Kokemäenjoen voimalaitokset

English translation (from the Finnish)

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Description

Power plants built along the Kokemäenjoki river in different decades, designed by well-known industrial architects and of high architectural quality, reflect the use of waterpower to meet growing electricity needs during the 20th century.

The rapids of the Kokemäenjoki river, which is over 120 kilometres long, begins at Liekovesi in Vammala, Pirkanmaa, and flows into the Selkämeri at Pori in Satakunta. During the 20th century, several hydroelectric power plants were built on its rapids, and they have become landmarks in the landscape.

On the Pirkanmaa side, the most significant power plants along the Kokemäenjoki river are those at Tyrvää and Äetsä. The same group includes, on the Satakunta side, the large Harjavalta power plant, completed in 1939 to plans by Erik Bryggman, on the rapids located on the border between Nakkila and Harjavalta.

The Tyrvää power plant was built at the head of the Kokemäenjoki river, at Hartolankoski, at the southern end of Liekovesi. The old power houses from 1906 and 1913, built on the shoreline, have been left on dry land after the shoreline moved. The reduced rationalist, brick-built power plant built by Tyrvään Voimaosakeyhtiö dates from 1951. The road that runs along the dam of the power plant connects the villages of Kaukola and Tyrvää. The power plant setting also includes a residential area built for the power plant staff on the western slope of Hiidenmäki. Above the visually central power plant, a lake landscape opens up, and below it is a steep-banked river channel with a park area on its southern bank.

The red-brick Äetsä power plant was built in the 1920s at Meskalankoski to secure the electricity supply to the Äetsä factory, founded at the end of the 1890s and later known as Finnish Chemicals Oy. The rationalist-minded power plant is, along with the Inkeroinen one in Anjalankoski, one of the power plants designed mainly by architect Sigurd Frosterus. The foundation and dam structures below the brick-built parts are of hewn stone and concrete. The large machine hall contains seven turbines, which are still in working order. The dam height of the power plant is 5.9 metres. The power plant setting also includes a newer automated machine station, commissioned in the 1990s and excavated entirely into bedrock. On the east side of the power plant, the Kokemäenjoki is crossed by the longest timber-framed suspension bridge in the country, built in 1948 with funding from Keikyä municipality and Finnish Chemicals Oy. The power plant and the suspension bridge, with their tall support pylons and cable arches, strongly characterise the landscape of the riverside.

The Äetsä and Tyrvää power plants are located in the nationally valuable Kokemäenjokilaakso landscape area.

History

For centuries, before power plants and their dam structures were built, the waterpower of the Kokemäenjoki rapids was used to operate mills. The oldest power plants on the Kokemäenjoki were placed in the current along the riverbank, in the manner of mills. Hartolankoski in Tyrvää was also a mill site for centuries, and the first electric power plants, from 1906 and 1913, placed on the Tyrväänkylä side of the river were also located in the current along the riverbank. Hartolankoski was dammed in 1946-1950, and architect Jarl Eklund, who designed the current power plant, also designed the dam.

The first power plant at Meskalankoski in Äetsä was completed in 1919-1921, when the Äetsänkoski rapids on the upstream side were dredged to raise the water. Äetsä was the first power plant to span the entire river. The construction of the Äetsä power plant was linked to the energy crisis of the early 20th century. The rise in the price of bituminous coal and growing power demand made hydropower construction topical. Therefore Björneborgs Kraft, a subsidiary of Oy Rosenlew, which owned a steam power plant in Pori that used bituminous coal as its energy source, bought the Äetsä, Peevola and Meskala rapids in Keikyä. The drawings for the power plant were ordered from the architectural office Frosterus & Gripenberg, and the extensive construction work on the Äetsä power plant took place mainly in 1921-1923. The masonry bricks were supplied by Rosenlew's own brick factory at Ulasoori in Pori. In the 1990s a new channel was excavated south of the dam to achieve greater efficiency, and the new power plant placed in it, designed by Oulu-based Uki Arkkitehdit Oy, was commissioned in 1996.