Ohaaki — New Zealand
Geothermal power plant in Waikato, New Zealand. Approximate location -38.5279, 176.2937.
GeothermalWaikatoNew Zealand
Ohaaki is a 122 MW geothermal power station in Waikato, New Zealand. It is operated by Contact Energy. Based on its capacity (estimated), it can supply roughly 229k homes (estimated). It ranks #18 of 50 New Zealand power plants by installed capacity. Commissioned in 1984, it is around 42 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, geothermal supplies about 21.8% of New Zealand's electricity; the national grid averages 93 gCO₂/kWh (88.5% low-carbon) (2025).
Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1000332.
Data status
Known data
Calculated from dataset
Not available
Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.
Data provenance
Capacity and fuel are the upstream open-dataset record, not yet matched to a 2026 registry or GEM entry.
capacity: WRI GPPD; fuel: WRI GPPD
In context: how this plant compares
At 122 MW, Ohaaki is around the median geothermal plant in New Zealand (113 MW). Geothermal plants tap underground heat to raise steam for a turbine; they provide steady, low-carbon baseload but are limited to geologically active regions.
Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.
Key facts
- Share of New Zealand geothermal capacity
- 18.2% of 670 MW across 7 plants in this dataset
- Age among peers
- 0 of 6 dated geothermal plants in New Zealand are older
Calculated from the capacity and generation records in this dataset (WRI Global Power Plant Database (CC BY 4.0)).
Capacity vs largest geothermal plants in New Zealand
Installed capacity (MW), WRI Global Power Plant Database (CC BY 4.0).
Owner
Operated by Contact Energy.
Local climate & thermal context
This geothermal plant taps underground heat to raise steam that drives a turbine. It sits in a temperate oceanic climate (Köppen Cfb) — Southern Hemisphere, latitude 38.5°S — which shapes how much energy it can produce and how its output varies through the year.
Monthly mean temperature
Heating degree-days here run 8% above the median power plant in this dataset — a proxy for how much extra energy heated equipment must replace through its surfaces in winter.
Climate heat-demand index: 53/100 — this site sits in the mid third of the power plants we cover by heating degree-days.
Climate normals: WorldClim 2.1 (1970–2000 monthly normals, 10 arc-min, CC BY 4.0); zone: Köppen-Geiger world climate classification (Kottek et al. 2006, 0.5° grid). Degree-days & heat-demand index computed by PowerAtlas — a modelled heat-demand proxy, not a measured site figure.
Site climate & environmental severity
This site sits in a moderately corrosive environment (estimated ISO 9223 class C3 — Medium), with humidity / wetness the leading environmental stress.
Indicative estimate via the ISO 9223:2012 informative method (atmospheric corrosivity from temperature, time-of-wetness and airborne salinity), using WorldClim climate normals, the Köppen-Geiger class and coast distance. Indicative, not a measured corrosion rate.
How it compares & nearby plants
The #3 largest geothermal power plant of 7 in New Zealand by capacity.
New Zealand has 7 geothermal power plants in this dataset, together about 670 MW of capacity.
Nearby power plants
- Rotokawa · Geothermal · 35 MW · Waikato
- Nga Awa Purua · Geothermal · 140 MW · Waikato
- Aratiatia · Hydro · 78 MW · Waikato
- Wairakei · Geothermal · 132 MW · Waikato
- Te Huka Binary · Geothermal · 28 MW · Waikato
- Ohakuri · Hydro · 106 MW · Waikato
Location
Coordinates -38.5279, 176.2937 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
Frequently asked questions
What type of power plant is Ohaaki?
Ohaaki is a 122 MW geothermal power plant in Waikato, New Zealand, commissioned in 1984.
Who operates Ohaaki?
Ohaaki is operated by Contact Energy.