Drone VS. Rover Inspections, AI Crack Monitoring
Allen Hall, Rosemary Barnes, Philip Totaro, and Joel Saxum discuss the evolution of wind turbine blade inspections, from external drones to internal rovers. They debate the potential of AI in predicting damage progression and managing repair priorities, with Rosemary emphasizing the complexity of crack propagation in composites. Joel highlights Top 7’s innovative drone technology for detecting lightning protection system faults in blades, as featured in PES Wind magazine.
Sign up now for Uptime Tech News, our weekly email update 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 Facebook, YouTube, Twitter, Linkedin and visit Weather Guard on the web. And subscribe to Rosemary Barnes’ YouTube channel here. Have a question we can answer on the show? Email us!
Pardalote Consulting – https://www.pardaloteconsulting.com
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Intelstor – https://www.intelstor.com
Allen Hall: On the mean streets of Lowville, New York, Phil that’s your neck of the woods. The local Kraft Heinz plant has reclaimed the Guinness World Record for the largest cheesecake. Tipping the scales at a whopping 15, 008 pounds. Yes, that’s right. That’s seven and a half tons of creamy goodness.
Joel Saxum: I absolutely love cheesecake. My brother loves cheesecake so much that’s what he had at his wedding. He had a smorgasbord of different kinds of cheesecake that you could pick from.
Allen Hall: They broke the record, almost double the record that was held from a team from Russia. So here we go. Now we’re back into the 1980s.
Olympic hockey
Philip Totaro: exit no that’s great that’s good that’s a good thing we should be world domination in cheesecake size
Allen Hall: and
Philip Totaro: wait.
Allen Hall: Yeah why did we get an invite joel i don’t understand we should’ve been top of the list to come to lowville.
Philip Totaro: That’s yeah that’s what i’m saying like did they pass it out to everybody in town like how do you eat a cheesecake seven tons of cheesecake.
Allen Hall: They donated to local food bank is what they did after everybody had a slice or two or three. But 15, 000 pounds of cheesecake. What’s that in metric tons, Phil? Come on. I need a sense of this for the Europeans in our audience. 6. 8 metric tons. That’s a lot of metric tons, but this, these are the things you got to keep your eyes open for, right?
So if they’re going for a world record. And anything food related, they need to be calling the Uptime Podcast and at least give us a heads up so we can plan our travel accordingly, because this cheesecake thing seems like we missed out.
I’m Alan Hall and here are this week’s top news stories. In our first story, Vestas has secured its largest onshore wind project to date in Japan. The company has received a 134 megawatt order from Invenergy. for the Inaniwa Wind Energy Center. The order includes 32 V117 4. 2 megawatt wind turbines and a 20 year service agreement.
Deliveries are expected to begin in the first half of 2027 with commissioning planned for Q1 2028. Moving to Spain, Windar has started preparatory work to construct a new monopile factory. The facility will have the capacity to manufacture monopiles up to 12. 5 meters in diameter, 3, 500 tons, and 130 meters in length.
With an annual capacity of 100 to 120 monopiles, the factory aims to supply wind farms in the North Sea, the Baltic Sea, as well as the East Coast of the United States. In a significant development for the Mediterranean region, nine Southern European Union member countries have pledged to turn the area into a renewable energy hub.
Officials from Cyprus, Slovenia, Malta, Croatia, Greece, Italy, France, Portugal, and Spain are focusing on harnessing offshore wind and solar energy. They aim to set up a joint renewable energies project across borders and have called on the European Commission to conduct a study on the region’s renewable energy potential.
Shifting to Sweden, Northvolt has announced a revised scope of operations in response to challenging market conditions. The company will focus on ramping up its first 16 gigawatt hour production capacity at Northvolt ET. resulting in the redundancy of approximately 1, 600 employees. Northvolt will suspend the expansion project at Northvolt at this time.
and slowdown programs at Northvolt Labs. In India, Xcel Composites and its joint venture Koneko Xcel India have won a bidding process to supply poultry to Carbon Planks for wind turbine spar caps to Vestas. The products will be manufactured in KECI’s new factory in Goa, India, with deliveries estimated to begin in the last quarter of 2025.
This agreement extends an existing multi year frame contract and deepens the collaboration between the companies. And Denmark is making strides in wind turbine testing capabilities. R& D Test Systems has completed the foundation of a test bench for main bearings at the Offshore Renewable Center in Odense Port.
The facility will be able to test both geared and direct drive main bearing arrangements for 25 megawatt turbines. The project, supported by a 10 million euro grant from the Danish Greenlab program, is expected to be delivered in 2025. Lastly, Nikon Corporation is set to provide Eurus Energy Holdings Corporation with a riblet film for wind turbine blades, aimed at improving wind turbine generation efficiency.
In Japan’s first such verification test, the film will be attached to turbine blades at the Yurisoya Misaki wind farm. Nikon anticipates that the Riblet film could improve wind power generation efficiency by approximately 3%. That’s this week’s top news stories. After the break, I’ll be joined by my co host, renewable energy expert and founder of Pardalote Consulting, Rosemary Barnes, the founder and CEO of Intel Store, Phil Totaro, And the Chief Commercial Officer of WeatherGuard Lightning Tech, Joel Saxon.
Lightning is an act of God, but lightning damage is not. Actually, it’s very predictable and very preventable. Strike Tape is a lightning protection system upgrade for wind turbines made by WeatherGuard. It dramatically improves the effectiveness of the factory LPS, so you can stop worrying about lightning damage.
Visit weatherguardwind. com to learn more, read a case study, and schedule a call today.
Allen Hall: It’s almost fall in the northern hemisphere, which means that blade inspections are occurring. A lot of drone inspections are happening right about now at the end of season after all the repairs have been done.
So you’re typically seeing two scans in some wind farms. One in the spring, one in the fall, just to keep track of how things are progressing. But there’s been a recent big shift, I think, in from moving away from external drone inspections, which had been the norm, to a lot more of internal rover inspections.
With a little automated car with the cameras on it and the lights and the beepers and the whole thing. And I think the industry has really learned from that. I’ve been talking to a number of blade engineers and we were at Sandia last week that the significant structural defects are turning up sooner on the inside.
And that’s a big shift, Rosemary, I think, because for so long, we were just doing drone inspections and when we got to standardized drone inspection, that was the big deal. But. Now we’re doing inside and outside.
Rosemary Barnes: Yeah, I actually wondered this because of a job I was on recently They were going to go do internal inspections that I mean to be honest I hadn’t even been doing external inspections properly But yeah They were going to go do some internal inspections and I just wondered how they actually get into the blade like I know that you can get in between the two webs and trailing edge is mostly pretty clear, but in the leading edge between the front web and the leading edge, there are bulkheads all the way down these bits of foam or whatever.
They’re structural, mostly not, mostly to assist with manufacturing, but they’re blocking off the cavity. You can’t just crawl into the leading edge cavity and crawl all the way down, no matter how small you are, because you’re going to encounter these solid obstacles. What do they do about that?
Are they punching their way through them, which it being, like I said they’re not primarily structural, but they’re not structural. How do they manage that?
Allen Hall: I don’t think they’re doing anything at the bulkheads. I think a lot of it is right between the spars, the shear webs. And I think from what I can tell so far, are they not looking for problems with core splice areas, transverse cracks?
Which are the Cat 4, Cat 5s that you would need to know. I know they have leading edge and trailing edge dis bonds, but the big ones seem to be in the mid span region.
Rosemary Barnes: That’s true, that they would catch most of the catastrophic, like most of the catastrophic stuff would happen on the main laminate, which is, yeah, right down the middle where it should be possible to get a really long way down, so I guess they can probably capture most of it.
But yeah the system that, or the, one of the things that, I know that they’re looking for with drone inspections is, when lightning flashover happens, then that can cause damage on the inside. And you might not see it on the outside until it’s like a category five and the blades about to snap in half.
That can obviously happen on the leading edge. And yeah, but I guess maybe they’re not catching all of that, but they’re catching other damage that. Might cause big structural problems. Makes sense.
Philip Totaro: Wouldn’t it make sense to have a channel running the length of the blade adjacent to the one of the, like the front or the rear spar so that you could put, rather than a Rover, couldn’t you use one of those, like a larger size of a surgical camera and just run it down this channel and have it do the inspection on the trailing edge bond line?
Rosemary Barnes: They do boroscope inspections. Although often that’s also from the outside. I think that they, find lightening damage and then poke around inside with a a broscript to see if there’s a lot of internal damage so that they would need to, cut it open and fully repair it or not.
But I was just thinking, I thought you were going to say shouldn’t the manufacturers make that channel so it makes maintenance and operations easier? I think they should and that they never will because no one cares about the full lifetime, life, yeah, full life cycle of a wind turbine.
It’s all just about that, upfront cost.
Philip Totaro: Not when they’re in the business of selling aftermarket blades. Yeah. Yeah. And they’re service. It’s Hey, we got a brand new blade you could buy instead
Rosemary Barnes: of repairing the old one. It’s basically like the inkjet blade. Printer model now and wind turbines like, Oh, give me the wind turbine for free.
But yeah, extort you on the service and and spare parts. But I was at this conference this week. It was a systems engineering conference. They brought me in to do yeah, one of the keynote speeches there. And so of course I stayed around for most of the rest of the conference and learned some interesting things.
And one of the guys I got talking to he, he does a system analysis. He’s worked with offshore wind in the Netherlands. For installations actually, but he was saying that, systems engineering approach, what the industry desperately needs is to do a systems engineering approach right from the start, where you take into account like the full life cycle of the turbine so that you are when you’re designing a wind turbine, you are actually thinking about, repairs and all that sort of thing that is going to need over the next 10, 20, 30 years of its lifetime.
And that should be a yeah, a design requirement early on. And I was thinking that, yeah, we do need that, but I just can’t see the mechanism that we could ever get that. Cause it would just cost money for the manufacturer and they wouldn’t be able to sell it for anymore. So yeah, they’re obviously not going to do it.
Joel Saxum: We were at the Sandia conference last week talking with a lot of operators and you’re starting to see a difference in approaches with internal inspections. So you see some that are, yeah, we do internal inspections just like we do external inspections. We inspect everything. There’s some that are even large operators looking at, we just do targeted ones on issues that we know exist, or blades that have a history of certain things, and some doing the, hey, we do 10 percent of a wind farm because they’re expensive, right?
They’re, in the United States, they’re between 1, 000 and 1, 800 per turbine. So they’re, five times the cost of an external inspection. So you have a lot of people doing 10 or 20 percent of their fleet or 10 or 20 percent of a wind farm. And if they find an issue, then they’ll go and start expanding the scope.
But one of the things that was common, right? Is we know that there’s quite a few people starting to look at doing crawlers and inspections internal in blades. With not just with people, but with actual, with the crawlers to get a good baseline from commissioning. So they’re either doing it right when they come out of the factory or right when they get delivered on site to make sure that they’ve got documented what that blade looked like before it was hung up.
And to me that is a fantastic idea.
Allen Hall: Are the crawlers still being operated by the ISPs or are the operators starting to rent them basically to do the internal inspections? You’re getting a little bit of
Joel Saxum: both and that’s driven by cost model, right? So same thing with external inspections where we started to see that Hey, you can rent a drone from us or you can buy a drone from us and you can fly whenever you have a good day or winds are negligible or whatever that may be in the external side.
You’re starting to see that in the internal side. I know our good friends Armando at Earthwind and Rodolfo and the team down there from Brazil they’re start, they have some of them up in the United States now. So they’re putting them out there and that their idea is they made it easy enough to pilot them.
Easy enough to collect the data where they can basically put one in a box, send it out to a site, they can do their inspections, and then the data goes back to the mothership, down in Sao Paulo, and they do all of the analysis and stuff down there. You have, there’s other places like like the Aarons team, they’re very efficient at doing these in a cost effective way because When they’re on site, a lot of times they’re doing LEP, external inspections, internal inspections, cleaning towers, all kinds of stuff, so they have the same crew, less mobilization costs.
But yeah, if it was me, the cost of these things are to rent them, it’s not and a robot internal crawler is not like a drone that requires a lot of maintenance. Drone after so many hours, you gotta replace motors, you gotta do this, it’s very difficult to fly, you gotta have special license, or not very difficult to fly, but can be, you gotta have special licenses, all this stuff a crawler is can your six year old kid drive a remote control truck?
Okay? They can basically do an inspection, so the technicians can do that themselves. Fairly easily with a little bit of training.
Allen Hall: And the latest generation of crawlers, the images are outstanding. It’s scary. The one,
Joel Saxum: the one I really like is what Aaron’s has done for the the root inspections, because of course, the root in some of these blades is huge, right? Especially offshore. Some of these things are. three meters across at the root. They’re massive. So what they did was they have, of course, their regular camera setups at the nose that can see in, 180 degrees as they go through the whole thing. But they actually took a full frame CMOS sensor, like what would be, like a Sony a seven R type thing.
And they put it on the back of the drone and it’s perpendicular, it’s pointed perpendicular to the path. Then it rotates in a 270 degree angle up. So you’re getting a very high resolution image of the root area as you go into the root or through the root area.
Allen Hall: Is that really changing the dynamic though?
I think that the key to all this data is in the, because the images are so heavy and detailed now, are we just into the phase of, we need some AI to go through the images to find out what’s going on.
Joel Saxum: Yeah, everybody that’s a big player in the internal inspection world is developing some kind of AI to handle the analysis, right?
Because to be honest with you, the most important thing in internal inspection robotics, whether it’s with the Helios drones or whether it’s with the crawler or whatever, is the lighting, the quality of the lighting. Because if your lighting isn’t good in there, or if your lighting is too vibrant or too high color, you end up with sheen and shear off the fiberglass and you can’t see, or sometimes you’re kicking up dust, or you got some other things going on, so if the lighting is right, and the lenses are correct, then you can get these amazing images, and you get a ton of them, right?
You’re gonna get a whole pile of data, so I think Marone’s is doing some AI stuff. I think Earth Wind’s doing a little bit of AI stuff. Of course, every trade show you go to, there’s another one kind of popping out.
Allen Hall: When does UT happen? I, we at Sandia, we ran into a number of people that were doing ultrasonic tests and looking at specific parts of the blade that was particularly the root area was a big emphasis.
We need to see what’s going on down there. Are we doing a lot of ultrasonic inspections in the fall? quantify what’s happening on our blaze before it gets
Joel Saxum: cold? Not really. The thing with UT is it’s very specialized. It is an amazing tool. In Rosemary, you know this better than probably all of us, but NDT is an amazing tool to get what you want.
However, it’s expensive. It’s difficult to get really highly skilled, level two, level three, NDT technicians out there. The processing Is in, is intensive because composite NDT is very difficult compared to steel. Steel NDT is pretty cut and dry.
Rosemary Barnes: Yeah. And also, really to get really good visuals, it needs to be quite flat and wind turbine blades mostly not flat.
Even in the factory where they’ve got like the full big kit and the, full time employee who’s a expert, they still can’t just scan everything and see everything inside a blade. It’s like there’s certain parts that you can get a pretty good image of. And yeah stuff does get missed, but I guess they’re developing the technology all the time to get more portable machines and also to just improve the kinds of image you can get and the amount of, Complexity that it can deal with in terms of curvature and that sort of thing.
Joel Saxum: And then the other thing about NDT that people maybe don’t realize as much, if you’ve never played in that space is NDT is not one technology, right? Like CIC NDT and the team over there, those guys have I think a half a dozen or even more, maybe even 10 different kinds of technologies where, you know, laser shearography and just the UT that you would think.
And then you have, you’re looking at microwave for composites and all kinds of stuff. It’s right now. I think that when there’s specific and targeted issues and wind turbines, yes, they’re getting some of them are getting regular quarterly inspections, right? You’re seeing the root sections of some of these turbine models being inspected quarterly out in the field, but that’s because they know there’s an issue and there’s a specific problem there, but to have a like an autonomous external drones style, we’re just going to look at everything.
Okay. Thank you. Doesn’t happen yet in the NDT world. And it’s cool that we’re developing robotics for, cause that could un, unlock a little bit more power in the NDT world. But right now you have like experts like Jeremy Hanks over at CIC NDT that they have the teams that know how to do it. It’s just not in super high demand.
Allen Hall: And does thermal imaging start taking some of that space in terms of inspection because of the, sort of the localization that has to happen with. Ultrasonic inspections, where thermal inspections, it gives you a quick sense of how the blade’s doing. If you can get images, the resolution you want, is that the next generation of inspection before you hit wintertime?
I
Joel Saxum: think thermal inspections are a good, or can be, when it gets developed a little bit better than it is now, can be a good screening tool, but I don’t think they’re an inspection method that is something you bank on.
Allen Hall: Going back to Rosemary’s comment, you can’t see the leading edge, you can’t see the trailing edge, because the access is poor.
Thermal imagery should get you some image of the
Joel Saxum: leading and trailing edge. I don’t think the leading and trailing edge besides the trailing, a trailing edge crack that’s doing this, but you can see that most likely with a visual drone, you don’t need a thermal drone for that. The ones you’re looking for are the ones that are under the gel coat that are causing some friction or something of that sort, or a little hairline crack.
That’s why I think it’s a screening tool. You may look and see, okay, we’ve got, Hey, there’s something weird going on here. Let’s go up and look at it.
Allen Hall: Going back to your 10 percent rule of look at 10 percent of the turbines, would you quick scan a number of turbines just to get a gross sense of, Hey we have these, we may have this potential issue, then come back with UT to, to suss it out.
Joel Saxum: And if it’s fast enough, like I know the Rom R MotionCam guys have been working on this for a while. The Rom R MotionCam concept. Is a very quick and speedy inspection process because you don’t need lotto, you don’t shut the turbines down, you don’t do any of that. Especially if you’re in like, cornfields or something, or cut cave fields, you just put that remote cam unit in the back of a truck and drive and boom, as the turbine spins, you take a peek at it, take some inspection images, you move on to the next one.
Like I just, in my opinion, that’s a good screening tool, but that’s not an end all be all inspection. You may find an or isolate an issue like, Hey, we need to look at blade B on this turbine because there’s something going on there, but you’re not going to be able to diagnose what the issue is from that.
At the end of the day, right now, thermal imaging technology, unless you’re getting some kind of ITAR approved thermal imaging system from a, like an Apache helicopter, like you’re not going to see any kind of detail that you need to be able to diagnose a problem.
Allen Hall: The next generation after thermal is terahertz.
We saw some of that at Sandia where the, you in theory can see individual layers of fabric in the layup because the wavelengths are so small you can measure that and detect dis bonds and it’s giving you, from what I saw, a really accurate look at an evenness in the composite structure, much more than ultrasound can do, but I’m sure it’s not nearly as fast as ultrasound is, Which is the problem, right?
Is so as technology develops, are we going to just know too much?
Philip Totaro: And look, the reality with AI is that the image quality we have today results in AI that can only be a certain level of accurate. If we address the issues that Joel’s mentioned, and you get higher quality and higher resolution, not only with visual, but some of these other technologies, and you start layering things together, it can be data overload if you don’t take AI to scrub it, and figure out how to actually take that results of the AI analysis and do something useful with it.
Which is where, that’s really where a lot of the AI developed predictive maintenance solutions have fallen down. Up until now, is, we’ve got a ton of data, people aren’t really using it right. With or without AI, it’s still too much to analyze even today, and you don’t even get the quality, so there’s a lot of false positives in the data sets that we have.
Assuming that you can improve the quality of the imagery and reduce the false positive rate down to a point where you could actually do visual or any other type of inspection, get actionable information out of it, the question is then, how are you leveraging that actionable information to be able to address things like We see something that’s maybe a cat two or three damage right now.
I need to be able to determine how fast that crack’s going to propagate to become a cat four or five so that we can avoid a crane call out. Do we prioritize fixing that now? Or do we only have the budget to be able to fix the cat four and five issues that we’ve got? That’s still a huge challenge for operators at the moment.
So that’s where AI can take us.
Rosemary Barnes: Can it though? It’s I never. Never heard anybody that thought that you could tell you to tell how fast a crack was going to propagate over composites It’s just it’s unpredictable. You know, like a cat one crack could become cat five tomorrow or might never progress and Yeah, and
Joel Saxum: There’s people that are working on that project, right?
Rosemary Barnes: Yeah, but it’s like the holy grail of composites for at least the last 20 years. So I don’t know if we’re close and It might be the sort of thing that AI can crack. Ha, funny intended. It might be the sort of problem that AI can crack if if they had the data, but how are they going to get the data?
I guess if you like, maybe a cool research project would be to put cameras inside a hundred thousand blades and just have them, like watching cracks, and then they might, AI might be able to pick up something that does give you a, a tip off for when something’s about to happen.
You would need at least tens of thousands of data points. It’s not something that you get from, the amount of data that’s being collected today and and if, yeah, someone was to go through it, it’s all just, like one off snapshots and I don’t see us learning anything unless we set out to learn it.
Joel Saxum: The trouble with that, Rosemary, is exactly like you’re saying, you need all those data points, but then you also have to. You also have to filter all that data by blade model, sub model, manufacturer, resin type, core ramp. There’s so many things that you can’t actually, if all the blades were the same, then yeah, we could probably do that.
But there’s so many variations and out in the field that. It’s not possible. I don’t at this stage.
Philip Totaro: No and that’s, but that’s the point, isn’t it? As, as technology evolves and becomes cheaper, because it’s more reliable, whatever, it’ll get used more, and then we’ll start building that catalog of information over time.
But now is when we really, up until now, what we’ve been doing is just Stumbling through the methodology of like, how do you leverage, technology to do internal and external inspections. We’re now at a point where the technology is sophisticated enough to actually start giving us meaningful data and feedback that could eventually be used to build models that’ll do some of that prediction.
I think you’ll start getting more useful information out of it from what we have the opportunity to collect. But you’re right, I we are just at the beginning of the meaningful data collection process to be able to do anything with all that.
Rosemary Barnes: Yeah. There is heaps of, in useful information that is coming out from ai looked at images and especially compared to a few years ago, it was doing, it was worse than.
Worse than not looking at the images because you just got so many damn false positive positives that no, no one like was just totally overwhelming. Cat five grease
Joel Saxum: smudges.
Rosemary Barnes: Oh yeah. Like on two thirds of the blades and one of the ones I looked at there, had cat five damage and everyone else spent, oh yeah, that’s cool.
And continued on, like no one ever looked into it. So it was just like, it meant that they didn’t. They did these inspections instead of other ones and then couldn’t use the information. So it was just as if I never did any inspections really. So they went backwards, only a few years since then, like we do say a lot of really useful information now from AI stuff.
And of course, like for cat five, you’re going to look at the image yourself like with the human eyeballs as well and get up to, get a better look around. We haven’t totally divorced the need for humans involved at this point and I’m sure it will get better. But there’s definitely some issues are much, much easier for AI than others.
And yeah, I think that’s the thing, like AI, you just need just so much data. And especially with crack propagation, that is such a such a complex topic to start with. I don’t think that is going to be one of the next ones that we say, but. I would love to be surprised by that.
Joel Saxum: If we rewind to what Phil said, like Rosemary, you’re a consultant in the wind energy and renewable energy world.
So you deal with people on blade issues and other things. So you hear this from your clients. I’m sure Phil, you and I have talked about this in the off air. Many times, Alan, you and I talked to everybody else about this. Everybody just wants to be told what to do. They would rather not even have to look at these inspections.
Just tell me on turbine 7 you need to do this and on turbine 8 you need to do this and you’ll be fine. Great. Thank you. That’s where I want to go. Because we know there’s this, we always talk about the shortage of technicians but there’s a Even worse shortage of good engineers.
Rosemary Barnes: I’m happy to tell people what to do.
If someone needs to be told what to do, they can, they
Philip Totaro: can call me and I’ll tell them. The, Joel, the other thing there’s a shortage of is budget. Because I hear all the time that, most of the owner operators, not all of them, and there was one I spoke to back in Minneapolis at the wind power event who, I asked him like, Hey, do you guys like ever run out of budget before you have the opportunity to fix your, Cat 2, Cat 3 damage on blades or whatever else.
And they were like,
Rosemary Barnes: no, we’re good. Cat 2 and 3. People are running out of budget before they get to all the Cat 4 damage in my experience. Maybe it’s just an Australian thing, but definitely Cat 2 is never being repaired unless maybe if they’re up there anyway, that it might get done.
Philip Totaro: One owner operator in the U.
S. is doing that, or so they say. But that’s exactly my point, is most of the time, companies run out of budget fixing the Cat 4 and 5 damage that they obviously have to fix, because you gotta get the turbines back up and running, or prevent further catastrophic failure. The issue with that is, can we figure out a way, because, something that’s a Cat 4 today wasn’t always a Cat 4, and that’s why I keep going back to, can AI help us figure out how you can avoid a crane callout, Because that’s where it just gets preposterously expensive.
That’s why everybody runs out of budget. Because they’re getting to these too late, they’re being reactionary in their repairs, and not just on blades, but even on things like gearboxes or anything else, generators. They’re being, they’re still being reactionary.
Rosemary Barnes: With a good spreadsheet of every blade and every inspection and damage and tracking over time.
what it was, knowing, you can know from that what the average cost is for different categories of damage. I think you could definitely come up with a better strategy for repairs. Yeah, and because it would be statistical then, you don’t need to know. This particular blade is going to go from cut three to cut five on, August 27th, it’s going to say that statistically, if you leave this, it’s going to cost you more than what it would cost you to get up and fix a few that were never going to progress.
It’ll tell you where that point is that at category two, or is that at category three? for that you should be doing them that day. Or I think that definitely like a larger operator with a good spreadsheet and people usually don’t have good spreadsheets in my experience.
The, like it’s always like a lot of the work that I do is so tedious. You’re going back through. manually opening PDFs for this blade, okay this, was there a, chasing up the, I can’t see the report, in this year, was there one, and you can’t expect AI to make anything of that either, but if you put it all in a in an organized database, then I think that you could definitely pull out a Better repair strategy.
I wonder if people are already doing that.
Joel Saxum: When you open any one of those spreadsheets at any one of these operators, and you go filter by lightning damage, that spreadsheet is going to tell you to call WeatherGuard Lightning Tech and get strike tape installed because it’s going to lessen your costs over time.
Philip Totaro: Well, Joel if that database doesn’t exist, they should be calling Intel store and we’ll help them build that database because that’s where, you The real value is in, in understanding how those things, how this can escalate. I’ve had literally three different asset owners say that if that kind of tool existed, they’d buy it.
Joel Saxum: As busy wind energy professionals, staying informed is crucial and let’s face it, difficult. That’s why the Uptime Podcast recommends PES Wind Magazine. PES Wind offers a diverse range of in depth articles and expert insights that dive into the most pressing issues facing our energy future. Whether you’re an industry veteran or new to wind, PES Wind has the high quality content you need.
Don’t miss out. Visit peswind. com today.
Allen Hall: The new PES win magazine is out and it is thick, Joel. I was looking at it in the office this morning. I thought I was getting a workout from holding this magazine. My gosh, there’s a lot in this episode or this issue of the magazine. And obviously the thing about PES Wind is that the images and the photographs are amazing.
So it’s very easy just to look at the pictures, which is something I like to do when I first get it, like Picture book kind of guy? It is! It’s The quality of the images and the printing is just way beyond what you usually see in a print Magazine today, but the article I stopped on was one from top seven because it said lightning and anytime I flip through and I see something about lightning, I have to pause and look at it.
But top seven, which is a essentially a drone company or drone based company has this technique where they can determine if your lightning protection system is broken. Without crawling inside or doing a bunch of resistance measurements. And Joel, you want to describe how this device works, how the system works?
Yeah,
Joel Saxum: absolutely. So tech, classically. LPS measurements are usually done by resistance. So you put physically put a meter on the end of a receptor and either a meter on, the ground or within the blade. If you’re just checking in the blade, you have to have a technician in there and a technician on ropes or something of that sort.
So it’s usually done by a resistance measurement. So if you have very low resistance, your LPS looks good. The challenge with that can be is low resistance is how do I explain this? The cable, the LPS cable within a turbine is so large that you can have damage to it, you can have cracks in it, you can have strands, you can have partial disconnects, where the next lightning strike that comes will break that thing.
But it will still give you a good ohm reading. What this drone does is this is not a from a physics and electrical engineering standpoint, this is not a new concept. But it is the first time we’ve seen it commercially readily available on a drone and able to do this. What they’re, what the concept is you put a, basically an electromagnetic pulse through the down conductor.
And then with the drone, you have a sensor on the drone that has an electromagnetic field reader. And then you chase that pulse along the blade. So you don’t actually touch the blade, you can do it remotely, so you’re not having to fly right into it or up against it. You can still do it back a little ways.
But what you’re gonna do, or what this solution does is it pinpoints where the damage is or where the break is within the blade. Something that technicians have wanted forever, right? So technicians will be, hey, we’ve got a broken LPS, we gotta fix it, where is it in the blade? We don’t know, we know it’s broken.
So you can put someone in the blade and you can get so far along it until probably, it gets pretty tight once you get about to the 40 percent mark. Where a guy the size of me is definitely not gonna make it. I’d probably make it to the 50 percent mark.
Allen Hall: I was gonna say the root, but
Joel Saxum: Yeah, scoot along with a skateboard on my belly or something.
Allen Hall: Yeah, I’d
Joel Saxum: peek in there.
Allen Hall: I can’t get through the access panel. I’m way too tall for that craziness, yeah.
Joel Saxum: So what this tool does is it’s able to let the technicians pinpoint exactly where the damage is. So if you need to open up a part of the blade to fix the LPS, you can do it in that specific spot. It’s a great time saver.
It is. It has the capability. Now, I’ve never seen this piece of kit run in the field, so I don’t know exactly what the operation looks like, but in theory, I get it and I like it. So again, Top 7, they’ve got high resolution cameras on drones, they’ve got some other things, they’re a drone company, but this is their kind of flagship device that we’ve heard about for a while, able to find where the break is
Allen Hall: in the LPS cable.
So if you haven’t read this Top 7 article, you better get that. To PESWIN. com, download it and read it. You get this great information in there.
Joel Saxum: Okay, I was just hanging out with some of my cousins from San Diego that live near La Jolla Beach, but this wind farm is called La Joya. Wind farm in New Mexico, and I don’t want to get that wrong.
It’s an Avangrid wind farm. It was built by Wanzik in February of 2020. They finished it in May of 2021 with balance of plant and everything else. The project has 111 turbines, and this is the interesting part of this wind farm. 74 of those 111 turbines are on state trust land. The other ones are on private land.
So there is Some SGRE G114s and 76 GE 2. 82127 machines in this wind farm. And to get it built on the state trust land, why they did it and how they did it. They had a bunch of support from U. S. Senator Tom Udall, U. S. Senator Martin Heinrich, a Congresswoman, Deb Highland from New Mexico’s 1st District.
And the governor of New Mexico, Michelle Luan Grisham. And one of the reasons that they pushed so hard to do this was on the state trust land, is it’s going to give a ton of money back to the state. New Mexico classically is a state that doesn’t have a huge tax base. So nice for them to get some income from a resource that they have in spades, which is wind.
So we’re seeing, the Sun Zia project. That’s in New Mexico. So New Mexico is becoming a haven for wind farm developers. There’s hundreds of thousands of acres of state trust land. That’s prime for renewable energy generation. Avon grid took advantage of this partnered up with PNM, which is the power corporation in New Mexico.
Helped PNM hit some other state emissions free goals. They’re well on their way to the 100 percent carbon free by 2040 benchmark that they’ve set with this wind farm in place. And some of the other ones that are moving there. So the Avon grid. La Joya Wind Farm in New Mexico is Torrance County.
Allen Hall: You are the wind farm of the week.
That’s going to do it for this week’s Uptime Wind Energy podcast. Thanks for listening and please give us a five star rating on your podcast platform and subscribe in the shows below to the Uptime Tech News newsletter and check out Rosie’s YouTube channel Engineering with Rosie. We’ll see you here next week on the Uptime Wind Energy podcast.
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Morten Handberg Breaks Down Leading Edge Erosion
Weather Guard Lightning Tech

Morten Handberg Breaks Down Leading Edge Erosion
Morten Handberg, Uptime’s blade whisperer, returns to the show to tackle leading edge erosion. He covers the fatigue physics behind rain erosion, why OEMs offer no warranty coverage for it, how operators should time repairs before costs multiply, and what LEP solutions are working in the field.
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: Morten, welcome back to the program.
Morten Handberg: Thanks, Allen. It’s fantastic to be back on on, on the podcast. Really excited to, uh, record an episode on Erosion Today.
Allen Hall: Wow. Leading as erosion is such a huge worldwide issue and. Operators are having big problems with it right now. It does seem like there’s not a lot of information readily available to operators to understand the issue quite yet.
Morten Handberg: Well, it, I mean, it’s something that we’ve been looking at for the, at least the past 10 years. We started looking at it when I was in in DONG or as it back in 2014. But we also saw it very early on because we were in offshore environment, much harsher. Uh, rain erosion conditions, and you were also starting to change the way that the, the, uh, the coatings [00:01:00]that were applied.
So there was sort of a, there was several things at play that meant that we saw very early on, early on offshore.
Allen Hall: Well, let’s get to the basics of rain erosion and leading edge erosion. What is the physics behind it? What, what happens to the leading edges of these blades as rain? Impacts them.
Morten Handberg: Well, you should see it as um, millions of, of small fat, uh, small fatigue loads on the coating because each raindrop, it creates a small impact load on the blade.
It creates a rail wave that sort of creates a. Uh, share, share loads out on, uh, into the coating that is then absorbed by the coating, by the filler and and so on. And the more absorbent that your substrate is, the longer survivability you, you’re leading into coating will have, uh, if you have manufacturing defects in the coating, that will accelerate the erosion.
But it is a fatigue effect that is then accelerated or decelerate depending on, uh, local blade conditions.
Allen Hall: Yeah, what I’ve seen in the [00:02:00] field is the blades look great. Nothing. Nothing. You don’t see anything happening and then all of a sudden it’s like instantaneous, like a fatigue failure.
Morten Handberg: I mean, a lot of things is going on.
Uh, actually you start out by, uh, by having it’s, they call, it’s called mass loss and it’s actually where the erosion is starting to change the material characteristics of the coating. And that is just the first step. So you don’t see that. You can measure it in a, um, in the laboratory setting, you can actually see that there is a changing in, in the coating condition.
You just can’t see it yet. Then you start to get pitting, and that is these very, very, very small, almost microscopic chippings of the coating. They will then accelerate and then you start to actually see the first sign, which is like a slight, a braided surface. It’s like someone took a, a fine grain sandpaper across the surface of the plate, but you only see it on the leading edge.
If it’s erosion, it’s only on the center of the leading edge. That’s very important. If you see it on the sides and further down, then it’s, it’s [00:03:00] something else. Uh, it’s not pure erosion, but then you see this fine grain. Then as that progresses, you see more and more and more chipping, more and more degradation across the, the leading edge of the blade.
Worse in the tip of it, less so into the inner third of the blade, but it is a gradual process that you see over the leading edge. Finally, you’ll then start to see the, uh, the coating coming off and you’ll start to see exposed laminate. Um, and from there it can, it can accelerate or exposed filler or laminate.
From there, it can accelerate because. Neither of those are actually designed to handle any kind of erosion.
Allen Hall: What are the critical variables in relation to leading edge erosion? Which variables seem to matter most? Is it raindrop size? Is it tip speed? What factors should we be looking for?
Morten Handberg: Tip speeds and rain intensity.
Uh, obviously droplet size have an impact, but. But what is an operator you can actually see and monitor for is, well, you know, your tip speed of the blade that matters. Uh, but it is really the rain intensity. So if you have [00:04:00] sort of a, an average drizzle over the year, that’s a much better condition than if you have like, you know, showers in, in, in, in a, in a few hour sessions at certain points of time.
Because then, then it becomes an aggressive erosion. It’s not, it’s, you don’t, you get much higher up on the. On the, on the fatigue curve, uh, then if it’s just an average baseline load over long periods of time,
Allen Hall: yeah, that fatigue curve really does matter. And today we’re looking at what generally is called VN curves, velocity versus number of impacts, and.
The rain erosion facilities I’ve seen, I’ve been able to, to give some parameters to, uh, provide a baseline or a comparison between different kinds of coatings. Is is that the, the standard as everybody sees it today, the sort of the VN curve
Morten Handberg: that is what’s been developed by this scientific, uh, community, these VN curve, that that gives you some level of measure.
I would still say, you know, from what we can do in a rain erosion tester to what is then actually going on [00:05:00] the field is still very two very, very, very different things you can say. If you can survive a thousand hours in a rain erosion tester, then it’s the similar in the field that doesn’t really work like that.
But there are comparisons so you can do, you know, uh, a relationship study, uh, between them. And you can use the VN curves to determine the ERO erosion aggressiveness. Field. We did that in the bait defect forecasting that we did in wind pile up with DCU back in 2019, uh, where we actually looked at rain erosion across Europe.
Uh, and then the, uh, the actual erosion propagation that we saw within these different sites, both for offshore and for onshore, where we actually mapped out, um, across Europe, you know, which areas will be the most erosion prone. And then utilize that to, to then mo then, then to determine what would be the red, the best maintenance strategy and also, uh, erosion, uh, LEP, uh, solution for that wind farm.
Allen Hall: Oh, okay. Uh, is it raindrop size then, or just [00:06:00] quantity of raindrops? Obviously drizzle has smaller impact. There’s less mass there, but larger raindrops, more frequent rain.
Morten Handberg: If you have showers, it tends to be larger drops. Right. So, so they kind of follow each other. And if it’s more of a drizzle. It will be smaller raindrops.
They typically follow each other. You know, if you’ve been outside in a rainstorm before we just showered, you would have sense that these are, these are much higher, you know, raindrop sizes. So, so there is typically an a relation between raindrop size and then showers versus a drizzle. It’s typically more fine, fine grain rain drops.
Allen Hall: And what impact does dirt and debris mixed in with the rain, uh, affect leading edge erosion? I know a lot of, there’s a lot of concern. And farm fields and places where there’s a lot of plowing and turnover of the dirt that it, it, it does seem like there’s more leading edge erosion and I, I think there’s a little bit of an unknown about it, uh, just because they see leading edge [00:07:00]erosion close to these areas where there’s a lot of tilling going on.
Is it just dirt impact worth a blade or is it a combination of dirt plus rain and, and those two come combining together to make a worse case. Uh, damage scenario.
Morten Handberg: Technically it would be slightly worse than if it were, if there is some soil or, or sand, or sand contamination in the raindrops. But I mean, logically rain typically, you know, comes down from the sky.
It doesn’t, you know, it doesn’t mix in with the dirt then, you know, it would be more if you have dirt on the blades. It’s typically during a dry season where it would get mixed up and then blown onto the blades. Honestly, I don’t think that that is really what’s having an impact, because having contamination in the blade is not something that is, that would drive erosion.
I think that that is, I think that is, that is a misunderstanding. We do see sand, sand erosion in some part of the world where you have massive, uh, sand, uh, how do you say, sandstorms [00:08:00] coming through and, and that actually creates an, an abrasive wear on the plate. It looks different from rain erosion because it’s two different mechanisms.
Uh, where the sand is actually like a sandpaper just blowing across the surface, so you can see that. Whereas rain is more of this fatigue effect. So I think in the, theoretically if you had soil mixed in with rain, yes that could have an impact because you would have an a, a hardened particle. But I do, I don’t think it’s what’s driving erosion, to be honest.
Allen Hall: Okay, so then there’s really two different kinds of failure modes. A particle erosion, which is more of an abrasive erosion, which I would assume be a maybe a little wider, spread along the leading edge of the blade versus a fatigue impact from a raindrop collision. They just look different, right?
Morten Handberg: Yeah, so, so sand erosion you could have spreading across a larger surface of the blade because it, because it doesn’t bounce off in the same way that a raindrop would, you know, because that’s more of an impact angle and the load that it’s applying.
So if it comes in at a, at a st [00:09:00] at a, um, at the, at the, at a, at a steep angle, then it would just bounce off because the amount of load that it’s impacting on would be very limited. So that’s also why we don’t really see it on the, um, uh, outside of the leading edge. Whereas sand erosion would have a, would, would have a different effect because even at a steep angle, it would still, you know, create some kind of wear because of the hardened particle and the effect of that.
Allen Hall: Okay. So let’s talk about incubation period, because I’ve seen a lot of literature. Talking about incubation period and, and what that means. What does incubation period mean on a leading edge coating?
Morten Handberg: So that is, that, that is from when you start having the first impacts until you get the, the, the change in structure.
So when you get to the mass loss or first pitting, that would be your incubation period, because that is from when it starts until you can see the actual effects. Would say that, that that is what would be defined as the incubation period of leading into erosion.
Allen Hall: Okay. So you wanna then maximize the incubation period where the coating still looks mostly pristine [00:10:00] once incubation period is over and you get into the coating.
Are there different rates at which the coatings will deteriorate, or are they all pretty much deteriorating at roughly the same rate?
Morten Handberg: I mean, for the really high durability. We don’t really have good enough data to say anything about whether the, um, the, the period after the incubation period, whether that would actually, how that would work in the field.
We don’t really know that yet. I would say, because the, um, some of the, the shell solutions, some of the high end polyurethane coatings, if they fail, typically it’s because of workmanship. Or adhesion issues. It’s has so far not really been tied in directly in, into leading edge erosion. Uh, the ones that I’ve seen, so typically, and, and, you know, all of these high-end coatings, they’re just, they, they have shown, you know, some of them you couldn’t even wear down in a rain erosion tester.
Um, so, so we don’t really know. Um, how, [00:11:00] how the, how the shells, they would, they, they, they, they, how they would react over the five, 10 year period because we haven’t seen that much yet. And what we have seen have been more of a mechanical failure in, in the bonding
Allen Hall: that, I guess that makes sense. Then operators are still buying wind turbine blades without any leading edge coating at all.
It is basically a painted piece of fiberglass structure. Is that still advisable today or are there places where you could just get away with that? Or is that just not reality because of the tip speeds?
Morten Handberg: For the larger, I would say anything beyond two megawatt turbines, you should have leading edge protection because you’re at tip speeds where, you know, any kind of rain would create erosion within, um, within the lifetime of the late.
That is just a fact. Um, so. I don’t, I don’t see any real areas of the world where that would not apply. And if it, if you are in a place where it’s really dry, then it would typically also mean that then you would have sand erosion. Is that, that, [00:12:00] that would, I would expect that it would be one of the two.
You wouldn’t be in an area where it couldn’t get any kind of erosion to the blades. Um, so either you should have either a very tough gel code, um, coating, or you should have have an LEP per urethane based coating. On the blades,
Allen Hall: well do the manufacturers provide data on the leading edge offerings, on the coatings, or even the harder plastic shells or shields.
Does, is there any information? If I’m an operator and I’m buying a a three megawatt turbine that comes along with the blade that says, this is the li, this is the estimated lifetime, is that a thing right now? Or is it just We’re putting on a coating and we are hoping for the best?
Morten Handberg: The OEMs, as far as I, I haven’t seen any.
Any contract or agreement where today, where erosion is not considered a wear and tear issue, there is simply no, no coverage for it. So if you buy a turbine and there’s any kind of leading [00:13:00] edge erosion outside of the end of warranty period, it’s your your problem. There is no guarantee on that.
Allen Hall: So the operator is at risk,
Morten Handberg: well, they’re at risk and if they don’t take matters into their own hands and make decisions on their own.
But they would still be locked in because within the warranty period, they will still be tied to the OEM and the decisions that they make. And if they have a service agreement with the OEM, then they would also be tied in with what the OEM provides.
Allen Hall: So that does place a lot of the burden on the owner operator to understand the effects of rate erosion, particularly at the at a new site if they don’t have any history on it at all.
To then try to identify a, a coating or some sort of protecting device to prevent leading edge erosion. ’cause at the end of the day, it does sound like the operator owner is gonna be responsible for fixing it and keeping the blades, uh, in some aerodynamic shape. That that’s, that’s a big hurdle for a lot of operators.
Morten Handberg: The problem is that if you have a service [00:14:00]contract, but you are depending on the OEM, providing that service. Then you have to be really certain that any leading edge erosion or anywhere on the leading edge is then covered by that contract. Otherwise, you’re in, you’re in a really bad, you’re in a really risky situation because you can’t do anything on your own.
Because if you’re a service contract, but you’re beholden to whatever the, your service provider is, is, is agreeing to providing to you. So you might not get the best service.
Allen Hall: And what are the risks of this? Uh, obviously there can be some structural issues. Particularly around the tips of the blaze, but that’s also power loss.
What are typical power loss numbers?
Morten Handberg: Well, there is a theoretically theoretical power loss to it, but for any modern turbine, the blade, the, the turbine would simply regulate itself out of any leading erosion loss. So, so the blades would just change their behavior that the turbine would just change, its its operation [00:15:00]conditions so that it would achieve the same lift to the blade.
So. Uh, any study that we have done or been a part of, uh, even, you know, comparing blades that were repaired, blades that were cleaned, blades that were, uh, left eroded, and then operating the, uh, the deviation was within half, half percent and that was within the margin of error. We couldn’t read, we couldn’t see it even for really, you know, really er road blades.
Of course there is different between turbines. Some turbines, they, they could show it, but I haven’t seen any data that suggests that erosion actually leads to a lot of power loss. There is a theoretical loss because there is a loss in aerodynamic performance, but because blades today they’re pitch controlled, then you can, you can regulate yourself out of that.
Some of that, uh, power laws,
Allen Hall: so the control laws in the turbine. Would know what the wind speeds are and what their power output should be, and it’ll adjust the [00:16:00]pitch of each of the blades sort of independently to, to drive the power output.
Morten Handberg: Typically, erosion is a uniform issue, so what happens on one blade happens on three.
So it’s rare to see that one blade is just completely erod in the two other they look fine. That’s really rare unless you start, you know, doing uh, abnormal repairs on them. Then you might get something. But even then, I mean, we’re not talking, you know, 10 per 10 degrees in, in variation. You know, it’s not, it’s not anything like that.
It’s very small changes. And if they would do a lot of weird DA, you know, uh, different angles, you would get instant imbalance and then, you know, you would get scatter alarm. So, so you would see that quite fast.
Allen Hall: Well, let me, let me just understand this just a little bit. So what the control logs would do would increase the pitch angle of the blaze, be a little more aggressive.
On power production to bring the power production up. If leading edge erosion was knocking it down a percentage point or two, does that have a consequence? Are like when you [00:17:00] start pitching the blades at slightly different angles, does that increase the area where rain erosion will occur? Is like, are you just.
Keep chasing this dragon by doing that,
Morten Handberg: you could change the area a little bit, but it’s not, it’s not something that, that changes the erosion, uh, that the erosion zone, that that much. It’s very minimal. Um, and one, one of the, another, another reason why, why you might see it might, might not see it as much is because voltage generator panels is widely used in the industry today.
And, and Vortex panel, they are. Uh, negating some of the negative effect from, uh, leading erosion. So that also adds to the effect that there, that the aerodynamic effect of leading erosion is limited, uh, compared to what we’ve seen in the past.
Allen Hall: Okay. So there’s a couple manufacturers that do use vortex generators around the tip, around the leading edge erosion areas right outta the factory, and then there’s other OEMs that don’t do that at all.
Is, is there a benefit to [00:18:00] having the VGs. Right out of the factory. Is that, is that just to, uh, as you think about the power output of the generator over time, like, this is gonna gimme a longer time before I have to do anything. Is, is in terms of repair,
Morten Handberg: it does help you if you have contamination of the blade.
It does help you if you have surface defects off the blade. That, that any, uh, any change to the air, to the aerodynamics is, is reduced and that’s really important if you have an optimized blade. Then the negative effect of leading erosion might get, uh, you know, might, might, might get, might get affected.
But there are, there are still reasons why I do want to do leading erosion repairs. You should do that anyway, even if you can’t see it on your power curve or not, because if you wait too long, you’ll start to get structural damages to the blade. As we talked about last time. It’s not that leading edge erosion will turn into a critical damage right away, but if you need, if you go into structural erosion, then the, then the cost of damage.
The cost of repairing the damage will multiply. Uh, [00:19:00] and at, at a certain point, you know, you will get a re structure. It might not make the blade, you know, uh, cost a, a condition where the blade could collapse or you’re at risk, but you do get a weakened blade that is then susceptible to damage from other sources.
Like if you have a lighting strike damage or you have a heavy storm or something like that, then that can accelerate the damage, turning it into a critical damage. So you should still keep your leading edge in, in shape. If you want to do to, to minimize your cost, you should still repair it before it becomes structural.
Allen Hall: Okay. So the blades I have seen where they actually have holes in the leading edge, that’s a big problem just because of contamination and water ingress and yeah, lightning obviously be another one. So that should be repaired immediately. Is is that the, do we treat it like a cat four or cat five when that happens?
Or how, what? How are we thinking about that?
Morten Handberg: Maximum cat, cat four, even, even in those circumstances because it is a, it is a severe issue, but it’s not critical on, on its own. So I would not treat it as a cat five where you need to stop [00:20:00] the turbine, stuff like that. Of course, you do want, you don’t want to say, okay, let’s wait on, let’s wait for a year or so before we repair it.
You know, do plan, you know, with some urgency to get it fixed, but it’s not something where you need to, you know, stubble works and then get that done. You know, the blade can survive it for, for a period of time, but you’re just. Susceptible to other risks, I would say.
Allen Hall: Alright. So in in today’s world, there’s a lot of options, uh, to select from in terms of leading edge protection.
What are some of the leading candidates? What, what are some of the things that are actually working out in the field?
Morten Handberg: What we typically do, uh, when we’re looking at leading edge erosion, we’re looking at the, the raw data from the wind farm. Seeing how, how bad is it and how long have the wind farm been operated without being repaired?
So we get a sense of the aggressiveness of the erosion and. Um, if we have reliable weather data, we can also do some modeling to see, okay, what is the, what is the, the, uh, environmental conditions? Also, just to get a sense, is this [00:21:00] material driven fatigue or is it actually rain erosion driven fatigue?
Because if the, if the coating quality was not, was not very good, if the former lead leading edge, it was not applied very, very, very good, then, you know, you still get erosion really fast. You get surface defects that, uh, that trigger erosion. So that’s very important to, to, to have a look at. But then when we’ve established that, then we look at, okay, where do we have the, the, the, uh, the structural erosion zone?
So that means in what, in what part of the BA would you be at risk of getting structural damage? That’s the part where that you want to protect at all costs. And in that, I would look at either shell solution or high duty, um, put urethane coating something that has a a long durability. But then you also need to look at, depending on whether you want to go for coating or shell, you need to look at what is your environmental condition, what is your, you know, yeah.
Your environmental conditions, because you also wanna apply it without it falling off again. Uh, and if you have issues with [00:22:00] high humidity, high temperatures, uh, then a lot of the coatings will be really difficult to process or, you know, to, to. Uh, to handle in the field. And, you know, and if you don’t, if you don’t get that right, then you just might end up with a lot of peeling coating or uh, peeling shells.
Um, so it’s very important to understand what is your environmental conditions that you’re trying to do repairs in. And that’s also why we try not to recommend, uh, these shell repairs over the entire, out a third of the blade. Because you’re, you’re just putting up a lot of risk for, for, uh, for detaching blades if you put on too high, um, uh, how do you say, high height, sea of solutions.
Allen Hall: Yeah. So I, I guess it does matter how much of the blade you’re gonna cover. Is there a general rule of thumb? Like are we covering the outer 10%, outer 20%? What is the. What is that rule of thumb?
Morten Handberg: Typically, you know, you, you get a long way by somewhere between the outer four to six meters. Um, so that would [00:23:00]probably equivalate to the, out of the outer third.
That would likely be something between the outer 10 to 15 to 20% at max. Um, but, but it is, I, I mean, instead of looking at a percentage, I usually look at, okay, what can we see from the data? What does that tell us? And we can see that from the progression of the erosion. Because you can clearly see if you have turbines that’s been operating, what part of the blade has already, you know, exposed laminate.
And where do you only have a light abrasion where you only have a light abrasion, you can just continue with, and with the, with, with the general coating, you don’t need to go for any high tier solutions. And that’s also just to avoid applying, applying something that is difficult to process because it will just end up, that it falls off and then you’re worse off than, than before actually.
Allen Hall: Right. It’s about mitigating risk at some level. On a repair,
Morten Handberg: reducing repair cost. Um, so, so if you, if you look at your, your conditions of your blades and then select a solution that is, that is right for that part of [00:24:00] the blade
Allen Hall: is the best way to repair a blade up tower or down tower is what is the easiest, I guess what’s easier, I know I’ve heard conflicting reports about it.
A lot of people today, operators today are saying we can do it up tower. It’s, it’s pretty good that way. Then I hear other operators say, no, no, no, no, no. The quality is much better if the blade is down on the ground. What’s the recommendation there?
Morten Handberg: In general, it can be done up tower. Um, it is correct if you do a down tower, the quality is better, but that, that, that means you need to have a crane on standby to swap out blades.
Uh, and you should have a spare set of blades that you can swap with. Maybe that can work. Um. But I would say in general, the, your, your, your, your cheaper solution and your more, you know, you know, uh, would be to do up tower. And if, and again, if you do your, your, your homework right and, and selecting the right, uh, products for, for your [00:25:00] local environments, then you can do up tower then leading it, erosion.
Not something that you need to, you should not need to consider during a down tower. Unless you are offshore in an environment where you only have, uh, 10 repair days per year, then you might want to look at something else. But again, if we talk for offs for onshore, I would, I would always go for up, up tower.
I, I don’t, I don’t really see the need for, for, for taking the blades down.
Allen Hall: So what is the optimum point in a blaze life where a leading edge coating should be applied? Like, do you let it get to the point where you’re doing structural repairs or. When you start to see that first little bit of chipping, do you start taking care of it then there I, there’s gotta be a sweet spot somewhere in the middle there.
Where is that?
Morten Handberg: There is sweet spot. So the sweet spot is as soon as you have exposed laminate, because from exposed laminate, uh, the repair cost is exactly the same as if it was just, you know, uh, a light abrasion of the coating because the, the, the time to, to, um, prepare the [00:26:00] surface to apply the coating is exactly the same.
From, you know, from, from, from light surface damage to exposed laminate. That is the same, that is the same repair cost. But as soon as you have a structural damage to your blade, then you have to do a structural repair first, and then you’re, you’re multiplying the repair time and your repair cost. So that is the right point in time.
The way to, to determine when that is, is to do inspections, annual inspections, if you do 10% of your wind farm per year. Then you would know why, what, how the rest of your wind farm looks like because erosion is very uniform across the wind farm. Maybe there are some small deviations, but if you do a subset, uh, then, then you would have a good basic understanding about what erosion is.
You don’t need to do a full sweep of the, of the wind farm to know, okay, now is my right time to do repairs.
Allen Hall: Okay, so you’re gonna have a, a couple years notice then if you’re doing drone inspections. Hopefully you put, as you put your blades up, doing a drone inspection maybe on the ground so you [00:27:00] have a idea of what you have, and then year one, year two, year three, you’re tracking that progression across at least a sampling of the wind farm.
And then, then you can almost project out then like year five, I need to be doing something and I need to be putting it into my budget.
Morten Handberg: When you start to see the first minor areas of exposed laminate. Then the year after, typically then you would have a larger swat of, of laminated exposure, still not as structural.
So when you start to see that, then I would say, okay, next year for next year’s budget, we should really do repairs. It’s difficult when you just direct the wind farm, maybe have the first year of inspection. It’s difficult to get any, any kind of, you know, real sense of what is the, you know, what is the where of scale that we have.
You can be off by a factor of two or three if, you know, if, um, so I would, I would give it a few years and then, uh, then, then, then see how things progresses before starting to make, uh, plans for repairs. If you [00:28:00] don’t have any leading edge erosion protection installed from the start. I would say plan, at least for year, year five, you should expect that you need to go out, do and do a repair.
Again, I don’t have a crystal ball for every, you know, that’s good enough to predict for every wind farm in the world, but that would be a good starting point. Maybe it’s year three, maybe it’s year seven, depending on your local conditions. That is, but then at least you know that you need to do something.
Allen Hall: Well, there’s been a number of robotic, uh, applications of rain erosion coatings. Over the last two, three years. So now you see several different, uh, repair companies offering that. What does the robotic approach have to its advantage versus technicians on ropes?
Morten Handberg: Obviously robots, they don’t, they don’t, uh, get affected by how good the morning coffee was, what the latest conversation with the wife was, or how many hours of sleep it got.
There is something to, with the grown operator, uh, you know how good they are. But it’s more about how well, uh, [00:29:00] adjusted the, the controls of the, of the, the robot or the drone is in its application. So in principle, the drone should be a lot better, uh, because you can, it will do it the right, the same way every single time.
What it should at least. So in, so in principle, if you, you, you, when we get there, then the leading it then, then the robot should be, should outmatch any repair technician in, in the world. Because repair technician, they’re really good. They’re exceptionally good at what they do. The, the, the far majority of them, but they’re, they’re still people.
So they, you know, anyone, you know, maybe standing is not a hundred percent each time, maybe mixing of. Um, of materials and they’re much better at it than I am. So no question there. But again, that’s just real reality. So I would say that the, the, the draw, the robots, they should, uh, they should get to a point at some, at some point to that they will, they will be the preferable choice, especially for this kind of, this kind of repair.
Allen Hall: What should [00:30:00] operators be budgeting to apply a coating? Say they’re, you know, they got a new wind farm. It’s just getting started. They’re gonna be five years out before they’re gonna do something, but they, they probably need to start budgeting it now and, and have a scope on it. ’cause it’s gonna be a capital campaign probably.
How much per turbine should they be setting aside?
Morten Handberg: I would just, as a baseline, at least set aside 20,000 per per blade
Allen Hall: dollars or a Corona
Morten Handberg: dollars.
Allen Hall: Really. Okay.
Morten Handberg: Assuming that you actually need to do a repair campaign, I would say you’re probably ending up in that region again. I can be wrong with by a factor of, you know, uh, by several factors.
Uh, but, um, but I would say that as a starting point, we don’t know anything else. I would just say, okay, this should be the, the, the, the budget I would go for, maybe it’ll be only 10 because we have a lesser campaign. Maybe it will be twice because we have severe damages. So we need just to, to, to source a, um, a high end, uh, LEP solution.
Um, so, so [00:31:00] again, that would just be my starting point, Alan. It’s not something that I can say with accuracy that will go for every single plate, but it would be a good starting point.
Allen Hall: Well, you need to have a number and you need to be, get in the budget ahead of time. And so it, it’s a lot easier to do upfront than waiting till the last minute always.
Uh, and it is the future of leading edge erosion and protection products. Is it changing? Do you see, uh, the industry? Winning this battle against erosion.
Morten Handberg: I see it winning it because we do have the technology, we do have the solutions. So I would say it’s compared to when we started looking at it in 14, where, you know, we had a lot of erosion issues, it seems a lot more manageable.
Now, of course, if you’re a, if you’re a new owner, you just bought a wind farm and you’re seeing this for this first time, it might not be as manageable. But as an, as an industry, I would say we’re quite far. In understanding erosion, what, how it develops and what kind of solutions that that can actually, uh, withstand it.
We’re still not there in [00:32:00] terms of, uh, quality in, in repairs, but that’s, um, but, but, uh, I, I think technology wise, we are, we are in a really good, good place.
Allen Hall: All the work that has been done by DTU and RD test systems for creating a rain erosion test. Facility and there’s several of those, more than a dozen spread around the world at this point.
Those are really making a huge impact on how quickly the problem is being solved. Right? Because you’re just bringing together the, the, the brain power of the industry to work on this problem.
Morten Handberg: They have the annual erosion Symposium and that has been really a driving force and also really put DTU on the map in terms of, uh, leading edge erosion, understanding that, and they’re also trying to tie, tie it in with lightning, uh, because, uh.
If you have a ro, if you have erosion, that changes your aerodynamics. That in fact changes how your LPS system works. So, so there is also some, some risks in that, uh, that is worth considering when, when, when discussing [00:33:00]repairs. But I think these of you, they’ve done a tremendous amount of work and r and d system have done a lot of good work in terms of standardizing the way that we do rain erosion testing, whether or not we can then say with a hundred uncertainty that this, uh, this test will then match with.
With, um, how say local environment conditions, that’s fine, but we can at least test a DP systems on, on the same scale and then use that to, to, to look at, well how, how good would they then ferry in in the, um, out out in the real world.
Allen Hall: Yeah, there’s a lot too leading edge erosion and there’s more to come and everybody needs to be paying attention to it.
’cause it, it is gonna be a cost during the lifetime of your wind turbines and you just need to be prepared for it. Mor how do people get ahold of you to learn more about leading edge erosion and, and some of the approaches to, to control it?
Morten Handberg: Well, you can always re reach me, uh, on my email, meh, at wind power.com or on my LinkedIn, uh, page and I would strongly advise, you know, reach out if you have any concerns regarding erosion or you need support with, um, [00:34:00] uh, with blade maintenance strategies, uh, we can definitely help you out with that.
Or any blade related topic that you might be concerned about for your old local wind farm.
Allen Hall: Yes. If you have any blade questions or leading edge erosion questions, reach out to Morton. He’s easy to get ahold of. Thank you so much for being back on the podcast. We love having you. It
Morten Handberg: was fantastic being here.
Cheers. A.
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