Mercury isn’t just building new generation assets, we are committed to enhancing our existing ones.

Our long-term hydro refurbishment programme is designed to maintain and improve the performance and resilience of our hydro stations along the Waikato River. This programme will likely continue over the next 15 years, adding significant value and capacity to Mercury’s hydro fleet, whilst continuing to supply Aotearoa’s grid with renewable energy for years to come.

Mercury Karapiro Hydro Station Dam

Photo: Head gate lift for the first unit at Karāpiro Hydro Power Station, April 2023.

The Karāpiro station, which was built in 1947 and is the last station on the Waikato River, is undergoing a refurbishment, as part of this programme, with an investment of around $90 million.

The project will enable the station to generate renewable power for the next 50 years and increase its capacity from 96MW to 112.5MW (32GWh/year) – enough to power another 4,500 homes.

This improvement will enhance the reliability and efficiency of Mercury’s hydro generation, which accounts for about 10% of New Zealand’s electricity supply.

Watch this timelapse video of the Rotor Lift for Unit One which was completed in May 2024. We expect that work to install the third unit will begin in October 2024 and the full project is scheduled for completion in September 2025.


You can read more about the project at Powering Change here.