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
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 |
Total 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) | Nova Energy | 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 |
TOPP1 | Norske Skog Tasman | 2013 | 25 | 772 |
Ngatamariki | Mighty River Power | 2013 | 82 | 854 |
Te Mihi | Contact Energy | 2014 | 166 | 1020 |
Wairakei Reduction | Contact Energy | 2014 | -40 | 980 |
* 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. |
The following table indicates upcoming developments.
Station |
Capacity (MW) |
Operation |
Developer |
Comments |
Te Ahi O Maui (KA22) | 10-15 |
2016? | Eastland Group and Kawerau A8D Ahuwhenua Trust & Innovations Development Group |
Project up to 50 MW announced but still requires consents and contracts. |
Tikitere | <45 |
2016? | Tikitere Trust (and partners) |
currently in consenting and investigation stage. |
Rotoma | 35 |
2016? | Rotoma No 1 Inc |
Consents under appeal. |
Tauhara II | 240 |
2018? | Contact |
Consents in place through Board of Inquiry. Production drilling to follow. |
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 expansion and cooperative development |
Ngawha 3 | 50 |
2020 | Top Energy |
Planning stage |
Ngawha 4 | 50 |
later | Top Energy |
Planning stage |
Misc | 400 |
By 2025 | Various |
Balance of unspecified projects including late stages of existing developments |