Geothermal power in New Zealand plays a significant part of the energy generation capacity of the country, constituting 25% of the total energy supply and 19% of electricity production in 2021. This positions New Zealand as the top user of geothermal energy among International Energy Agency (IEA) countries in both total energy supply and electricity generation.[1] [2]
Geothermal energy constitutes New Zealand's second-largest renewable electricity source, with the North Island estimated to have a potential of 1,000 MW for power generation. However, full exploitation may be constrained by economic, environmental, and social considerations. Exploration in the South Island has revealed geothermal prospects beneath the Alpine Fault, yet the Institute of Geological and Nuclear Science (GNS) suggests these resources are likely minor, suited more for small-scale direct use than for extensive electricity generation.
Geothermal energy has been described as New Zealand's most reliable renewable energy source, above wind, solar and even hydroelectricity, due to its lack of dependence on the weather. It has also been described as the currently (2000s and 2010s) most attractive new source of energy for New Zealand, as petrochemical fuel prices rise and easy hydro power sites have been tapped - it has been estimated that another 1000MW of geothermal resource can be used for generating electricity.[3]
In 2021, New Zealand generated a total of 45 TWh of electricity, with renewable energy sources contributing 81%, or 36 TWh. Among these, geothermal energy stood out by providing 19%. Over the period from 2005 to 2021, there has been a consistent increase in the share of renewable energy in electricity production. Specifically, the use of geothermal sources for generating electricity saw a substantial rise, growing by 165% during this period.
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 Taupō Volcanic Zone (which also has most of the currently operating generation capacity),[4] 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.[5]
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.
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).[6] 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.[4] [5]
The Mokai and Rotokawa geothermal plant was the first to come into operation via a resource consent applied for and issued under the Resource Management Act. The 5 years up until 2016 saw a number of new power stations completed. Kawarau 90MW, Nga Awa Purua 140MW, Ngatamariki 80MW and Te Mihi 140MW.
For over six decades, geothermal energy has been a key component of New Zealand's electricity landscape, with the majority of its facilities situated in the Taupō Volcanic Zone. Looking ahead, it is projected that by 2030, the electricity generated from geothermal sources in New Zealand will reach approximately 10.3 terawatt-hours (TWh).
Considerable geothermal research expertise exists at New Zealand's Crown Research Institutes and universities. In particular, at GNS Science,[7] Industrial Research Limited,[8] and the Geothermal Program at the University of Auckland. New Zealand is also one of the partner nations of the International Partnership for Energy development in Island Nations (EDIN). As part of EDIN,[9] New Zealand is involved in international research projects to evaluate and increase geothermal power generation domestically as well as in 18 Pacific Island nations.[10]
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".[11]
See also: List of power stations in New Zealand.
| Name | Location | Field | Operator | Capacity (MW) | Annual Generation (average GWh) | Commissioned | |
|---|---|---|---|---|---|---|---|
| Kawerau | 28 | 208 | 2018 | ||||
| Kawerau (GDL) - Geothermal Development Limited | Kawerau, Bay of Plenty | Kawerau | Eastland Generation | 8.3 | 70 | 2008 | |
| Kawerau (TOPP1) | Kawerau, Bay of Plenty | Kawerau | Norske Skog Tasman | 25 | 210 | 2012 | |
| Kawerau (KGL) | Kawerau, Bay of Plenty | Kawerau | Mercury | 100 | 800 | 2008 | |
| Mokai | Mercury | 112 | 900 | 2000 | |||
| north of Taupō | Rotokawa | Mercury | 140 | 1100 | 2010 | ||
| north of Taupō | Ngatamariki | Mercury | 82 | 670 | 2013 | ||
| near Kaikohe, Northland | 57 | 78 | 1998, 2020 | ||||
| between Rotorua and Taupō | Ohaaki | 70 | 300 | 1989 | |||
| north of Taupō | Wairakei | Contact Energy | 55 | 350 | 1997 | ||
| north of Taupō | Rotokawa | Mercury | 33 | 210 | 1997 | ||
| north of Taupō | Tauhara | Contact Energy | 152 (up to 174) | Unknown | 2024 | ||
| Tauhara | Contact Energy | 23 | 190 | 2010 | |||
| north of Taupō | Wairakei | Contact Energy | 159 | 1200 (approx) | 2014 | ||
| north of Taupō | Wairakei | Contact Energy | 161 | 1310 | 1958, 2005 |
Geothermal development projects include Tauhara stage 2 and Te Huka Unit 3.
| Name | Location | Field | Operator | Capacity (MW) | Expected Commissioning Date | |
|---|---|---|---|---|---|---|
| Te Huka Unit 3 | north of Taupō | Wairakei | Contact Energy | 51 | 4th quarter of 2024 | |
| Ngatamariki Unit 5 | north of Taupō | Ngatamariki | Mercury | 46 | 4th quarter of 2025 |
| Name | Location | Field | Operator / Owner | Capacity (MW) | Development Stage | |
|---|---|---|---|---|---|---|
| TOPP2 | Kawerau, Bay of Plenty | Kawerau | 49 | Capital raising stage (2023) | ||
| Taheke | Okere, Bay of Plenty | Taheke | Eastland Generation / Taheke 8C | 35 | Consented (2023) | |
| Ngawha Unit 5 | near Kaikohe, Northland | Ngawha | Top Energy | 32 | Consented |
| Name | Location | Field | Operator | Capacity (MW) | Annual Generation (average GWh) | Commissioned | Decommissioned | |
|---|---|---|---|---|---|---|---|---|
| Kawerau TA3 | Kawerau | Kawerau | Tasman Mill. Later Norske Skog Tasman (NST) | 8 | Unknown | 1966 | 2004 | |
| Kawerau TG1 & TG2 | Kawerau | Kawerau | Bay of Plenty Energy (later Nove Energy) | 6.4 | 35 | TG 1989. TG2 1993 | TG1 was decommissioned in 2014. TG2 was decommissioned in 2017. |