Trustpower's proposed Waverley Wind Farm will inject $40 million into the Taranaki economy while being built, and $3.3 million a year after that, says New Zealand Institute of Economic Research senior economist Peter Clough.
His analysis forms part of Trustpower's application to build the 48-turbine wind farm on 980ha of coastal land between Waverley and Patea.
Trustpower applied to South Taranaki District Council for consent to build, operate and maintain the wind farm last month. The consent has been publicly notified and the deadline for submissions is June 16.
It would take two years and cost $325 million to build it, the application says.
About $243 million of that will pay for things sourced overseas. A remaining $82 million will be spent locally - on consumables such as food, accommodation and fuel with a further $40 million added to the economy through wages, salaries and the profits of local businesses.
That $40 million is 0.6 per cent of the economy of the Taranaki region, and Mr Clough said some of it would likely be spent in the Whanganui District.
During the peak of building the wind farm, 80 to 100 people will be needed.
Operating and maintaining it after that will add $3.3 million a year, 0.05 per cent, to Taranaki's gross domestic product (GDP).
Trustpower will pay the landowners - mainly the Alexander and Lupton families - a rental. Mr Clough said the amount was confidential. They will be able to carry on farming among the turbines and internal roads once those are built.
The farm is expected to be able to use wind about 40 per cent of the time, and to generate 460GWh per year of electricity, a maximum of 130MW at a time. It's enough to power 50,000 homes.
Because it will use the power of the wind and not emit climate-changing gases, it will save New Zealand many millions of dollars a year in carbon emissions - depending on the price put on carbon at the time. At the moment the price of a tonne of emitted carbon is nearly $17 and Mr Clough said it could go higher.
Among renewable energy projects this one is likely to be an early contender for building, because it is relatively low cost compared to other wind farms.
It will also improve security of electricity supply in the North Island, by reducing the distance electricity will have to travel to users and eliminating possible problems crossing Cook Strait.
Having it will mean water can be stored for longer in hydro lakes, and available for use at important times.
New Zealand electricity demand is growing, but slowly. At the same time, generation fuelled by gas and coal is being phased out. Using wind to generate electricity is more sustainable and has fewer environmental effects.
"It's a saving for the nation, but also a reduction for the companies that run thermal power stations," Mr Clough said.
At the moment the aluminium smelter at Tiwai Point in Southland uses about 13 per cent of New Zealand's electricity. If it closed, electricity demand would drop and new generation would become less worthwhile.