Geothermal Energy & Electricity Generation
Geothermal energy produces about 13% of New Zealand's electricity supply. Most of New Zealand's installed geothermal generating capacity of about 750 MWe is situated in the Taupo Volcanic Zone, with another 25 MWe installed at Ngawha in Northland. The temperature and conditions of a particular geothermal reservoir determine which type of generation technology is used: dry steam, flash steam or binary cycle.
When
the first generator was commissioned at Wairakei
in 1958, it was only the second geothermal plant
in the world to begin large-scale commercial operation
and the first to exploit a wet (rather than dry
steam) geothermal resource. The impetus for the
development of Wairakei came in 1947 from severe
electricity shortages following two dry years
which restricted hydro generation, and a desire
by the New Zealand Government for the electricity
supply to be independent of imported fuel. New
Zealand has recently faced similar situations
which geothermal energy has the potential to alleviate.
There are currently six fields used for geothermal electricity generation, which is dominated by Contact Energy Ltd (a listed company) and Mighty River Power (a State Owned Enterprise). A significant factor in recent geothermal projects has been the high level of commercial participation by Maori-owned enterprises.
Historical Changes in NZ Geothermal Electricity Generation Capacity
| Plant Name | Current Owner | 'Commissioning' Date |
Installed Capacity (MWe) |
Cumulative Capacity (MWe) |
| Wairakei | Contact Energy | 1958-63 | 193 | 193 |
| Kawerau | Norske Skog Tasman | 1966 | 10 | 203 |
| Wairakei | Contact Energy | 1982 | -36 | 167 |
| Kawerau Binary (TG1) | Bay of Plenty Electricity | 1989 | 2.4 | 169 |
| Ohaaki | Contact Energy | 1989 | 114* | 283 |
| Kawerau Binary (TG2) | Bay of Plenty Electricity | 1993 | 3.5 | 287 |
| Ohaaki Rerating | Contact Energy | 1996 | -10 | 277 |
| Wairakei BP | Contact Energy | 1996 | 5 | 282 |
| Poihipi Road | Contact Energy | 1996 | 55 | 337 |
| Rotokawa | Mighty River Power | 1997 | 29 | 366 |
| Ngawha | Top Energy | 1998 | 10 | 376 |
| Mokai 1 | Tuaropaki Power Company | 1999 | 55 | 431 |
| Ohaaki Derating | Contact Energy | 2001 | -38 | 393 |
| Rotokawa Extension | Mighty River Power | 2003 | 6 | 399 |
| Kawerau BP Decom | Norske Skog Tasman | 2004 | -10 | 389 |
| Kawerau BP2 | Norske Skog Tasman | 2004 | 8 | 397 |
| Wairakei Binary | Contact Energy | 2005 | 14.4 | 411 |
| Mokai 2 | Tuaropaki Power Company | 2005 | 39 | 450 |
| Ohaaki Derating | Contact Energy | 2005 | -16 | 434 |
| Mokai 3 | Tuaropaki Power Company | 2007 | 17 | 451 |
| Ohaaki Rerating | Contact Energy | 2007 | 10 | 461 |
| Kawerau | Mighty River Power & partners | 2008 | 100 | 561 |
| KA24 | Eastland Group | 2008 | 8.3 | 569 |
| Ngawha 2 | Top Energy | 2008 | 15 | 584 |
Nga Awa Purua |
Mighty River Power & Tauhara North No. 2 Trust | 2010 | 140 | 724 |
| Te Huka | Contact Energy | 2010 | 23 | 747 |
* Although Ohaaki still has 114 MWe of plant installed on site, one high pressure turbine is now decommissioned and other turbines operate on restricted duty. The station generates around 45 MWe due to field limitations. |
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The following table indicates upcoming developments.
| Station | Capacity (MW) | Operation | Developer | Comments |
| Kawerau Topp 1 |
25 |
late 2012 | Norske Skog, upstream NTGA |
Using existing NS consents. Contracts signed. Under construction. Ormat plant, reduced output from existing plant, 16 MW increase |
| Ngatamariki I | 82 |
Mid 2013 | MRP & Tauhara North No. 2 Trust |
Consents for 110 MW in place, contracts signed, under construction, production drilling progressing with Iceland Drilling 4 turbine Ormat plant. |
| Te Mihi I | 166 |
2013 | Contact |
Consents in place through Board of Inquiry for a 240 MW development, contracts signed, under construction, production drilling progressing. This will replace 45 MW of existing Wairakei plant but this initial stage will result in a 114 MW net gain. |
| Te Ahi O Maui (KA22) | 10-15 |
2014 | Eastland Group and Kawerau A8D Ahuwhenua Trust & Innovations Development Group |
Project up to 50 MW announced but still requires consents and contracts. |
| Tauhara II | 240 |
2015? | Contact |
Consents in place through Board of Inquiry. Production drilling to follow. |
| Tikitere | <45 |
2015? | Tikitere Trust (and partners) |
currently in consenting and investigation stage. |
| Rotoma | 35 |
2013? | Rotoma No 1 Inc |
Consents under appeal. |
| Taheke | ? |
? | Contact & Taheke 8C and the Adjoining Blocks Inc |
3 Exploration wells drilled. |
| Te ia o Tutea | ? |
? | MRP, Okere Inc and Ruahine Kuharua Inc |
Agreement for explanation and cooperative development
|
| Misc | 400 |
By 2025 | Various |
Balance of unspecified projects including late stages of existing developments |