Transpower, Aurora Energy and PowerNet’s joint investment will see two new transformers installed at Transpower’s Frankton substation by winter 2025, along with upgrades to the high-voltage transmission lines from Cromwell which feed the region.
Construction is expected to start later this year.
Transpower grid development general manager John Clarke said the Cromwell-Frankton transmission line was subject to regular checks and condition assessment surveys, ensuring it remained a highly reliable part of Transpower’s network.
Adding resilience to the region’s electricity supply, whether from new lines into the Wakatipu Basin or other local electricity options, would take time to identify, consent and build, given the strict environmental controls protecting the outstanding landscapes in the region, he said.
The upgraded equipment would increase the Frankton substation’s capacity by 35%, ensuring Wakatipu residents could depend on "clean, renewable energy" provided by the national grid.
He said it was essential the power system could meet future demand for electricity in Queenstown, which continued to grow.
"Transpower, Aurora Energy and PowerNet have been working closely on a variety of solutions to ensure this need is met and it’s great to be able to announce this investment decision."
Late last month, Aurora Energy started installing a 33kV cable from Malaghans Rd toward the Lower Shotover Bridge, working towards the grid exit point at Frankton.
The cabling install is expected to be finished this month, with commissioning completed by winter.
That was prompted, in part, by a series of unscheduled power cuts last winter when about 2300 residents in the area were left without power three times in three weeks in June and July, during some of the coldest days of the year.
Following investigations, the Dunedin City Council-owned company made "operational adjustments" aimed at reducing the load on the Queenstown network.
At present, Arrowtown, Coronet Peak, Dalefield, The Remarkables and part of Arthurs Point were fed by two lines sharing the load between them, with limited access to alternative supply if a fault occurs on either one.
Aurora Energy chief executive Richard Fletcher said the population and economy in the region had continued to grow, and everyone expected power — generated through renewable resources — to be there "at the flick of a switch".
"The upgrades enable Queenstown to enhance its green tourism credentials by enabling electric vehicles and low carbon heating, as well as reduce the potential threat to our tourism industry that could be the result of significant unplanned power outages."
PowerNet chief executive Jason Franklin said Transpower had also agreed to undertake flood mitigation work at the Frankton substation during the transformer installation.
It would bring the substation up to Transpower’s one-in-450-year-flood standard.
"Given the number of recent weather-related events, I think we’d all agree that reducing flood risk and increasing resilience is a priority, given our dependence on this critical site," he said.
Simultaneously, discussions were beginning "in earnest" about the Queenstown-Lakes’ long-term electricity supply and resilience.
Queenstown Lakes Mayor Glyn Lewers said the planned investment would provide surety of capacity through the traditional supply model, while the next phase would be to focus on ensuring resilience and sufficient supply to meet the district’s decarbonisation objectives, including the goal of zero carbon 2030.
"We can all sleep a little easier and now need to keep up the momentum by working together to understand all potential opportunities for renewable energy generation in the district.
"This will ensure we electrify our economy as much as possible and remain resilient through any emergency situation."
Mr Clarke said Transpower was keeping a close eye on the longer-term power needs of the region.
While the upgrades would increase the capacity of the line and associated work would add some additional resilience to the line route, other longer-term solutions would be needed.
"From a grid supply perspective, we expect to have sufficient margin and options to meet demand until the work we announced today is completed in mid-2025.
"New infrastructure will ultimately be required both for further power capacity increases and improved resilience as we all become more and more reliant on electricity in the drive to decarbonise our economy.
"We will continue to talk with the council, Aurora Energy and PowerNet, and we will be consulting with the community as and when our future plans begin to take shape."
