Geothermal power in New Zealand is a small but significant part of the energy generation capacity of the country, providing approximately 10% of the country's electricity with installed capacity approaching 600 MW. New Zealand, like only a small number of other countries worldwide, has numerous geothermal sites that could be developed for exploitation, and also boasts some of the earliest large-scale use of geothermal energy in the world.

Geothermal energy has been described as New Zealand's most reliable renewable energy source, above wind, solar and even water power, due to its lack of dependence on the weather.

Geothermal fields

The exploration of New Zealand's geothermal fields has been very extensive, and by the 1980s, most fields were considered mapped, with 129 found, of which 14 are in the 70-140 °C range, 7 in the 140-220 °C range and 15 in the >220 °C range. Currently, some potential new geothermal fields are being surveyed that have no surface expression.

New Zealand's high-temperature geothermal fields are mostly concentrated around the Taupo Volcanic Zone (which also has most of the currently operating generation capacity), in the central North Island, with another major field at Ngawha Springs in Northland. However, more systems (some of them potentially exploitable) are scattered all over the country, from the Hauraki Plains to the Bay of Plenty to numerous hot springs in the South Island, most of them associated with faults and other tectonic features.

Many applications of geothermal energy in New Zealand reinject the cooled steam / fluid back into the underground fields, to extend or infinitely use the fields as power sources.

History

Geothermal energy use in New Zealand is strongly tied to Wairakei, where the first geothermal plant was opened in 1958. At that time, it was only the second large-scale plant existing worldwide (the first being the Valle del Diavolo 'Devil's Valley' plant in Larderello, Italy opened in 1911). Several new plants and efficiency-enhancing second-stage equipment have been added since, though there is also some loss of steam generation due to the decade-long drawdown. Some plants are therefore capped in steam extraction volumes to allow the fields to regenerate, and a percentage of the steam/water is reinjected.

The Ngawha geothermal plant was the first to come into operation via a resource consent applied for and issued under the Resource Management Act. Recent geothermal developments include an upgrade of this plant as well as the commissioning of the Kawerau Power Station in 2008.

Geothermal energy is expected to contribute an increasing proportion of the nation's electricity in the future, with several large geothermal projects underway. The 132 MW Nga Awa Purua station is currently under construction and Contact Energy is developing the 23 MW Centennial Drive Plant, a binary plant. Both are located near Taupo and due to enter commercial operation in 2010. Other developments include the 220 MW Te Mihi Power Station which is expected to begin operation in 2011.

Research

Considerable geothermal research expertise exists at New Zealand's universities. In particular, the Geothermal Institute of the University of Auckland (until 2003) and now the Geothermal Program in the Institute of Earth Science and Engineering. The University of Auckland has in excess of 20 faculty members dedicated to geothermal research and teaching. Their efforts are coordinated by Professor Paul W. O. Hoskin.

Laws and regulations

Geothermal Energy Act 1953

The Geothermal Energy Act 1953 was made redundant by the Resource Management Act 1991 (RMA). The Geothermal Energy Act granted water rights, which have generally been replaced by RMA resource consents.

Geothermal Energy Regulations 1961

The Geothermal Energy Regulations 1961 define the role of "geothermal inspectors" and specifies processes for applications for authorities and licences.

Rotorua City Geothermal Energy Empowering Act 1967

The Rotorua City Geothermal Energy Empowering Act 1967 is an Act to enable the Rotorua City Council to make provisions for the control of the tapping and use of geothermal energy in the city of Rotorua.

Resource Management Act 1991

The Resource Management Act 1991 (RMA) is a significant, and at times, controversial Act of Parliament passed in 1991. The RMA regulates access to natural and physical resources such as land, air and water, with sustainable use of these resources being the overriding goal. New Zealand's Ministry for the Environment describes the RMA as New Zealand's principal legislation for environmental management.

The Resource Management Act is the principal legislation controlling the use of geothermal resources in New Zealand. The New Zealand Geothermal Association considers the procedures which are currently being adopted under the RMA as the single largest obstacle to further geothermal development, holding that "the regulatory process leads to long delays which impose a significant up-front cost on projects, reducing their financial viability".

List of geothermal power stations

• Centennial Drive Binary Plant
• Kawerau Power Station
• Mokai Power Station
• Nga Awa Purua
• Ngawha Power Station
• Ohaaki Power Station
• Poihipi Power Station
• Rotokawa Power Station
• Te Mihi Power Station
• Wairakei Power Station

See also

• Electricity sector in New Zealand
• Renewable energy in New Zealand

References

External links

• Geothermal energy in New Zealand (from Te Ara Encyclopedia of New Zealand)