Kárahnjúkar Hydropower Plant

Kárahnjúkar Hydropower Plant , officially called Fljótsdalur Power Station is a hydroelectric power plant in Fljótsdalshérað municipality in eastern Iceland, designed to produce 4,600 gigawatt-hours annually for Alcoa's Fjarðaál aluminum smelter 75 kilometres to the east in Reyðarfjörður. With the installed capacity of 690 megawatts , the plant is the largest power plant in Iceland. The project, named after the nearby Kárahnjúkar mountains, involves damming the rivers Jökulsá á Dal and Jökulsá í Fljótsdal with five dams, creating three reservoirs. Water from the reservoirs is diverted through 73 kilometres of underground water tunnels and down a 420-metre vertical penstock towards a single underground power station. The smelter became fully operational in 2008 and the hydropower project was completed in 2009.
The Kárahnjúkar Dam is the centrepiece of the five dams and the largest of its type in Europe, standing 193 metres tall with a length of 730 metres and comprising 8.5 million cubic metres of material.

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