Búrfell II Power Station

With Búrfell Power Station II, the generation output increases by up to 300 GWh per year. This is due to improved utilization of flow to Búrfell Power Station and a decreased efficiency losses, when the load is transferred.

The new power station was built underground in the Samsstaðaklif Hill and houses one 100 MW Francis turbine. The 370 m long headrace canal is connected to the existing intake reservoir Bjarnalón and the 2,200 m long tailrace canal discharges the harnessed water into the Fossá River, approx. 1 km downstream from the original Búrfell Station.

The harnessed water travels between the headrace and tailrace canals through a 110 m long pressure shaft which connects to the turbine.

There are six hydropower stations in the catchment area of Rivers Thjórsá and Tungnaá: Búrfell, Sultartangi, Hrauneyjafoss, Vatnsfell, Sigalda and Búdarháls, with combined energy of 1040 MW. Water for all the power stations is provided by three main reservoirs, Thórisvatn, Hágöngulón and Kvíslarveita, along with smaller reservoirs connected with each station.

Lake Thórisvatn, Iceland’s largest lake, is the largest reservoir and an important part of Landsvirkjun’s utility system. All water accumulated in Kvíslarveita and Hágöngulón reservoirs runs through Lake Thórisvatn.

Lake Thórisvatn became a reservoir with the harnessing of River Thjórsá at Búrfell Mountain in 1970-1972. River Kaldakvísl was diverted into the lake at the northern edge of the lake and a controlled outflow constructed at the southern edge.

A canal was dug from the lake and a concrete gate structure built in the canal to manage the flow rate. The canal is named the Vatnsfell Canal, and carries water from Lake Thórisvatn through the Vatnsfell Station into the Krókslón Reservoir above the Sigalda Station, and from there to other stations further down in the catchment area.

Work on the Kvíslaveita Reservoir began in 1980 and was completed in 1997. Kvíslaveita is the collective name for the dams, canals, bottom outlets and gate structures that manage the flow rate from the River Thjórsá and its tributaries into Lake Thórisvatn.

The Háganga Reservoir was constructed in 1997–1999 and covers an area of 37 km². Its purpose is to increase the efficiency of the catchment area of River Kaldakvísl. During the summer months, water accumulates in the Hágöngulón Reservoir, with very little water flowing down the Kaldakvísl riverbed.