Meridian Energy's Harapaki wind farm, in Hawke's Bay. Photo / Supplied
Chris More, engineer and veteran of half a dozen big power projects, keeps a notebook of what he calls black swan events.
Over his 30 years in the game, he’s come to expect two or three setbacks per project.
But when it came to building Harapaki, Meridian Energy’s new wind farm in the Hawke’s Bay, his notebook started to swell.
“The average that we have observed over all our other wind farms would be two or three black swans that require major mitigations that could trip you up - not nine.”
More, who is Meridian’s head of renewable energy, said getting Harapaki finished within a month of its deadline was no mean feat.
Before a sod was turned, getting consent was challenging, as was getting approval from local iwi.
Then, once Meridian had some certainty that New Zealand Aluminium Smelter would keep the power-hungry Tiwai Point smelter open for, at that point, another three or four years, it was enough to make the economics of Harapaki work.
The NZX-listed power generator and retailer then pushed “go” on the project in 2021.
Soon afterwards, the Covid-19 lockdown of August 2021 meant work had to stop for a period.
“When we came back, it was a very constrained environment with work bubbles,” More says.
“It was a very confusing time in terms of translating legislation into what we needed to do in terms of vaccinations.”
Then there were earthworks problems, with roadside walls proving less stable than was first thought.
A wet weather pattern followed for the next two years’ summers.
There were also pavement issues.
Cement that worked in the laboratory did not work well on site, so the company shifted to a different design.
The project caught a break in that it was able to “win” a lot of the limestone for roading, thanks to the geology of the site.
“By winning it onsite it was a bit cheaper, but more importantly, we kept thousands of truckloads off State Highway 5.”
Cyclone Dovi followed in April 2022, resulting in some protracted insurance claims.
By that stage, inflation was starting to become a real issue.
Then, the Russia-Ukraine war pushed prices higher worldwide, making shipping costs balloon.
The war also disrupted the flow of componentry from Ukraine which, as it turned out, is a key supplier to the world.
Then came ex-tropical cyclone Hale in January 2023, followed by the more devastating Cyclone Gabrielle a month later.
Adding to all the issues was the challenge of working in a sub-alpine environment.
At 1100m above sea level Harapaki, in the craggy Maungaharuru Range, is the highest windfarm in New Zealand.
The site is riddled with tomos - voids typically found in limestone rock formations.
The geology meant Meridian had to drill through the voids, insert sleeves, and fill them with concrete to anchor the base for each turbine.
More says for all the projects’ “black swan” events, mitigations and changes of tack were put in place.
“That was only achievable by having a highly skilled on-site team,” he says.
Harapaki, which took just under a million man-hours to build, is three times larger than Meridian’s Mill Creek wind farm near Wellington and is the second biggest in the country after Mercury’s Turitea farm in the Tararua Range.
The project uses Siemens “Typhoon” class machines, which employ direct drive technology.
“Direct drive is to the wind industry what EVs are to the vehicle industry,” More says.
The traditional mechanical turbine is connected to a shaft and then to a gearbox that steps up to a nominal 1500 revolutions per minute and has a standard electricity generator at the back of it.
“With direct drive, the rotor spins inside a stator and that’s it - there is no shaft.
“It is converted to electrical energy as opposed to all those mechanical steps, which all have losses and limitations.”
The Typhoon class, originally designed for the early offshore wind farms, require less maintenance and has higher “up-time”, he says.
The farm which cost $448 million to build, has been generating since last November and was at about 90% capacity by the end of June.
It’s now running at full capacity.
Guy Waipara, Meridian’s general manager of development, said if New Zealand is to meet its net carbon zero by 2050 commitments, then the electricity system needs to double in size.
“As well as doubling it, most of what is currently running will need to be rebuilt,” he said, adding wind farm turbines typically last around 30 years.
“The Huntly power station will (by that time) be kaput and the gas turbines will be out of life.
“So it’s not just the growth, but replacing what we have got - it’s a mammoth task.”
Meridian says the country needs two or three wind farms per annum. The company plans to build one farm a year over the next seven years.
“Harapaki shows that we have the capability to deliver,” Waipara says.
The farm, located north-west of Napier, can produce 176 megawatts of energy from its 41 turbines - enough to power 70,000 average homes on a good day.
Waipara said Harapaki is the company’s first big project in 10 years.
He says most commentators see the need to double the size of the electricity system by 2050.
“If you bring that back down to reality, that means a project [per] year for our company and two or three for the country as a whole.
“Wind in New Zealand is a fantastic resource - we are one of the windiest countries in the world.”
He says wind farm output in New Zealand is in some places double that of some wind farms in Europe. “We get a hell of a lot of bang for our buck from wind farms in New Zealand.”
He says building Harapaki was difficult, hard work. “But the fruits of our labour are here.”
Jamie Gray is an Auckland-based journalist, covering the financial markets and the primary sector. He joined the Herald in 2011.
Jamie Gray’s trip to Harapaki was funded by Meridian Energy
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