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.
We are currently working on a ~$90million upgrade to the Karāpiro Hydro Power Station. When the upgrade is complete the station will generate an additional 16.5MW, taking output from 96MW to 112.5MW and increasing the average energy production by 32GWh to 537GWh each year.
The upgrade will extend the power stations life span by another 50 years and make it more efficient in generating more renewable electricity for New Zealand.
We have already replaced two of the three units and headgates and on 6 August 2024 we re-opened the road across the dam. We plan to commence the third and final stage of this project from Monday 21st October and the road across the dam will be closed again from that date. The full project is scheduled for completion by the end of 2025.
Access over the Dam has been part of the landscape for 75 years and we appreciate that not having access during our refurbishment of the power station may be inconvenient for some locals and other road users. We thank everyone for their patience as we continue to undertake this important work on the station.
You can watch this timelapse video of the rotor lift for Unit One which was completed in May 2024 here:
FREQUENTLY ASKED QUESTIONS Are you allowed to close the road? While the public are allowed to use the road that crosses the dam, it is privately-owned by Mercury. Under the rules of the easement that Mercury has with Waipa District Council, Mercury is allowed to restrict public access when we need to maintain the dam.
Will there be access for pedestrians and cyclists when the road is closed to traffic? Unfortunately, we will not be able to provide safe crossing for pedestrians or cyclists during this second phase. During this phase, there is additional work being undertaken and large equipment needed on the dam. This equipment will be left on the dam for extended periods of time. It will not be possible to safely secure the site over night or on weekends and therefore access across the road would be very unsafe for members of the public at any time.
Why is Mercury doing this? It’s vital that we maintain and, where possible, improve upon our generation assets to make sure they continue to provide as much renewable energy to New Zealanders as possible. We have nine dam structures on the Waikato hydro system aged 60 to 97 years. About $350 million is being spent on the upgrading these dams over the next 15 years. Construction of Karāpiro Hydro Power Station was completed in 1947 and it was commissioned in 1948. This is the first time since the station was commissioned that the turbines have been replaced. This project will extend the asset’s life by 50 years and make the power station more efficient.
How much more efficient will it be? When the upgrade is complete the station will generate an additional 16.5MW, taking output from 96MW to 112.5MW and increasing the average energy production by 32GWh to 537GWh each year. This means that Karāpiro power station will generate, enough new renewable power for approximately 19,000 New Zealand homes. That’s 17% more than its current output.