They have blown themselves almost a hundred meters down the mountain in Fiskumfossen. More than a kilometer of tunnels have been built that partly run under the E6 and close to the railway. This is environmentally friendly, says NTE’s project manager Randi Reitan Troset. – We borrow the river for a few minutes, make a current from it and send the river just as clean on the downstream side. The construction is also taking place without visible natural encroachment, says Troset. She points out that a new dam has not been built. They have only taken a hole outside the old power station and built a completely new power station underground. The old power plant a few meters away was built during the war. It will soon be stopped and the water from Namsen will be leased to new turbines and supply electricity to 20,000 households. Two new turbines will ensure that the power plant produces electricity for 50,000 trønders. Photo: Vegard Woll / news Lønnsamt The price tag for the new power plant is NOK one billion. And despite the still low electricity prices in central Norway, it is a profitable investment. – When we calculated whether we should build a new one or rehabilitate the old power plant, it was on the verge of being profitable. But we took the chance. The tax rules have changed since we started and made it more profitable to upgrade old power plants, says NTE’s project manager. Other upgrades/renewals of hydropower plants Photo: Torbjørn Selseng / news Lysebotn II in Rogaland: A new station and waterway have been built that have intakes into both Lyngsvatn and Storetjørn. Here, it was originally planned that the old power plant with intake in Storetjørn would be taken out of operation, but there are plans for continued operation of the original power plant with reduced output. Nedre Røssåga in Nordland: A new parallel waterway and station with a new aggregate were built here. The original power plant originally had six aggregates. Three of these units were phased out and three rehabilitated. Vamma in Viken: One more unit was put into use in a separate station (Vamma 12). Embretsfoss in Viken: A new parallel station and waterway was built. A station from 1954 is still in use, and the then oldest station was taken out of service. Eiriksdal in Vestland: This replaced two old power plants and relieved production from the Høyanger K5A power plant. Source: NVE Nord-Trøndelag E-verk has, when the new power plant is put into operation, upgraded five of its eight power plants in Namsen. They are not alone. In the last 20 years, over 200 similar upgrades of power plants have been carried out in Norway, according to Seming Haakon Skau, who is a senior engineer at NVE. This has increased electricity production by almost 5 TWh, which corresponds to 5 billion kilowatt hours. Project manager at NTE, Randi Reitan Troset, is proud that they can build a new power station with almost no apparent intervention. Photo: Vegard Woll / news Considers several upgrades In Trøndelag, NTE is looking at whether they should do another upgrade in Namsen. – We are now considering whether to upgrade the Aunfoss power plant, which is located a little further up the river, but that has not yet been decided, says Troset. It is challenging to build a power plant in a salmon-carrying river like the Namsen. The salmon must both get up and down the dammed waterfall, and NTE has used large resources to ensure that the fish are not harmed. Among other things, a migration tunnel has been blown up for fish going out to sea after spawning. The intake is equipped with fish hatches, which guide the fish towards the migration tunnel. Troset says they have had a close dialogue with the student ownership team and election owners in the area. The river owners’ association has, among other things, been present after explosions and crossed the river to see if fish have been damaged. Almost 1.1 kilometers of tunnels have been built in the power plant. Along this staircase, cables must be run up to the transformers. Photo: Vegard Woll / news Blasted out 130,000 cubic meters of rock The work that contractor Skanska has carried out deep inside the mountain and outside has been demanding. Transporting transformers weighing over 60 tonnes into cramped mountain halls requires careful planning. Large quantities of concrete and explosives have also been used. – We have used between 14 and 15,000 cubic meters of concrete in tunnels and halls so far. I have no idea how many tonnes of dynamite have been used, but we have blown out approximately 130,000 cubic meters of rock, says assistant project manager for developer Skanska, Kjell Ove Lænd. Both he and NTE’s project manager underline the positives in that this type of development is very environmentally friendly. Most of this happens underground, and does not affect the surrounding environment. The power plant in Nedre Fiskumfoss will produce 382 GWh over the course of a year. In comparison, an average wind turbine will produce approximately 15 GWh, so the production in Fiskumfossen corresponds to approximately 25 wind turbines. – I am very proud to be involved in building water power. It’s as sustainable as it gets, says Länd. A lot of heavy lifting is being done to build the power station in Grong. Here, the 26-tonne top of one of the turbines is hoisted into place. Photo: Vegard Woll / news Great potential Troset and NTE now hope that they will be able to finish by the time the opening takes place in the third quarter of next year. At NVE, they always receive new applications to upgrade and renew both small and large power plants, says Seming Haakon Skau, senior engineer at NVE. Only in the second quarter of this year was permission given to upgrade two smaller power plants. But there are still many older power plants in the country, and according to NVE, there is a great potential to extract much more power by upgrading or renewing them. Over a kilometer of tunnels have been blasted into the mountain below Fiskumfossen. Photo: Vegard Woll / news
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NTE builds a billion-dollar power plant under E6 – provides power to 50,000 Trønders – news Trøndelag
