Langfos Power Plant is the third power plant from the top of the Kragerø watercourse.
Langfos Power Plant was built in 1954. The power plant is located 7.5 km below Dalsfos and is number three from the top. The plant consists of an arched dam with a pier walkway on top. Flood waters are diverted in a spillway above the dam. Additionally, a diversion tunnel has been blasted out, which contains two hatches.
The waterway in this compact structure is mainly built of concrete including turbine drum and draft tube. The intake also has fine trash racks, two rolling hatches and two gliding hatches. The turbine is a Kaplan.
Borregaard NEA sold Langfos Power Plant to Skagerak Kraft in 2003, and it is now wholly owned by Skagerak Kraft AS.