The Ohaaki Power Station is a geothermal power plant owned and operated by Contact Energy. A distinctive feature of this power station is the 105 m high natural draft cooling tower, the only one of its kind in New Zealand.

Although initially constructed to generate 104 MW, decline in the steamfield has meant maximum net capacity is about 65 MW with an annual output of around 400 GWh pa.

There are currently three turbines in operation. One smaller turbine runs off high pressure steam which then backfeeds into the main intermediate pressure system that feeds the two main units. Condensers on the back end of the main turbines are fed cooled water from the cooling tower to condense the steam back into water. Additional condensate gained in this process is reinjected back into the ground.

The Ohaaki geothermal power plant is located adjacent to the Ohaaki Marae (Ngāti Tahu) on the banks of the Waikato River in New Zealand. Gradual sinking of the marae has been attributed to draw-off of geothermal fluids by the power station. The area of the marae is sinking approximately 170mm a year. In the 1960s, the marae was moved to its present location because the previous site was flooded when the dam for the Ohakuri Power Station was filled.

Ohaaki Power Station
Location	Waikato
Owner	Contact Energy
Status	Operational
Fuel	Geothermal
Maximum capacity	104 MW
Commissioned	1989

The Nesjavellir Geothermal Power Station is the second largest geothermal power plant in Iceland. The facility is located 177 m (581 ft) above sea level in the southwestern part of the country, near Thingvellir and the Hengill Volcano.

Plans for utilizing the Nesjavellir area for geothermal power and water heating began in 1947, when some boreholes were drilled to evaluate the area's potential for power generation. Research continued from 1965 to 1986. In 1987, the construction of the plant began, and the cornerstone was laid in May 1990. The station produces approximately 120MW of electrical power, and delivers around 1,800 litres (480 US gal) of hot water per second, servicing the hot water needs of the Greater Reykjavík Area.

Nesjavellir Geothermal Power Station
Nesjavellir Geothermal Power Station
Location	Thingvellir, Iceland 64°6′29″N 21°15′23″W / 64.10806°N 21.25639°W / 64.10806; -21.25639Coordinates: 64°6′29″N 21°15′23″W / 64.10806°N 21.25639°W / 64.10806; -21.25639
Status	Completed
Fuel	Geothermal
Installed capacity	120 MW
Commissioned	May 1990

Nga Awa Purua is a geothermal power plant located near Taupo in New Zealand. The project was developed by Mighty River Power. Nga Awa Purua is New Zealand's second largest geothermal power station and the steam turbine is the largest geothermal turbine in the world.

The geothermal power plant is a joint venture between Mighty River Power and the Tauhara North No 2 Trust. The $430 million project first generated electricity on 18 January, and was officially opened by Prime Minister John Key on 15 May 2010.

The Rotokawa Power Station is situated close by.

Nga Awa Purua
Location	Waikato
Owner	Mighty River Power
Status	Operational
Fuel	Geothermal
Turbines	1
Maximum capacity	140 MW
Commissioned	2010

The Reykjanes Power Station is a geothermal power plant located in Reykjanes at the southwestern tip of Iceland. As of 2009, the plant produces 100MW of electricity, with an expansion plan to increase by 50MW in 2010.

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

The Jermaghbyur Geothermal Power Plant will be Armenia's largest geothermal power plant having an installed electric capacity of 150 MW. It will be situated in Syunik Province of Armenia.

Low-potential sources of geothermal power were founded in Garni, Arzni,Jermuk, Ankavan and Sisian. The geothermal power can be utilizedfor heat-supply, heating of hothouses, residential buildings and industrial enterprises.

"Ameria" CJSC was contracted by World Bank Energy Invest PIU to develop a detailed feasibility study for the construction of "Jermaghbyur" geothermal power plant in Syunik Marz of the Republic of Armenia. The study was carried out in the scope of the process aimed at diversifying energy resources in Armenia and achieving a higher level of independence from the importing energy sources. The document, elaborated by Ameria consultants, proved the strategic importance and effectiveness of utilizing geothermal energy in Armenia, as well as the investment attractiveness of the overall project. Geothermal energy is considered as an effective resource for heat supply and generation of electric power. Today geothermal plants with the total heat production capacity of 12000 MW operate in more than 30 countries. The geothermal plants generate also electric power with the total capacity of 8000 MW. The share of geothermal energy in the world installed capacities is 0.4%.

"Jemaghbyur" station, which commissioned in 2008-2009, is a unique project. It does not have any analogues in the region and will positively differ from the majority of other energy generation capacities, especially in its renewability of resources, independence of importing energy sources, as well as in the minimal environmental impact.

The feasibility study of the project has indicated that the station based on 6 direct wells with the depth of up to 2.5 km each can have a capacity up to 25 MW and generate up to 195 mln KW/hour electric power a year.

Ameria is a group of professional services companies registered in Armenia with the objective to provide a comprehensive package of professional advisory and assurance services. Ameria specializes in four major areas of professional activities: management advisory services; assurance and advisory services; legal advisory services; investment banking. Established in 1998, the company has become a leader in the Armenian market of advisory services bringing an
international reach and local touch to complex issues rising in more than 30 industry sectors.

The Wairakei Power Station is a geothermal power station near the Wairakei Geothermal Field in New Zealand. Wairakei lies in the Taupo Volcanic Zone.

The geothermal power plant was built in 1958, the first of its type in the world, and it is now being operated by Contact Energy. A binary cycle power plant was constructed in 2005 to use lower-temperature steam that had already gone through the main plant. This increased the total capacity of the power station to 181MW. The Wairakei power station is due to be phased out from 2011, replaced by the Te Mihi geothermal power station. The Poihipi Power Station was built in 1996 at a nearby site in the same field.

The use of steam from the field has had a number of visible effects on the local environment. Visible geothermal activity has increased (due to changes in the water table / water pressure allowing more steam to be created underground, upsurging at places like Craters of the Moon), while there has also been some land subsidence and reduction in steam volumes from the field after some decades of use. So far, total electrical production has been sustained or increased, with the investment in additional power stations such as the binary plant of 2005 designed for lower-temperature generation. Some power stations in the field are now capped in their extraction capacities and a substantial part of the water / steam is being reinjected after use.

The hot geothermal fluid that is extracted is originally cold rainwater that had percolated downwards and been heated by hot rock; pumping back the warm water that emerges from the exhaust of the generator system thus reduces the heat drawn from the ground. Also, the Waikato river water is already too high in arsenic content to be safe to drink without special treatment, and so reinjection of the facility's water does not exacerbate this problem.

Wairakei Power Station
The Wairakei Power Station, with the main two blocks at the left rear. The binary plant is in front.
Location	New Zealand
Owner	Contact Energy
Fuel	Geothermal
Maximum capacity	181MW
Commissioned	1958
Decommissioned	2011 onwards (planned)

The Wayang Windu Geothermal Power Station is the largest geothermal power plant in Indonesia. The facility utilizes two units, one with 110 MW and the other with 117 MW, totalling the installed capacity to 227 MW. The power station is located in Pangalengan, West Java, in Indonesia. An estimated cost of US$200 million was incurred in constructions and development.

Wayang Windu Geothermal Power Station
Location	Pangalengan Indonesia
Coordinates	07°12′00″S 107°37′30″E / 7.2°S 107.625°E / -7.2; 107.625Coordinates: 07°12′00″S 107°37′30″E / 7.2°S 107.625°E / -7.2; 107.625
Owner	Star Energy
Employees	1,500
Status	Operational
Fuel	Geothermal
Technology	Steam turbine
Turbines	1 × 110MW 1 × 117MW
Installed capacity	227 MW
Commissioned	2000

Construction of Wayang Windu Unit II Geothermal Power Plant Inaugurated

The construction of geothermal power plant (PLTP) Wayang Windu Unit II officially inaugurated by Minister of Energy and Mineral resources, in Pangalengan, Bandung, in Saturday (26/8). The construction of this 110 MW power plant is expected to be completed in 2008 and will improve the security of power supply in the region.

According to Minister Purnomo, the reliability of power supply system in Java-Bali system is now improved following the construction of some new power plants in West Java including the Wayang Windu Unit II as well as the completion of the construction of 500 KV transmission southern line, stretching from Tasikmalaya in West Java to Jakarta. Minister Purnomo also added that the construction of Wayang Windu Unit II will be followed by the Wayang Windu Unit III with the same capacity of 110 MW. “The development of geothermal power plant will improve the security of power supply for West Java region” said Minister Purnomo.

The Hellisheidi Power Station is the second largest geothermal power plant in the world, and the largest geothermal power plant in Iceland. The facility is located in Hengill, southwest Iceland, 11 km (7 mi) from the Nesjavellir Geothermal Power Station. As of February 2009, the plant produces 213 MW of electricity, with a target capacity of 300 MW of electricity and 400 MW of thermal energy. Once this capacity is reached, it would rank as the largest geothermal power station in the world, in terms of installed capacity.

Electricity production with two 40 MW and 45 MW turbines commenced in 2006. In 2007, an additional steam turbine of 30 MW was added. In 2008, two 40 MW and 45 MW turbines were added with steam from Skarðsmýrarfjall Mountain. The hot water plant will be introduced in 2010.

Country	Iceland
Location	Hengill
Coordinates	64°02′14″N 21°24′03″W / 64.03722°N 21.40083°W / 64.03722; -21.40083Coordinates: 64°02′14″N 21°24′03″W / 64.03722°N 21.40083°W / 64.03722; -21.40083
Owner	Orkuveita Reykjavíkur
Status	Operational
Fuel	Geothermal
Technology	Steam turbine
Turbines	5
Installed capacity	213 MW (February 2009)
Maximum capacity	400 MW
Commissioned	2006

The Cerro Prieto Geothermal Power Station is the largest geothermal power station in the world, with an installed capacity of 720 MW, with plans for expansion up to 820 MW by 2012. The facility is located in south Mexicali, Baja California, in Mexico, and is built in five individual units, namely CP1, CP2, CP3, CP4 and CP5.

Cerro Prieto I
The CP1 powerhouse has a total installed capacity of 180 MW, generated by four units of 37.5 MW and one unit of 30 MW. Units 1 and 2 of this powerhouse was commissioned between 1973, followed by 3 and 4 in 1981.

Cerro Prieto II
The CP2 powerhouse has a total installed capacity of 220 MW, generated by two 110 MW units which were commissioned in 1982.

Cerro Prieto III
The CP3 powerhouse has a total installed capacity of 220 MW, generated by two identical units as CP2, measuring 110 MW. This powerhouse was commissioned in 1983, a year after the commissioning of CP2.

Cerro Prieto IV
The CP4 station commenced operations in July 2000, and consists of four turbines, each with a capacity of 25 MW.

Cerro Prieto V
The CP5 station is the newest powerhouse of the Cerro Prieto station. It was proposed in July 2009, with the commencement of constructions in September 2009. CP5 will consist of two 50 MW units, increasing the total capacity of the Cerro Prieto Geothermal Power Station by 100 MW.

The following page lists all the geothermal fuel power plants that are larger than 50 MW in nameplate capacity which are currently operational or under construction. Those power stations that are smaller than 50 MW, and those that are only at a planning/proposal stage may be found in regional lists, listed at the end of the page.

Station	Country	Capacity (MW)
Cerro Prieto Geothermal Power Station	Mexico	720
Hellisheidi Power Station	Iceland	400
Inyo Power Station	United States	272
Wayang Windu Geothermal Power Station	Indonesia	227
Salton Sea Power Station	United States	185
Wairakei Power Station	New Zealand	181
Calistoga Power Station	United States	176
Jermaghbyur Geothermal Power Plant	Armenia	150
Reykjanes Power Station	Iceland	150
Nga Awa Purua Power Station	New Zealand	132
Nesjavellir Geothermal Power Station	Iceland	120
Ohaaki Power Station	New Zealand	104
Centennial Drive Binary Plant	New Zealand	100
Kawerau Power Station	New Zealand	100
Svartsengi Geothermal Power	Iceland	77
Olkaria II Geothermal Power Plant	Kenya	70
Krafla Geothermal Power Station	Iceland	60
Serrazzano Power Station	Italy	60
Poihipi Power Station	New Zealand	55
Mutnovskaya Power Station	Russia	50