The pioneering Reykjanes Geothermal Power Plant in Iceland is now producing 100MWe from two 50MWe turbines. The plant uses steam from a reservoir at 290 to 320°C – the first time that geothermal steam of such high temperature has been used to generate electricity on a large scale.

The new plant is located on the Reykjanes peninsula, in the south-western corner of Iceland. Owned by Sudurnes Regional Heating Corporation, the plant was designed by Enex, a conglomerate from the Icelandic energy sector with wide experience in developing geothermal energy and hydropower. The two turbines started operation in May 2006 after testing and were formally brought on-line in December 2006.

HIGHEST TEMPERATURE YET FOR GEOTHERMAL STEAM

The Reykjanes plant uses steam and geothermal brine extracted from twelve 2,700m-deep wells. After extraction, the brine is piped into a steam separator. From there, the separated steam passes under 19 bars of pressure to a steam dryer and into the two 50MW turbines.

The plant is situated close to the ocean front, so seawater (4,000l/s) at 8°C can be pumped through a condenser for cooling and condensing the brine.

NEARLY 20% OF ICELAND'S ELECTRICITY FROM GEOTHERMAL

Geothermal resources have been used for over 70 years in Iceland. The geothermal area at Reykjanes is located on top of the Mid-Atlantic Ridge, formed by plate tectonics that are moving in separate directions. That gives high geothermal energy, with the Reykjanes area being where the plate boundary of the Reykjanes Ridge comes on land. The area is about 2km2 in size. Energy has been extracted from the area for around 30 years without significantly reducing the geothermal reserves.

Geothermal power plants produce nearly 20% of the country's electricity; geothermal heating also supplies nearly 90% of the country's domestic heating and hot water requirements. Nearly all the rest comes from hydroelectric generation, with less than 0.1% from fossil fuels.

Geothermal brine cannot be used directly for heating because of its high mineral content. On cooling, it releases great quantities of hard deposits (silica) which block pipes and other equipment. The high temperature and salt content of the water therefore demands heat exchangers.

Reykjanes Power Station
Reykjanes Power Station
Location	Reykjanes, Iceland 63°49′35″N 22°40′55″W / 63.82639°N 22.68194°W / 63.82639; -22.68194Coordinates: 63°49′35″N 22°40′55″W / 63.82639°N 22.68194°W / 63.82639; -22.68194
Owner	SRHC
Status	Completed
Fuel	Geothermal
Technology	Steam turbine
Turbines	2
Installed capacity	100 MW
Maximum capacity	150 MW
Commissioned	May 2006