High-voltage transmission lines for above tourist rail trail

The medium-sized wind farm will have up to 19 220m-high wind turbines. Photo / File

New Zealand energy generator Mercury's $200 million Kaiwaikawe wind farm has moved a step closer after the Kaipara District Council's approval for high-voltage overhead power lines along part of its major new Northland tourist rail trail.

The high-voltage lines – which one Kaipara District Council (KDC) councillor says bring with them the risk of buzzing and swinging in the wind above trail users – are to be strung on 15m-high power poles along a 1.8km-long easement on Northland's new $10 million Kaihu Valley Trail.

KDC at its last current-term council meeting in Dargaville on Wednesday,voted in a lukewarm decision, to allow Mercury subsidiary Tararua Wind Power Limited (TWP) a 12.5m-wide easement for the 66 kilovolt (kV) overhead lines stretching the equivalent of 18 end-to-end rugby fields along the trail.

Outgoing KDC councillor and former Kaipara acting mayor Peter Wethey said he was concerned about 1.8km of the trail being in the shadow of the 66 kV power line, warning of its negative impact for some trail users in comparison with other Northland rail trails.

Wethey expressed concern at last month's KDC council meeting in Mangawhai about the overhead power lines buzzing and swinging in the wind above trail users.

He asked Mercury representatives at the Dargaville meeting whether overhead power lines of this nature had been put up along any other New Zealand cycle and walking trails.

Mercury Kaiwaikawe wind farm project leader Jim Pearson said after the meeting that he was unsure what was happening in that sense on other New Zealand rail trails.

The TWP- constructed and Northpower owned-and-operated high-voltage power lines are part of connecting Mercury subsidiary Tararua Wind Power Limited's Kaiwaikawe wind farm at Omamari into the national electricity grid at Dargaville. There will be four lines - three 66kV power conductors and one fibre-optic cable – carried on 25 power poles along a 12.5m-wide trail easement.

Kaiwaikawe is one of New Zealand's furthest progressed in-the-making wind farms and Northland's first.

Kaihu Valley Trail has been identified as Northland's highest-priority new rail trail. It runs between Dargaville and Donnellys Crossing and is being developed by KDC with the help of $4 million in government funding.

Construction started this year. The trail follows an old railway line, construction of which started in 1883 for exporting kauri via Kaipara Harbour. It will eventually become one of almost two dozen New Zealand Great Rides - as part of the Ancient Kauri Trail from Kaipara's Maungaturoto to the Far North's Omapere in Hokianga and taking in Waipoua Forest's Tane Mahuta.

Just over half of KDC's nine elected representatives voted in Wednesday's 3:2 decision in favour of the easement. Kaipara mayor Dr Jason Smith and councillors Karen Joyce-Paki and Mark Vincent voted in its favour, in a one-person majority vote over councillors Victoria del la Varis-Woodcock and Johnathan Larsen, who voted against. Deputy mayor Anna Curnow, Peter Wethey, David Wills and Wilson-Collins abstained from voting.

Kaiwaikawe is about 12km northwest of Dargaville. The medium-sized wind farm will have up to 19 220m-high wind turbines.

It will cost $200m to build. Pearson said $90m of this would be of direct economic benefit to Northland, about half of that to Kaipara. Construction is expected to start in mid-2023, with power generation from the end of 2024.

The wind farm is expected to generate about 230-gigawatt hours (GWh) of energy annually. Genesis Energy has a 20-year agreement to buy the wind farm's power for further sale.

Councillor Eryn Wilson-Collins said she was conflicted about the new infrastructure.

"I am extremely conflicted. I love the wind farm sustainability and having it in Northland. This is a solution that Northland needs. I really support the wind farm, but I am really concerned about the trail," Wilson-Collins said.

Tararua Wind Power has offered $40,000 compensation to KDC for any potential loss to tourism from the overhead high-voltage lines' presence. The trail easement is from Babylon Coast Rd to Parore West Rd.

A further $40,000 has also been offered for trail promotion and sponsorship.

Wilson-Collins said the combined proffered $80,000 was not a large amount.

"$80,000 for an in-perpetuity easement is not too exciting for what we may be giving up," Wilson-Collins said.

Northland this year became New Zealand's first renewable energy zone.

Smith said 1.8km was only a tiny portion of the Kaihu Valley Trail's 45km length and took just two minutes to traverse by e-bike.

Several councillors were interested in the power lines being put underground rather than overhead.

Curnow said this would save a lot of problems.

Northpower contracts and services manager Alan Rawson said locally produced Northland power had become even more important in the wake of new national legislation which will see the North paying the most expensive power in the country because of its distance from where the power it uses is generated.

An artist's impression of the rail trail with high voltage power lines shown as part of a presentation at this week's KDC meeting by Meridian Kaiwaikwae project leaders. Photo / Susan Botting

Mercury Kaiwaikawe wind farm project leader Stephanie Cook said the new wind farm would mean Northland could produce more than 50 per cent of its own power. This would be up from the current 34 per cent via the Ngawha power station.

Cook said the new wind farm's production will provide power for 25,000 houses annually and save the production of 170,000 tonnes of carbon dioxide from power otherwise generated via coal.

Kaiwaikawe was formerly called Omamari wind farm but has been renamed in conjunction with local iwi Te Roroa.
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