Working with rehabilitation of Røssåga Hydropower station

My last rotation as a Statkraft trainee

The time goes by so fast and I am already in my fourth and last rotation as a Statkraft trainee! Since my last blog post I have moved on from Jostedalen back to the main office, and at the moment I am spending my last rotation at a construction site on a large hydropower project in Korgen in Nordland in the North of Norway. The project is to upgrade one of the old hydropower plants of Røssåga

Many of Statkrafts hydropower plants are from the 1950 – 60s, meaning that they have been in operation for over a half century. A lot of them are therefore in need of refurbishment and upgrading to make sure they will continue to produce in the years to come! In recent years Statkraft has upgraded many of these old hydropower plants, Røssåga being one of them.

Røssåga – providing energy since the 1950’s

The year was 1947 and the Second World War had just ended, leaving Northern Norway in ruins. No other part of the country had been so marked by the ravages of the war, and was in desperate need of new housing, infrastructure and industry.

Construction of the Røssåga hydropower plants was initiated to provide electricity to the new ironworks in Mo i Rana and for regular power supply to the people. It was an important step in the governmental plan to rebuild and economically strengthen the country after the war. The construction took more than seven years and employed more than 1100 persons! The two hydropower plants of Røssåga were taken into operation by the end of 1958. Nedre Røssåga takes advantage of the elevation difference between Stormyrbassenget and Korgen.

Røssåga 1957. The protective gear and tools were a bit different than today. (Photo by Statkraft)

The new Nedre Røssåga hydropower station

Statkraft decided in 2012 that it was time to upgrade Nedre Røssåga hydropower station. The project started in 2013 and involves rehabilitation of three of the generating units in the old station, in addition to constructing new parallel tunnels and a completely new hydropower station next to the old one. The new station will have one generating unit with a capacity of 225 MW. In this way the capacity of the whole facility will increase with 120 MW, without exploiting new regulations!

Hello down there! Me and the turbine in the new station. (Photo by Tor-Arne Sandnes)
The last inspection of the new draft tube. (Photo by Tor-Arne Sandnes)

Tunneling through the rock

The new tunnel which will lead water down to the new station at Røssåga has been constructed with a Tunnel Boring Machine (TBM), instead of the conventional drill and blast method. This machine has a cutter head in the front (see the picture below), which is used to grind its way into the rock, leaving completely circular tunnels. This technology has not been used in Norway since the last large hydropower projects in the early 90s.The project at Røssåga was accordingly the first in Norway for over 20 years that used a machine like this! This was actually my topic for master thesis in 2014, so it was very exciting to come back to see the progress!

TBM Breakthrough
The breakthrough: The Tunnel Boring Machine has just completed over 7 km of tunnel (Photo by Statkraft).

My experiences as a trainee

During my time at Røssåga I have among other things been working with following up the tunnel construction and a number of various tasks related to the construction of the new station. Working on a place like this where new things happen every day, makes me realize that I still have so much to learn! However, I feel that I have a really steep learning curve when I work like this “out in the field” and I really recommend it to get some practical experience!

Inspection at the new intake in Stormyrbassenget


(I credit and “De som bygde vår velstand” by Anne Lene Lien for the facts about Røssåga)


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