Norsk Hydro has approved the construction of the Illvatn pumped-storage project in Luster, western Norway, the company’s largest hydropower development in more than 20 years, which will add 107 GWh of annual storage.
The system will add around 107 GWh of annual energy production and increase flexibility at Hydro’s Fortun power operations. No figures around power output in kW or MW were provided by Hydro.
The project involves constructing an eight kilometer tunnel to connect a lower reservoir called Fivlemyrane at 1,018 meters above sea level with the Illvatn reservoir at 1,382 meters, and the new pumped storage power plant will be built in Sogn. The permitted water level minimums at Illvatn will be lowered to boost available reservoir capacity, and the whole thing is expected to enter service in 2030.
Hydro, in its press release, said “By pumping water to Illvatn, water that would otherwise be lost during the summer months, water loss in the Fortun system is reduced, and total production increases during winter when power demand is high.”
Hydro estimates a gross capital expenditure of NOK 2.5 billion, or about $245 million. The net investment, after accounting for Norway’s somewhat unusual tax rules for hydropower, is projected at NOK 1.2 billion, or approximately $118 million.
“This is the largest investment in our hydropower portfolio since the development of the New Tyin power plant in Årdal in 2004,” said Kari Ekelund Thørud, executive vice president of Hydro Energy. “The Illvatn pumped storage plant will contribute increased energy production, reservoir capacity, as well as installed power capacity from our facilities in Fortun.”
In addition to the main works, the build will include a 13 km transmission lines which Hydro will build using 48 aluminum lattice towers, an output from its own operations and quite different to the usual steel build. Hydro says it is “paving the way for a new and sustainable approach to power grid development” by using the material, and will connect Fivlemyr to Sveinsøystølen.
The Illvatn plant will be designed to store water during surplus periods, usually in the Norwegian summer, and release it during winter. Hydro expects construction to begin in November 2025, during the cold seasonwinter.
