29 Jun 2026
Transpower has confirmed a contract with specialist global cable supplier Prysmian to manufacture and install four new undersea electricity cables, ensuring the Cook Strait electricity link can continue to serve Kiwis for decades to come.
The contract confirmation is a major step forward in Transpower’s work to renew the critical High Voltage Direct Current (HVDC) link that connects the North and South Islands’ electricity systems. The link ensures energy security, resilience and the ability to deliver lowest cost electricity to consumers. Key parts of the link, including the undersea cables, are due for renewal in the early 2030s.
Transpower Chief Executive James Kilty said the agreement with Prysmian today is an important milestone and means detailed design can begin immediately.
“The undersea cables required for this project are highly specialised, in high demand globally, and have long lead times to manufacture and install, which is why securing the supply of new cables and specialist installation resources is critical.”
The four new 40 km cables will be delivered to New Zealand and installed in 2031 by a state-of-the-art cable-laying vessel, following onshore works to upgrade the cable termination stations they will connect to.
Mr Kilty said the cables will be designed to meet the specific requirements of New Zealand’s electricity system and installation will be carefully planned to manage the challenging conditions in Cook Strait.
“The electricity flow across the Cook Strait cables can change direction multiple times a day depending on weather, lake levels, generation availability and electricity use. This gives our electricity system resilience and flexibility, but also means we need a particular type of cable that only a small number of suppliers in the world can produce.”
Prysmian is a global leader in the cable industry and designs, manufactures and installs undersea electricity transmission systems. It is headquartered in Milan, Italy, with operations worldwide.
“Prysmian brings significant expertise to this work. We are pleased to be working with them to deliver this important project.”
Today’s confirmation follows the Commerce Commission’s final decision earlier this month to approve Stage One of the HVDC investment programme.
Transpower will now seek environmental approvals for the physical works, including the new cable termination stations and earthworks for cable installation. Subject to approval, work on-site is expected to begin in the summer of 2027/28.
Further information is on Transpower’s website at www.transpower.co.nz/hvdc-upgrade.
ENDS
For further information, please contact:
Transpower’s Communications team on 021 195 8613 or [email protected].
Notes to editors
- The HVDC link transfers bulk electricity between Benmore in the South Island and Haywards in the North Island. It includes an overhead transmission line as well as the undersea cables across Cook Strait.
- The link was first commissioned in 1965, with the current undersea cables installed in 1991.
- The HVDC Link Upgrade Programme includes two planned stages. Stage 1 has Commerce Commission approval and includes installing four new cables, increasing transfer capacity to 1400 MW, and upgrading associated infrastructure including the cable termination stations at Oteranga Bay and Ōraumoa/Fighting Bay. Stage 2 includes replacing the IT systems that operate the link, and Transpower plans to consult at the end of this year on a major capex proposal to do this work.
- Work on-site is expected to begin in the summer of 2027/28. Cable manufacture will start in 2028. New cables are expected to be installed in 2031, with commissioning of the new cables and control system planned for the first half of 2032.
- HVDC link upgrade programme video, photo and map resources for media are available here: HVDC link upgrade programme - media resources