Grønvollsfoss Power Plant is a typical run-of-the-river power plant, located in Tinnelva river, about five kilometres downstream of Årlifoss waterfall. Construction of this plant was begun in the crisis period in the early 1930s and was completed after a three-year construction period.

In 1997, the dam by the station was reinforced and the flooding capacity extended. A carriageway was also added to the dam. In 2008, the station was significantly upgraded with new Kaplan turbines with an increased flow rate and new generators and other equipment.

Grønvollfoss Power Plant has a flow rate of 160 cubic metres of water per second, like the other three power plants in this part of the watercourse.

There is an important switching station near the power plant that connects transmission lines from the north and west of Telemark county.

Owner: Skagerak Kraft, 100%.