Transpower exploring future role of New Zealand’s inter-island HVDC electricity link

07 Mar 2024

Cable station on the coast

The demand for electricity in New Zealand will grow as it takes the place of fossil fuels. Transpower is asking today what role the cable linking the North and South Islands should fulfil in the future electricity grid.

Transpower Executive General Manager Grid Development John Clarke said the cables that transport electricity across Cook Strait as part of the HVDC system will reach the end of their life in the early 2030s, so it’s timely to consider future possibilities.

“The need to replace the existing cables raises an opportunity to discuss with industry and other stakeholders the future role of the link in New Zealand’s power system and ensure it is fit-for-purpose,” Mr Clarke said.

The link connects the North and South Islands’ electricity systems between Benmore in the South Island and Haywards in the North Island, including undersea cables across the Cook Strait. It brings renewably generated electricity northwards and allows surplus North Island renewable generation to go south, as well as supporting system stability.

While a recently approved equipment upgrade at Haywards will boost the link’s capacity in the shorter term – with the exact timing subject to further engagement – the discussion paper, ‘Examining the purpose and future role of our HVDC link’, looks to its long-term future.

“We are planning infrastructure now for a future where electricity powers more of our transport and more of our industry in New Zealand. By 2050, we expect electricity use to have increased almost 70% compared to 2020, and we need to consider what role the HVDC link will play in that future,” Mr Clarke said.

The discussion paper is available on the Transpower website

Comments on the paper are welcomed and should be emailed to [email protected] by Friday 26 April 2024. 


Additional Background

In February 2024, in response to Transpower’s Net Zero Grid Pathways 1 stage one major capital investment submission, the Commerce Commission announced approval for a $76 million investment in the HVDC link to increase transfer capacity from 1071 MW North / 762 MW South to closer to 1200 MW North / 850 MW South by installing reactive plant, filter banks, and associated equipment to upgrade the link. Under the Commerce Commission’s decision, the work has an approval expiry date of 31 December 2035 and gives Transpower flexibility to determine the best time for this investment depending on uncertain need and delivery timeframes, which are expected to become more precise as additional information is confirmed. 



For further information, please contact: 

Rachael Drummond, Senior Corporate Communications Advisor, 021 394 803.