Sog Hydropower Stations
Steingrimsstod Station went on line in 1959. It harnesses the 20.5 m head where the Upper Sog drains from Lake Thingvallavatn into Lake Ulfljotsvatn through a semi-circular chasm along the ridge that separates the two lakes. A dam was built at the outflow point from Lake Thingvallavatn, where the main headrace runs in a tunnel through Drattarhlid into an open-air surge tank above the powerhouse. A shaft leads from the surge tank to two turbines with a capacity of 13.5 MW each.