Rakiura cable plan resurfaces
A cable from the mainland to Stewart Island is now the preferred option of a subcommittee looking into the island’s electricity needs, its newly elected district councillor Jon Spraggon says.
However, whether it ever happens is another question.
Connecting a cable would cost tens of millions of dollars, and Transpower says the beneficiary [in this case Stewart Islanders] generally pays for any connection to the national electricity grid.
Transpower grid development general manager John Clarke said he understood the electricity demand on Stewart Island was only about 400kW or equivalent to about 100 homes on the mainland.
‘‘It is unlikely to be economically feasible to connect directly to the grid.’’
Other possibilities include connecting to the local distribution network in Southland or installing a mix of solar and wind generation on the island with some battery storage, Clarke said.
Stewart Island is currently reliant on five diesel generators for power to its 400 residents and its businesses. But the cost of using diesel continues to rise and it isn’t considered sustainable for the future.
District councillor Jon Spraggon, who lives and works on the island, said the Government had made it clear fossil fuels were on the way out.
‘‘We advertise the island as a green place yet here we are burning thousands of dollars of diesel to make our power. It doesn’t seem to fit in with the image.’’
A sub-committee made up of council representatives and islanders had looked at several options and decided a power cable from the mainland, via the Foveaux Strait seabed, was the best option, Spraggon said.
Other options including wind, solar and hydro had been considered. But an agreed site could not be found for wind turbines and in all cases, diesel would still be required, he said.
The island’s power consumption would rise as tourist numbers and electric-car usage increased.
‘‘When we have looked at it and thought about it a cable seems the only real way to go.’’
The sub-committee was preparing a case to take to the Government for funding the cable which was now the ‘‘number one priority’’, he said.
When the Government last considered the matter a cable wasn’t its top priority, and this week it gave no indication it may fund one.
Energy Minister Megan Woods said the island’s best option was for safe, reliable, secure, environmentally friendly and affordable electricity [i.e. not diesel].
With this in mind, several investigations had been undertaken over many years, with the options including marine, hydro generation, an undersea cable from Bluff, and most recently solar and wind.
The most recent evaluations in 2018 determined that wind turbines came out on top, Woods said. That’s why in 2018 the Government had allocated $3.16m through the Provincial Growth Fund to consent and construct a proposed two-turbine wind farm on Stewart Island, with the capability to expand it further in future to ensure a fully renewable system on the island.
‘‘It was disappointing this initiative was unable to proceed after being rejected by the affected landowners,’’ Woods said.
As for a cable, Woods said costings had been provided to Southland District Council in 2016. A single cable through the Foveaux Strait oyster beds would have cost $10m while a two-cable option to the east would have cost $20m. A cable to the west would have cost much more, given the extra distance.
‘‘It’s likely a cable option now [six years later] would be much higher,’’ Woods said.
‘‘No decision has been made to fund a cable by Government.’’
Southland District Mayor Rob Scott said he was unaware a subcommittee had decided a cable was the best option moving forward, but he would look into it.
‘‘The reality is there is an issue on the island with the cost of diesel escalating.’’
There was no ‘‘obvious straightforward solution’’ sitting in front of him, he said.
‘‘We have a significant issue we need to deal with, and deal with fast. There’s been lots of reports and investigations over many years, and we need to get to something that turns into action.’’