WEEKLY ELECTRICITY USAGE EMAILS HAVE MOVED TO THE MERCURY APP
You’ll now find your weekly usage summary in the Mercury App. On your dashboard, select your electricity service. At a computer? You can also log in to My Account. Learn more about tracking your usage. 
Taupo generation site river rapids

HYDRO.

We harness the power of water through our nine hydro plants along the Waikato River to produce about 10% of New Zealand’s electricity. The great thing about hydro generation is that it can be increased or decreased quickly to meet peak demand for electricity. Our hydro system is the largest peaker in the North Island – and located close to the country’s largest city Auckland. Find out about the Mercury Taupō Community Fund.
HYDRO STATIONS
KARĀPIRO

Since 1947

188km downstream of Lake Taupō, the Karāpiro Lake is the home of NZ Rowing.

Current work.

MARAETAI I AND II
Since 1952 and 1970

Combined they offer the largest output from any lake on the Waikato River.
ŌHAKURI
Since 1961

Lake Ōhakuri covers 12 sq km and is the largest lake on the Waikato River.
ARAPUNI

Since 1929

Protected under the Historic Places Trust Arapuni has the largest capacity of any station in the Waikato hydro system.

Current work.

WHAKAMARU
Since 1956

The main switching station for upper Waikato generation and supplies the transmission system that leads north.
ARATIATIA
Since 1964

13km downstream from Taupō, Aratiatia is the smallest hydro reservoir in the Waikato Hydro System.
WAIPĀPA
Since 1961

The smallest power station on the Waikato River and is used to supplement other stations.
ĀTIAMURI
Since 1958

Originally designed for three generators, a fourth was later added and commissioned in 1962.
TAUPŌ GATES

Since 1941
The Gates help manage the volume of water flowing down the Waikato River, in response to inflows to Lake Taupō and energy demand.

Current work.

CHECK OUT OUR HYDRO STATIONS

Watch a short video on some of our hydro stations in action and see how they harness the energy that fills your home or business.
Play Video
Video Length: 4m 17s

UPGRADING OUR VITAL HYDRO ASSETS

Our hydro stations on the Waikato River were constructed from the late 1920s to the 1970s and have worked hard to keep the country powered. We have a long-term hydro refurbishment programme to protect these assets to ensure they can manage water flow that looks after the environment but also can optimise energy from the awa.

We’re presently working on the upgrade to our Karāpiro Hydro Power Station. Find out more here.

Maraetai Hydro Power Station will be upgraded next, with the site works planned for 2027. All its turbines, generators and governors will be replaced. The upgrades will add about 32GWh annual output to the station.

At the Ātiamuri Hydro Power Station, work is scheduled for 2028 to upgrade all four of its generators. These upgrades will add an estimate 2-4MW per unit and 18GWh of additional generation.

Hydro river
Play Video
Video Length: 1m 53s

ELECTRICITY FROM WATER

Hydropower or water power is mechanical energy generated using the flow of water. Watch our video to see how we turn the flow of water into renewable electricity!
Play Video
Video Length: 0m 39s

WHAKAMARU TIME LAPSE

Watch 8 months' work in 30 seconds. Teams can be seen rehabilitating generator and turbine technology to make Whakamaru station more productive. Wonderful.