Geothermal Energy & Electricity Generation
Geothermal energy produces about 10% of New Zealand's electricity supply. Most of New Zealand's installed geothermal generating capacity of about 600 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 is now faced with a similar situation
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 | 'Commiss- ioning' 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 | Independent | 2008 | 8.3 | 569 |
| Ngawha 2 | Top Energy | 2008 | 15 | 584 |
* 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 60 MWe
due to field limitations. |
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The following table indicates upcoming developments.
| Station | Capacity (MW) | Operation | Developer | Comments |
| Nga Awa Purua (Rotokawa) | 130 |
2010 | MRP + Tauhara North No 2 Trust |
Consents in place, construction contracts in place, construction well advanced. |
| Centennial Drive (Tauhara) | 23 |
2010 | Contact | Consents in place, contract let to Ormat, construction well advanced. |
| Te Mihi | 220 |
??? | Contact | Consents in place through Board of Inquiry (Call-in). This will largely replace Wairakei so represents a net gain in generation of around 65 MW. |
| Tauhara | 220 |
2012 | Contact | Recent wells very encouraging and an active exploration drilling program is proceeding. Initial concept floated to public. Consent application likely in 2009. Will proximity of Taupo township constrain development? |
| Ngatamariki | 120 |
2012? | MRP + Tauhara North No 2 Trust |
Currently testing wells. Consent applications have been lodged. |
| Rotoma | 35 |
2012? | Rotoma No 1 Inc | Consent Application lodged (not included in projection). |
| Geotherm (Wairakei) | 55 |
2012? | Geotherm? | Consents in place. Project is currently being offered by receivers with results of negotiations pending (not included in projection). |
| Tokaanu | ?? |
?? | ?? | Genesis is funding supplementary geoscience. Relationship building continues (not included in projections). |
| Misc | 400 |
By 2025 | Various | Balance of 1000 MW of unspecified projects. |