Last updated: 10 Apr 2024
What we're doing
We need to continually operate, maintain and develop New Zealand's transmission network – the National Grid – to ensure we meet the ongoing electricity needs of New Zealanders.
There are three areas of potential constraint in Transpower's North Island network with respect to the amount of generation required to be connected/transported around the island due to New Zealand's progress to a zero-carbon economy. This project is about increasing the capacity of the 220 kV grid between Bunnythorpe and Whakamaru in a staged manner to meet the requirements of increasing generation and demand. Similar projects are underway with respect to the capacity of the HVDC and further investment in the Wairakei Ring (subsequent to the Atiamuri series reactor project underway). The first project underway is to increase the operating temperature of the sections of our two lines that connect between Tokaanu and Whakamaru (known as a thermal upgrade).
Why we're doing it
As part of our Net Zero Grid Pathways work, we have identified that with the expected eventual closure of Tiwai Aluminium smelter and expected new generation in the North Island there is significant economic benefit to New Zealand in relieving potential constraints in our core network in addition to the Clutha Upper Waitaki Lines Project which has recently been completed. More information on the Net Zero Grid Pathways Project can be found here. The thermal upgrade work is the first tranche of projects to increase capacity - and will provide around an extra 220 MW of capacity in the region.
More Information
Because of the relationships between this project, the capacity of the HVDC and the capacity of the Wairakei Ring, we are undertaking the investigations concurrently. A long-listing document outlining the need and long list of options for each project was released and consulted on towards the end of 2021, and at the end of 2022 a Major Capex Proposal was submitted to the Commerce Commission