Wairakei Power Station
Encyclopedia
The Wairakei Power Station is a geothermal power
station near the Wairakei
Geothermal Field in New Zealand
. Wairakei lies in the Taupo Volcanic Zone
.
. 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 2013, replaced by the Te Mihi geothermal power station
. The Poihipi Power Station
was built in 1996 at a nearby site in the same field.
), while there has also been some land subsidence and reduction in steam volumes from the field after some decades of use. Recent 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, but the total still does not reach the early power levels such as the 192MW reported in 1965 (NZED Annual Statistics), for instance. 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, so reinjection of the facility's water does not exacerbate this problem.
Geothermal power
Geothermal energy is thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. Earth's geothermal energy originates from the original formation of the planet and from radioactive decay of minerals...
station near the Wairakei
Wairakei
Wairakei is the name of a power station, small settlement and a geothermal area a few kilometres north of Taupo, in the centre of the North Island of New Zealand, on the Waikato River.- Geothermal field :...
Geothermal Field in New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
. Wairakei lies in the Taupo Volcanic Zone
Taupo Volcanic Zone
The Taupo Volcanic Zone is a highly active volcanic V shaped area in the North Island of New Zealand that is spreading east -west at the rate of about 8mm per year...
.
History
The power station was built in 1958, the first of its type (wet steam) in the world, and it is currently owned and operated by Contact EnergyContact Energy
Contact Energy Limited is a New Zealand electricity generator, natural gas wholesaler and electricity, natural gas, and LPG retailer.The company is the second-largest electricity generator in New Zealand , generating 24 percent of New Zealand's electricity in the year ending 31 December 2009, and...
. 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 2013, replaced by the Te Mihi geothermal power station
Te Mihi Power Station
The Te Mihi Power Station is a 159 MW geothermal power station being developed by Contact Energy north of Taupo in New Zealand.The resource consent for the power station was "called in" by the Minister for the Environment Trevor Mallard under the terms of the Resource Management Act...
. The Poihipi Power Station
Poihipi Power Station
The Poihipi Power Station is a geothermal power station owned and operated by Contact Energy. It is located on Poihipi Road near Taupo in New Zealand....
was built in 1996 at a nearby site in the same field.
Effects
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 MoonCraters of the Moon (geothermal site)
Craters of the Moon Thermal Area is a region with geothermal activity north of Taupo, New Zealand. It is a part of Wairakei, the largest geothermal field in New Zealand, with a surface area of about 25 km2, which lies in the Taupo Volcanic Zone.The name springs from the many hydrothermal eruption...
), while there has also been some land subsidence and reduction in steam volumes from the field after some decades of use. Recent 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, but the total still does not reach the early power levels such as the 192MW reported in 1965 (NZED Annual Statistics), for instance. 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
Waikato River
The Waikato River is the longest river in New Zealand. In the North Island, it runs for 425 kilometres from the eastern slopes of Mount Ruapehu, joining the Tongariro River system and emptying into Lake Taupo, New Zealand's largest lake. It drains Taupo at the lake's northeastern edge, creates the...
water is already too high in arsenic content to be safe to drink without special treatment, so reinjection of the facility's water does not exacerbate this problem.
External links
- New Zealand Geothermal Association - Wairakei Power Station information page