The power station was put in operation in 1969.
The station utilises water from the eastern part of Telemark County, the Hjartdal watercourse, Lake Sundsbarm and the Tokke-Vinje watercourse. Akershus Energi is the owner of the station, which is located in the lower part of the Skien watercourse. It has a catchment area of 10300 km2.
Several regulation authorities
Øst-Telemarken brukseierforening regulates the eastern part of the watercourse. Skiens Brugseierforening is responsible regulatory authority for Lake Hjellevannet. Hjartdøla river and Lake Sundsbarm are regulated by Skagerak Kraft A/S, while The Tokke-Vinje part is regulated in a governmental regulation from the 1950s and 1960s, managed by Statskraft SF.
At Klosterfoss power station, there is a dam with two flap gates which regulate the dam.
Typical run-of-river power station
The plant is a typical run-of-river power station; however, with a reservoir of 4241 million m3. Mean annual inflow is about 1541 million m3.