Windflow replies to critics

26 September 2005

New Zealand wind turbine manufacturer Windflow Technology has sent a letter to Meridian Energy and TrustPower in response to recent public criticism of its technology by the companies' spokesmen.

"It was very disappointing to see the inaccurate criticism of our technology," said Windflow CEO Geoff Henderson. "We are not in competition with their companies, and we believe that we should all be working co-operatively to grow a strong New Zealand wind industry."

The Windflow 500 is a two-bladed turbine that is based on a proven UK design, a design which has been in operation on wind farms since 1993. The main proponent of two-blades (the United Kingdom Wind Energy Group) was bought out by the Danish three-blade company NEG-Micon in 1998 and development of the technology was discontinued.

Mr Henderson said: "We are aware that some doubt was thrown over the design after the turbine was damaged by a freak wind change in March. After a detailed technical investigation, our insurers recently approved our claim for all the damage. This confirms that the accident was caused by events that would not be reasonably anticipated by any professional engineer. Our modifications to the turbine design and its control systems will ensure that the same conditions will not damage the turbine again."

Windflow believes that two-bladed turbines are the only type that can be manufactured commercially in New Zealand's unsubsidised economy. "The two-bladed design results in a much lighter turbine. We believe that the viable manufacture of the heavier three-bladed machines requires subsidies that are provided in countries like Denmark," said Mr Henderson. The lighter turbine offers additional environmental and financial advantages in New Zealand's topography. "It can be erected using a normal mobile crane, requires less earthworks and its construction uses fewer resources, such as concrete and steel," Mr Henderson said.

Wind turbines are sometimes criticised for noise and vibration, and Windflow has developed technology to reduce both the vibrations and sound emissions from its turbine. Tests on its prototype at Gebbies Pass (near Christchurch) put its machine amongst the quietest in the world.

The Windflow 500 is the only wind turbine that can run a synchronous generator directly synchronised with the national electricity grid. A common problem world-wide is the integration of large wind farms into the national grid. This is a particular concern in New Zealand's isolated situation.

Subsidiary company, NZ Windfarms has a resource consent to place 97 Windflow turbines on the Te Rere Hau wind farm near Palmerston North, and plans to list on the New Zealand stock exchange later this year. All going well the company plans to begin construction on the Te Rere Hau wind farm this summer.

"Te Rere Hau will give us the track record we believe is necessary to convince wind farm developers that New Zealand has a better machine than the present imports," Mr Henderson said. "And we trust that fellow New Zealanders will support our efforts to build a world-class wind power industry for this country."