In a world where much of the focus for wind power has been on large-scale developments using multi-megawatt-sized turbines, New Zealand's Windflow Technology is noticeable for its persistence in promoting its small 500 kW machines. Largely ignored by its home market until recently, that perseverance in espousing the virtues of its smaller machines is starting to pay off for New Zealand's only domestic wind turbine manufacturer. "We are finally getting a track record," says the company's Sheralee MacDonald.
Incorporated in 2000 and publicly listed on New Zealand's alternative stock exchange a year later, its determination, and a solid phalanx of staunch, small-scale shareholders, has taken Windflow from a single, one-man band, experimental unit sitting on the hills behind Christchurch to a company now employing 55 staff working out of a base in industrial Christchurch with full-scale production facilities.
That growth, adds MacDonald, has been in a country where government support has been limited to verbal encouragement only. There has been no mechanism or support in the form of subsidies for renewables research and development to back up that encouragement. But with a new shareholder now in tow, in the form of Mighty River Power, a large New Zealand electricity generator that acquired a 19.95% stake in Windflow last year (Windpower Monthly, August 2008), the company is at the point of fulfilling the long-held dream of founder Geoff Henderson of having a sustainable wind turbine manufacturing unit in his home country.
The highly flexible Windflow 500 turbine designed by Henderson is a two-bladed unit. The proprietary technology comprises a torque-limiting gearbox system of power control and a pitch-regulated, teetering rotor designed to handle extremely turbulent conditions and high wind speeds. While the company originally planned to outsource the production of its machines, it gradually found itself doing virtually everything itself from manufacturing the blades to full nacelle assembly.
Around 90% of the turbine's components are produced in New Zealand, including the towers, which come from Petone, near Wellington, and the 16 metre wood epoxy blades, produced in Auckland by Wind Blades Ltd, now a wholly-owned subsidiary of Windflow. Specialist components, such as the pitch and yaw bearings, come from as far afield as France and Spain, however.
Output at the Christchurch factory is for one nacelle a week at present, but plans for expansion will see that rise to 20 a month. The factory has a linear production layout and includes a 15 tonne gantry crane inside the building to enable up to three fully assembled nacelles a day to be lifted directly onto trucks when required. The nacelles are small enough to be transported on standard -sized trucks, which can also take four blades. Fully assembled, the 14 tonne load can be lifted with a standard crane rig to the top of the 30 metre tower. The small size of the blades and tower units means major advantages in everything from transportation logistics through to public perception of visual impact, says Windflow.
Its most significant contracts to date have been to supply a combined total of 97 units for the Te Rere Hau project, run by NZ Windfarms. The first five units have been operating since 2006 and further 28 have been put online since then. The next 32 turbines are currently being installed and the final 32 are to go up by early next year.
While the early construction at Te Rere Hau used large gravity pad foundations, Windflow has recently shifted to single-pile construction. This method uses less than a third of the steel and half the concrete, says the company's Rick Ward, and offers the practical advantage of allowing better crane positioning. Environmental impact is also minimised, he says. Meanwhile, a further 15 MW could be added at Te Rere Hau later if NZ Windfarms gets approval to extend.
For the future, Henderson says if all the planned projects currently earmarked to use the company's machines in New Zealand get resource consent it would mean orders for a further 275 machines, on top of capacity already in the works, which also includes 25 turbines for Mighty River's Long Gully wind farm near Wellington. At Long Gully, Windflow notes, the landowner is keen to see the development on marginal farmland and the small scale nature of the wind plant and the turbines have led to far less local opposition than the nearby Makara development by Meridian Energy, which finally overcame its battle for approval in 2007, although at a cost of adding NZ$100 million to total project costs (Windpower Monthly, July 2007).
Exports could also be on the cards with Windflow dealing with a number of enquiries from overseas, most recently for supply to South America, says MacDonald. The complex terrains and strong wind regimes of South American countries have a lot in common with the conditions in New Zealand that the Windflow turbine has been designed for, she says. Work to adapt the Windflow 500 for the US market is also ongoing.
The company plans to take its next steps cautiously, however, to ensure they are manageable. "We are very focused on doing what we do with the resources we have," says MacDonald, adding one of the main challenges the company has faced as enquiries mount is "learning to say no."