The development of hydropower in the Forsland River system has a long history. The first plans for development were proposed over a hundred years ago, but it wasn't until 1939 that the Sjøfossen Power Plant, located at the river's outlet into Leirfjorden, was built. During the war years, 1940-1945, the occupying forces dammed Dalvatnet, a bit higher up in the river system, to provide more stable winter power. This paved the way for the second power plant in the river system, Storfossen Power Plant, which was completed in 1949. The early power plants were replaced by Forsland Power Plant (near the fjord), completed in 2003, and Upper Forsland Power Plant, completed in 2015. The old facilities utilized only an 18-meter drop, while the new ones (from 2003 and 2015) harness an 80-meter drop from Dalvatnet to the sea.