Koivukoski I-II & Koivukoski III
Koivukoski I-II is located on the River Kajaanijoki that flows through downtown Kajaani. It is in the vicinity of the ruins of the medieval Kajaani Castle. Koivukoski III is a tunnel plant that was finished 1995. The tunnel runs under the city while the power house is located in the Petäisenniska industrial area.
The power plant, designed by Eino Pitkänen, was finished in 1943. The power house has an in-situ concrete frame and plastered brick cladding. The power plant was originally built by Kajaanin Puutavara Osakeyhtiö (Kajaani Lumber Company) for its private use. The plant was acquired by Kainuun Voima Oy (Kainuu Power Company) in 1995. Nowadays the plant produces power for the company´s customers. The plant has two turbines and a maximum production capacity of 6.5 megawatts.
The city´s business district was built in accordance with the functionalist planning principles during the economic boom of 40s and 50s by Architect Eino Pitkänen. Koivukoski I-II is part of this modernist ity centre. 
 Veli-Pekka Huhmo. Oulujoen vesistön voimalaitosarkkitehtuuria. Oulu: Humanpolis Oy, 2017, 84-85
 Karoliina Kikuchi, 2020
Owner: Kainuun Voima Oy
Designer: Eino Pitkänen, architect
Capacity: 6.5 MW, Head 9 meters
Power house: In-situ concrete frame, plastered brick facades
Special features: Large gable window, situated downtown Kajaani
Protection status: Classified as RKY (Nationally significant built cultural environment – RKY 2009: Hydropower plants on the River Oulujoki and Sotkamo Route).
 Veli-Pekka Huhmo. Oulujoen vesistön voimalaitosarkkitehtuuria. Oulu: Humanpolis Oy, 2017, 85
The apartment building located nearby has apartments for workers.
Koivukoski III is a hydropower plant that is located in the Kajaani River area. It is also known as the Tunnel Power Plant or Kajaaninjoki Tunnel Power Plant, because a part of the power plant processes take place in a tunnel created under Kajaani city center. The power house is located in Petäisenniska industry park, which is near one of the marinas of Kajaani. The outlet of the tunnel is located in the vicinity of the ruins of the medieval Kajaani Castle.
Owner: Kainuun Voima Oy
Capacity: 20 MW and head 15-17 meters.
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.