1,000-Turbine Study Reveals Which Parts Fail Most

Announcer [00:28] The Uptime Wind Energy Podcast, brought to you by StrikeTape, protecting thousands of wind turbines from lightning damage worldwide. Visit StrikeTape.com. And now your hosts.
Allen Hall [00:42] Welcome to the Uptime Wind Energy Podcast. I’m Allen Hall, here with Rosemary Barnes, Matthew Stead and Yolanda Padron. If you haven’t registered for WOMA 2027, you’d better do it pretty soon. It’s March 3rd through the 5th in Melbourne at the Pullman, and we’re starting to firm up the list of speakers. If you go to woma2027.com, you can see who’s attending. I just heard some news today, and I don’t want to break it here, but there are some pretty important people attending WOMA 2027. Matthew, we’re still looking for a couple of sponsors, right?
Matthew Stead [01:20] Yeah, there are a few sponsor spots left, so contact any of us and we’ll put you in touch with the opportunities. I think we’ve said it before, but this is the conference that operators say they attend.
Allen Hall [01:35] Right. And if you have interesting technology that needs to be used in Australia, it’s a good place to meet everybody. You can meet all the operators and discuss the opportunities in Australia, and a number of people are coming from overseas for the event. There’s a limited number of seats, a little over 200 this year. We expanded it slightly, but we’re going to run out. So to register, Matthew, where do you need to go?
Matthew Stead [02:04] woma2027.com.
European turbine reliability study
Allen Hall [02:10] There’s an interesting research paper that came out of a group of European researchers, one of them being Fraunhofer, and I think it was ultimately published by DTU. It’s a turbine reliability study that ran over many years and covers about 1,000 turbines and 4,200 operating years across Europe. It’s unique data because they broke the turbine down into its components to look at the reliability and performance of each one.
Offshore machines fail a little more often, but per megawatt onshore is worse, at about 1.73 failures a year versus 1.09 for offshore. Offshore turbines tend to be much larger. The big items, pitch systems, controllers and converters, are still at the top of the list.
There’s a ton of data, and I encourage everybody to go online and search for it, or we’ll put it in the show notes. Some of these systems are pretty well known. They have a lot of design and testing behind them, pitch systems being one. But I think we’ve all noticed on certain turbines that the pitch system hydraulics are leaking all over the place, or the electric drive isn’t working quite right, or the pitch system isn’t as accurate as you want it to be. Same thing for controllers and converters, which are at the heart of a turbine. They’re converting the power, and you have to have them to run. Does the fact that pitch systems, controllers and converters are at the top of the list surprise you at all?
Rosemary Barnes [04:13] It’s interesting to me because I’m not sure it matches the kinds of technologies I see out there. Everybody is hyper aware that offshore wind has really high maintenance costs. I was a bit surprised the report says there isn’t a huge difference in reliability for offshore, because the capital cost is way higher, partly because they’re so focused on making this stuff more reliable. The operating environment is harsh, so the grade of stainless steel matters much more and it’s more expensive. There are all kinds of seals and enclosures you don’t need so much onshore.
There are so many technology companies whose whole business is based on the idea that you’ll have less maintenance as a result. But the products out there seem more focused on other parts of the turbine, like rotating components and blades, which probably account for a large share of the spending. Still, every single visit offshore is expensive on its own. So maybe there’s a mismatch there, and a big opportunity. Maybe it’s a prompt for people designing wind turbine doodads: make a doodad for converters or those components.
Allen Hall (?) [06:08] There are cost constraints, right? They’re trying to minimize the cost that goes into the component, and that tends to decrease its reliability if it’s not done carefully.
Onshore vs offshore maintenance and year nine failures
Matthew Stead [06:20] I’ve worked with some OEMs on offshore wind turbines, and my observation is that they take offshore wind really, really seriously. They know the additional costs, the cost of each trip, and the cost of unplanned call-outs. In my experience they try to make it highly reliable. So I was actually surprised that offshore came in at a ratio of 1 to 1.6. I thought offshore would have been way better. Separately, my experience with onshore is that whenever you go to a site or talk to a site, everyone is flat out. There’s always more work than can ever be done in a day. So for onshore, that makes complete sense to me.
Yolanda Padron [07:24] I think some of the failures, at least onshore, are almost built into the site’s maintenance strategy. People tend to pay more attention to things like the rotating components that are more expensive, because they hurt the budget a lot more.
Something I thought was really interesting was that failure rates climb quite a bit in year nine. For onshore US, that’s an important date to keep in mind because of the PTC expiring in year ten, or at least the flip date when you have tax equity. After year ten, if you’re the owner of a site, you start taking on the majority of the costs, versus the tax equity partner. So it’s definitely something to plan for in the long-term maintenance of a site. If you’re going to start seeing a lot of failures you didn’t see before, right when you take on most of the cost burden, it’s important to maintain everything from years one to ten as if it were your own.
Allen Hall [08:37] Is it that a lot of the wind farms in Europe tend to be smaller, 10 or 12 turbines? You could maintain ten turbines even with this failure rate, and it’s not a big deal. But when you scale it up to 100, 150, 200, 300 turbines, it becomes almost impossible with a small staff of technicians, which is where everybody’s been driven. The scale becomes almost unwieldy.
Yolanda Padron [09:10] From what we’ve seen in the field, it’s more common for European onshore site teams to keep everything almost perfectly maintained, almost to the standard you’d use for an offshore site. Onshore in the US, and Rosie, tell me if it’s different in Australia, we usually see a lot of issues that really wouldn’t fly in Denmark or somewhere else in Europe. It’s almost part of the plan at this point. You can recognize a failure point and recognize that an issue isn’t as big as someone in Europe might think. I’ve heard it described as a cowboy way of thinking.
Damage categories and OEM feedback
Rosemary Barnes [09:57] That’s what I thought when I moved here and started working in O&M. I was shocked when a client would say, “Okay, we’ve got these 20 Cat 5 damages. Which ones do we need to repair this year?” I was like, what do you mean? Cat 5 is supposed to mean you stop the turbine and repair it before you start it up again.
In Australia, the early wind farms mostly have full service agreements with European manufacturers. I think they based the number of technicians they expected to need on their European learnings. But the operating environment here is much harsher, and I know the same is true for certain American locations like Texas. So they simply haven’t had the ability to do maintenance to the same level. But now that I’ve been in this environment for five years, I’m starting to see that a lot of the stuff that should have been repaired doesn’t need to be. I’ve kind of lost faith in the category one, two, three, four, five system altogether.
Yolanda Padron [11:06] For sure.
Rosemary Barnes [11:07] A Cat 5 is not a Cat 5. It doesn’t mean the same thing on every blade in every environment. If you’ve got a Cat 5 lightning damage right at the tip, it usually doesn’t do anything. I’m thinking of one particular example that looked terrible in the images. I was shocked the first time I saw it. It didn’t make the list of repairs they could get through that year. It was back again the next year, exactly the same, and now a third year, literally exactly the same again. Whereas other types of damage, maybe a trailing edge crack at a certain location, are only a Cat 3 according to the inspection reports, which don’t use a standardized methodology for assessing how bad a damage is. Some of those will progress on a particular blade, and you’ve got to do that one now or you’ll be replacing the blade soon. So there’s a lot to be done on a site-by-site basis, figuring out the right maintenance strategy for you.
One other thing I’ve been surprised about as I’ve moved through my career in wind energy: I started in academia doing my PhD, then moved into industry working for a manufacturer on design, certification, manufacturing and a little maintenance. Now I work on the operations and maintenance side. In either of the earlier two phases, I would have loved to have had operating data to feed back into the design process and make the design better. I’ve been surprised at how little that happens onshore, which is all I work with at the moment. Every condition is there for the OEMs to be doing way better at this, and I don’t see it for the types of issues I work on.
I’m not saying they’re not doing it for other things. But for example, we should be measuring what kind of lightning strike causes what kind of damage in what kind of lightning protection system. The big OEMs have thousands upon thousands of turbines around the world under service agreements. There’s nothing stopping them from collecting that information and using it to design a better product, and I don’t see that beyond the most obvious things. If blades start falling off turbines, they’ll eventually redesign the system so that doesn’t happen anymore. Less than that, I don’t really see it. I guess the incentive isn’t there, because owners pay for lightning damage. But for any number of other things, like leading edge erosion, the information isn’t getting back to the designers as far as I can tell. I think that’s such a wasted opportunity.
I’ve got to assume that’s not the case for offshore, because the stakes are so much higher. When I was working in industry, everyone was obsessed with offshore reliability and talked about it constantly. So I’m hopeful my comments don’t apply to that part of the industry.
Purchased components and data sharing
Allen Hall [14:37] Isn’t it interesting that the components failing the most are purchased components? The OEM wouldn’t have much design input into them. Converters, pitch systems, those are components being acquired. Maybe there’s just a spec for how they’re supposed to perform and the work is subcontracted out, and maybe that’s not the right move. Even GE: GE made electrical components and still does a little, but for the most part it’s now an assembly business. Controllers, same thing. GE doesn’t make a controller. GE buys a controller, so does Vestas, so does Siemens. Those purchased components are the things that are failing. Blades, you’d think they make themselves, except GE doesn’t really make them either. That’s very interesting. Where it’s subbed out may be where some of the problem lies, because they just don’t have direct control over it.
Rosemary Barnes (?) [15:45] Yeah, I think it’s information sharing. I bet the power converter or controller company making those components would love the opportunity to learn how they’re failing in the field and improve. And I bet they’re not getting the information and access they’d want in many cases.
Rosemary Barnes (?) [16:21] I also think we haven’t seen this level of data published before for people to know. What’s still missing is which brands are doing well. It says the worst manufacturer is around twice as bad as the best ones, and I don’t think that information is obvious. When I talk to people developing a new site and choosing turbines, for the most part they’re not that interested in knowing how reliable they can expect that turbine to be later. If I suggest, “I know you’re really far along with this OEM, but just FYI, the lightning protection system is not the best, and I have some questions about it,” they don’t want to know. Once you’ve started talking with somebody, you’re so locked in to finishing with them that you almost don’t want that information. So there’s a lack of information and misaligned incentives as well.
Yolanda Padron (?) [17:13] But this study that’s been published is definitely the first step. That’s great.
IEC standard and certification testing
Matthew Stead [17:20] Can I respond to a few points you’ve been making? First, for WOMA 2027, we’re talking to a potential speaker about the new IEC standard for blade O&M. Going back to your point, Rosie, about categorization, a lot of work has been done behind the scenes on improving that in the new IEC standard. That’s a real reason to come to the conference, to hear what’s going on and what the plans are.
Allen, on the EU versus US point: wind turbines in the EU do appear to be better maintained. But they’re spaced out. The technicians have to drive a long way, and it’s really expensive to get to them. So the argument that a big site is just overwhelming applies in Europe too, because of all the travel time between individual turbines.
Yolanda and Allen, you were talking about pitch bearings and pitch systems. That seems to be coming up more and more as a topic. Just this week alone I’ve had four conversations about it. Even though they’re off-the-shelf products, the OEMs specify them. I’m aware of at least a few examples where the OEM specified something that, and I’m not going to use the words “not fit for purpose,” maybe the manufacturer wouldn’t have recommended for that application. So I think that’s a big concern, where some of the OEMs need to take a bit more responsibility. Very cryptic.
Allen Hall [19:30] Here’s a comparison with aerospace. Before you’re allowed to license an aircraft and get its production or type certificate, you have to fly it for, I believe, 50 hours, though it could be 100, without anything breaking. That includes light bulbs. If a light bulb went out, you started the clock all over again. Do we have requirements in IEC to run turbines a certain length of time without an issue? You go to these test sites, and Rosemary was just at the one in Denmark. Do they have to run for 500 hours, 2,000 hours, whatever it is, without failure before they’re considered deliverable? Or is it up to the OEM to determine that?
Rosemary Barnes [20:25] I don’t think running without any maintenance is a requirement. That’s one of the big things you’re trying to figure out when you put a prototype up. When you put a prototype in Denmark, very close to all your engineers, it’s because you expect to have to go out to it, look at things and change things. Certification is much more about making sure something doesn’t become unsafe or unusable at all. It’s not nearly as aligned with reducing your operating costs or making a turbine less annoying to operate. So I don’t believe that’s part of it.
Allen Hall [21:12] It must not be, based on some of the evidence in the report. Longevity and being maintenance-free aren’t really checked before production starts. Maybe they should be, but that’s a hard thing to do. In the aircraft world, you’re typically building four or five aircraft and flying the living bejesus out of them to see what breaks, and hopefully none of it does. I’m not sure wind turbines are in the same mode.
Rosemary Barnes [21:43] It is a requirement in a sense. That was something I had to adjust to when I went to an OEM and started designing systems that go up in blades. Those are supposed to have no maintenance. That’s your design intent. I remember the first system we put in was a hot air system. It’s basically a giant hairdryer bolted onto the root of the blade, blowing hot air through the blade to coax ice off the surface. There are bolts involved, and you’d want to check the torque every now and then. I said, okay, they’ll go up once a year and check the torque on these 16 bolts, and it takes one minute. And it was an absolute no. That’s not going to happen.
There is maintenance required eventually. You do need to check the torque on bolts from time to time and replace filters and so on. So we had to design around that with that particular system, and with other ones you can. People are aware you shouldn’t have maintenance requirements. It’s not that nobody cares. But it took a lot of effort for me to get out into the field and see how my system looked. I knew how it looked in a computer model and coming fresh out of the factory. What I didn’t know was what it looks like three months later or three years later. I had to work really hard to do all the training to be able to climb, which wasn’t routine when I was there.
And we sell the turbines. We don’t own them anymore after that. So it’s not a given that an engineer will have access to the information they need. We had to have really great partners. De-icing was a good project like that. Some of the early wind farms in Canada were seeing something like 20% AEP loss because they didn’t expect how much ice would shut them down. So they were absolutely desperate for a solution and absolutely wanted to work with the engineers to make it as good as possible for future developments.
Offshore lightning blind spot
Matthew Stead [24:11] I became aware this week of an offshore wind project somewhere in the world, and it’s prone to lightning.
Allen Hall [24:23] Wind turbines get struck by lightning, you say, man? Especially really —
Matthew Stead [24:29] Yeah. So for this particular project, for some reason, they only had lightning cards. No one remotely ever knew when they were struck. They didn’t know how often they were struck, and they didn’t know whether they had to go and inspect them or not. I just could not believe that in this modern day, a new, massive offshore wind farm could be built without knowing what’s going on with the turbines, given all the potential consequential issues around lightning. Allen, I guess you’ve seen that all the time.
Rosemary Barnes (?) [25:13] Given how cheap and reliable it is to just throw a sensor on the tower. It sticks there, and then you know. [inaudible]
Matthew Stead (?) [25:36] [inaudible] I know you’re a big baseball fan, Allen. [inaudible] Compared to anything else on an offshore wind turbine, I think it’ll be less than the cost of the technician’s lunch break while installing it, probably.
Industry experience and knowledge sharing
Allen Hall (?) [26:03] I think it relates to operators, and it’s hard. Unless you have someone around who’s been in the industry for 30 or 40 years, like Rosemary, you don’t know what you don’t know, and you don’t know how to prioritize. Everything’s a problem as soon as it pops up. The industry hasn’t developed an employment base with a lot of years on it. Europe totally has, and you can see it in the quality of work there. They’re just on a different level, but that takes time.
I was talking to a gentleman in Singapore for the podcast who was speaking about Southeast Asia, and they just don’t have a lot of subject matter experts there. So when problems pop up, they turn into big problems because people aren’t aware of how to address them. Same thing here. The industry needs to age a little. The industry in the United States is maybe 20-odd years old, so you go through that first generation, and there were a ton of layoffs and chaos in the middle of that. So you don’t have a John Zeller at every wind site yet. Maybe they will. That would be awesome. We’ll get there at some point.
Matthew Stead [27:32] I’ll do another quick plug for the new IEC standard, and I don’t get paid for this, by the way. The IEC committee members are all volunteers doing it for the good of the industry. There’s a new section being developed on reasonable processes around inspections and around lightning. So I’m hopeful that what is normal becomes normal, and some of that industry knowledge gets shared.
Allen Hall [28:02] I had somebody reach out about a difficult aircraft project they were working on. They called and asked, can you help? They called because they were googling for help and landed on one of our YouTube videos where I was talking about protecting homes and airplanes. I thought, oh my gosh, maybe we’re part of the solution for the industry, and I hope we are. If you’re having trouble learning how a system works, or finding somebody knowledgeable, use the podcast as a resource to make this go faster.
Yolanda Padron (?) [28:47] Because it is hard. Having read through a number of IEC standards, it’s hard to suss out the intent or what I should be doing, because they’re not written in a user-friendly way in a lot of cases, especially the ones developed in the early 2000s.
Allen Hall [29:04] That’s how we fix anything anyway, right? Rosemary, don’t you go to YouTube?
Rosemary Barnes [29:10] You can, but you won’t. Every now and then I do try when something comes up that surprises me, and I have yet to learn anything interesting from the internet, other than once finding out about a serial remediation campaign for a blade. For me, it’s a matter of calling the people I know who might have worked on it and always being on the lookout for people who might have a bit of information I need to solve a problem.
For example, the other night I was talking to somebody about a current project. I was on their LinkedIn page and saw they had worked for the manufacturer of a blade I have the craziest problem with. I’ve had the hardest time understanding what the blade design was, and you need to understand the design intent to figure out why they’re breaking and what kind of repair makes sense. It turns out this person worked for that manufacturer just a few years after that design, and he’s going to introduce me to somebody he knows who was working at Vestas when it was designed. It’s the opposite of googling. It’s such hard work to get the information you need for these blades, and no one writes it down. You have to know the people.
Allen Hall [30:36] You’re on YouTube, or at least occasionally I see you on YouTube. Why wouldn’t you take your phone out, take pictures of this thing and create a two-minute video about what you saw? That’s the way to fix this problem globally.
Rosemary Barnes [30:52] My clients do not like that. Nobody wants to publicize the fact that their assets are breaking, and some of that is absolutely reasonable. As an engineer, you’ve always got to be careful about what you talk about, because you can tend to freak people out. You can’t say everything until you know what the solution is and it’s under control. So one, it’s not my choice, because they’re not my assets, and I’m not going to try to convince my clients to share this stuff. I want to keep working for them and solving their problems. And two, I don’t disagree. You do have to keep things close to your chest. It is frustrating, but there are a lot of informal networks. Anybody working in this area, networking is not something you do just for fun as an optional extra. You have to talk about this stuff at events and just shamelessly ask people for the answer.
Operator forum and wrap-up
Matthew Stead [32:02] I’ll do another plug for WOMA 2027, in case you don’t know it’s happening. One of the most popular parts of the last event was the operator-only forum. The industry does not talk operator to operator enough about these issues. So on the Thursday morning of the event, there’s an operator-only breakfast. I think that’s a great opportunity and a good reason for operators to come along and join the event.
Allen Hall [32:40] That wraps up another episode of the Uptime Wind Energy Podcast. If today’s discussion sparked any questions or ideas, we’d love to hear from you. Reach out to us on LinkedIn or email us at [email protected]. And if you found value in today’s conversation, please leave us a review. It really helps other wind energy professionals discover the show. Don’t forget to subscribe so you never miss an episode. For Rosie, Yolanda and Matthew, I’m Allen Hall, and we’ll see you here next week on the Uptime Wind Energy Podcast.