Pamilo

The company Pamilo Oy was founded in 1943. Its owners – the forestry company Enso-Gutzeit (now Stora Enso) and the mining company Outokumpu – wanted to generate electricity for their businesses. Although the potential of Lake Koitere and the Koita river for generating hydro power had been recognised as early as 1908, construction of the hydro power plant did not begin until 1952. This was because Pamilo Oy had originally planned to build two power plants, but purchasing the rights to exploit the state-owned waters proved difficult. The solution was to build a canal and a new lake at Palovaara and construct the underground power plant there. The water flows from Lake Koitere through Lake Palojärvi to Lake Jäsys.

The original hydro power plant comprised two units and was completed in 1955. A third unit was completed in 1997. Vattenfall has owned the power plant since 2000. The turbine and generator of the second unit were upgraded in 2006 and 2013.

The power plant is located in a wilderness area, with the plant itself below ground. The control room building, designed by Alvar Aalto – Finland’s most famous architect – is the only visible structure and stands 50 metres above the machine room. The control building's irregular windows are described as "an architectural refinement which transforms the white building into a miniature work of environmental art".

Hydro power in Finland

During the Second World War, Finland lost most of Finnish Karelia to the Soviet Union, as well as a substantial part of its built and potential hydro power capacity.

At that time, the largest users of energy were the forestry industries, particularly paper and pulp mills. These industries were forced to replace the lost power before they could expand. One solution was to harness the untapped waters of the north of the country. However, Finland’s mountains are relatively low, which restricts the amount of electricity which can be generated from hydro power.

Vattenfall's hydro power plants in eastern and central Finland and the Ostrobothnia region are monitored and controlled from a central control room in Porvoo (Borgå).