Hrauneyjar Hydroelectric Station
Construction of Hrauneyjafoss Hydro Station began in 1977 and it went on stream in 1981-82. Its three 70 MW turbine units are the most powerful employed in the Icelandic electricity system. A dam has been built on the River Tungnaá, on a plain between Hrauneyjafoss waterfall and the Sigalda Station, to create an 8.8 km_ reservoir. A 1 km headrace channel runs northwards through a dip in the Fossalda hill to an intake point by its northern edge. Three steel penstocks with a diameter of 4.8 m convey the water 272 m down the slope to the powerhouse. The harnessed head is 88 m. The tailrace channel, just over 1 km in length, enters the Spordöldukvísl waterway, which leads to the old course of the River Tungnaá. Gas-insulated switchgear is housed inside the powerhouse. One 220 kV transmission line links Hrauneyjafoss to Sigalda Station and another to Sultartangi Station. The powerhouse wall is decorated with the artwork “Against the Current” by Hafsteinn Austmann.
At the peak of construction activity, 640 people were employed on the site. Now roughly two dozen people are employed at the power station, and are also responsible for monitoring and servicing the Sigalda and Vatnsfell Stations.