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New route needed to get giant turbine blades to wind farm

A bypass road off the Pahīatua Track for wind turbine blades has failed.
DAVID UNWIN/STUFF

Power generator Mercury has run into a slippery slope that is thwarting plans to get its turbine blades up the hill to the Turitea Wind Farm.

The 99 12-tonne, 55-metre-long blades stored in Palmerston North were due to start being transported to the top of the Tararua Range in September.

But a new track being built to bypass a steep, tight S-bend on the Pahīatua Track has slipped and failed, forcing turbine suppliers Vestas to look for another way up.

Vestas project manager James Cameron told a community liaison group meeting in Palmerston North on Wednesday evening “a bad thing happened”.

“It has slipped unexpectedly and now we have a problem.”

Cameron said the affected land would be repaired and replanted before contractors could walk away from the site, and an alternative route was urgently being sought.

The schedule for completing the 60-turbine, $465 million wind farm had already been challenged by the Covid-19 lockdown, when work on turbine tower foundations and transmission line preparations stalled.

The current goal is to have the 33-turbine first stage of what will be New Zealand’s largest wind farm completed in April to July 2021 and the second, southern stage by Christmas 2021.

Part of the challenge of getting the turbine blades up the hill was that they were 10m longer than envisaged 10 years ago.

The other problem was created by a change in direction for delivery to the site.

The original plan was for the blades to land at the Port of Napier, but when that was not convenient for the port company, Taranaki was used instead.

Many of the blades were transported from New Plymouth to Palmerston North during lockdown.

Mercury project director Dennis Radich said the resource consent for building the wind farm included an approval to cut a new track on the eastern side of the hill, which was one possibility.

Cameron said an alternative route from Palmerston North could involve going over the Saddle Rd, which has been the east-west state highway since the Manawatū Gorge was closed, and following the Ballance Rd to the Pahīatua Track.

Using helicopters, which were lifting other equipment and parts to the site, was not an option for the blades, as even a Black Hawk could only lift 3.6 tonnes, less than a third of the blades’ weight.

Cameron said improving the Pahīatua Track itself was an unlikely solution.

A single 55m-long turbine blade for the Turitea wind farm weighs in at 12 tonnes.
WARWICK SMITH/STUFF

The main challenge with the blades was getting them around corners, but they could be hauled “by brute force” up inclines too steep to be acceptable on a public road.

Radich assured members of the community at the meeting that any tracks or road improvements it carried out would be subject to appropriate consents and approvals and would be lawful.

Resident Jan Dickson said it was worrying that the wind farm team had got it wrong in believing the soil structures at the site of the failed bypass were suitable for the track.

Cameron said while he could not defend the exercise as “best practice” he was confident “clever engineers” would solve the problem.