Wind power back on the agenda

Wind power is again being considered as a solution to electricity demand.

Northpower and Mighty River Power are seriously exploring setting up wind farms at Kaipara in Northland after Energy Minister Trevor Mallard predicted that up to 35 per cent of New Zealand's power needs could be provided by wind in the future.

However, wind power alone will not meet expanding electricity demand and a back-up power supply would still be needed, Northpower warns.

State-owned Mighty River Power, the country's third-largest electricity retailer, is considering building a wind farm near Rototuna Forest, 42km south-east of Dargaville on the Pouto Peninsula.

The company is understood to have asked landowner Evergreen Forests to allow it to set up a wind monitoring site near the forest.

Mighty River chief executive Doug Heffernan said the site had good potential for wind generation, while its relative closeness to Auckland -- the country's biggest power market -- was also an advantage.

"It's one of a number of sites we're looking at across the country," Mr Heffernan said. "It's right at the very first stages of investigation."

Northpower also has a site near Dargaville -- at Redhill, 15km to the south of the town -- that it is looking at as a potential wind farm.

Northpower chief executive Mark Gatland said the company owned the land and had explored the possibility of a wind farm at the site several times in the past.

However, each time the idea had not been viable, but advances in wind technology meant the company was now re-exploring the option.

"We have been monitoring that (Redhill) site for years, with feasibility studies, but it's always been marginal or not viable," Mr Gatland said.

"But what's happening now is that (wind turbine) machine technology has improved dramatically and we are in the process of re-assessing Redhill's viability."

Northland has a maximum electricity usage of about 160 megawatts at any one time and it was too early to say how much of that demand could be filled by wind power. However, wind would probably need to provide between 20 and 40MW of power to be viable.

But, Mr Gatland warned, any wind power generation would need to be backed up with conventional power sources such as hydro, gas or coal.

"Wind power saves us burning oil or coal or using the water from the (hydro dam) lakes, but we will still need to back wind up with some other source or energy," he said.

"The wind doesn't blow every day and (wind turbines) can't be used if the wind is too strong so we would need the same capacity (of electrical supply) as a back-up just in case."

A major advantage of wind power was that a site could be built up in small increments rather than a huge initial outlay on a power station or hydro dam, he said.

Wind was also a renewable energy source that was good for the environment.

"But there are definitely issues with stability (of supply) with wind," Mr Gatland said.

- NORTHERN ADVOCATE (WHANGAREI)