Búrfell Hydroelectric Station
The river Thjórsá is harnessed at Búrfell by a dam on the river which previously flowed south above Mt. Búrfell, diverting it northwards through the Sámsstadamúli mountain ridge and down into the Thjórsárdalur valley. A tunnel has been blasted for this purpose through Sámsstadamúli, which runs north from Búrfell and south from Mt. Skeljafell, and the powerhouse stands at its foot in Thjórsárdalur.
A dam 4 km above the station diverts the River Thjórsá to the west through a special ice-barrier running at right angles from the north of the dam to the west bank of the river. A surface waterway containing a sluice runs to the west and into a cirque between the mountains Búrfell, Skeljafell and Sámsstadamúli, where the water collects in a 1 km2 reservoir, Bjarnarlón, which is used to meet fluctuations in demand during the course of the day. Water is channelled from the western edge of the reservoir to a headrace tunnel which has been blasted through the basalt strata of Sámsstadamúli.
The headrace tunnel divides into two concrete-clad pressure shafts which utilize a head of 100 m, then convey the water 200 m horizontally to the powerhouse. Steel cladding is used in the final 100 m and the shafts branch out to feed the six turbines. After driving the turbines in the powerhouse, the water exits via surge basins into a short channel before entering the River Fossá in Thjórsárdalur, which joins the River Thjórsá 2 km downstream.
The front wall of the powerhouse is decorated with a mural by Sigurjón Ólafsson, who also made the sculpture “The Noise Troll” standing in front of it. Three 220 kV transmission lines lead to Reykjavík two to the Sultartangi Station.
Water wheels for all six turbines at Búrfell Station were upgraded in 1997-98, boosting its installed capacity from 210 to 270 MW.
Hydro Development on the River Thjórsá
Ideas for harnessing Thjórsá at Mt. Búrfell were originally proposed some fifty years before the project was launched. From 1915-1917, Norwegian engineer Gotfred Sætersmoen made studies of the Thjórsá area on behalf of Titan, a private company founded with the aim of developing hydropower in Iceland. In his report, Sætersmoen suggested harnessing Thjórsá at Mt. Búrfell to produce electricity which would mainly be utilized for fertilizer production. He envisaged five stations on Thjórsá from the Urrida foss falls and upriver beyond Búrfell, as well as a station at Hrauneyjafoss on the River Tungnaá. Búrfell would have been by far the largest station. The plan was to dam Thjórsá at Klofaey and divert the water through an open channel into Bjarnarlón and to an intake dam at Sámsstadaklif.
Around 1960, the Thjórsá development was first given serious consideration. Such a large project offered very economical electricity production if high utilization could be achieved from startup, but consumption in Iceland then was not growing fast enough to make the Búrfell station viable. Attention soon began to focus on the possibility of setting up power-intensive manufacturing industries which could utilize a substantial part of the production from the start. Feeling that it lacked the resources to undertake such ventures itself, Iceland set up a committee for power-intensive industry in 1961 to explore the possibility of negotiating with parties from other countries to own and operate industrial plants. At the same time, an intensive programme of preparatory research for the Búrfell hydro project was launched. Eventually, in 1966, these two programmes converged with the signature of a contract with Swiss Aluminium Ltd. for the construction of an aluminium smelter in Straumsvík, and the go-ahead for the Búrfell project, both of them scheduled to enter operation over the period 1969-1972. This arrangement thereby also secured economical electricity production for the general market.