After being used in the Fljótsdalur Power Station, all water used in electricity production is discharged into the river Jökulsá í Fljótsdal.

The underground Fljótsdalur Power Station contains six vertical-axis Francis turbine generators rated at 115 MW each.

Power produced is then transmitted to Alcoa's Fjarðaál aluminium smelter 75 kilometres (47 mi) to the east in Reyðarfjörður.

[4][5] The Fjarðaál aluminium smelter was completed June 2007 and reached full operation in April 2008.

Construction began in 2004 and the facility contains a smelter, cast house, rod production and deep-water port.

From 1975 to 2002, several international companies had planned or attempted to build a metal plant at Reyðarfjörður that would be powered by a hydroelectricity project similar to the Kárahnjúkar.

In mid-2008, the Kelduá and Ufsarstífla Dams were complete and the Ufsarlón Reservoir headrace tunnel was ready.

[10] There were several workplace fatalities during the construction process including: Arni Thor Bjarnason, Eilifur Gopi Hammond, Ludvik Alfred Halldorsson and Kresimir Durinic.

[13] For the construction of Kárahnjúkar Hydropower Plant in East Iceland, five dams in two glacial rivers created three reservoirs, that together flooded over 440,000 acres of unspoilt Highland territory.

The megastructure is on a scale like nothing the nation has seen before or since and, as such, has been a constant source of protest and controversy due to the landscapes irretrievably lost.