Hellisheiði Geothermal Plant

Hellisheiði Geothermal Plant is situated at Hengill, an active volcanic ridge in SW Iceland.  The plant´s purpose is to meet increasing demand for electricity and hot water for space heating in the industrial and domestic sectors.   Production capacity is 303 MW electricity and 130 MW thermal energy.

Hengill area

The construction area is on Hellisheiði heath and its vicinity south of Hengill volcano. The area is divided into the upper geothermal area above Hellisskarð pass and the lower area below the pass. A much larger area has, however, been included in research to assess the environmental impact of the power plant. Ground water research covers the area from the south coast, west to Faxaflói bay, north to Esja mountain and Þingvallavatn lake and east to Ölfusá river. 

Exploratory drilling
In 1985, a research borehole was made by Kolviðarhóll hill (in the same area that the plant is situated). In 1994, another borehole was made on Ölkelduháls ridge. Both boreholes offered some clues, but the evidence was not enough on which to base a decision. In 2001, two boreholes were made in Hellisheiði heath and three more in 2002. The information from these holes provided the grounds for the power plant.

Stages

• 2006 - electricity production in two 40-45 MW turbine units.
• 2007 - a 30 MW low-pressure turbine brought into use.
• 2008 - electricity production in two 40-45 MW turbine units with steam from Stóra-Skarðsmýrarfjall mountain.
• 2010 - 130 MW thermal station (space heating) online in December.

 

Plant Layout
Flexibility is key in the plant layout. The idea is to have everything that the whole power plant uses in the central building, while each production unit will be in independent units around the main building. Generator rooms for electricity production will face south from the central building and the hot water plant north.

 

Geology of the Hengill area

The geothermal activity in the Hengill area is connected with three volcanic systems.  At least three volcanic eruptions have occurred in the Hengill area in the last 11,000 years, the most recent being 2,000 years ago.  The Hengill area is part of the Hengill region, which covers 112 square kilometers and is one of the most extensive geothermal areas in Iceland.

       

Environmental Impact

In accordance with laws and regulations, Orkuveita Reykjavíkur carried out an extensive environmental assessment on the effects of the Hellisheiði Geothermal Power Plant.  The results indicate that construction of the plant will not have a lasting influence on the area´s vegetation.  Any sort of impact is limited to construction areas of boreholes, pipes, roads, mines, and buildings.

Efficient use of resources in energy production ensures that the volume of greenhouse gases released will be extremely low compared to that of fossil fuel production.  
 

Noise levels during both construction and operation may exceed recommended levels for an industrial site, especially during drilling and testing of production wells.  Silencers are installed at production wells to reduce noise impact. 

 

General public opinion of exploiting the geothermal resources in the Hengill region is positive.  Survey results indicate that the construction of a power plant will not reduce the number of visitors to the Hellisheiði and Hengill areas.  In fact, the number of visitors pursuing outdoor activities in the area is expected to increase.

No known cultural remains are at risk in the development area.  A steam transmission pipe will cross the ancient Hellisheiði trail but it will be kept open and cairns along the trail will be preserved.  Cultural remains at Hellisheiði are particularly linked to transportation with old trails crossing the area.  Two sport clubs have skiing facilites in the area, but there are no residential houses.

Geothermal Energy Exhibition
A geothermal energy exhibition is on display at the Hellisheiði Plant´s visitors centre. Click here for information on the exhibition.