Construction go-ahead for Norway hydro 07 Oct 2014

Skanska is awarded NOK409 million dam and underground works construction associated with a new hydro project on the River Rosten, near Brenna in Norway.

Tunnel and adit configuration

Excavation work begins immediately on the 80MW installed capacity facility, which is scheduled to come online in December 2017. Once completed it will contribute 192 GWh of annual renewable energy.

Project scope includes construction of a 90m wide x 20ft high dam across the river, intake structure, more than 5km of drill+blast tunnels and adits, and a machine hall excavated into the mountains north of Brenna. The project utlises a height differential of approximately 103.5m.

The main headrace tunnel from the intake structure will be 4.1km long, blasted out of rock to a cross section of 50m². A smaller tailrace tunnel of approximately 500m long will discharge water back into the Rosten River. A 350m access tunnel of 20m² cross section will be driven into the mountain for construction of the machine hall cavern that will house the transformers and the power station itself.

“The hydropower sector is an important part of our construction business, and we are very pleased that Eidsiva Hydropower has selected us to take part in this clean renewable energy project,” said Steinar Myhre, Executive Vice President for construction activities in Skanska Norway.

Energy company Oppland Energi, which owns nine other hydro facilities in Norway, part owns two more, and is itself and part-owned by Eidsiva Hydropower, will hold a majority 72% ownership of the new facility at Rosten. Eidefoss, another Norwegian energy company, will hold 28% ownership. The project has been in the planning since 2007.