Just five percent of New Zealand's electricity is generated by wind. Photo: Getty Images

New Zealand is blessed with an abundance of wind. With Global Wind Day upon us and electricity demand likely to double by 2050, Farah Hancock takes a look at our lagging wind generation scene and finds its proponents remarkably relaxed.

If anyone has bragging rights on Global Wind Day, it should be New Zealand.

Below the top half of the North Island is smack bang in the middle of the Roaring Forties which supplies an abundant supply of gusty, howling, and roaring wind ideal for creating electricity.

Weather Watch’s Philip Duncan described the latitudinally gifted winds as consistently blowing with surges through winter and spring. He said the winds are most prevalent from Whanganui southward.

“Those are the areas that tend to have a consistent wind blowing all the time. If you look at Manawatu to Wellington, the trees grow on an angle there for a reason. The wind is always blowing from the west and that’s what the Roaring Forties does.”

Is climate change going to take the winds out of the Roaring Forties sails though?

Not likely, said Duncan.

“I can’t imagine climate change will affect the Roaring Forties too much. The reason why it blows a gale down there is because there is no land. You’ve got Antarctica this huge continent with this high pressure parked over it all the time, it’s the driest place on earth … That big belt of high pressure basically squashes against the low pressure that forms south of New Zealand over the Southern Ocean.”

Duncan said this forms what’s referred to as the squash zone. The belt of low pressure, which is the Roaring Forties, consistently produces wind around the latitude of 40.

It’s a particularly valuable resource. With no surrounding countries, New Zealand doesn’t have the option of buying electricity from a neighbour. Solar doesn’t supply much power during grey winters when demand soars and dry years mean risk for hydro lakes.

Wind-generated electricity could plug the winter gap.

Despite this abundant source of potential power, local Global Wind Day gloating is subdued. Wind provided just 5 percent of New Zealand’s electricity in 2017.

Hydropower is New Zealand biggest electricity source at 59 percent, geothermal energy accounts for 17 percent. Gas provides 14 percent of electricity and coal 3 percent.

Wind comes in second to last for commercial scale energy production just in front of wood, solar and biogas’s 2 percent. There are just 17 wind farms and 490 turbines. These have a capacity of 690 MW per year.

Compared to other countries New Zealand’s 690 MW is miniscule. China is the world leader in wind power capacity, with a staggering 221,000 MW capacity. The United States has 96,400 MW, Germany 59,300 MW and India 35,000 MW capacity.

For some countries trying to use wind to supply over half their electricity from wind, the variable nature of it is a problem. Denmark, which obtained 43 percent of its electricity from wind in 2017, buys electricity from Norway on days when the wind isn’t blowing.

Batteries are another solution; Scotland just announced a massive “super battery” is going store power from a 215-turbine wind farm. The 50 MW lithium-ion battery is the size of half a football field.

In New Zealand we have an excellent back-up for days that aren’t windy. Our hydro lakes effectively become big batteries. Water can be stored and then used on calm days to replace wind electricity.

From 5 percent to 20

The New Zealand Wind Energy Association’s vision is to grow wind power to supplying 20 percent of New Zealand’s electricity by 2035.

The 690 MW currently produced by wind powers roughly 300,000 homes per year.

Another 2500 MW worth of wind farm electricity is consented, but there’s no guarantee what’s consented will be built.

It all comes down to the way New Zealand’s electricity market works, according to the association’s chief executive Grenville Gaskell.

“A lot of countries have subsidised renewables. In New Zealand we have an electricity market which is a commercial market where generators build new generation when there’s market demand for it.”

Gaskell is not keen on subsidies.

“We’d rather see a market-based approach taken to how we reduce fossil fuel use and carbon emissions and that’s the Emissions Trading Scheme.”

No wind farms have been built for five years. Gaskell said there had been some growth this year after the hiatus. Near Palmerston North, Mercury is building stage one of its Turitea Wind Farm. It will hold 33 wind turbines with a capacity of 119MW. Mercury say it’s a $256-million build.

Another wind farm near Waverly in South Taranaki is a step closer with an agreement from Genesis in place to purchase the electricity it creates.

“Wind farms get built when investors can make a return on doing so,” said Gaskell.

Why are we lagging behind other countries?

Massey University Professor Ralph Sims thinks the reason we don’t have many wind farms is simple: we just haven’t needed the extra electricity.

Like Gaskell, he mentions there’s pride in the fact New Zealand’s renewable sector isn’t reliant on subsidies.

“It’s now anticipated that demand will start to creep up. Electric vehicles would be part of the reason why people want more electricity and the population is increasing. Now there’s interest in using some of the consented wind farms.”

Transpower estimates electricity demand will double by 2050.

Wind will become a no-brainer solution to demand because of cost.

“The cheapest form of electricity generation at the moment is wind and geothermal, they’re cheaper than building more gas or coal or hydro.”

Distinguished Professor Robert McLachlan, also from Massey University has a slightly different view.

Without storage wind electricity producers will accept prices given to them. For companies with fossil fuel plants this drives down the price their fossil-fuelled electricity can demand, as well as not making them much money.

For electricity companies who have gas or other non-hydro facilities, wind risks driving their profits down.

“That’s my theory why no one was doing it. You would need a new company to come in and build it whereas if an existing company built a wind farm it would be eating into its profits.”

For Mercury though the scenario is different. McLachlan points out Mercury own 58 percent of all hydro in the North Island. Turitea will allow it to save hydro for when the wind isn’t blowing.

He thinks the Turitea wind farm could reduce the need for gas peakers – gas plants that are switched on when hydro supplies run low. McLachlan estimates the potential carbon emissions would reduce by 235,000 tonnes per year if wind from Turitea replaced gas.

The barriers to wind

New Zealand Wind Energy Association’s Gaskell thinks the biggest barrier to wind farms is probably local objection.

There’s the undeniable fact they don’t look great. The windiest spots are normally ridge lines and rows of towering turbines can be an eyesore.

This was the case in Central Otago where a wind farm – set to be New Zealand’s largest – met with fierce opposition from high-profile locals including former All Blacks. Its visual effect on the outstanding local landscape saw its consent application rejected.

Another community farm of just three turbines in Dunedin’s Blueskin Bay, which aimed to supply power to 1000 local homes, received 153 submissions to the consent application and was turned down due to the adverse effect the three turbines would have on three properties.

Noise is another concern, however, modern wind turbines are quieter than older models and there’s better understanding of the distance needed between homes and turbines. 

There’s also worry that turbines pose a risk to birds or bats. Some research suggests the risk could be over-estimated and more birds get hit by cars than by turbines. Importantly though, effort needs to be made to ensure turbines aren’t in migratory flight paths.

Gaskell describes the “whole consent process” as a barrier where there’s a risk local interests can override national interests.

“Some of the new technologies, they’re [turbines] getting bigger and more efficient. It is possible to build economic wind farms that are below the ridge line.”

He said he thinks most people support renewables.

“Depending on what country you source the componentry from, a wind turbine can pay for its carbon footprint in three to five months. You’re getting 20 years of life and the carbon footprint is paid for in the first half year of life.”

When asked what he’s got planned for Global Wind Day on Saturday, he said some years the association holds a stakeholder function and others it sends out a press release.

“This year we’re just doing a release to our mailing list around how things are looking and the positive future.”

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