We operate five geothermal plants located in the central North Island that power base-load – this means they make power 24/7 ensuring a constant supply of power night and day. Geothermal is a reliable electricity source that is not dependent on the weather, unlike hydro and wind, and is a distinctive strength for Mercury.  

Geothermal stations.

Geothermal Stations.

Five stations in the central North Island. Steady base-load geothermal runs at full capacity about 95% of the time.


Since 2008
Located in the eastern Bay of Plenty. A Fujielectric-Sumitomo flash plant completed under budget, ahead of schedule and produces more electricity than planned. 


Since 2000 
Located on the Mōkai geothermal field, 30km northwest of Taupō. Owned by Tuaropaki Power Company and Mercury.


Since 2000
Located on the Rotokawa geothermal field, 14km northeast of Taupō. A joint venture with Tauhara North No.2 Trust.


Since 2013
17 km northeast of Taupō, with the largest Ormat 20MW Binary Cycle units in the world. 

Ngā Awa Pūrua

Since 2010
Located on the Rotokawa geothermal field, 14km northeast of Taupō. A joint venture partnership with Tauhara North No.2 Trust. A Fujielectric-Sumitomo flash plant with the largest single-shaft geothermal turbine in the world. $430 million project.

Generation Development.

Generation Development.

New Zealand leads the world with 80% renewables, and a big part of the growth in renewables over the last decade has been Mercury’s investment in geothermal generation in partnership with Maori landowners. 

Mercury is one of the world’s largest geothermal power station owners following the successful completion of three major geothermal power stations between 2008 and 2013 – Kawerau, Ngā Awa Pūrua and Ngātamariki. The combined output of electricity from these stations, which normally run 24/7, provides enough renewable electricity to supply 330,000 New Zealand homes (2800 GWh).

$1.4b invested in reliable base-load geothermal since 2008


Reliable Geothermal.

Reliable Geothermal.

Geothermal expertise is a point of difference for Mercury, and we work hard every day to keep the five geothermal plants we operate running reliably and efficiently. As part of this we drill make-up wells at our plants from time to time to maintain reliable geothermal fuel supply so our customers can enjoy using renewable energy every day.  

We recently drilled four new make-up wells to replenish the fuel supply - two at Rotokawa and another two at our Kawerau field. Geothermal wells can go as deep at 3,000m underground, and are built to operate in excess of 20 years.