Rehabilitation and Repair

113-year-old Swedish hydropower plant to get new units, capacity boost

Untra’s capacity will be increased from 42 to 48 MW and the expected production will increase from 270 to 300 GWh per year.

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113-year-old Swedish hydropower plant to get new units, capacity boost

Fortum is modernizing the 113-year-old Untra hydropower plant in the municipality of Tierp, Sweden, and replacing three out of five turbine-generator units.

The capacity of the plant will be increased from 42 MW to 48 MW and the expected production will increase from 270 GWh to 300 GWh per year. AFRY is assisting with electricity and control expertise on the project, which aims to secure another 100 years of electricity production. AFRY will deliver electrical and control contracts for the three new units G1, G2 and G3. The assignment also includes new relay protection, excitation equipment and adaptation of all new and existing equipment to the new control equipment.

Untra is one of Fortum’s oldest hydropower plants, and it began operating in 1911. The Swedish Land and Environment Court approved Fortum’s permit amendment in 2021, and renovation of the power plant has now begun.

The existing plant, which has units with horizontal shafts, will be replaced with new equipment with a vertical design. A new machine room will also be built with a glass superstructure connecting the current intake house and the old machine room.

The project period is ongoing, and commissioning for the last unit is planned for the end of 2030.

The Untra project was constructed on the Dalalven River in late 1911, with the goal to provide Stockholm with electricity, and played an important role in electrifying the Swedish capital during the past century. The capital’s growing demand for electricity exceeded Untra’s capacity in less than eight years, but the powerplant has remained an important part of the Swedish power system, Fortum said.

Fortum delivers energy in Europe, with its core being “reliable and flexible production methods like nuclear power and hydro power.”