The plans would double Statkraft's current output from wind farms and boost the effect of the company's hydro power plants, adding some 3 terrawatt hours (TWh) of additional electricity output, the company told a press conference in Oslo.

Statkraft will spend between 1.8 billion and 3 billion euros on upgrades of hydroelectric plants, between 1.2 billion and 2 billion euros to rehabilitate older dams and plants and some 1 billion euros on renewal and construction of onshore wind farms.

"All projects will depend on a predictable regulatory framework, getting the necessary concessions, the level of power demand, and a good dialogue with local communities," Nordic operations chief Birgitte Ringstad Vartdal said in a statement.

Norway has traditionally enjoyed a healthy electricity supply surplus but this is expected to all but disappear as early as 2028, as demand growth from electrifying industry and transport is set to outpace new generation additions.

Statkraft previously announced plans to upgrade its Mauranger hydro plant in western Norway but many other projects were put on hold after the Norwegian government's decision in 2022 to curb profits during Europe's energy crisis.

($1 = 0.9145 euros)

(Reporting by Louise Breusch Rasmussen and Nora Buli, editing by Stine Jacobsen and Terje Solsvik)