Transpower to consult on future-proofing North and South Island power link

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Eddies of water from rivers in Golden and Tasman Bay reach more than 100 kilometres out into greater Cook Strait.
Photo: NIWA

Transpower is consulting with the energy sector to gauge demand to replace the undersea high voltage direct current link (HVDC) connecting the national grid between the North and South Islands.

The Commerce Commission last month approved Transpower’s near $400-million interim proposal to strengthen the national electricity grid.

This round of consultation on the long-term future of the cables was ahead of another round about the $103m interim upgrade to improve the Cook Strait undersea link.

Power customers will eventually pick up the overall interim $392.9m cost to upgrade the national grid, though it will be up to the Electricity Authority to decide who pays for what.

Transpower executive general manager grid development John Clarke said the existing Cook Strait cables would reach the end of their life in the early 2030s, so it was “timely” to consider future possibilities.

He said this round of consultation was about the long-term plan to replace the Cook Strait cables, which were reaching the end of their life, and would cost in the order of $400m to replace.

“We are planning infrastructure now for a future where electricity powers more of our transport and more of our industry in New Zealand,” he said.

“By 2050, we expect electricity use to have increased almost 70 percent compared to 2020, and we need to consider what role the HVDC link will play in that future.”

He said the consultation needed to happen now, to give Transpower enough time to order and replace the cabling, before the existing undersea cables fail.