Sog Hydropower Stations
Irafoss Station harnesses two waterfalls, Irafoss and Kistufoss, in the lower part of the River Sog, with a combined head of 38 m. A dam has been built above Írafoss at virtually the same altitude as the Ljosifoss Station outflow. Intake structures are situated on the east bank of the river, where the water enters a steep shaft to the underground powerhouse. From there, the water flows along an almost horizontal tailrace tunnel underneath the course of the river, which curves beneath the dam and re-enters the river at its west bank, below Kistufoss. The station went on line in 1953 using two 15.5 MW generating units, and was expanded with the addition of a 16.7 MW turbine in 1963.