Hirvikoski Hydro Power Station

The third-highest in Finland in terms of head

General facts about Hirvikoski Hydro Power Station

Hirvikoski is situated by the Nurmonjoki River, which is a tributary (side river) of the Lapua River, which in turn flows into the Gulf of Bothnia at Uusikaarlepyy. The first hydro power facilities were built in the river in 1926 when Uusikaarlepyy Power Station was built. Several power stations were subsequently constructed, and the largest is Hirvikoski.

The head (drop) at Hirvikoski Hydro Power Station is 47 metres, making it the third-highest in Finland in terms of head, which is very surprising as the Ostrobothnia area is widely known for its flatness. Hirvikoski is an underground facility and the water to the station is led through a tunnel that is 500 metres long. The intake and outlet gates in the Nurmonjoki River were automated – and must be operated on site – as a part of refurbishment of automation and electrification of the plant in 2008.

Some renovations and modernisation measures have taken place at Hirvikoski Hydro Power Station over the years. The latest such project was implemented in 2007-2008, when the turbine and electrical equipment were renovated and renewed.

The only part of the power station that is visible above the ground is the control room, which is situated in a small brick building. 

Hirvijärvi is an artificial lake built by the Finnish state to regulate the Lapua River, which substantially reduces the risk of flooding. A total of eight lakes, all regulated, are part of Hirvijärvi’s lake system. Nearly all the dams in the lake system can also be remotely controlled. The Finnish state owns the dams and is responsible for regulating Hirvijärvi’s lake system. 

General information about hydro power in Finland

After World War Two, large-scale hydro power plant construction took place when the country’s rebuilding work and the paper and pulp industry required a great deal of energy. As Finland is a relatively flat country, hydro power makes a small contribution to Finland’s total electricity generation.

The largest hydro power stations are located in rivers in north and north east Finland. About half the watercourses have been expanded for electricity generation. Unregulated rapids are protected, so extra capacity can be obtained by increasing the efficiency of the old power stations or from artificial lakes.