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Leppikoski hydroelectric power plant is located on the Kiehimäjoki River in the municipality of Paltamo. It was designed by Reino Laaksonen.

Jylhämä Pyhännänkoski


Leppikoski started as an independent project by Kajaani Oy (Kajaani power company). In 1962, Oulujoki Power Company bought the power plant that was under construction. They also bought the property and a section of the river. Leppikoski was finished in 1963. Reino Laaksonen designed the brick-built power house. The two sets of machinery were connected to the power grid on 5 December 1962 and 8 February 1963. Leppikoski has a capacity of 23 MW.



Technical information

Owner: Fortum Power and Heat Oy

Finished: 1963 

Designer: Reino Laaksonen, M.Sc. (Eng)   

Capacity:  23 MW, head 11.1 – 13.3 m

Power house: Brick  

Special features: Bought by Oulujoki Power Company from Kajaani Oy in 1962

Protection status: Classified as RKY (Nationally significant built cultural environment – RKY 2009: Hydropower plants on the River Oulujoki and Sotkamo Route).[1]

[1] Veli-Pekka Huhmo. Oulujoen vesistön voimalaitosarkkitehtuuria. Oulu: Humanpolis Oy, 2017, 83


Residential area

Leppikoski has a medium sized residential area with wooden detached houses.


All pictures below are part of the power plant's history. All images are copyrighted. You may use the images for personal use but the images may not be used in commercial contexts or printed matter without our permission. Click on the pictures to enlarge them.

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