Beyond Zero Emissions interviews Geoff Henderson of Windflow  

Beyond Zero Emissions has an interview with the CEO of New Zealand wind turbine manufacturer Windflow - Beyond Zero interviews Geoff Henderson of Windflow.

Geoff Henderson: I decided back in ’76 really to get into wind power. One of the contributing things I remember was one of my school mates had actually done a summer course on renewable energy at I think the University of Sydney, and he came back with some interesting information about the relative merits of solar and wind and so on. And I remember out of that that the basic flux(?) available, the solar resource, is of the order of a few hundreds watts a square metre of land area taken on a year-round basis, that very sunny places can have an average flux of 400 watts a square metre.

And by contrast, wind power, you can get the same or higher flux(?) 5.00min, but in warps(?)5.05min per square metre of vertical space, and therefore inherently the wind power uses a lot less land area than any of the other forms of solar. And I know this sounds a bit dry and boring and technical, but that is actually a very fundamental reason why wind power is the most economic form of renewable energy and has had the highest growth rate over the last 20-30 years.

So that the wind resource is huge – New Zealand of course is beautifully positioned in the Roaring Forties and I believe we will get most of our new electricity generation out of wind power over the next few decades. In some years – in the last ten years – wind power has actually been 100 per cent of new generation already. We’ve had no other new power stations going on but we’ve had 100 or 200 megawatts of wind power going in. ...

Scott Bilby: And your flagship technology to take you there is what you call the Windflow 500 Turbine. Can you tell us, you know, give us some basic specs to just to start off with that wind turbine, but also, what is it that sets it apart from other turbines. Why have you chosen that type of turbine?

Geoff Henderson: ,Sure. It’s a 500 kilowatt rating, 33-metre rota diameter with a hub height of about 30 metres which means that the top of the blade is about – when it goes through the top of its arc is about 46 metres above ground level, so less than 50 metres high. That’s enough for about 200 households at a very windy site, or 100 households at least. And given that our footprint is about a two-and-a-half metre diameter monopile concrete foundation now puts it in perspective the amount of power that we can get out of this turbine.

The two main technologies that set us apart are the two-bladed teetering rotor and the torque limiting gearbox, both of which come out of my time in the UK working for Wind Energy Group which was the leading R&D contractor to the UK Department of Energy, and the torque limiting gearbox was my contribution and my invention and that works with a two-bladed or a three-bladed windmill, and gives you some real torque control and electrical advantages as well.

The two-bladed teetering was something that I learnt over in the UK – became a convert to, having had a background in three-bladers prior to that. It does really work and it enables a lighter machine.

So, to summarise the commercial advantage, we’re coming in at about half the weight of comparable European three-bladed machines. So we’re using half the Earth’s resources if you like, tones of steel and concrete and other materials per unit of output. We’ve got less environmental impact in terms of earth works and road works and so on and my, the perspective that I’ve always taken on this is that I’m trying to get wind power going in New Zealand primarily, it’s the windiest country in the world so you’ve got to have tough turbines, but we’re also very much an unsubsidised environment in New Zealand, especially since the 1980s with the Rogernomics years. Subsidy has become a dirty word in New Zealand and in that lean and mean economic environment we have to make something that’s fundamentally cost effective.