Rosemary leads off this week with a drag-based wind turbine design from Xenecore – are drag-based turbines making a comeback? Equinor and bp are investing in the NY area with the Offshore Wind Innovation Hub – will the companies selected for the incubator change the wind industry? The Mass CEC expands their structural test capability – will this lead to fewer blade failures? And, our wind farm of the week is the Wild Horse Wind Farm in Washington State!
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Uptime 173
Allen Hall: So Rosemary in the United States, it’s, it’s sort of golf season, so every weekend you turn on and there’s some crazy golf tournament. I, I’m not a golfer. I think Joel is actually,
Rosemary Barnes: are you serious? They show golf on tv. I know.
Allen Hall: It’s sad, isn’t it? We
Rosemary Barnes: show cricket on TV here and that’s probably, probably close.
But
Allen Hall: in Australia, in Australia, they’re having problems because I guess there’s a lot of wildlife on the golf courses like kangaroos. And I, I saw a picture this week of like 30 kangaroos hopping around this golf course where this caddy is. I’m thinking, my gosh. Is it just the wilderness in Australia or what?
Like you can’t even golf in peace in Australia. You can’t swim in pe you
Rosemary Barnes: can’t golf in peace. Kangaroos love golf courses because, you know, they’re like, they’re like open grasslands. Traditionally there wasn’t that much open grassland in Australia, and so they’ve really thrived where we’ve come and made, made lawns.
They, they absolutely love that. You know, they they don’t drink water. They, they just eat it off the, the dew on the grass and, you know, then they. Hang around eating, eating grass, and. They’re like, great, these people have come here and put in, put in all these lawns for us, and they keep them nicely Moaned, soften our feet if you’re a kangaroo.
Isn’t that why you’d wanna hang out? I, I
Allen Hall: totally would. Yeah. I would stay away from the other dangerous areas of Australia, like pretty much everywhere
Rosemary Barnes: else. Well, a kangaroo can mess you up,
Allen Hall: you know, that It’s probably one of the most TikTok things that I’ve ever seen, or kangaroos fighting people weirdly enough.
I don’t know what it is in America. We think like that we can manhandle kangaroo, but you’re outta your, you’re outta your mind. Those things are powerful. You’re crazy. And then don’t they have sharp, sharp hooks or whatever on their feet? I claws. Oh, they have c they call
Rosemary Barnes: claws. I don’t know. I wouldn’t worry about their about their claws.
I guess they’ve got claws on their hands, but their arms are, are not that strong. No, you gotta worry about getting kicked. They. They sit on their tail and then they you know, kick kick you with both legs at once. Can’t
Allen Hall: wait to book a trip to
Rosemary Barnes: Australia. Yeah, well if you do, just don’t pick a fight with the kangaroo.
Allen Hall: All right, Rosemary, hold on tight. This one’s gonna be a good one. Xena Core is a company that develops materials and processes for composite parts, and they have a, a new technology or, or one of the company technologies I’m using Thermoplastic Microspheres. And I don’t know if you’ve seen Microspheres in use Rosemary, but it, it’s sort of a thing you add in to make really cool composites.
Well, they’re using it in a structural, lightweight foam. And as part of that, they’ve, they’ve found an application which is drag based wind turbines or basically fan shaped wind turbine blade design. So it’s, it’s more based on like the old style Holland, Denmark wind turbine, not, not even wind turbine, like Yeah, it’s just the wind hits it and it spins sort of thing.
And be, so the design idea is to make these fan turbine blades from a, a one piece monocoque construction with this, with reinforced carbon fiber and epoxy in this foam. So it’s, it’s sort of a slick way of making These blades. Now they’re throwing out some numbers about the efficiency of these things and, and their, their contention is at in low wind conditions.
These drag based designs are, are more efficient than the typical aerodynamic blade design we, we see all over the world. And when I read that, I thought, oh, come on. That can’t really, so here you go, Rosemary. It’s, it’s all yours.
Rosemary Barnes: Yeah, so I guess the first thing is to say that, you know, drag, drag based is inherently less efficient than lift base.
And it, it can’t, it can’t be. Otherwise, and I’m trying to think of a, a good way to explain that, but y you know, an airplane flies right, because of the magic of lift a lift force is, is really big. And if you compare that to you know, the kind of force when you’re standing there and you’re gonna get blown over by the, the wind, you know, like it’s It’s just a lot bigger.
So if you stick your arm out of the car window and you’ve got your hand flat, you know, to act like a sail against the wind then that’s gonna, you know, push a certain amount. And then if you can kind of like tilt it so it acts like a wind, then maybe you felt that you can actually get quite, you know, quite a high, high force when you angle it right and you get a lift force.
That’s, you know, like, it’s surprising how, how hard the lift force is when you look at the equations. You, you’re never, you’re never gonna get the same power from a drag based system than a lift based one. I do think that when you look at this their design, it looks like the kind of thing that I know that people who don’t understand how wind turbines work are gonna think, oh, that’s what, much better.
It’s gonna be much more efficient. Cause they’ve got these four really big flat blades and when you look at it, it nearly, you nearly can’t see through it. Right? It’s nearly, the blades are nearly covering the entire area of the disc. And one thing that I get told a lot on my, you know, the comments on my YouTube channel is they should put more, more blades because all the air is just rushing, rushing through.
There’s so much space in between those blades. Why don’t they put more blades on and you know, capture more of the wind. But because the blade is, is turning, if you have designed your lift based you know, three blade at all, however many blades you wanna put on there, if you’ve designed it properly, every air molecule that goes through that.
That disc is going to interact with the, with a blade and have its energy, you know, some of its energy taken out. So it’s because, you know, you the. Rotor is turning at the same time as the wind’s going through. So an air molecule is moving, and by the time the next one gets there, the blade has gone a bit bit further.
The
Allen Hall: blades are moving faster than the air molecules velocity, speed wise, right?
Rosemary Barnes: Yes, that’s true. And, and so, you know, they all, they all get affected by by the rotor and their e Every air molecule in a well-designed turbine is slower. That’s then you know, when it exits the wind turbine, then when it entered it.
So so that’s the first thing. But I can see that it definitely looks to someone who doesn’t understand that, that thinks that most of the air is just rushing through without having any energy taken out. It looks like this new design is gonna be better, but yeah, when you read through what the. Company is saying about their new wind turbine.
I mean, it sounds like a really cool material. I will definitely give them that, that the material sounds cool. And the article that we’re talking about is in Composites World and you know, that’s a materials publication, not a wind energy publication. So that part of it, yeah. Cool. But it just doesn’t give the impression to me that the whoever designed this wind turbine understands how wind energy works or what the current state of the art is, or not even state of the art.
You know, like anyone can build a backyard wind turbine that would be more efficient than this one if they did it, you know, a lift based one. But yeah, they’re talking about how, you know, back in the day, all wind turbines were drag based and the reason why they didn’t weren’t very efficient was because of materials.
So now we’ve solved the materials problem, but it’s just wrong. It’s not. That’s not why the old turbines weren’t efficient. And so yeah, changing to a better material is not going to undo that. They also said, you know, they fall into the same thing that you see a lot of people with new. Wind energy, people outside the industry come in with a new way to make wind energy.
They often fall into this kind of arrogance, I’ll say, I’ll call it, where they’re like, oh, well obviously the whole wind industry, they’re just, you know, they’ve just, it’s full of. Mindless automations that just are, you know, copying what everybody else did in this like massive group think. And no one is ever thinking originally.
And so, you know, the only reason why this is done this way is because it’s always been done this way and I’ve thought of a different way to do it. And so they say, you know, there aren’t analysis methods for anything other than the traditional wind turbine, and that’s why you don’t ever see anything different.
Whereas it’s the other way around. The reason why there’s a lot of design tools for, you know, the modern type of wind turbine is because that’s what works and what everyone wants to make. Anyway, so they’ve said, you know, they’ve, they’ve found an analysis method and it’s ansys, which incidentally is like the most common finite element analysis and computational fluid dynamics software available.
That’s what I used in my PhD research and what many, many, many people use in industry. They’ve done some, I assume that, you know, someone has taken a, a day or two to learn how to use this very complicated software because then they’ve ended up with results that don’t make any sense, which is saying that drag based system is better than a, a lift based system.
And y you know, with cfd, I found when I was doing that in using cfd in my PhD research, I was doing load distributions to. You know, figure out which parts of the blade needs to be how strong, basically, and you can get any result that you want if you aren’t validating it. So CFD is really good for you know, doing design iterations for making small changes and seeing how you expect that that would change things.
What it’s not good for is starting from a brand new concept and saying, you know, what’s this gonna do? Because you’ve never made it. You don’t have anything to pin it. Pin it to, so you can just tweak parameters in your simulation until you get whatever result you want practically. And, you know, I had to go to a lot of trouble to find a reference design where I could model it and have an actual physical test that I could tie that result back to before I could then make any changes in the model.
Because otherwise it’s totally meaningless. You might as well just write down a number that you wish that it would generate. And y you know, why even bother doing your analysis if you haven’t? Haven’t got something to, to tie it back to. And, you know, it’s the same problem when you often see reports of, you know, better, more efficient wind turbine designs reported, but it’s only done with CFD modeling and it’s, it, it’s total junk.
I wish that, you know people who are writing articles would learn that point that if you haven’t, haven’t made one, you haven’t validated your model, then it is totally. Totally worthless. It’s worse than worthless because it makes people think that they’ve got something. But the other interesting thing about this, I went onto the the site, the fan turbine.com fan turbine by Zencorp Donne.
Yeah. I mean, they’ve just, they’ve got a lot of, a lot of issues that, you know, every new wind turbine design, you know, I often go through and, you know, tear, tear apart, new designs that are. Not really new. I mean, this one legitimately does look different to anything I’ve seen before. So, you know, they’ve got, they’ve got that, but, you know, they’ll, they make a lot of claims that they can’t back up because it doesn’t e exist yet.
So, you know, price, the annual output reliability, their startup wind speed, guess what? Their startup wind speed is. Alan,
Allen Hall: two meters
Rosemary Barnes: per second. No, it’s one mile per hour, which is less than half a meter per second. So 0.3 watts, it’s gonna be making it at half a half a meter per second. Wind speed. So yeah, that’s, I mean, that’s one of the things that you see over and over again for, you know, new wind turbine designs, especially small ones, is always, you know, it works in low wind speeds and it’s like, okay, what are you gonna do with 0.3 of a what?
And really nothing probably, but I also calculated the efficiency based on what they, they’ve got a power curve there for it. And I, I mean, I did this while we were talking, so it’s possible that I made a mistake, but it seemed like they’re calculating 40% efficiency, which is too high for a drag based system.
Definitely. But on the other hand, also less than, A, a regular wind turbine, horizontal access, lift based wind turbine. So yeah, I mean the claims claims don’t add up, which you know, obviously they wouldn’t, but I don’t know. It’s disappointing to me to see this composites world is a, you know, that’s a respected public publication that I trust for news about composite materials, and I’m a bit disappointed to see.
You know, there are ridiculous wind energy stuff in there, but yeah, I’m frequently disappointed. So there you go.
Allen Hall: Hey uptime listeners. We know how difficult it is to keep track of the wind industry. That’s why we read p e s Wind Magazine. P e s Wind doesn’t summarize the news. It digs into the tough issues, and p e s Wind is written by the experts, so you can get the in-depth info you need. Check out the wind industry’s leading trade publication, PEs wind, PEs wind.com.
Well, maybe we gotta keep on the, on the new innovator technology front in the news. And I, I wanna bring this into the discussion because I, I, I think this sort of ties in with things I’m seeing, generally speaking in the sort of the venture capital innovator hub. In wind the offshore wind in Innovation Hub has selected six startups to participate in their first accelerator program.
So the Offshore Wind Innovation hub is a collaboration between Ecuador and bp. The Urban Future League, the NYU Tandon School of Engineering and the National Offshore Wind r and d consortium. So it’s like all around New York City, right? And it’s supported by the New York City Economic Development Corporation.
There you go. And they had a, basically a Shark Tank event, and there was a pool of 49 applicants from all over the world, and they chose six of them to move on to the sort of the next phase, which includes mentorship, business development support. And access to offshore industry around the New York City area.
So, and there’s a lot of smart people down there. It could be really helpful to you. The companies that they chose. Let me, let me read them off. Benchmark Labs, which is a turbine specific weather forecasting piece of software it sounds like, to improve operational margins. So maybe knowing a little bit about what kind of wind’s coming in Flu o which usually uses sensors, GPSs and camera data for offshore wind farm installations to increase product precision harima engineering solutions, which is, is creating a software tool to simulate and complete offshore.
Construction processes in an event simulator, kind of Star Trek ocs as is talking about industrial metaverse simulation for de-risking and cost cutting offshore wind farm planning. RCA Technologies, R C A M technologies is a low cost 3D printed, environmentally friendly concrete anchors for floating offshore wind.
And then the last one, which is Vinci vr, it’s a virtual reality for workforce safety and training. So all these are interesting and I think they, they probably could add something to the offshore wind industry. Oh, I just wonder like, how applicable is it? Are there other companies that are not already doing these things?
Particularly like on the weather front? There’s a lot of companies that are involved in weather at the moment. Vaisala being one of many. Is there anything here that really stands out? Like, oh, that’s a really cutting edge technology. We, we needed that five years ago. I
Rosemary Barnes: think all of them seem to be solving real problems, so that’s at least a, a start.
None of them jumped out at me as being something that nobody else is trying to do currently, or, you know, that doesn’t exist or that isn’t already somebody that’s probably more advanced. But yeah, I, I mean, it’s, it’s interesting because I kind of would’ve intuitively thought, A competition like that, you’re gonna see, you know, vertical access, wind turbines or you’re gonna see, you know, some sort of crazy out there wind turbine designs I don’t know, blades made of, I don’t know, corn starch or, you know, like just stuff like that.
There’s like kind of categories of, of innovation that are pretty, pretty normal and not. Always solving problems that need to be solved, usually not solving problems that need to be solved. So it, it is interesting that they have managed to kind of, you know, funnel it into funnel, this kind of, yeah, innovation competition into really industry applicable types of things.
But at the same time, nothing really captured my imagination and made me go, wow, that’s such a cool idea. I never thought of that before. And
Allen Hall: a lot of software based technology, right? Virtual reality, I. Simulation tools for weather plant tools for planning. It’s all software based, which, and then gets into the sort of the, the, the SaaS play for a lot of venture capitalists because it can be quick money.
Yeah.
Rosemary Barnes: I wonder what the, the competition parameters were like, what’s the, what’s the prize? You know, if the prize is a hundred thousand dollars, then it’s pretty hard to see how you would install something physically, you know, do any kind of like real, real offshore testing. So I think a lot of the times you see too much focus on software solutions because yeah, investors love it because, you know, you can take a clever idea and make a lot of money off it without too much risk.
Whereas if you have a brand new wind turbine design then you need lots of millions of dollars to be able to. Even though if it does what you think it’s going to to do and you know, a lot of millions more before it would be to the point where you were able to commercialize it. So I, I suspect it’s probably to do with the, I I doubt if EOR had hundreds of millions on the line for the, you know, for the winners.
No, no,
Allen Hall: no. But I, I just think the, where the industry is today, it’s, the needs are more hardware based than they are software based. My impression, like there are real problems happening out in the wind turbine world and those problems are difficult because they are not software, they are structural issues, electrical issues and those are hard, right?
Cause they take cash to create a product to solve them. And it’s weird in this sense that the innovation hub didn’t see that. And it’s not listening to the industry about what the issues are. I think Siemens Gomaa is a good example, right? GE has similar problems of if, if GE or Siemens Gomaa wanna knock your door and say, we need a solution for X, would any of that be software?
Rosemary Barnes: Yeah. I think with software, I mean, it can already take care of it itself. It’s not so hard to get funding. I mean, even I think about my, my. Friends that are, are founders the ones that found funding very easy to come by are the ones with, you know, with software. Or real kind of like intelligence kind of where, yeah, their product is digital, I guess.
And the ones where they’ve got a physical, a physical technology. That needs to be designed, developed, manufactured, tested, and then, you know scaled up. Those people, no matter how smart their idea is, they all really, really struggle. But it would be, it would be interesting if I a company, you know, maybe.
Not eor. I mean it could be EOR or you know, any of the major manufacturers. If they ran this sort of thing then you know, they would be the people where it wouldn’t cost them so, so much. Cuz you can imagine if you have a new wind turbine design and you are not already manufacturing anything at all, it’s a much bigger step for you to be able to test that out compared to someone, you know, like Vest every now and then does like a way out there kind of.
Design things like, you know, decade or so ago they did this multirotor thing and then I saw a friend of mine recently was actually saying that he was leaving so, Leaving Sters and he had been working on a project that had like these ties on, you know, to get really long blades. They had tied the blades together at, you know, the midpoint of the, of the blade to keep it more more stiff and probably to help with yeah, keeping the natural frequencies under, under control.
Yeah, again, I don’t think I described that very well, but, you know, like it’s a, it’s a weird, it’s a weird out there kind of thing that you would probably intuitively go, oh, like an interesting idea. I bet it won’t work. But, you know, that’s kind of how every interesting thing is gonna start. But you can imagine that someone like Vester or any of the other manufacturers has a much smaller hurdle to, to jump to be able to test that because they’re already making other big stuff.
And they’ve already, they already have the engineers there that know all the normal things that can go wrong. They’ve just gotta worry about the, the new things. Whereas if you, you are designing from scratch and you’ve got engineers from outside the industry, then it’s very easy to go in. It, it’s easier to be creative like that because.
Sometimes it can be a real you know, like engineers are real party poopers. You know, someone comes to you with a new idea and an engineer will just tell you a hundred reasons why it can’t work. And if you don’t know those reasons, then you’re much more likely to, to try. So that’s, I think it’s good for innovation to have people outside the industry, but they’re gonna experience so many more problems because they don’t only have to deal with the new problems associated with, you know, the novelty and their idea.
They also have to deal with all the mundane stuff. Yeah. And so I think it, it could be really cool to see more competitions like this from the manufacturers, cuz then that’s a way that you can get both the new ideas from the outsiders and then the resources and know-how of the incumbents.
And maybe that would be a way that you could see hardware innovation. Yeah. I think that would be really cool. Anyone needs a judge for their, their wind energy shark tank. Then, then Alan and I are available. And Joel too. We shouldn’t leave Joel out just cuz he’s not here.
Allen Hall: No, no, no. Joel will be really good at that.
The, the, I think the key about any of these judge judges is where do they come from in the industry? Are they a Rosemary Barnes that has been deep inside of a blade manufacturer who has seen all the ugly things that happened and wish they had a tool to fix some of them. I, I doubt that’s who’s on the panel.
My guess is that it, it’s more sort of top level people or management people that maybe don’t live in the trenches like the engineers do. And I, I always think, man, engineers would love to have access to this really smart person who knows us one thing and I wanna plug that person in and help us get this problem solved.
That doesn’t seem to happen in these Shark Tank events. Why? I don’t know. But I will say that, you know, you mentioned Vestus earlier. Vestus has invested and does, did have a, like an innovations group that they were investing in, companies they thought had a future, and a lot of them were hardware companies.
And I always felt like, oh yes, that makes sense to me. Like someone internally has said to them. We need a solution for X. And it’s not an easy thing, it’s not a piece of software, it’s a piece of hardware and it’s gonna take, you know, a year to develop, but we need somebody on it to do it. And they would invest in companies like that.
And I haven’t seen a lot of that happen, obviously because of OEMs are in financial trouble at the minute, but when they get picked, picked back up Rosemary, don’t you think that would be the right thing to do? Like to bring in. Some outside voices. They could be right, they could be wrong, but at least you’re not spending a lot of money.
But you could, in theory, solve a big problem in Massachusetts in Bo outside Boston. They have something called the Massachusetts Clean Energy Center. So it’s a, it’s a test center for structural testing of blades. Well, they just received a, or starting to use a, a new structural fatigue test rig that was built and designed and assembled in Denmark.
By r and d test systems and Rosemary, they’re planning on testing blades up to 130 meters long at this facility, sort of right on the water in, in Boston. And when I saw this, I thought, man, there’s no blade manufacturing facilities anywhere near Boston at the moment. Why a tus facility in Boston unless it has something to do with.
Know the, the LM plant up in Canada and that’s right on the water. Right. And they could just ship the winter blades right down to the test facility in Boston and test them. I assume that’s what’s happening. I Are there many other facilities that can actually do this work? Is this the only one? What I, I don’t, I haven’t been involved that much on the structural testing of blades, and I know you have seen a lot more than I have.
Is this facility
Rosemary Barnes: unique? Yeah, it, well, it’s unique in that it’s the biggest currently available. So I, I mean, there’s some blades getting close to that length that have been made, and they’ve obviously been tested. Usually what you do when you’re. Testing a really long blade that can’t fit in a, a facility an existing facility, is you chop the end of it off and only test the, the inboard part of it, which to a certain extent, they’re actually all blades are only, it’s only the inboard part that’s tested, which makes sense because that’s where, you know, all the big loads are, and that’s where they’re more likely to fail.
And if they fail there, then that’s a, you know, catastrophic thing. Whereas on the tip it’s not, not such a big deal. So yeah, I guess this facility will enable more of the, the blade to be tested for those lung blades. And I guess you can go even longer if you start cutting the blades off there.
As well. It’s, I I, I don’t quite know the reasoning behind the location of it. I, I guess if it’s the only one in the world, then people will, will go to it, but there’s not really anything stopping someone building one somewhere else, but. It’s just weird. Yeah, it’s weird that there wouldn’t be one in Europe first, I guess, because, you know, like all of the, except for ge, all of the big manufacturers that are installing turbines in Europe are all European companies.
Where there, and, and I mean even in With ge, you know, their blade design is still happening in in Denmark primarily. And so it’s just a bit strange that you would put your test facility far away from the engineers that are designing it. Yeah, because yeah, you’re either, you either wanna put it where the factory is, or actually it’s kind of easier to put it where the engineers are because you know, then you can be quite involved in, in the testing.
And yeah, do. Do a lot more. Rosemary, can I ask
Allen Hall: you about that? Because I, I wonder when we see some of these blade failures that we’ve been reading about more recently, how are they structurally testing them if there isn’t a facility near them? Are, are they shifting them all to Massachusetts to be tested?
Do, are there some blades that just don’t get tested this way? Like they’re testing the one in Massachusetts has a, a flap wise and an edgewise motion. Right. So they’re testing both axes, I guess. Is, is that common even.
Rosemary Barnes: Yeah, ev you have to do that testing. So ev everybody does that testing. If you want to get it certified and you’re going to a blade certificate and have insurance for your turbine and meet your planning you know, planning rules, then you definitely have to do a flat, flat wise and edgewise test.
And so the way that they do it is they take a, a blade, or at least most of a blade and they mount it, you know, they at the root where it would normally go onto the hub, they’ll put that onto a test rig. And then there are these big, like, eccentric loads. I’m trying to think of something that is, is similar to it on a small scale, but you know, it’s something that’s, that’s rotating but off center a bit.
And so it kind of gets the thing vibrating. Or, you know, like moving up and down in the natural frequency of the, the blade doing a, a motion for everyone that’s watching on YouTube. But I know that mostly people aren’t watching their listening. I mean, imagine you’ve got a, a drill and then you put your drill bit off center and it’s got a mass on it.
Wobble. Yeah, wobble. Wobble. That’s a good, good technical word. And that wobbling is gonna excite the blade on the, the natural frequency. And so it’s gonna start flapping up and down. So they’ve got a couple of places where they put these exciters and it, it gets the blade moving up and down and everywhere from the blade root up to where the exciter is that’s being tested.
And so they don’t put them on the very, very tip of the blade. They put them you know, a little bit inboard from there. And so it’s never the whole blade that’s, Tested, but you know, they sit there for months doing that. And that’s, yeah, it’s just necessary to do that. But they also rarely fail those tests.
And so usually you’ve already made a lot of blades by the time that your test is completed. And if there was a problem, then it would be a big problem. So they’re pretty safe. Usually they, you know, are on the side of caution and no, like, it’s really rare to fail one of those tests. You’re more likely to fail a, a static test, which ha would happen.
Earlier on where you just, you, you still mount it in the same way, but then you just put, you know, some ropes and straps on it and pull and check that it, you know, deflects the way that it’s, you expected that it would, and also that it’s strong enough. And then every now and then engineers will just, you know, get a, a, a rush of blood to the head and say, you know what, let’s break it.
And then, then they, they pull it, you, you know, further than they expect it to go. And you do that just to make sure that you are You know, your, your design code and your analysis methods would tell you when what load you think it should break, and you wanna. Check that you are approximately right, but you never wanna design a blade really close to that because like I said, kind of the whole design process is, is based around not failing that, that fatigue test and especially, I mean even, yeah, it’s rare, rare for anyone to, to fail those tests because they’re pretty conservative and they know a lot after decades of making blades.
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Allen Hall: dive into this just a little bit? I wanna understand a more of the structural testing and what we’re seeing in the field versus what we’re testing in the laboratory. There seems to be a difference, like there’s sec as it’s been described to me as an electrical engineer of like secondary vibration modes of that weren’t necessarily tested in the structural evaluation phase.
That they’re seeing in the field that’s causing, causing some, cracking some disc bonds. Is that a, a function of just not having the right test facility or the right test configuration or lop at the end off the blade? What, what’s causing some of these things and why are we not catching them when we’re in these demonstration tests?
Rosemary Barnes: Yeah, so I, I don’t think that sort of thing is super, super common. So I don’t think it’s a big. A big oversight, but you do see that sometimes and the way that they test for that. So and everything’s got. Anything that can vibrate it has a natural frequency, but it, it has more than one. You know, it has, like with music going up the octaves, you know, you’ve got harmonics and, and that sort of thing.
And so they’ll do simulations, finite element analysis. And also they’ve got some design codes, which are kind of, you know, mathematically going through and calculating. What the different natural frequencies are, and then you make sure that none of them are gonna get excited by anything that you expect the blade to see.
So, you know, the tower passing frequency would be one. You wouldn’t want to, you know have the tower passing frequency be something that gets set, set off resonance in your blade. But then I, I guess that there are some that are harder to know for sure. And some of the you know, the aerodynamic loads can set things off and, you know, you get flutter and that sort of thing.
I mean, it’s in airplane wings too, right.
Allen Hall: But we test that we, and lemme I, I can describe the flutter test cause I’ve seen it, right? You, you put a wobbly mass at the end of the wing and then you. Turn it on and it just sits there and vibrates and just show that it’s damped, right. That you don’t oscillate to the point of destruction.
That seems like a pretty straightforward test to do. I haven’t seen anything like that on a wind turbine blade. I assume that’s done or are there flutter tests done?
Rosemary Barnes: I haven’t seen them physically done. They, they do more simulations. Yeah. I, I mean, I haven’t seen a, a blade that shook itself apart from From Flatter either.
So I, I’m not a hundred percent sure of the reasons why it’s not as important for wind turbine band blades. So that’s very odd, isn’t
Allen Hall: it? I, I, I, I’ve noticed just because of the work we do in lightning and looking at aerodynamics, the airflows, cuz lightning is made of air. You, we kind of look at blades a little bit differently, but we’re trying to see what the airflow.
Is on the suction side of the blades, and a lot of times it looks like it’s turbulent, right? On the pressure side, it’s always very laminar and smooth and all that, but a lot of times around the tips, it doesn’t look like it’s flowing in the way that I would expect to see, like on a CFD model. And I always wonder like, are there things happening out there that are, that are causing some of these weird structurals, these flexing twists, maybe some twisting that’s happening that is exciting in other mode?
Rosemary Barnes: De definitely. And the torsional stiffness of a blade, the way that it deflects, you know, like twisting is, is way less well modeled. Then, The, the main kinds of bending modes, like just, you know, straight, flat wise or straight edgewise. That’s pretty accurate between the finite element model or I mean, it’s not even a finite element model to start with.
It’ll be, you know, some. Just some simple calculations using the geometry and materials, properties that everyone knows and all, you know, run through and, and design it. And then you’ll use your finite element analysis you use for design features usually because it’s, it’s very hard to model a. A whole wind turbine blade with finite element analysis, cuz you’ve got this it, it’s a great complicated design problem, which is why that’s what I chose for my, my PhD on structural design methods for composites because it’s so complicated.
You’ve got the comp composite materials. Are the really small scale matters, you know, so you’ve got the fiber and the, the resin interaction. And then a little bit bigger than that. You’ve got sandwich panels where you know, it matters how the. You know, the thickness, so the materials are distributed through that thickness.
The glue bonds are really hard to model with just your normal sandwich elements. You know, you can’t use a 2D model to model a glue a glue feature accurately. And then, yeah, they’re really big. So, you know, you might be able to model a, a one meter section of a wind turbine with a full 3D model, but you know, to go up to a hundred meter long blade is really very computationally expensive.
Allen Hall: Is that the reason it’s not done is just because it’s computationally expensive? I know in the aerospace world, they’ve been doing it for a number of years because obviously there’s people traveling in airplanes, but. Is it really just comp computationally expensive to do? Or, or is it like an insolvable problem?
It needs empirical data to, to put a solution together.
Rosemary Barnes: Yeah. So it’s not unsolvable, but it’s you, it’s the empirical data that’s a problem as well. And also it’s a lot of people, you know, to do the analysis and I mean, all the manufacturers do have teams doing finite element analysis. You know, there’s plenty of engineers hired exclusively to do FES for any of these manufacturers.
So it’s not that they’re not doing it. But I guess you’re kind of targeting where the, where the features are that, you know, need this kind of modeling, but the glue, glue joints especially is, is quite tough and it really affects the the al stiffness. So it’s, it’s hard to model and it’s definitely an area that, you know, continues to get a lot of academic research attention paid to it.
But like you hinted at, it’s also hard to validate. So you can easily measure the, you know, the deflection of a blade, but measuring the twist is harder. And then with the aerodynamic testing of it it, it’s very hard to test that in a wind tunnel. Like an aeroplane is very easy to test in a wind tunnel cuz you can easily scale it.
You’ve got all of the, the wind is coming in one direction, whereas on a wind turbine blade, because it’s rotating and a lot of the speed that the blade sees is actually from the rotation, not from the incoming wind. It makes it very impossible actually to, to scale it down and get everything to scale at the same the same rate.
So you can’t really, some tests you can’t do on the scale. You would have to actually, you know, make a big wind turbine and, or you can test like a little part, you can test a blade tip and approximate the wind direction and speed that it’s going to see, but you’re not gonna be able to, to test the whole blade unless you actually get it out on a.
Yeah, on a, on a turbine, I guess you could, you could always put like little strings all over a real full-sized wind turbine. But even then, I mean, you’re not gonna know there’s wind shear, right? So the wind speed at the hub height is not the same as it is at the tip. And how are you gonna know exactly what’s going on?
So, yeah, those are all the reasons why it’s a bit a bit hard and you account for that by having big safety factors at. First, you know, early on in wind turbine history safety factors were a lot higher. And then over time you start to, you know, as you learn more, you get more confident that there’s nothing that you have not thought of.
You know, cuz your turbines aren’t failing, then you kind of bring those in. So they’re safety factors are lower than they they used to be. In many, maybe most cases. And. Yeah, you kind of like iteratively get more confident in everything, but you know, you’ll always get surprised. And I think that lightning is a really good example of that, where for decades we had lightning protection systems that did a pretty, pretty good job.
There were failures but not, you know, an abnormal amount. Everyone was pretty okay with it. And then, All of a sudden recently, so many more failures things have changed and we’re just a lot less sure than we used to be. I mean, would you agree with that kind of summary about lightning?
Allen Hall: Yes, I do. And I think it’s the same thing on the structural side.
So weirdly, the structural side and the lightning side are, are been tossed a little bit into chaos. Everybody’s trying to figure out what’s going on and I. More recently, you’ve heard of some discussions of particular OEMs looking to add mass or change the weight distribution of some of the blades to, to dampen out some of these modes that they’re seeing, which is really odd because I, I would assume they would know that going in, like what the modes were for a particular blade because they have data and like you’re saying, because they could probably estimate it off some of the things that they know.
It, it just really gets hard to grasp like, what is going on? Are we just because we’re pushing the boundaries of technology, are we, and like you said, in terms of glues and joints and those kind of things, are those really affecting the overall parameters? The, the way that a blade moves flexes, that we, it’s not doing exactly what we thought it was gonna do, and some of this is just trial and error.
Rosemary Barnes: Yeah, I mean, it’s a, an issue that has popped up every, every now and then, you are surprised that, you know, you’ve got some sort of yeah, vibration that you weren’t expecting and you have to try and damp it out somehow. I’d, I’d say that’s like a periodic thing that happens every now and then. Just like, you know, every now and then you get a blade that’s noisier than you expected it to be.
It noises another thing where it’s really hard to know exactly what it’s gonna be until you actually, you know, get it really out there. I, I don’t know, maybe I haven’t looked at any data or anything. I haven’t seen a whole lot of that. But it also might be the sort of issue that is really always caught by the, the manufacturer, you know, on their test turbine.
If it’s, you know, if it’s a really big problem, then it’s gonna happen on the very first one. So it might be that it just doesn’t get far enough that I would ever get called in to, you know, help. You know, cuz I, I get employed by. With farm owners to help them with problems once they’re already installed.
It’s not like manufacturers are calling me in to help them with their, their engineering, you know, they’ve got their own engineers. Well, let, let
Allen Hall: me ask you this because I think it ties in nicely to some aerospace situations that I’ve seen used to make composite airplanes composite. Propeller airplanes and composite jets, right?
So you have a composite two very similar and also composite wings. One of the issues that we had in the design of composite airplanes is the noise is horrible. The engine noise is horrible, especially propellers inside the cabin. It’s really loud. And, and you would’ve thought that everybody would figure that out before you had flown the airplane, but they didn’t.
And so, and some of the airplanes at least one in particular, they added a bunch of lead mass or, or tuned masses all over the aircraft on the inside to get rid of some of the engine noise and the vibration that way. And I kind of wonder if we’re in that same situation like the, we got a lot of smart people in a room designing wind turbine blades, no doubt about that, but.
There’s just some things we haven’t paid that much attention to, and now they’re just starting to peek their heads out and we gotta figure out quick solutions to them. It’s a really complicated problem and I, I know when you talk to technicians and and engineers on the sort of the support side out in the field, What is going on?
Why are we having these problems? And I, and no one can really put their finger on it. I, and weirdly, you know, obviously you don’t hear a lot from the OEMs, so we have to talk to people like you who were once on the inside to tell us all the, all the magic that happens and why some of these things kind of escape the design engineering group and get out into the field that it’s a really fascinating problem that we need to solve.
Rosemary Barnes: Yeah, it is. And I mean as an engineer, that’s the interesting stuff. It’s not actually very interesting to just design, you know, the same blade over again. Like, you know, like a standard blade design is gonna be basically like a recipe book, right? You, you know, the manufacturers have done it so many times, they’ve got the process dialed down that any.
Graduate could, could run through the steps and come up with a blade that you know, that was adequate. And that’s, that’s very boring. So I think to a certain extent, engineers like it when unexpected things happen because then you’ve actually gotta use your, you know, your engineering skills, your creativity, your judgment, your experience, and.
Yeah, so I don’t know. Selfishly, I think it’s exciting when things go wrong.
Allen Hall: We have to keep following this Rosemary. And I know over the summer into the fall, we’re gonna hear more news reports and more stories about some of the late issues that are happening. And when we get to them, I want you to.
Diagnose them and give us your opinion on ’em. Be because it’s always interesting to hear what your thoughts are. A wind farm of the week is Wild Horse Wind Farm in Washington state. Puget Sound Energy operates a wild horse wind farm in eastern Washington. The site was built in about 2005, 2006. With additional turbines being installed in 2009, there were 127 Vestus V 80 s, 1.8 megawatt machines, and 22 V 82.0 megawatt machines, plus a 500 kilowatt solar array that was added.
The site was originally developed by Horizon Wind, which was Goldman Sachs, and eventually became E D P R. And but the thing about this site is that they have a nice visitor center. It’s called the Renewable Energy Center and has guided tours. So between April and October, you can go check out all the things that are happening.
At the Wild Horse Wind Farm in Washington. So Wild Horse is our Wind farm of the week. Congratulations. That’s gonna do it for this week’s Uptime Wind Energy podcast. Thanks for listening. Please give us a five star rating on your podcast platform and subscribe in the show notes below to Uptime Tech News, our weekly newsletter.
And check out Rosemary’s YouTube channel Engineering with Rosie. And we’ll see you here next week on the Uptime Wind Energy Podcast.
