Rasdalen power plant

The Rasdalselva river flows down a side valley from the south by the Bolstadøyri mountain, about 40 km west of Vossevangen. The power plant is built on the ground at the foot of the side of the valley, right by the E16 highway, about 100 metres from the confluence with the Bolstadelvi river, (Vosso).

History
The name “Rasdal” (literally translated as “landslide valley”), has nothing to do with landslides, but rather with water. Centuries ago, the valley was known as “Hradall”, meaning “fast” and “he who hurries”, and was named for the steep waterfall below the farms. Later, the letter “H” disappeared, and the name of the valley was changed to “Radallsdal” and later “Rasdal”.
The Rasdalen valley has been settled since the early Iron Age. The river has had a significant impact on the farms in the valley. Here, there were mill houses, grinding stones and later, sawmills. A dam with a hatch had also been established at the Radalsvannet lake, ensuring operations for technical installations even during dryer periods of the year.
The Rasdalselva river flows into the Bolstadelva river, which is known for its particularly large salmon population and salmon fishing traditions.
Rasdalen did not have roads until 1954, or electricity until 1956, and the valley has only periodically had its own school.

The project
As part of the administrative “Samlet plan” (Norwegian plan for the national management of watercourses), the intent was first to divert the Rasdalselva river to the Bergsdal watercourse. Due to strong local opposition, the plans were put on ice.
In 2006, a licence application was submitted with a plan to utilise the waterfall in Rasdalen, and then as a purely run-of-river power plant, without any form of transmission or reservoir storage. A licence was granted, and construction began in the spring of 2008. The project presented major technical challenges, including a waterway that partly led through the rock in the mountain and partly through a trench with more than a 30-degree slope. Yet the project was efficiently implemented by everyone involved, and the power plant was completed in November 2009. The Rasdalen power plant has become a facility that both landowners and Småkraft are extremely proud of.

Rasdalen power plant, Voss
The Rasdalselva river is a tributary of the Bolstadelva river, is located south of Bolstadøyri village, about 40 km west of Vossevangen. The power plant is built on the ground at the foot of the side of the valley, right by the E16 highway, about 100 metres from the confluence with the Bolstadelvi river and Vosso.

Technical information
The power plant has a Pelton turbine with a flow rate of 2.2 m³/s. Installed capacity is 5.2 MW. The waterway consists of a 305-metre shaft and a 760-meter buried ductile cast iron pipe with a diameter of 900 mm. The maximum elevation is 30º.

Technical data

Rainfall field

14.0 km²

Minimum water flow

Summer: 100 l/s

Intake elevation

300 m

Power station elevation

20,0 m

Drop height

280 m

Production

17,9 GWh
This corresponds to electricity 1119 households.