Nicholas Gaudern, CTO at PowerCurve, joins to discuss India AEP gains, DragonScale VGs, and Silent Edge noise reduction. Sign up now for Uptime Tech News, our weekly newsletter on all things wind technology. This episode is sponsored by Weather Guard Lightning Tech. Learn more about Weather Guard’s StrikeTape Wind Turbine LPS retrofit. Follow the show on YouTube, Linkedin and visit Weather Guard on the web. And subscribe to Rosemary’s “Engineering with Rosie” YouTube channel here. Have a question we can answer on the show? Email us! Welcome to Uptime Spotlight, shining light on wind energy’s brightest innovators. This is the progress powering tomorrow Allen Hall: Nicholas, welcome back to the podcast. Nicholas Gaudern: Thanks, Allen. Great to be back. Allen Hall: So there’s a lot going on at Power Curve, and I saw some news online about Power Curve in India. Nicholas Gaudern: Yes. Allen Hall: Which is a new development. Nicholas Gaudern: Yeah, so we’ve been working in India for, for some years now, and we have, uh, more than 100 turbines out there with our equipment on, primarily vortex generators so far. And what we’re seeing in India is some of the highest AEP gains we’ve ever recorded with our vortex generators And I think a lot of this is being driven by the fact that in certain parts of India, there’s some very unique, uh, environmental conditions, climatic conditions, and there’s parts of the year, like the dry season up in [00:01:00] the north of India, where you’re getting this very sticky dirt accumulating on the blades. And it’s really quite dramatic when you see the photographs, but that means that the blades are actually starting to, to stall, have flow separation on them. Allen Hall: I’ve seen pictures of that. Yeah. I was really shocked at the time, uh, ’cause I didn’t know it was just kind of a black, gooey- Yeah … kind of tar-like substance- Yeah, yeah on the blades, and, uh, it, it was only on there a limited time. As soon as the monsoons come through and the rains hit, it would wash, eventually wash it off. Yes. But while it’s there, you could see the airflow over the blade surfaces. You, you could definitely see separation happening really early on those blades. Dramatic. Nicholas Gaudern: Yeah, absolutely, and I think the, um… Like you say, it’s not all year. No. But it doesn’t have to be all year to have a huge impact on, on how many, you know, megawatt hours you’re getting out the other end. So there’s a few months of the year where this problem is particularly severe, maybe sort of December through to February, something like that. And what we’re finding is that when you see, uh, the power curves for these [00:02:00] turbines, some of them aren’t even hitting rated power. They’re not able to hit rated power because there’s so much flow separation on the blades. Allen Hall: Wow. Nicholas Gaudern: And that, I mean, just imagine that. You’ve got a two megawatt turbine, for example. Maybe it doesn’t cast- get past 1.5 megawatts for this, uh, time of the year. I mean, that’s crazy. Allen Hall: Does the turbine try to adjust itself when that happens? Because the pictures I s- have seen indicates, like, the turbine is pitching the blades to, ’cause it knows- It can- … Nicholas Gaudern: what the wind Allen Hall: speed is- I mean, yeah … and it knows what it should be putting out, and it’s not putting that out. Nicholas Gaudern: It’s very turbine specific, kind of controller logic specific, but what we see is even the turbines that try to do something, they’re very limited in how much pitch authority they have from the controller. They might be able to just do a little bit, a degree. Okay. Two degrees. You know, very, very small pitch adjustments. And when you have this kind of dirt on the leading edges, a degree of pitch ain’t gonna save you really. Um- N- Allen Hall: no. And I think that’s what we’re seeing. And it’s not gonna get that power back. No, no. Nicholas Gaudern: No. Allen Hall: But does it add extra load onto the blade structurally over [00:03:00] time when you do that? Nicholas Gaudern: In terms of the pitching, or- Allen Hall: Yeah, in terms of the pitching, where you’re trying to be more aggressive on the angle of attack to get the power out of the turbine. Potentially. And the winds are still pretty strong, you just, the blades are inefficient. Nicholas Gaudern: I think it’s one of those things where there’s, there’s so many interconnected items with the dirt and the controller and the structure. It’s actually pretty difficult, I think, to say with confidence how much life impact you would have from that. But what I would say is the more that you might end up trying to pitch, if that’s what’s going on on some machines, that obviously puts wear on the pitch bearings themselves. But yeah, I think at the moment we’re kind of at the beginning of really trying to understand how some of these turbines do deal with this phenomenon. But what we’re trying to do is get to a point where the turbine doesn’t really have to deal with it. Because if you fix the problem at the source, which is stop the flow separating, then the controller doesn’t really have to, to worry. It doesn’t have to try to, to fix it itself. Allen Hall: Yeah. That makes a lot more sense. Just the number of images I’ve seen over the last couple years from India- Nicholas Gaudern: [00:04:00] Yep … Allen Hall: you realize how difficult it is to operate a wind turbine there. Nicholas Gaudern: So even when we, um, have this issue for a few months that we’re resolving with the VGs, we can still be seeing over the whole year more than 5% increases in annual energy production. Because those months are really important. Um ‘ Allen Hall: Cause that’s when they need the Nicholas Gaudern: power. Yeah, yeah, yeah. Exactly. For sure. And this is primarily coming from the vortex generators towards the tips of the blades. So that’s where you’re having this, uh, heavy contamination issue, and that’s where all the power would be produced. So kind of the outer third of a blade is 50, maybe 60% of the power production of a turbine, maybe closer to 50. So that means that if you have a problem out there, it’s, it’s a big problem in terms of your annual energy production. So- Allen Hall: Right … Nicholas Gaudern: the VGs are, what they’re doing is they are, they’re injecting energy back into the flow. Allen Hall: Redirecting the flow, in a Nicholas Gaudern: sense. So, so basically you have all this contamination on the leading edge. It’s generating more turbulence. The flow isn’t able to retain, uh, remain attached [00:05:00] across the entire chord length. So the VGs are putting energy back into the flow and allowing it to remain attached all the way to, uh, to the trailing edge. Allen Hall: So even with the blades are dirty- Nicholas Gaudern: Yes … Allen Hall: you get that power out- Exactly … put, that you really desire or- Nicholas Gaudern: Yeah … Allen Hall: are paying for. Yeah. You, you paid a lot of money for that turbine- Yeah, exactly … you need to get the power out of it. Nicholas Gaudern: Yeah. Allen Hall: And- Nicholas Gaudern: So of course, you know, that suggests that if you had a, a super clean blade, you went and pressure washed it, uh, you would get, uh, an increase in power as well, and that’s true. You, you- That’s true … you will do. But that’s a one-time thing. Um, so- And Allen Hall: it’s expensive to do- Yeah … and time-consuming. Nicholas Gaudern: Exactly. Maybe a few days later, the dirt’s back. So- Sure … you know, it’s not really a sustainable thing for you to be going out washing these blades the whole time. And washing the blades may not be great for the surface of the blade either. So, you know, a VG is just sat there the whole time. It doesn’t matter if it’s dirt, bugs, erosion, frost, it’ll recover those losses that, that you’re seeing. Allen Hall: Do the VG installations in a situation like that, [00:06:00] the actual location differ because of the contaminants that are present and the kind of, uh, leading edge effects that you’re seeing? Do you design it for that environment? Or- Yeah … is every- Oh, you do. So- Yeah, we Nicholas Gaudern: do. I mean, typ- typically our, our VG arrays are turbine model specific. But in India, we’re finding we’re actually having to be more site specific as well. Oh, Allen Hall: wow. Nicholas Gaudern: Because some of this contamination is so severe, we’ve seen that we need to design the VG layout a little bit differently to make sure that we’re giving enough, uh, energy recovery potential when you have these really severe, uh, situations. Allen Hall: Are you using the AeroVista tool to do that? How do you, how do you quantify the contamination that’s happened on the leading edge at a particular moment or roughly on scale a- and then try to model that? That just seems like a difficult computation. Nicholas Gaudern: It is. And, um, you know, we’re, we’re getting better all the time. AeroVista is definitely part of that. So AeroVista’s primary function really is to look at, um- [00:07:00] AEP losses due to structural damages, things like erosion. But actually, erosion behaves very similar to dirt when it comes to, like- It, right … aerodynamic behavior. Yeah. So we can actually use kind of the AeroVista engine to help us understand what is the loss from different levels of contamination. So we can add contamination levels into AeroVista, as well as, uh, erosion. And we can start to look at, well, what happens if the blade looks like this? What if it looks like this? And then this gets combined with our computational fluid dynamics, our CFD models that we’re running, three-dimensional, two-dimensional. We sometimes do some aeroelastic modeling as well. So we basically have a big toolbox, and like with any engineering problem, it’s about picking the best tool for the job. So we just go in, and we have all these great tools, and we, we put them together in a workflow that allows us to design the, the best solution for each site that we look at. Allen Hall: And it’s not India-specific in terms of leading-edge contamination. No. I’ve seen pictures from the US, Brazil, um, [00:08:00] Australia, a number of places where there’s just bugs. Yeah. Right? Those, especially in places where there’s large bugs- Yes. … you kind of get this splatter effect going on. Yeah. And you can have a really contaminated blade surface. In the US, in the middle of the US, you’ll have grasshopper season, and- Nicholas Gaudern: Yeah, absolutely … Allen Hall: tho- those grasshoppers are big, and they splatter. And they leave a disaster. We’ve seen Nicholas Gaudern: that in, uh, in the Midwest, for sure. Oh, yeah. Some really, really severe contamination from bugs. Allen Hall: And you, you don’t think about, as an engineer or a site supervisor, that- All right. This sort of, uh, grasshopper season that happens is affecting my AEP, but 100% it is. And that stuff is gooey, so if you ever drive through the Midwest in the summertime- … you run through, uh, any kind of insect swarm and try to get it off your vehicle. Yeah. It takes some scrubbing. Nicholas Gaudern: Yeah. It re- it really does. And imagine when you’ve gotta go up there for, like, 100-meter diameter rotor. Allen Hall: Right. ‘ Nicholas Gaudern: Cause that’s quite a challenge. So I think, yeah, they have all these challenges, uh, in terms of environmental conditions, and a lot of people consider aerodynamic [00:09:00] behavior blades quite binary. Either the blade is clean or the blade is dir- Or it’s dirty or it’s dirty. Right. But it’s this entire spectrum. It’s everything in between, and I think that is kind of a little bit of a different way of thinking about the problem. And then it makes the argument around why to put VGs there kind of, uh, easy to, to answer, because the blade is never really truly clean. Allen Hall: No. I… Unless it’s right after a rainstorm- Yeah … I rarely see clean blades. Okay, so the … If VGs are going on, are you using the DragonScale VGs to solve some of the India problems, some of the contamination problems? Nicholas Gaudern: So DragonScale’s not in India yet. That’s something that we’re looking at. So we, um, we got all the tooling finished for DragonScale some months ago now, and we’re shipping DragonScale kits. Uh- Oh, wow. Okay … not, not to India yet, but they are out in, in the field, and we’re gonna be having some more out just in the next couple of weeks, actually, which is quite exciting. We’re doing our first project, um, in Canada. Allen Hall: Oh. Nicholas Gaudern: So we’re starting to kinda come across the, the pond with the VGs now, [00:10:00] with the DragonScale VGs. Allen Hall: So the DragonScales, uh, uh, uh, thank you for bringing a, a sample here today, but the, the DragonScales are really interesting in terms of just the way the airfoil shapes are and how they’re s- kinda stacked and layered- Yeah … and there’s different depths to them, heights to them, to get the flow back where you want it to. Yeah. And it, I guess it depends on where you are on the blade. If you’re near the root, they’re gonna look something like this. Exactly. Yep. If you’re getting near the tip, they’re Nicholas Gaudern: much Allen Hall: smaller- Yeah, we have some smaller ones. Yep … scale, scale of this. So- This then, the Dragon Scales do require a little bit of computational knowledge of what’s going on- Yep with the blade. And as you say, they- You just can’t willy-nilly stick Nicholas Gaudern: them on … they’re, they’re quite different. You know, they’re quite different from a standard triangle of VG. Allen Hall: Right. Nicholas Gaudern: And, you know, there’s lots of ways that you can create a vortex aerodynamically. And triangles- Sure … create a vortex, sure, but they, they really create one through a process of separation. Yeah. You have a flow hitting this, this plate that’s angled to the flow. It’s rolling over the top, and it’s tripping into a, into a vortex. But that’s quite a draggy way [00:11:00] of- It is … creating a vortex. Yes. Um, so VGs work. We’ve seen that. You know, we have more than 2,000 turbines now with VGs, so we, we know they work. Yeah. But Dragon Scale, the whole idea is not that we … This is still a VG. It’s still creating a vortex. Sure. But it’s doing it in a much more efficient manner, so we get the same lift recovery benefits, lift boosting benefits, but at a much lower drag. So we have a better drag ratio. ‘Cause it’s the drag, right? Allen Hall: It’s the drag. The little triangular- Nicholas Gaudern: Yeah … Allen Hall: vortex generators are draggy. Nicholas Gaudern: So anything you stick on a blade, it, it has a drag. It has a parasitic drag component. Um, they have a huge benefit that outweighs that. That’s why we put them on. Allen Hall: Yeah. Nicholas Gaudern: But of course, you can always do better. And I think here we really try to take inspiration from, from lots of the aerodynamic developments we’ve seen over the past decades in aviation and motorsport and, and these other disciplines. Allen Hall: Right. I always say these look like a Formula One Nicholas Gaudern: add-on. Yeah, yeah. Exactly. A bigger blade. Or maybe some front slats of a aircraft or some, uh, gas turbine cascading elements- Oh, sure. Allen Hall: Yeah … Nicholas Gaudern: these Allen Hall: kind of things. Yeah. Nicholas Gaudern: Yeah. Allen Hall: Gas turbine people would easily recognize this. Yeah, [00:12:00] I Nicholas Gaudern: think so. Allen Hall: Uh, so the, the Dragon Scales then in terms of, uh, the location of them on the blade, would it differ than the triangular VGs in terms of generic location? A, a Nicholas Gaudern: little bit, but broadly it’s the same because- Okay … you know, ultimately the fundamental physics of what we’re trying to do hasn’t changed. Allen Hall: Sure. Nicholas Gaudern: Um, so we’re kind of, we’re addressing the same areas of the blade. But the Dragon Scale gives us a bit more flexibility. We can have these three fin versions that create a very powerful vortex, so we find those down in the root, ’cause that’s where we just want as much lift as possible. Right. Allen Hall: Yeah. Right. Nicholas Gaudern: Uh, but out at the tip we actually have a two fin variant. Oh. Because there we’re, we’re more focused on L over D. We wanna maximize our lift-to-drag ratio. Allen Hall: Sure. Nicholas Gaudern: Because that’s where the drag really hurts you, out towards the tip. Allen Hall: So are they in a strip form then? Yes. Very similar to the triangular VGs? Nicholas Gaudern: Yeah, exactly. So the, the smaller ones on the strip, just because they’re only, like, five millimeters high. Allen Hall: Yeah. They wanna Nicholas Gaudern: see more- So otherwise it’s, it’s kind of watchmaking if they’re individual- … little pieces, uh, going down on the blade. O- Allen Hall: okay. Yeah. Well, that’s fascinating. All right. Uh, I wanna talk about [00:13:00] Silent Edge before I, I lose you today. The Silent Edge product has been out in the field- Mm-hmm … and there has been some noise testing done, which I always think is very interesting because I’ve- Yeah … I’ve watched videos from, mostly from DTU, explaining how they do this, where they got the microphones around. And like- Yes … wow, that’s a really complicated test to go pull off. But you just got through a series of these- Nicholas Gaudern: We did … Allen Hall: noise tests with Silent Edge. And you have the results back. Nicholas Gaudern: We do, yeah. I mean, it was a really exciting, um, test program, and we were partnered together with, uh, Statkraft, who very kindly lent us a few of their wind turbines up in Sweden. Uh, and we are working with the Danish Technical University, DTU Wind, to help with the measurements and actually figure out what’s going out on the turbine. So this was a project that we were, um, able to secure some funding from, from the Danish, uh, EUDP. So that’s the Energi [00:14:00] Teknologisk Udviklings- og Demonstrationsprogram. Allen Hall: Right. Nicholas Gaudern: Yeah. Nothing to do with the EU. It’s a very, it’s a Danish thing. Danish, yeah. But there is EU in the name. Right. Um, so they supported this project with Statkraft and DTU, and what we found is that when we put a Silent Edge on a, uh, it was like a two, two and a half megawatt machine, it had no serrations before. Okay. Allen Hall: So we measured- So just a out of the factory blade. Nicholas Gaudern: Yeah, exactly, and it was in good condition. It had had a recent repair campaign, so the blade was in, in good shape. And then what we did, uh, or what DTU did, is they went out and they measured the noise of this turbine according to the IEC standard. So there’s an IEC standard on how you should measure noise and what microphones to use and how to post-process it, and then we installed the Silent Edge serrations. And firstly, before we’d even done any measurements, we had people out at site, and they, they live out there. They’re the technicians. They see these- Okay turbines every day, and they went, “What, what have you, what have you done to, to this turbine?” Because it sounded so different. It sounded much [00:15:00]quieter. The, the quality of the sound was very different, and they just, they just stepped out the car and went, “Wow.” “This is, this is really impressive.” Um- Allen Hall: So what, give me a description of what the sound is. I know generally, when you come with a standard blade, it has that kind of shoop, shoop- Nicholas Gaudern: Yeah, exactly … shoop. It basically just really brings down that perceived loudness of the sound, so it’s just a m- it’s a much quieter sound, and we’re also taking out quite a lot of low frequency component. Allen Hall: Okay. Nicholas Gaudern: That’s what- These serrations are really targeting the lower frequencies, so kind of around the kilohertz and, and under. Allen Hall: Mm. Nicholas Gaudern: That’s where these things are really starting to bring down the, um, the decibels. Allen Hall: This- So, okay. So Silent Edge is, uh, sort of a unique design, or is a unique design i- in terms of the- What you see on the typical trailing edge, which are a bunch of triangles or dino tails, right? Yes, dino tails. Yes, Nicholas Gaudern: yeah. Allen Hall: Dino tails is, was the generic term for years, and they looked like dino tails, so, so it’s a good description- Yeah … of them. But these more, look more like a cathedral in Nicholas Gaudern: a sense. Yeah, these, these are quite different though. So we have kind of this iron-shaped, uh, tooth fundamentally, [00:16:00] but we have three different tooth sizes, uh, and they’re asymmetric. Allen Hall: Mm. Nicholas Gaudern: And I would love to come here and tell you that we know exactly how this works. Um, but I can’t unfortunately, and, and that’s just how it is sometimes with engineering. We cannot simulate this in the detail required to really understand exactly why each geometric feature does what it does. And if someone claims they can do that, then, then I may be a bit suspicious. Or, or I’d really like to talk to them, one of the two. Um, but that means that to develop this kind of product successfully, you have to go to the wind tunnel. Okay. Because the simulation is so demanding. So we go to the wind tunnel. We spent a lot of time in the Paul Ricard wind tunnel at DTU, so we can measure aerodynamics and acoustics at the same time And we went with lots of components and 3D prints, and we iterated through design paths, and we came up with this, I think it’s a really wonderful shape we’ve ended up with. And it was proven out in the field because the final result was we reduced the overall sound [00:17:00] pressure level of the turbine by five decibels. And that is- Whoa … that is huge. Allen Hall: That’s a lot. Nicholas Gaudern: So in terms of, like, perceived, uh, loudness of the sound, that’s like a 30% reduction. So this is why the, the technicians who st- stepped out the car heard such a difference, because it’s a massive reduction in, in what the turbine produces. So Allen Hall: you’re lowering the decibels coming off the, the trailing edge. Yeah. But also moving around the frequencies so it’s a little less- Nicholas Gaudern: Yeah, so a lot of that- … uh- That… So the- … Allen Hall: noticeable Nicholas Gaudern: also … the five decibels, that’s, that’s this OASP, or we call it overall sound pressure level. This is an integration of all of the reductions we see across the frequency spectrum. Oh, Allen Hall: okay. Nicholas Gaudern: All right. So we’re getting more reduction at lower frequencies. Right. Good. There’s also some high frequencies. But the lower frequencies matter more. So what we do when we’re doing acoustic measurement is we A-weight, we, we weight the, the noise because it relates to how the human ear perceives sound. Allen Hall: Sure. Nicholas Gaudern: So it matters more to you, the one [00:18:00] kilohertz frequency than the 20 kilz- kilohertz frequency. Allen Hall: Yeah. Can’t hear Nicholas Gaudern: 20 kilohertz. E- exactly. So that’s right at the upper end. So we weight the results, and this is part of the ICE standard, to understand how the human ear perceives the sound. Allen Hall: Oh, wow. Okay. Nicholas Gaudern: Um, and this is where we get our, our five decibels Allen Hall: from. So this, this was really an iterative process then- Yeah … in the DT laboratory. Yeah. Ooh, wow. I didn’t realize that. Mm-mm. I, I figured you had gotten relatively close by computational methods and then- We- … honed it a little bit … Nicholas Gaudern: we, we come sort of computate… We do a lot of computation around the angle of the serrations, because the angle of the serration is really critical for, uh, lift generation and loads. Allen Hall: So when you’re speaking of angle, you’re talking about- E- Nicholas Gaudern: exactly … this angle back here at the- You can see that angle there. Okay. Allen Hall: Yeah, Nicholas Gaudern: yeah. Because you don’t want to put a serration on a turbine and add 20% to the lift of the blade. Right. No. Because- Allen Hall: That’s not- … Nicholas Gaudern: lift means loads. Yeah. Allen Hall: You know? Right. You’re adding load. Nicholas Gaudern: So you have to be very careful about how you design these products to make sure that you’re not gonna add extra load to the turbine. And, and on the flip side, you also don’t wanna reduce lift significantly, which then [00:19:00] there’ll be less power produced. So it’s a bit of a balancing act, and this is where the computation comes in. We do a lot of CFD on these to make sure that we’re, we’re handling the loads correctly. Allen Hall: And how important is the material choice- Yeah … in terms of the noise quieting? Is there a little bit to it about, well, one, durability. Yeah. You, you want to put them on once and leave them forever, so there’s a lot of interactions between the air and these parts that are gonna flex and bend, and you got- I think there’s, you know- 20 years of Nicholas Gaudern: doing Allen Hall: that … Nicholas Gaudern: the, you’ve, you’ve s- you’ve hit the, hit the nail on the head there. The durability is critical. Yeah. It doesn’t matter if you put these products on the blade, and they perform beautifully for six months and then fall off or, or snap or whatever. Allen Hall: Right. Nicholas Gaudern: So no, we, we make these products out of the same material as our VGs, and this is a material, uh, it’s an ASA, uh, plastic. And we’ve had these out in the, in the field for a long time now, so we know- It’s- … this, this is great. Allen Hall: It’s ex- it’s kind of a flexible material. Nicholas Gaudern: Yeah, there’s Allen Hall: a little b- It’s stiff but flexible. Nicholas Gaudern: Yeah, exactly. There’s a bit of give in there- Yeah … uh, which is important, but it’s very impact-resistant. Uh, it doesn’t really suffer much in terms of [00:20:00] UV aging, which is obviously critical- Oh, wow. Yeah … when you’re, when you’re- Very critical, yes … out in the field. Yes. So yeah, we’re, um, we’re really happy with the material choice because we know from all our other campaigns with VGs that they last. It doesn’t matter whether it’s sun, rain, ice, snow. These products can survive out in the field for 20 years. Allen Hall: That’s one of the things I’ve noticed, uh, looking at a lot o- of blade photos with OEM trailing edge serrations. That the little triangles on the back edges break off. Nicholas Gaudern: Yeah. And I think- There’s Allen Hall: a lot of them. I was shocked on Nicholas Gaudern: some sites. One thing you have to be very careful as well is, is lifting and handling as well. Oh. So, you know, sometimes if these products are installed in the factory, then how do you safely transport that blade and lift that blade? Allen Hall: You really can’t. Nicholas Gaudern: So in some ways it’d be better if you put them on at site, but obviously I, I know that’s not always possible. No. So we’re typically acting, um, as, you know, a retrofit. Mm-hmm. So in that sense we, we minimize a lot of that risk of the, the transport and handling that the OEMs may have to deal with. Allen Hall: So [00:21:00] what’s next for Power Curve? What’s h- happening this summer? Nicholas Gaudern: So we’re gonna be really pushing to get Silent Edge and Dragon Scale out in the field more. Yeah. Um, Dragon Scale is, is really exciting, and we’re gonna get our, our first, uh, turbines in different countries equipped with these products. And Silent Edge, uh, we’re currently putting some of the finishing touches on the, um, the tooling, the injection molding tooling. So the part we have in front of us, this is actually one that we had in the wind tunnel. So this one here is a 3D print. A very nice 3D print. Oh, yeah, it’s- Uh, it’s had vapor smoothing on it, so the surface- It is really smooth is, is super nice. And you can put these out in the field. So the, the trial with Statkraft was actually with 3D-printed components. If you wanna do a trial for a few months, it’s very possible to do it with 3D prints. Oh. And I, I think they’d actually last way, way longer than that, but, you know, the test was designed to put them on, measure them, take them off again. Yeah. And that’s what we did. Allen Hall: Offshore. Nicholas Gaudern: Mm. Allen Hall: Uh, uh, w- we’ve had some people write into the podcast talking about offshore wind turbines. And in the States, offshore wind turbines are [00:22:00] usually 10, 15, 20 miles from the shore, but that’s not always the case. Over in Japan and some other areas, the turbines are pretty close to shore. Nicholas Gaudern: Yeah, def- They’re Allen Hall: almost- Nicholas Gaudern: They’re definitely near-shore … Allen Hall: they’re almost- Yeah. Yeah, yeah … onshore turbines, but because they’re offshore, they get really big, right? So y- you can build a really big offshore turbine. And some of the comments we have received is, “Hey, these turbines are noisy.” Nicholas Gaudern: Yeah. And, you know, the, the water surface can do some weird things- Allen Hall: Well, that’s what I wanted to know acoustically. Okay. Yeah. That’s what I wanted to know- Yeah. Yeah … because if you have trees and hills that kind of block the noise- Yeah … that’s easy. But if you have a turbine and you live on the, essentially the beach- Yep … or real close to the shore- Yeah … that turbine is right there. In some cases in Japan, it’s not very far. Yeah. You can see it. Nicholas Gaudern: Particularly on a still day, you know, when you have a very flat water surface, that can mean that sound is able to propagate a little bit further than maybe it otherwise would. Allen Hall: So is there a, a real need then to pay attention to the acoustics and noise- Yeah … coming off of offshore wind turbines? Nicholas Gaudern: [00:23:00] I think, uh, c- certainly the near-shore, the things you’re describing now. Yeah. Offshore’s an interesting question because I think often, if I think about the UK and, and Denmark, they are quite offshore, and I think in that, in that sense, the noise is much less of a, a concern. And I think it may be more driven by regulatory r- requirements- Mm-hmm than actual, you know, neighbor complaints perhaps. So noise is interesting because people put serrations on for different reasons. Yeah. Some put them on because there’s a regulation. Yeah. Uh, some put them on because they want to be shown to being a good neighbor, you know, doing the best they can to reduce noise- We should Allen Hall: try to- Nicholas Gaudern: which we should absolutely be doing … Allen Hall: do that every time we can. Nicholas Gaudern: And some are doing it because they have curtailment on their turbines. Allen Hall: Yes. Nicholas Gaudern: So in order to meet a regulation perhaps, they have to basically turn down the turbine, and it means that it spins slower. And if it spins slower, the noise is lower, sure. But the power output is also lower. And what we found is that on some turbines that are in noise modes, they’re losing 3, 4, 5% AEP- Ooh. Ouch … [00:24:00]every year because they’re having to turn down the turbine to meet a regulation or to, to satisfy, you know, uh, neighbor relationships. But just imagine what that means for finances if you put a serration on. You can turn the turbine up again, which you’re now addressing the noise at the source, so you don’t actually have to stop it spinning slower. You’re actually killing the noise where it’s being generated. Allen Hall: So there’s a big financial incentive- Yes … to look at trailing edge and try to quiet them as much as you can, particularly onshore. I think that case has- Yeah … been well made over time. I’m always shocked that a lot of operators that, uh, even in the US Midwest, and we s- we drive around quite a bit in the Midwest, there’s a lot of turbines that are near homes. Nicholas Gaudern: Yeah, Allen Hall: absolutely. Y- you know, there’s one or two or three homes. This isn’t like there’s a suburb right there, but there are homes out there, and, and they would like to have enjoyment of their property. Yeah, of course. And if you can knock down the noise a little bit, it would make it Nicholas Gaudern: a much more pleasant place. Well, if you take, you know, if you take 30-plus percent off the perceived loudness, that’s, you know- Allen Hall: Oh, that’s very noticeable … that’s gonna, that’s gonna make a difference. Yeah, you’ll get a thank you letter- Yeah for [00:25:00] sure. So that’s exciting. The- Yeah … all this is exciting. It- It’s Nicholas Gaudern: gonna be, it’s gonna be a really great summer, I think, to get more of these components out in the field. Allen Hall: So if, uh, an operator or an asset manager wants to get ahold of Power Curve, understand what Silent Edge is, and how to get it installed or put some dragon scales on this season, how do they do that? Nicholas Gaudern: So you can check out our website, uh, powercurve.dk. That has all of our contact details on. Uh, you can find me on LinkedIn, uh, as well. I’m often around these, uh- … events that we find- Yeah … uh, in different countries. So no, look, look us up, reach out by email, phone, whatever, and we’d be very happy to talk to you. Allen Hall: Or reach out to the India office. Nicholas Gaudern: Yes, that’s something that we’re hoping to have up and running, uh- So Allen Hall: if you’re Nicholas Gaudern: in India- … Allen Hall: later this year. Yeah. Reach out. Yeah, that, that’s gonna be an exciting advancement. Yeah. Great. For Nicholas Gaudern: sure. Allen Hall: Nicholas, it’s great to have you on the podcast again. Nicholas Gaudern: Nice talking to you, [00:26:00] Allen.

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