Hafslund and Eidsiva have approved a NOK 2.5bn (US$245m) investment to build the Hemsil 3 hydroelectric power plant in Hallingdal, Norway, marking the largest power development in the region in six decades. The companies say the project’s primary impact will be a significant boost in output from the Hemsil watercourse.
“This project shows how, by thinking innovatively about existing developed watercourses, significant new amounts of power can be obtained by better utilising water resources. We simply get more power out of every drop,” said Kristin Lian, CEO of Hafslund Kraft.
Hemsil 3 will draw water from the Eikrebekken dam in Hemsedal, using the same intake point as Hemsil 2. A new tunnel will run parallel to the existing one, and the new power station will be built inside the mountain next to Hemsil 2 in Gol, with an outlet placed close to the current discharge into the Hallingdalselva river.
The development will increase annual production by about 110GWh and raise installed capacity by 86MW.
The project also includes upgrades to the Eikrebekken dam to meet newer safety requirements and improve flood-handling capacity. “With this investment, we ensure continued power production from the water from Hemsedal to the center of Gol for the benefit of society for several generations to come,” Lian said.
According to the companies, roughly 10 to 20% of the contract value is expected to remain in Hallingdal. They report that environmental impact will be limited, with most permanent land use occurring in areas already altered by earlier developments. Measures such as low-carbon concrete and the use of electric machinery are expected to reduce project-related greenhouse gas emissions by around 22%.
Hemsil 3 received its license from the Ministry of Energy in June 2024. The boards of Hafslund Kraft AS, Hafslund AS, and Eidsiva Energi AS have approved the investment, and Hemsedal Municipality has granted an exemption from its land-use plan. The main contractor, Leonhard Nilsen and Sønner (LNS), signed the agreement on November 20, 2025. Construction begins immediately, with completion planned for summer 2029.
