Turitea Wind Farm's second stage rises high above Palmerston North

Tuesday, 28 February 2023

The southern stage of Mercury's Turitea Wind Farm rises above the Tararua ridgeline east of Palmerston North.

The 33 turbines on the completed, northern stage of Mercury’s Turitea Wind Farm are taking a breather.

It is not that the wind has stopped blowing on one of the world’s windiest sites along the Tararua ridgeline above Palmerston North.

Instead, it is to allow another step to be taken in the process of building the second, southern stage of the wind farm, which is nearing completion.

Project manager Glen Twining said contractors were connecting the wind farm’s second substation, at Brown’s Flat, to the 27 southern turbines and the transmission line from the north and down to Linton and the national grid.

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A heavy vehicle carts earth along a road created for the completion of the Turitea Wind Farm above Palmerston North.

The work required a two-week outage for the northern turbines while systems were reprogrammed and the protections were reconfigured for the joined-up wind farm.

The 55-metre blades were expected to be turning again around March 12.

And a couple of weeks after that, the first completed southern turbine was on track to start generating electricity.

The site is currently a hive of activity with about 120 people at work delivering fill, pouring concrete, and bringing in and installing turbine components.

Turitea Wind Farm project manager Glen Twining stands near a crane about to lift turbine blades on to their tower.

So far 11 of the 27 turbines have been built, their blade tips covered in protective netting, allowed to move slightly until they are ready to face the wind and start generating.

Each completed tower stretches 125 metres tall to the tip of the highest 15-tonne blade.

All but one of the tower sites have had their 15-metre diameter concrete foundations poured.

Each tower has a foundation of 30 to 40 tonnes of steel reinforcing through an octagonal base.

Turbine blades delivered to the Turitea Wind Farm lie ready to be lifted into place.

The 330 cubic metres of concrete for each tower has to be delivered in one pour, helping to explain the presence of a batching plant on site.

Without it, a concrete truck would have been delivering from off-site every 10 minutes.

Once the last foundation was poured, the concrete batching plant would be dismantled.

In between the earthworks still being compacted and the completed turbines, there are towers, assembled from two 34m sections, waiting for their blades to be lifted into place.

Twining said the plan at the moment was to have the full farm operating in May.

That would be followed by a programme of planting, ground reinstatement, and decommissioning the vast array of environmental protection works and detention ponds required during construction.

About 15,000 plants would go in at the beginning of this year’s planting season, with another 16,000 in the southern section the following year. Mercury would also plant 10 hectares at Brown’s Flat in line with consent conditions.

Completion of the wind farm would be celebrated, after the Covid-19 Auckland lockdown at the end of 2021 prevented people travelling to mark the commissioning of the northern stage.

Construction began in October 2019, picking up resource consents that were granted in 2011 after a protracted Board of Inquiry process.

When completed, the 222-megawatt wind farm will be the largest in New Zealand to date, generating about 840GWh a year.