Vestas turbines are being installed at Kaiwaikawe Wind Farm in Northland.
Twelve of New Zealand’s biggest wind turbines are now rising above rolling farmland northwest of Dargaville, as Mercury Energy’s $287m Kaiwaikawe Wind Farm enters its final construction phase.
The project will host the country’s first Vestas V162‑6.4MW turbines — colossal machines standing 125 metres with 162m rotors and a tip height of 206m.
The wind farm is on land owned by Pāmu (formerly Landcorp), which will continue to run its Friesian bull operation across the property.
Site manager Mark Bell describes it as similar to a solar farm grazed by sheep — the land use is “augmented,” not replaced.
Much of that integration has depended on opening up the remote site with new roading.
Over the past two years, crews have built nearly 15 kilometres of internal roads and cut new access tracks across steep, previously rough terrain that’s now engineered to carry oversize trucks transporting components up to 90 tonnes.
The convoy movements of parts from Northport to the project site 12 km north-west of Dargaville, have been closely followed, residents watching late‑night transports along a route that required trimming trees, widening corners and strengthening bridges.
“It’s been a mission,” Bell said. Trial runs early on identified multiple pinch points where trees had to be removed.
Where necessary, the project paid for replanting and, in one case, purchased a house on the route to secure safe access for the largest loads.
With foundations now poured and paddock excavations completed to install underground cables, the site is preparing for its most visible phase.
Work began on assembling the first turbine tower about a fortnight ago, with full assembly to take about a week.
The farm is expected to begin generating electricity in mid‑year and reach full output by the end of 2027, delivering about 221GWh annually — enough to power 27,000 homes.
Despite the size of the machinery, noise is expected to be minimal. Bell said the final sound level from the operating turbines would be low: “In reality, it’ll be less than that heat pump going”.
Noise modelling and compliance fall under the project’s consent requirements, but his own explanation reflects how turbine sound is often misunderstood.
Bell said monitoring has identified at least seven male bittern. Protection will include high-fenced corridors through wetland sections of the access route to prevent birds crossing the road.
As for turbine operation, Bell said blades are set much higher than the flight paths typically used by birds.
The project includes a new on‑site substation and a transmission line that will carry electricity from the farm across the Dargaville landscape for the national grid.
Overseas and New Zealand contractors are involved. Local firms have played key roles, with Higgins delivering civil works, concrete being produced onsite by Firths and brought in from their Dargaville plant, ElectroNet handling electrical systems, and Northpower building the transmission connection.
Australian Tiana Story, who has installed Vestas turbines across the ditch for four years, is the site installation supervisor, sharing her practical experience.
She also emphasises the shared undertaking between Vestas and staff from NZ firm Smiths Construction.
As public interest in the project has grown, so too has online debate. The Northern Advocate put some of the criticisms to Mercury’s principal project manager Glen Twining:
Comments such as “Someone warn the birds” reflect concerns about the bittern population in the area - concerns initially shared by The Department of Conservation (DoC) which opposed the project until negotiating improved mitigation measures.
Mercury says bittern numbers on the site have remained stable.
Mitigation required through consenting include bittern fencing, speed reductions, pest control and environmental enhancement work, as well as a Bittern Fund (reportedly $640K) “to support conservation activities in the local area”.
On general bird strike, Mercury says incidents at New Zealand wind farms are mostly limited to introduced species, with only “two individuals” of threatened native species recorded nationwide.
Some critics question how loud the turbines will be.
Mercury says: “All New Zealand’s wind farms must comply with strict noise‑related resource consent conditions” and the company’s Noise Management Plan was “a key consideration” during consenting.
While wind turbines may be audible at times, the level of sound heard at a nearby house will not be out of place with other sounds in the environment.
Today’s turbines are “significantly quieter” than earlier generation ones.
Some critics describe turbines as “a money pit… expensive to decommission” and posing “recycling challenges”.
Mercury says the wind farm is designed to operate for 30 years before being decommissioned, refurbished or repowered. Components are supplied by Vestas, which is “investigating new recycling pathways.
According to Vestas, its turbines are currently at least 85% recyclable or re-usable, the remaining challenge mostly lying in the recycling of wind turbine blades, which are largely composed of epoxy resin and glass fibre. Vestas is aiming for 100% blade recyclability by 2030.
On concrete use, Mercury says each turbine foundation contains “approximately 800 cubic meters of concrete”, mostly produced on site.
The company donated to Trees That Count to help “replace” trees removed, though “only a small number needed to be replaced”.
Some residents ask: “Yay — does that mean cheaper power?”.
Mercury says many factors affect electricity prices, but “overall, renewable energy is lower cost … and helps with security of supply”.
On claims that “power users subsidise wind farms”, which are “more expensive than they’re worth”, Mercury says it is funding the development “through our existing balance sheet”.
While Mercury’s capital investment in the project is high, operational costs are low over its expected lifespan. Technology improvements “allow us to generate more energy” from modern turbines.
Kaiwaikawe’s installed capacity will be 77 MW, generating about 221 GWh per year — enough to power 27,000 homes.
Mercury cites research showing NZ wind turbines repay their lifecycle carbon emissions “after just 1.5 years of operation”.
Critics warn the turbines will “hammer the roads” and the componentry is “hugely expensive” to transport.
Mercury says transport costs are commercially sensitive but loads range from 27 to 90 tonnes. Road and bridge upgrades were carried out, and specialised transport units distribute weight “across multiple axles” to minimise road damage.
On transport emissions, Mercury says there are currently no electric alternatives for moving turbine components, but “Mercury’s own vehicle fleet is either fully electric or hybrid”.
The wind farm itself “will not rely on fossil fuels to operate”.
Some critics questioned the reliance on overseas (mainly Chinese) manufacturing of wind farm componentry. Mercury says: “Wind farm manufacturing in New Zealand is not at the scale where it could support a wind farm project like Kaiwaikawe”.
Some claim overseas experience shows turbines are inefficient.
Mercury says: “Wind farms have been a part of New Zealand’s energy landscape for almost 30 years. They help keep the lights on and give us more than one way to generate renewable energy“.
Twining pointed to a substantial amount of independent studies and reports on the demand for wind energy, including information on the NZ Wind Energy Association website and Transpower’s live data showing wind energy’s contribution to national electricity capacity.
Sarah Curtis is a news reporter for the Northern Advocate, focusing on a wide range of issues. She has nearly 20 years’ experience in journalism, most of which she spent court reporting in Gisborne and on the East Coast.