,0 m

Drop height

188 m

Production

17,9 GWh
This corresponds to electricity 1119 households.