Edo Kuipers from We4Ce and Søren Kellenberger from CNC Onsite discuss their Re-FIT blade root repair solution, which has been successfully implemented at a wind farm in Southeast Asia. The solution allows operators to keep blades onsite while repairing critical blade root bushing failures. 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! Welcome to Uptime Spotlight, shining Light on Wind. Energy's brightest innovators. This is the Progress Powering Tomorrow. Allen Hall: Ed0o and Soren, welcome to the program. Edo Kuipers: Thank you very much. Thank you both. Allen Hall: We have some really exciting news from you, from the field, but first I, I want to start with the problem, which. A lot of operators have right now, which is this blade root, bushing it in or insert issue, which is really critical to blades and you're the creator of the device that's gonna save a lot of blades. You want to talk about what happens? When these blade root bushings fail? Edo Kuipers: Uh, yeah. What we have seen is that it especially concerns, um, uh, polyester type of blades. And what we see is that, um, bushings and, and, and composites, they are not attached to each other anymore. And after a [00:01:00] while, blades are simply flying off. That's the, that's the whole, that's the whole problem. Of course. And now going back to the root cause, the root cause here is we are working with, with foes and. The fact is that if you're working with polyesters, they already have, um, at the, uh, uh, during the process, the curing process, they have already curing shrinkages. So we have already curing shrinkages, which means we have already initial micro flagging going on, on the interface between the bushing and, and, and, and the limited around it. And that reduces, that reduces the um, surface. Carrying area. And by doing so, because we have less area, surface area that can transfer the loads from the hub, um, from the blades to the hub, eh, we have limited amount of, of years on running. So we are reducing, uh, the, the amount of years [00:02:00] that the blades are on the, on the, on the turbine safely. Joel Saxum: This problem is compounding right now simply because there's a lot of the global wind turbine fleet that's starting to age. Right. Like we, we, we went through a big push in, you know, the early two thousands, 2000 tens, 2000 twenties to now where, you know, if you look at the country of Spain, we hear that regularly, Alan is, Hey, we're getting to the end of life. We're close to the end of life. Then there's people saying, what is the remaining useful life? Where are we at? Um, and this is one of those issues where. It can develop rapidly, right? So if there's an issue, you can, if you catch it in time, great. You're good. But it can develop rapidly and that can lead to catastrophic losses. But I guess my, one of the questions I want to ask you, and you guys of course have done some commercial here. Uh, how many turbines do you think are affected by this globally affected by this root bushing issues? Edo Kuipers: Oh, that's a good one. If I, if I talk a number of blades at the moment, we are more or less at a ball point figure about 30, [00:03:00] 40,000. Blades. Wow. Worldwide. So we see many us, we see many in South America and we see also in Southeast Asia, like India. And those blades are running, let's say from 10 years, 12 years, and some of them also after six years, Allen Hall: and a lot of manufacturing. Uh, blades happens in multiple sites, right? So if you have a particular OEM wind turbine, you may have a variety of different blades on your site. You typically do. Some of them are polyesters, some of them may be epoxy, but it's the polyester ones we need to pay attention to first, right? Edo Kuipers: Correct. The one we are, uh, concentrating on with our solution are dealing with polyester blades because there we see the problem, especially in the, in the interface layer. There are also root problems with epoxy types, but they are from a, from a different level. Allen Hall: So the thing that we're looking for when we start to see [00:04:00]the problem, so if I'm an operator and I have technicians out in the field and they're looking at blades from the ground, typically very quickly, what are the first signs that you have problems with the bushings? Edo Kuipers: What we generally see, the first signs is that there is a cracking going on in the ceiling, which is between the blade. The pitch bearing. So if you go up tower as a surface guy, then then look for those initial cracks, and if you see cracking, cracking in that sealant, then remove the sealant just by with a knife and, and, and go with a fill gauge to see if you're caping going on between the root lum. Uh, so between the bushing and the, and the, and the pitch bearing, Allen Hall: so that sealant or gasket between the blade and the pitch bearing shouldn't be moving or shouldn't have flexed it. It shouldn't have broken. It can flex. It's made to flex a little bit, but if it breaks, it tells you there's too much stress [00:05:00] on that sealant. That's really the first sign. Edo Kuipers: That's really the first sign. Then you still have time, but then you have to start monitoring Allen Hall: and the, the monitoring is telling you what, Edo Kuipers: once you. Notice this. What you have to do is, for example, you are positioning a leading edge, uh, under the tensile loading of the dead weight. Then you measure a cap, then you pitch the blade, eh, that the, that, the, that the, that, that side is down. So it's, it's, it's feeling a compressive loading, and then you can see if there is a difference. So what you're doing is you're measuring the variable cap. That's a static gap, but the variation of the capping due to the, due to its own weight of the blade, and that is a sign that that movement is going on. Allen Hall: So you'll see compression versus tension, that gap get larger and smaller. There is always some movement in that gap, but it's very limited if you, what typically is a threshold where you say. [00:06:00] If it's beyond a couple of millimeters, that's a problem. Where is that dimensional gap become an issue Edo Kuipers: with our present customers? We are saying, um, um, one millimeter and you have to hoist, uh, hoist the blade down. Allen Hall: One millimeter is 40 thousandths of an inch. That's not very much. Edo Kuipers: If it's, for example, five millimeters, I mean. It's, it's not, you're in a, in a bad stage that within three months your, your blood, your blade could fly off. And if you are in, in the range of one millimeter, the nice thing on that is that you have a limited amount of bushings, which needs to be replaced. So you are li limiting the effect of the repair. Joel Saxum: So, but that's the big thing here, right? So catching it early, it's like anything in blades, we talk about this. We've been, we've been beating this, this horse for a long time. Catch it early, fix it early, or you're gonna be in a bad state. Because I mean, the, the, the worst thing that happens here, of course is the safety issue, loss of life or anything like that. But what? But the, [00:07:00] what We have seen blade breaks, blade comes down, hits the tower. Then the tower comes down, then you're replacing an entire turbine. And that's, that's horrible for the operator, the industry, everything in, in, in general. Um, but if you catch it early, now each blade has de, depending on the model, the make the design, um. 60 to 80 bushings. 60 to a hundred bushings. What's that number? Edo Kuipers: Yeah. 92 for example. Or 74 or, yeah. In that area. Joel Saxum: Right. So, so, and when you, and when your solution is engaged, when the, you have to bring the, bring the blade down tower and then fix it if you catch it early. Are you talking, we're fixing six of these, we're fixing 40 of these. What does it usually look like? Edo Kuipers: It's, uh, in the, in the area of 24 to 30. Joel Saxum: Okay. Edo Kuipers: The nice thing on that, the nice thing is on that if we working with a drilling machine, we can do that in 24 hours drilling. So limited time. Limited time of, of [00:08:00] taking out the bushings. And if we would wait longer and we need to repair 60 bushings, it takes, let's say 60 hours to, to drill out, so to lower the cost of the repair. Because it's like a chain reaction. Once it starts, it, it grows to lower the amount of the repair and the cost of repair, let's, let's not wait too long. Allen Hall: Okay. So that's a really good input into this discussion because I think a lot of operators assume if I have to do this repair, replace the bushings, I'm replacing a number of bushings regardless of the level of damage, because they're gonna fail eventually. But you know, what you're saying is that. It starts in a highly loaded couple of bushings and spreads from there, if you can, if you can fix or upgrade those particular bushings, then the remaining bushings may be okay. Edo Kuipers: Correct. Because there is always a highly loaded, like you said, and there's always a a side which is more tensile loaded, and the other side is more compressive loaded, and especially the tensile loaded part is, is [00:09:00]more severely for the fatigue. Joel Saxum: The other side of this is a blade replacement. So you're either gonna, you're going to have to, you're gonna do something like this, or you're gonna replace the blade. And,