The Vestas wind turbines to be built north of Dargaville will be the tallest in New Zealand, towering 206m from ground to rotor tip
Photo: Supplied

Power company Mercury will start building Northland’s first wind farm next month, using the largest turbines ever seen in New Zealand.

Kaiwaikawe Wind Farm – on the west coast north of Dargaville – will have 12 turbines, with a tower height of 125 metres and a rotor diameter of 162m.

That makes a height of 206m to the top of the rotor blade – equivalent to two rugby fields, and taller than any office or apartment building in New Zealand.

Only Auckland’s Skytower, at 328m, will be taller.

Executive general manager generation development Matt Tolcher said the $287 million project was due to be completed in mid-2026 and would produce up to 77 megawatts (MW) when the wind was blowing.

It was expected to annually produce 220 gigawatt-hours (GWh), enough to power 27,000 homes – or almost every occupied house in the Whangārei District.

Tolcher said it made sense to build generation close to “load centres” such as Auckland.

“That makes this a great location. It’s also coastal, which is a benefit in terms of unfettered west coast winds. And the third advantage is that the country benefits when there is geographic diversity in terms of wind farms. For instance, the wind in Dargaville is not highly correlated with wind in the Manawatū, and it’s essentially uncorrelated with wind in Southland – so when the wind’s not blowing in Southland, it’s likely to be blowing in Dargaville.

“That geographic diversity gives us a nice spread of assets and ensures all our eggs aren’t in one basket,” he said.

Tolcher said Kaiwaikawe would be a relatively small wind farm with a small number of turbines – but their sheer size meant the power output was significant.

It was the first time turbines of this size would be used in New Zealand, he said.

Produced by Danish firm Vestas and assembled in China, each turbine could produce 6.4MW, almost double the output of the turbines used in Mercury’s recently completed Turitea Wind Farm near Palmerston North.

“They’re very tall, that’s how we achieved that increased production per turbine. They’re almost twice the height of other turbines in New Zealand, so very large machines, and great output per machine. It’s 206 metres from the ground to the tip of the turbine. A good analogy is that it’s more than two rugby fields, but in height.”

Photo: Supplied

Tolcher said studies of the wind farm’s visual impact and any effect on bird life had been part of the resource consent process.

The company was also contributing to the restoration of wetlands and bird habitat in the area.

Up to 100 jobs would be created during construction, with local firms such as Northpower among the contractors.

Tolcher said Mercury had worked alongside mana whenua,Te Roroa, while planning the project, and looked forward to continuing to work with the iwi during construction and operation.

Mercury chief executive Stew Hamilton said once the construction of Kaiwaikawe started in January, the company would have three renewable energy builds underway simultaneously.

The others were expansions of Ngā Tamariki geothermal power station near Taupō and Kaiwera Downs Wind Farm in Southland.

The Kaiwaikawe project, 12km northwest of Dargaville and 3km inland, continues Northland’s transformation from a region dependent on energy transported from the south on sometimes fragile networks – as illustrated by the toppling of a pylon earlier this year – to a hotspot for renewable energy.

The Far North is already a net exporter of energy, thanks primarily to Top Energy’s geothermal power station at Ngāwhā, near Kaikohe.

A solar farm near Kaitāia is currently the largest in New Zealand, though that is a title owner Lodestone Energy won’t hold for much longer.

After the Skytower, the title of tallest building in New Zealand is currently held by Auckland’s PwC Tower, at 180m – significantly lower than Kaiwaikawe’s turbines.

The stalled Seascape building, also in Auckland, will be 187m tall once completed, and, if built, the proposed NDG Ritz Carlton Hotel will be 209m high.