Skarelva power plant

The power plant utilises the watercourse from a section of the 11.1 km2 long watercourse in Sør-Skjomen, Narvik municipality. The rivers Vestskarelva and Snøskarelva conflux to become the Skarelva river and on into the Storelva river. Storelva's outlet is in Lake Skjomenbotn in the far south of Sør-Skjomen.

History

Sandvoll and Skjomboten are the innermost farms of Skjomen in Narvik municipality. Together, they encompass large wilderness areas and rivers. Much of the power resources in Skjomen were developed in the early 1970s, but neither of the rivers Vestskarelva or Snøskarelva were affected by development at that time.

The landowners were aware that the river could have a good potential for small-scale hydropower. Realisation of the value creation from the river has been the subject of intense discussion over the years, and a decision was made to partner with a professional developer.

In 2004, a contract was signed with Småkraft, which assumed the risk, the work with the licensing process and the development itself. NVE granted a licence in 2008. This was appealed by Narvik municipality. The appeal was rejected by the Ministry of Petroleum and Energy (OED) in December 2009. Excavators arrived in 2011, and in 2012, the power plant was ready to deliver its contribution in the form of new renewable energy and local business revenues.

With its natural stone walls and a glass façade, the station building has an attractive exterior and has been nicely adapted to the terrain by the river.

The project

The implementation of the project has had its challenges, including the appeal of the licence to OED, as weøø as the penstock that was mostly laid in a rocky trench, a difficult and costly access to the power and telecommunications network, and a tough winter during the construction phase – just to name a few.
Collaboration with the landowners has been good. Their contribution in the form of local knowledge and their presence during the construction phase has enabled a smooth project implementation.

All suppliers have delivered as expected. The progress of the construction has therefore gone according to plan. That is not always the case for this type of project.

The Skarelva power plant has an inflow from two rivers, Snøskarelva and Vestskarelva, with a total catchment area of 11.1 km2. The minimum water flow is 20 l/s in winter for both intakes, while it is 300 l/s for Snøskarelva and 20 l/s for Vesterskarelva in summer. Intakes at both rivers are at elevation 455, while the power station is at elevation 18, which gives a fall height of 437 metres. Power production is an estimated 11.9 GWh in a normal year.This corresponds to an electricity consumption for 595 households.

The Pelton turbine has 4 nozzles with a maximum flow rate of 1.35 m3/s, and it operates a 5500 kVA, 6600 v generator. All power is converted to 22 kV and delivered to the grid.

The intake dams are built as blasted pools with low dams in reinforced concrete with a prefabricated intake structure. The intakes are well adapted to the terrain of the site, and appear to be a very modest intervention. The penstock in made of PE pipe for each branch, and in cast iron from the branching site to the station. The diameter of the PE is 0.6 m, while the cast iron diameter is 0.7 m. The entire waterway is buried.

The 80 m2 power station building is constructed in the familiar Småkraft style, well integrated into the terrain. Outflow is led through pipes into the river.

Technical data

Rainfall field

11.1 km²

Minimum water flow

Summer: 300 l/s

Intake elevation

455 m

Power station elevation

18,0 m

Drop height

437 m

Production

12,0 GWh
This corresponds to electricity 750 households.