Ulla-Førre is a hydropower complex in Southern Norway. It is situated along the borders of Suldal Municipality and Hjelmeland Municipality (in Rogaland county) and Bykle Municipality (in Agder county), Norway. It has an installed capacity of approximately , and the annual average production is (1987âÂÂ2006), while its reservoir capacity is about ; at full production, it can last seven to eight months. The complex includes the artificial lake BlÃÂ¥sjø, which is made by dams around above the sea level. The hydroelectric power stations in the complex are Saurdal, Kvilldal, Hylen and Stølsdal, operated by Statkraft.
BlÃÂ¥sjø is the tenth largest lake in Norway by area. It is located on the border of Bykle Municipality in Agder county and Hjelmeland Municipality and Suldal Municipality in Rogaland county. The lake is about west of the village of Bykle. It has a surface area of . Its surface swings between above sea level depending on seasonal weather and power consumption, and it has a shoreline of about . At the highest regulated water level, BlÃÂ¥sjø contains of water.
The Kvilldal Power Station is a located in Suldal Municipality. The facility operates at an installed capacity of , making it the largest power station in Norway in terms of capacity. Statnett plans to upgrade the western grid from 300 kV to 420 kV at a cost of , partly to accommodate the North Sea Link cable from Kvilldal to Blyth, UK.
The Saurdal Power Station is a hydroelectric and pumped-storage power station located in Suldal Municipality. The facility operates at an installed capacity of (in 2015). The average energy absorbed by pumps per year is (in 2009 to 2012). The average annual production is (up to 2012).
The Hylen Power Station is located at the bottom of Hylsfjorden in Suldal Municipality. It operates at an installed capacity of , with an average annual production of . The plant exploits water through a tunnel from the lake Suldalsvatnet.