Sultartangi Hydroelectric Station
Construction at Sultartangi began in 1997 and the station became fully operational in January 2000. It utilizes water from the Sultartangi reservoir which was formed when the rivers Thjórsá and Tungnaá were dammed in 1982-1984 at the eastern foot of Mt. Sandafell, approximately 1 km upstream from their confluence. The Sultartangi dam is the longest in Iceland or 6.1 km. In conjunction with the construction of the power station, the dam crest was raised by 1.0 metre. A headrace tunnel transports water from the reservoir through Mt. Sandafell to a surge basin on its southwestern side. At the end of the surge basin is the station intake, where penstocks lead down to the two 60 MW Francis turbines in the powerhouse. A tailrace canal exits the powerhouse and extends 7 km along the river to a spot 800 m above the Búrfell dam to enter again the river course.
The two generating units are connected by cables to a high voltage substation which is located close to the powerhouse. The substation has three outgoing transmission lines, one to Burfell Hydro Power Station, one to Hrauneyjafoss Hydro Power Station and one to Substation Brennimelur.