Tornionlaakson Voima Oy’s Portimokoski hydropower plant, located on the Tengeliönjoki River, will undergo a major overhaul in the second half of 2026.
During the overhaul, the original turbine from 1987 will be refurbished. Additionally, the auxiliary equipment and generator will be serviced.
“The purpose of the overhaul is to improve the operational reliability of the power plant and enhance its performance. Together with fishway investments, the power plant will be made more future-proof,” says Sakke Rantala, CEO of Tornionlaakson Voima Oy.
The increase in weather-dependent energy in the electricity system affects the use of hydropower plant equipment. This means continuous adjustment of turbines to ensure a stable frequency in the power grid.
“The technical condition of the Portimokoski hydropower plant’s runner has limited the plant’s regulation use. Improved performance will enable regulation use of the plant and ensure the production of balancing power needed by the domestic power grid,” states Arttu-Pekka Alaperä, project manager and expert in projects and safety at PVO-Vesivoima Oy.
The main contractor for the project is Andritz Hydro Oy.
The overhaul will begin in the summer of 2026 and will last approximately four months.
In addition to the overhaul, two fishways will be constructed at the Portimokoski power plant, opening nearly a thousand kilometres of migration routes. One natural bypass channel was completed in autumn 2024, and another fishway is scheduled to be built this year.
For more information:
Sakke Rantala, CEO, Tornionlaakson Voima Oy, sakke.rantala@tls.fi, tel. +358 40 664 6132
Arttu-Pekka Alaperä, expert in projects and safety, PVO-Vesivoima Oy, arttu-pekka.alapera@pvo.fi, tel. +358 50 386 2614
Portimokoski Hydropower Plant
- Located in Ylitornio on the Tengeliönjoki River
- Commissioned in 1987
- Automation system renewed in 2014
- Capacity: 10.5 MW
- Head: 16.5 m
- Flow rate: 70 m³/s
- Annual production: approximately 40 GWh
Tornionlaakson Voima Oy is jointly owned by Tornionlaakson Sähkö Oy and PVO-Vesivoima Oy. In addition to the Portimokoski power plant, Tornionlaakson Voima Oy owns the Kaaranneskoski and Jolma hydropower plants on the Tengeliönjoki River.
Tornionlaakson Sähkö is a local company focused on electricity distribution and production, with production shares exclusively in carbon-free generation in Finland, Sweden, and Norway. www.tornionlaaksonsahko.fi
PVO-Vesivoima Oy produces electricity with hydropower plants on the Iijoki, Kemijoki, and Kokemäenjoki rivers. The company’s electricity production averages 1.7 terawatt-hours per year. The company is part of the Pohjolan Voima Group. www.pohjolanvoima.fi