18 Sep 2025
The reliability and resilience of electricity supply in Hawke’s Bay, Tairāwhiti, Wairoa and the East Coast has been given a significant boost with the installation of an additional larger capacity transformer at Transpower’s Redclyffe substation.
The new 220 kV/110 kV interconnecting transformer will allow 250 MW of electricity to be imported into the region via Transpower’s high voltage national electricity transmission grid, almost double the previous carrying capacity of 130 MW.
Transpower Executive General Manager Grid Delivery Mark Ryall said the work is part of Transpower’s ongoing commitment to the regions to build the local electricity transmission infrastructure back better after the damage caused by Cyclone Gabrielle.
“We’ve worked closely with our local lines company partners Unison Networks and Firstlight Network to understand the communities’ needs for electricity supply into the future,” he said.
“Central to that is continuing with plans already in place to boost the reliability and resilience of supply in the region while also rebuilding Redclyffe substation to a higher level of flood and earthquake resilience.
“This new interconnecting transformer is a big step forward that will enable us to bring in almost double the amount of electricity from outside the region to ensure that there is enough electricity to power local communities as they continue to grow.”
The increased capacity will also reduce the reliance on generation from Genesis Energy’s Waikaremoana Power Scheme and support additional local renewable generation development.
“Waikaremoana Power Scheme was absolutely critical following Cyclone Gabrielle and we are very grateful to Genesis Energy for their efforts to keep it running then and also while we have been working to connect the additional transformer,” Mr Ryall said.
“Genesis Energy will, of course, continue to play an important role in the region. But the additional power we can bring into the region will take significant pressure off Waikaremoana to keep running near full capacity to meet local demand.”
The new interconnecting transformer will also make it easier to plan and do essential maintenance work on critical electricity supply equipment without impacting consumers’ electricity supply.
Improved flood and earthquake resilience
The new equipment has been designed to be resilient to a 1-in-450-year flooding event. This is in line with plans to rebuild other parts of the substation that were damaged in Cyclone Gabrielle to this modern flood resilience standard.
Transpower currently has a proposal with the Commerce Commission for this work. Once approved, the work is expected to start in October 2026 and finish by December 2027 to make the site fully resilient against 1-in-450-year flooding events.
The work can be completed without any impact to local electricity supply.
Interim upgrades have already been made since Cyclone Gabrielle and more work is planned to make the substation more resilient to and recoverable from flooding until the rebuild can be completed.
For pictures or for more information, call Transpower’s media phone 021 195 8613 or email [email protected]