Hrauneyjafoss Power Station

The Hrauneyjafoss Station is Iceland’s third largest power plant, producing 210 MW. It is located near the Sprengisandur Route on the edge of the highlands; southwest of the Sigalda Station, and utilises the same water as Sigalda Station. Hrauneyjafoss Station was commissioned in 1981.

The Tungnaá River is dammed on rather flat land approximately 1.5 km above the Hrauneyjafoss Waterfall and 7 km below the Sigalda Station. The difference in altitude is approximately 15 m. Hrauneyjalón, an 8.8 km² reservoir, was formed by the dam. A low soil wall dam stretches along the lava flatlands on the south bank of the river.

A headrace channel runs 1 km northwards from the reservoir through a dip in the Fossalda Hill to an intake point at its northern edge. Three steel penstocks (4.8 m in diameter) run 272 m down the hill to the powerhouse. The tailrace canal, just over one kilometre in length, enters the Sporðöldukvísl waterway, which runs into the Tungnaá River.

The Þjórsá and Tungnaá area is home to seven of Landsvirkjun’s hydropower stations: Búðarháls, Búrfell, Búrfell II, Hrauneyjafoss, Sigalda, Sultartangi and Vatnsfell. The area also includes Vaðalda Wind Farm, Iceland’s first wind power plant, as well as Hafið, a wind energy test site with two experimental turbines.

At the heart of the system is Þórisvatn, Iceland’s largest natural lake and the region’s main reservoir. Water collected in the Kvíslaveita diversion system and Hágöngulón flows through Þórisvatn before being used by power stations farther downstream.

The Þórisvatn reservoir system was developed between 1970 and 1972 as part of the expansion of hydropower generation in the area. Its reservoirs, dams, canals and control structures make it possible to store water, regulate flows and optimise energy production throughout the year.

Construction of the Kvíslaveita diversion system began in 1980 and was completed in 1997. The system collects water from tributaries and the upper reaches of the Þjórsá River and diverts it to Þórisvatn.

Hágöngulón was developed between 1997 and 1999 and covers an area of 37 km². It increases the utilisation of water resources in the Kaldakvísl catchment by storing water during the summer months.

Together, Þórisvatn, Kvíslaveita, Hágöngulón and a number of smaller reservoirs form the backbone of the hydropower system in the Þjórsá and Tungnaá area.