20 Aug 2025
Transpower has today submitted a proposal to the Commerce Commission for approval to invest $193 million in the upper South Island as electricity demand in the region continues to grow.
The option put forward by Transpower is to build two new switching stations near Orari and Rangitata, upgrade two transmission lines through the Waitaki Valley, and to install voltage management equipment.
Transpower Executive General Manager Grid Development Matt Webb said the proposed grid upgrades will strengthen the transmission network and ensure areas north of Twizel will continue to have a reliable electricity supply into the future.
“Demand in these areas has been growing steadily, particularly during the summer months when power is used for irrigation,” he said.
“With more homes and businesses switching to electricity use, and forecast electrification of South Canterbury’s farming and primary processing sectors, demand for electricity is expected to increase even further.”
There is limited electricity generation north of Twizel, so power travels from the Waitaki Valley via high voltage transmission lines to Christchurch and further north to reach the top of the South Island.
Mr Webb said that electricity transmitted over long distances needs voltage support to keep the supply stable and avoid surges or other disruptions.
“The more electricity we move, the more voltage support we need. Our proposed upgrades will create connections between existing electricity circuits, increase transmission line capacity, and help keep voltage stable,” he said
Transpower is also considering what other solutions could support or defer this investment.
“Our proposal includes $7 million for initiatives that could defer or avoid some investment in transmission infrastructure,” Mr Webb said.
“Known as ‘non-transmission solutions’, these include large batteries and demand response, where industrial customers or electricity retailers work with their customers to shift demand away from peak demand periods.
“By investing in our national network now, we are future- proofing a reliable electricity supply that serves a huge part of the South Island, enabling its people and businesses to thrive. This investment will ensure this part of our upper South Island’s network has the strength and resilience it needs to meet increased demand into the 2030s.
“We’ve engaged extensively on what the options are to continue to provide a reliable power supply and, overall, our key stakeholders support our investment proposal and acknowledge that grid reinforcement in the region is required.”
The proposed investment amount includes an allowance for inflation and interest during construction.
The Commerce Commission will consider Transpower’s investment proposal, including consulting on it, as part of its process to ensure New Zealanders receive good value for money from Transpower’s investments.
More information about our upper South Island upgrade project can be found here.
For more information:
Please contact Transpower’s Communications team at [email protected] or 021 195 8613.