Reinåga power plant

Reinåga is a tributary of the Røssåga river in Hemnes municipality, Nordland county. The river starts at the mouth of Reinåvatnet lake and flows into Røssåga at Reinåmoen, about 5 km from the village of Korgen. The intervention in Reinåga will be about 1.8 km along the river. The power station will be placed some distance from the road and will use an existing road.

History

The Reinåmoen farm is located just south of Korgen in Hemnes municipality. There are five farms that own waterfall rights in the Reinåga river. 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 several plans over the years. Much of the power resources around Korgen were developed in the 1950s, 60s and 70s, but Reinåga was not affected by the development at that time.

In 2007, 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 2012. Excavators arrived in the spring of 2013, and in 2014, 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 facing Kattuglhola.

The project

The implementation of the construction project has had its challenges along the way. These included a pilot project with long-hole drilling of over 1 km, costly access to telecommunications networks, a harsh winter during the construction phase, and a mini-tunnel through the mountain. The waterway in Reinåga is the first, and so far the only one with drilled holes that are more than 1 km long, using Nordhard’s drilling technique.
One of the most important factors for the smooth implementation is that both project teams and suppliers had recent experience from similar power projects. Having a local contractor and experienced project management will undoubtedly also ensure good progress and results. Construction has therefore gone as planned, which is not always the case for this type of project.

The Reinåga power plant has inflow from a catchment area of 4.3 km2. The minimum water flow in winter is 12 l/s, while in summer it is 72 l/s. The intake at elevation 700 and the power station at elevation 124 provide a fall height of 580 metres. Power production is an estimated 12.3 GWh in a normal year. This corresponds with an electricity consumption for 615 households.

The Pelton turbine has 3 nozzles with a maximum flow rate of 800 l/s and operates a 4350 kVA, 6600 v generator. All power is converted to 22 kV and delivered to the grid.
The intake was built as a blasted tunnel/channel between Reinåvatnet lake and drilling holes. The threshold at the outlet is well adapted to the terrain of the site. There is permission for Reinåvatnet to be regulated by 0.5 metres, which corresponds to the self-regulation of the lake.

The waterway consists of pipes in a trench at the bottom, while the steep section at the top is construction using a directional drilling of the shafts. The penstock is made of cast iron from the shaft to the station, while the shaft has steel pipes with a diameter of 600 mm. The entire waterway leads through the rock mountain or is buried.

The 80 m2 power plant building is constructed in the familiar Småkraft style and stands on the ground, well integrated into the terrain. Outflow is led out into the Reinåga river.

Technical data

Rainfall field

4.1 km²

Minimum water flow

Summer: 72 l/s

Intake elevation

700 m

Power station elevation

133,0 m

Drop height

567 m

Production

12,8 GWh
This corresponds to electricity 800 households.