Commissioning of the Búðarháls HEP


Búðarháls HEP, Landsvirkjun latest hydroelectric power plant, was formally commissioned during an opening ceremony on March 7th, 2014. Rated capacity of the station is 95 MW and the energy generating capacity is estimated at 585 GW/h annually.

The station is located in the lower highlands of southern Iceland on the rivers Tungnaá and Kaldakvísl at Búðarháls in the Rangárvallasýsla County. The Project Area extends over the Búðarháls ridge between the river Kaldakvísl and the existing Sultartangi reservoir, some 150 km east of Reykjavík.

The station utilizes the head difference of approximately 40 metres between the Hrauneyjafoss HEP tailrace and the Sultartangi Reservoir.

The main features of the project are summarized below:


  1. The Sporðalda reservoir is formed mainly by two rockfill dams, the NW-dam that crosses the river Kaldakvísl, just upstream from the confluence with the river Tungnaá and the SE-dam that crosses the Sporðaldakvísl just upstream of its confluence with the river Tungnaá. The Sporðaldakvísl conveys the discharge from Hrauneyjafoss HEP tailwater into the river Tungnaá. The NW-dam is about 1100 m long whereas the SE-dam is approximately 170 m long. Both dams have a maximum height of around 25 m. The reservoir normal water level (NWL) is 337,0 m a.s.l. and the reservoir stores some 50 hm3 (Gl) of water with a surface area of 7 km2.
  2. A conventional drill and blast Headrace Tunnel around 4 km long through the Búðarháls ridge conveys the water from the reservoir to a Surge Basin immediately upstream of the Penstock Intake. Two 60 m long steel lined Penstocks connect the Penstock Intake to the Powerhouse.
  3. The Powerhouse is a conventional surface structure provided with two 47,5 MW Kaplan type turbines. The rated net head is 36,0 m, rated discharge is 280 m³/s and the total rated capacity 95,0 MW. The energy generating capacity of the station is estimated at 585 GW/h annually.
  4. The generators are connected to the unit transformers by isolated phase busbars.
  5. A Tailrace Canal about 0,4 km long conveys the discharge from the powerhouse to the Sultartangi reservoir.
  6. The unit transformers are located outside at the front of the Powerhouse. High voltage cables connect the transformers to Landsnet´s Substation Building which is located just south of the Powerhouse.
  7. The Substation Building is connected to a 220 kV transmission line crossing the Búðarháls ridge and connecting to the main grid just east of Tungnaá river.

Only minor work is unfinished and during next two summers, final clean-up and final landscaping will be carried out and the project completed.

The design of the Búðarháls HEP was carried out by EFLA Consulting Engineers, Arkitektastofan OG, Landslag, Verkís Consulting Engineers and Mannvit. Landsvirkjun and Hnit carried out the construction supervision.

EFLA Consulting Engineers was in charge of all civil design of the Búðarháls HEP as well as being responsible for overseeing and coordinating all design, scheduling and cost estimating of the project.