Fortum is modernising the more than 100-year-old Untra hydropower plant in the municipality of Tierp and replacing three out of five generators. The output will be increased from 42 to 48 MW and the expected production will increase from 270 to 300 GWh per year. AFRY assists with electricity and control expertise in the assignment, which aims to secure another 100 years of fossil-free electricity production.
Untra is one of Fortum's oldest hydropower plants, which has been in operation for over 100 years. After the Swedish Land and Environment Court approved Fortum’s permit amendment in 2021, the necessary renovation of the power plant will begin with replacing three out of five generators with new ones.
Thanks to the modernisation and higher efficiency of the new turbines, Untra's output will increase by 6 MW to 48 MW and the annual production from 270 to 300 GWh, with the same amount of water as before. This corresponds to the annual electricity consumption of approximately 18,000 electrically heated detached houses.[1]
AFRY has been entrusted with delivering 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.
"We are very proud to contribute our expertise in electricity and control equipment to the project. This type of large-scale power increase of existing power plants is important to increase electricity production in Sweden and not least for residents and industries in the area," says Miriam Mesquine, BU Manager Hydro Sweden, AFRY.
The existing plant, which has a horizontal shaft and generator, will be replaced with new equipment with a vertical design. The new machines have improved efficiency due to new modern waterways and new technology, but the biggest gain is that they can continue to supply renewable and carbon-free electricity for another 100 years.
A new machine room will be built with a glass superstructure connecting the current intake house and the old machine room. The new units will be equipped with modern control equipment, which will result in better operation and more efficient maintenance.
The project period is ongoing and commissioning for the last unit is planned for the end of 2030.
