Electricity from strong winds in New Zealand

New Zealand is the 'Saudi Arabia' of wind!  (Just ask anyone who has been to Wellington.)
Windflow Technology makes wind turbines with torque limiting gearboxes, synchronous generators, and just two 'teetering' blades, to suit windy sites.  And they are made in New Zealand.
Geoff Henderson tells lots more to Matthew and Scott.

Beyond Zero interviews Geoff Henderson of Windflow

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Transcript

Scott Bilby:    My name is Scott and this morning we’re talking to Geoff Henderson. He’s the CEO and director of Windflow Technology based in Christchurch in New Zealand. So we’re interested to speak to some more wind guys, wind power guys, because we’ve spoken to a lot of solar power guys.

Matthew Wright: Maybe they’re hiding. I don’t know what the story is, but I’m sure Geoff will bring them back into the fold.

Scott Bilby: Yeah, well I’ve heard that, you know, Geoff’s got a pretty big picture sort of view on wind and so he should because it’s going gangbusters around the world. So let’s hear what he’s got to say. Now, just before we go to Geoff we’ll say that Windflow Technology, they manufacture wind turbines and develop and operate wind farms and Geoff has quite a long history in the area of renewable energy and he graduated from the University of Canterbury with a batchelor’s degree in mechanical engineering and worked for a consulting engineer for three years on energy related projects.

Geoff joins us live from New Zealand. How are you going?

Geoff Henderson: Very well thanks Scott. Good morning to you.

Scott Bilby: You’re pointing at something there Matthew. What?

Matthew Wright: I was just going to say that Geoff also managed a wind farm at Altamont Pass, and the first sort of wind revolution I think happened in California at Altamont Pass.

Scott Bilby: Oh fantastic. Geoff, can you tell us a little bit about your past and the wind power project that Matthew just mentioned?

Geoff Henderson: Sure. Well I suppose I should also mention the Australian connection that I, I actually spent my high school years in Australia. My father taught at the University of New South Wales, sorry the University of Newcastle in New South Wales, moved over there in 1968 when I was ten. I went to high school in the Lake Macquarie area. I decided to come back to New Zealand and do my engineering as you mentioned.

After working for a consulting firm in Auckland I headed over to Altamont and managed to get a job on the wind farms there as a site mechanical engineer for a couple of years, at a time when the wind industry was growing at 400 per cent per annum [laughs].

Scott Bilby: [Laughs]

Geoff Henderson: And then moved on to the UK and worked for Wind Energy Group, which was a 50/50 consortium of British Aerospace and Taylor Woodrow. Ended up having four-and-a-half, five years over in the UK before returning to New Zealand in the early 90s.

Matthew Wright: Now, can you tell us a bit about – obviously you’re a big believer in wind power – can you tell us a bit about the potential of the global wind resource, and if you know about Australia’s wind resource, relative to say New Zealand and other places.

Geoff Henderson: Sure. Well just to sort of get – I don’t want to talk too much about my background, but it is interesting with context.

Matthew Wright: Yep.

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: That’s fantastic, and New Zealand is one of the windiest countries in the world….

Geoff Henderson: That’s right.

Scott Bilby:    …and  my Dad’s a Kiwi and when we went over there we would visit Wellington where he just used to live just south of….

Matthew Wright: [Interrupts] Is your Dad a Kiwi too?

Scott Bilby: He’s a Kiwi.

Matthew Wright: [Laughs] So is mine.

Scott Bilby: Your Dad’s a Kiwi [laughs]. And we’d go to Wellington, and  Wellington is the windy, they call it the ‘windy city’ don’t they?
Matthew Wright: Yeah. Yeah.

Geoff Henderson: Absolutely.

Scott Bilby: So one of the windiest countries in the world and power generation there is what, it’s less than three per cent from wind I think at the moment? So you’ve obviously got a lot of scope to improve there with your company.

Geoff Henderson: That’s right. That’s right. I think the potential market in New Zealand is something like 250 megawatts a year of wind power. That’d be operating at a 40 per cent capacity factor, which you can achieve in very high wind sites. Works out about 100 average megawatts of generation and that is about the rate at which demand is growing - hundred megawatts a year of demand growth - so we, I think we will meet most, or almost 100 per cent of that from wind power in New Zealand as I say.

Windflow itself, we’re now producing five turbines a month which works out at about 30 megawatts a year, so only 12 per cent of the potential New Zealand market that we announced last year when the Prime Minister opened our factory in Christchurch; that we are targeting more like four times that amount which would be about 50 per cent of the potential market in New Zealand.

Matthew Wright: There’s also an export market for you I believe?

Geoff Henderson: Absolutely. Well, of course Australia is of great interest, and I think Australia has got a fantastic wind resource as well. And in absolute terms, I think that’s probably about the same magnitude as New Zealand. You know, looking in places like Tasmania and southern Victoria, South Australia, the bottom of Western Australia. There’s plenty of land area there, plenty of physical resource. In terms of relative contribution, I’m not sure it’ll have the same relative contribution because you’ve got great solar resources and less wind in other areas, and of course I think biofuel should be a huge thing that Australia should be looking at in future, in particular wood-fired power stations because of all the fantastic eucalypt growing capability that you’ve got there. I think the amount of energy released in Australian bushfires each year is probably comparable to the amount consumed by the whole Australian economy which brings home to you the magnitude of the solar resource that’s actually going to go to waste with bushfires each year.

Matthew Wright: Now, in terms of that. Now in New Zealand, you’ve got this great sort of hybrid situation where you’ve got a sort of a dispatchable hydro power resource, and the wind works with that. And in Australia we’ve got the potential for solar thermal with molten salt storage. Can you tell us a bit about the sort of levels of penetration that you can go to with wind. In fact, I think the Federal Energy Regulation Commission chairman in the United States, the new one, Jon Wellinghoff, he was talking about wind being the renewable source, not even the renewable source, but the energy source you’d dispatch first, and that it was going to be the cheapest energy source that you can get.

Geoff Henderson:    Well certainly it’ll be top of the merit order in any electricity market because, well that’s because it’s not so readily dispatchable as it were, because you’ve got intermittency, you’ve got – it’s like run of the river hydro – you want to take the free energy that the wind provides when the wind’s blowing. A lot of people make a big deal of that, as if that’s a huge problem, but it’s not because electricity systems have evolved to deal with variability as you know.

In terms of penetration in New Zealand, what I’ve been saying, and for many years, is that I think we can get 30 or 40 per cent of our electricity from wind in the longer term - hydro being the remaining 60 or 70 per cent. And certainly there’ve be plenty of studies that confirm that up to about the 20 per cent level before you even have to think about integration issues. But when I say think about integration issues, you’ve got to bear in mind that in 20 years’ time we should have technologies like smart metering, plug-in hybrid vehicles and other forms of useful storage but controllable storage, well controllable load, that enable you to not only dispatch generation but dispatch load. And once you can do that, which of course modern internet communication enables, it changes the whole paradigm. And unfortunately the electricity industry hasn’t caught up with this whole new paradigm, but the potential in the future is huge. And America is going to lead the way. You’ve got Barack Obama and people in America now talking about plug-in hybrids and starting to realise the potential of smart metering.

Scott Bilby: And Geoff – I’ll just say that we’re speaking to Geoff Henderson, he’s the CEO and director of Windflow Technology based in Christchurch, New Zealand and they make wind turbines.

Geoff, now as we said, there’s less than three per cent of New Zealand’s current electricity generation comes from wind – and given that you’re the ‘Saudi Arabia’ of wind in New Zealand, just as Australia is the ‘Saudi Arabia’ of solar, you’re company has, you know, it started off from a small R&D sort of background and its quickly grown to now employing 50 people or so. That’s what I read from your website. And you’re manufacturing 60 turbines a year as you just said recently. That’s quite quick growth. Given the huge potential still to go, can you tell us a little bit about how the company began and what were some of the key things that got you where you are and, you know, where you’re going to go into the future?

Geoff Henderson: Sure. Well we floated the company in 2001 - raised $3 million dollars from about 400 investors back then, and we’ve had a number of capital raisings since then. We’ve raised about $15 or $20 million over the last few years, as we’ve gone from the prototyping to the commercialisation stage. Last year was a real landmark for us in that we got a cornerstone investor coming in being Mighty River Power which is one of the three big state owned generators in New Zealand. They came on as a 20 per cent shareholder. And, so that has given us a strong capital base to move forward. We have grown a lot in the last couple of years. Two years ago we probably only had about 15 staff and now we’ve got 50. It used to be very much a one-man band with people calling it Geoff Henderson Incorporated or whatever, but….

Scott and Matthew: [Laughs]

Geoff Henderson: ….what we’ve always had to do, and I’ve recognised as had to do, in order to grow is create a complete new management structure. We’ve got a very, very good team of senior managers including Tom Hooper, our chief operating officer, who’s been a very good hire coming back from the UK for his native New Zealand, and he provides the commercial strength to complement my engineering background.

We’re working with a whole lot of New Zealand suppliers to get quality systems in place. We’ve got our ISO 9000 accreditation now and we’re just finishing off IEC certification of the turbine which will establish its international pedigree if you like.

So we are very much poised to go to the next level which is to say we’re aiming to grow something like fourfold over the next few years.

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.

Scott Bilby: And can you just tell us, ‘cause you mentioned two aspects of the wind turbine, the Windflow 500 Turbine. You mentioned the two-bladed pitch teetering and the torque-limiting gearbox. Which one do we want to ask him about first Matthew?

Matthew Wright: I think the two-bladed teetering because that’s the more general one. Can you explain that to the listeners, you’ve got to understand our listeners aren’t all wind engineers.

Geoff Henderson: Sure. Fair enough. Well the teetering refers to the rotor being on a hinge. Imagine a see-saw that you’ve got in a kids’ playground, and you pick the whole thing up off the ground and tip it through 90 degrees so it’s facing into the wind, spin it around. While there’s a hinge in the middle the blade, one blade could go upwind while the others go downwind. That’s the teetering motion.

What it does is it takes the bending off the low speed shaft, which is the main wind turbine shaft, and as a result it significantly reduces the fatigue load on that shaft, and everything downstream of that point, which is everything else in the windmill, the structure at the top of the tower, the tower itself, can be lighter because you simply don’t have to have the tonnes of steel that are required to resist those massive loads. The three-blader doesn’t have that option. If you think about it, you can’t put a hinge that’ll work because of the three blades, and so three-bladers inherently have to take higher bending loads on that low speed shaft and they have to be heavier to withstand the wind loads.

All else being equal of course, there’s different classes of site that you need to design for. But in the business we talk about Class 1A down to Class 3C sites. And Windflow’s going from a Class 1A certification, because that represents the high wind New Zealand sites, and to make it robust while remaining light, we really have to have that teetering hinge.

Matthew Wright: Now Geoff, when there’s a 50 kilometre an hour wind going along and your two-bladed machines are sort of running near optimal, is the main advantage cost economics, like would a three-bladed machine also be extracting the same sort of amount of energy out of the wind if it was optimised for that speed?

Geoff Henderson: Yes. In terms of the energy catcher for the same rotor diameter or swept area, then there’s really nothing in it. The two-blader has to run a little bit faster to sweep through the wind in the same time, but it doesn’t have to go 50 per cent faster or a third faster or whatever. It typically goes 15 or 20 per cent faster and gives you the same efficiency and energy interaction as a three-blader.

Matthew Wright: And the torque limiting gearbox. Now, I was trying to work it out. It seems there’s different types of generators that you can have in wind turbines, and you’ve managed to actually keep the speed constant, and you’ve got some hydraulic pump. Can you tell us a bit about that?

Geoff Henderson: Yep, sure. The different generators in the wind industry tend to talk about four or five different types nowadays, but you can split it into two types really. There’s ones that vary the speed of the generator or ones that keep the speed constant. And there’s not many that can keep the speed constant. This is the synchronous generator running directly online with the grid. The useful thing about running a synchronous generator at constant speed is that that’s pretty much the electricity industry norm. If you’re doing diesel gen sets or coal-fired steam turbine generators that you’ve got dotted around the countryside in Australia, they all run with the generator at constant speed synchronous because that’s performing a very important function of actually setting the frequency on the grid as well as voltage, whereas a lot of wind turbines in the 80s, they couldn’t do anything to control frequency or support voltage. They were basically just exporting current, or amps - which is useful because that’s basic energy - but there are other things than energy that a generator needs to provide.

So the Windflow turbine enables the use of a synchronous generator, and that’s got real electrical advantages. It actually started out as torque control - trying to protect the gearbox was the original economic motivation – and that’s because the gearbox is the single most expensive component in a wind turbine and it’s also been a source of significant unreliability over the years because the torque control problem hasn’t been very well addressed in my opinion.

The thing that’s unique about a wind turbine, just comparing it to other forms of generation that your listeners might be more familiar with, is that in the case of wind you can’t control what engineers call the working fluid before it goes into the turbine. In the case of wind turbines that’s the wind. You can’t control the wind. In any other form of power generator you can control the steam going into the steam turbine, the water going into a hydro turbine et cetera, et cetera, but you can’t control the wind and that makes the problem of torque control unique in the wind industry.

I came up with a way of doing which I think is the most elegant, cost effective way of doing it. It’s pretty simple. It involves a differential stage in the gearbox, which a lot of cars use differential epicyclic gearbox nowadays, and there’s a hydraulic torque controlled device in there as well.

Matthew Wright: Now, just with a one second sort of answer, is there a chance that - because we’re running out of time - is there a chance that you could be licensing that technology then to other wind turbine manufacturers whether they be three or two-bladed in the future?

Geoff Henderson: I would always look at any chance to commercialise the technology. If there are turbine manufacturers want to come and talk to us, I’d be more than happy to look at that. The other way of doing that is expanding into other markets and in time we are aiming to get into the Australian market, and the US market as well.

Scott Bilby: Um, Geoff, look, we’ve just run out of time but that torque limiting gearbox, you know, we could have kept talking about that because it’s pretty amazing, and I do hope that people are listening and some other wind manufacturers pick up on that idea too. But it sounds like Windflow’s really growing and given that New Zealand has a New Zealand energy strategy, where they want to achieve 90 per cent of their electricity generation from renewable energy sources…..

Matthew Wright: …..by 2025….

Scott Bilby: …..by 2025. So there’s great scope for you guys and I think you’re going to be very successful. So thank you very much for joining us this morning.

Geoff Henderson: Thank you.

Scott Bilby: Now we’ve just been talking to Geoff Henderson, CEO and director of Windflow Technology Limited in New Zealand. And if you want to learn more about Windflow’s work visit windflow.co.nz. And if you want to know more about us, where do you go to Matthew?

Matthew Wright: beyondzeroemissions.org. That’s beyondzeroemissions.org. You can listen to all our past podcasts, find out about us – how you can volunteer, join us or donate. So, beyondzeroemissions.org.

Transcript by Jenny Gibson