DNV GL engineers and wind energy consultants Alex Byrne and Matt Malkin came on the Uptime podcast to talk about wind turbine lightning damage, force majeure, assessments, data & more. With decades of industry experience, they discuss common turbine blade damage modes, how data is helping to better assess the lightning environment of wind farm sites, why on-turbine sensors are so critical, and where the industry is headed. Check out their recent article here, which brought to light many of the contract difficulties that are presented when all lightning damage is classified as force majeure.
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Full Transcript: EP28 – Alex Byrne and Matt Malkin from DNVGL Talk Lightning Damage, Assessment, Forecasting & Force Majeure
Welcome back to the uptime podcast on today’s show. We’ve got two amazing guests, engineers, Alex Byrne, and Matt Malkin from DNVGL. Alex and Matt are both experts on lightning’s effect on wind turbines. And these two are gracious enough to join us, to share their expertise. We reached out to them actually for conversation after reading their really good article titled Lightning, wind turbines, and force majeure – a risky mix.
So first let me tell you a little bit more about our guests. Alex Byrne brings over 15 years of experience in the wind industry. Her areas of expertise include understanding and assessing lightning protection systems. Using statistical methods, evaluating blade failures, including performing inspections and identifying root causes, developing, operating wind farm data analytic models and evaluating site-specific turbine loading for broad applications, such as failure analysis site suitability re powering and life extension.
Ms. Byrne has also performed turbine certification for DNV GL in Denmark and holds a master’s degree in mechanical engineering. And our second guest, Matt Malkin has 20 years of engineering experience and 11 years of experience in wind energy with a focus on blade technology. He has led multiple blade failure, investigations and field assessments of blade damage.
Matt has analyzed SCADA and meteorological data in support of blade failure investigations, and is familiar with blade construction, failure mechanisms and failure modes. He has conducted multiple blade and turbine manufacturing and quality surveys in North America, Europe and Asia. Mr. Malkin has participated in the examination and evaluation of composite turbine blades, structural design analysis methods, and manufacturing methods for technical due diligence.
So Allen, what were some of your key takeaways from this really in-depth conversation with, engineers, Alex Byrne and Matt Malkin.
Allen Hall: [00:02:38] first that Matt and Alex are really knowledgeable about the lightning and wind turbine interaction space. There’s very few people who have as much experience in such a broad area of winter been lightning protection.
so it’s kinda special to talk to them because they have such a huge knowledge base and have worked with so many customers around the world on helping operators with their wind turbines and lightning protection systems and making sure that they’re operating at peak efficiency. so that was fascinating.
I think, Alex describing her, way of providing, as a field assessment where she has, over time been able to predict what lightning environment will be for new wind turbine sites or, even for existing, wind turbine sites, what to expect in terms of lightning protection, and then, Matt’s very knowledgeable in the blade structure and, how that lightning protection system interacts with the blade structure and how
defects in the blade structure or damage to the blade structure can, affect later on in the blade’s lifetime. So there’s just a huge amount of knowledge between those two.
Dan Blewett: [00:03:44] And like you said, there’s just so much that I think is still unknown, but yet they’ve seen a tremendous amount in each of their, decades plus of experience each in the industry.
And I think a lot of us take it for granted just how complex lightning is, like you said, every site’s different, every turbine is different, the environment’s different. and they’re just trying to make good forecasting models to say, Hey, this is what you, as a wind farm owner should, They expect so they can make a profitable business.
so yeah, it was pretty interesting. So without further ado, let’s jump right into our conversation with Alex Byrne and Matt Malkin.
So Alex, DNV GL operates like in two separate branches right there so there’s a certification side and advisory side. And they both, stay relevant, relatively independent of each other. So can you tell us a little bit about, DNV GL as far as, your experience and I know you’re more on the advisory side.
Alex Byrne: [00:04:45] Yeah. that’s exactly right. Yeah. So we have a certification branch that certifies wind turbines and components and projects, and then I’m on the advisory side and we help owners and operators, we actually help a lot of stakeholders in the wind industry, with various problems that they bring to us.
So my experience is pretty broad, all the way from, loads assessment site, suitability, looking at re-powerings, life extension. But I also have a lot of experience looking at lightning and lightning interaction with wind turbines.
Matt Malkin: [00:05:19] Yeah, I would like to just underline what Alex said about, the advisory and certification and roles of the broader brand of DNVGL.
we treat the certification side of DNVGL as we would treat any other certification agent, we being advisory. So we are consultants and we represent, typically owners and operators of wind projects, it’s different stakeholders as Alex put it. yeah, myself. I, I am a byte specialist have been in wind for a little over 10 years now and have, as a result of that, been exposed to lightning and various forms, and the damage that it does to play it’s so yeah, looking forward to discussing with,
Dan Blewett: [00:05:58] and so Alex, you’re a little more on the data side.
Is that right? Or at least you’re pretty widespread, I think, by your own admission.
Alex Byrne: [00:06:04] Yeah. that’s exactly right. yeah, I’ve got more experience looking at data, doing data analytics. I worked for a few years for data analytics company is producing software, and for operating wind farms, that applied machine learning to operating one data.
and yeah, when we get to looking at lightning, I’m usually looking at lightning data itself. And doing analysis on performance of lightning protection systems.
Dan Blewett: [00:06:31] Got it. so both of you spend a lot of time with wind farm owners and operators, and I think, one of your big jobs is making forecasts.
So if I was, in the market to buy a bunch of wind turbines and start a farm, obviously I’d want to have as accurate a financial forecast as I could. And obviously that’s, not just the upfront cost, but the operations, the maintenance and then the damage that we might be incurring.
Matt, I’ll throw this to you first, but is this something that you typically help with operators with? Like you can establish a baseline of lightning damage.
Matt Malkin: [00:07:03] That’s a good question. And you’re right that having a good understanding of how much things are gonna cost is essential to, financing a project and getting it going and developing a project.
Alex and I, we provide inputs to the team within DNVGL that supports, developers and those who are building projects, we do provide support to them. I think a lot of our, a lot of our work that we do is for operating projects. So projects that have been built and that are, at that have some operational experience, that I’m talking now specifically related to lightning.
So we may get operators that come to us and say, Hey, look, we’ve got, I’ve got some whitening damage here. is this a reasonable amount of lighting damage, or not, and what can we expect in the future? That type of thing. Cause there’s a lot there, to inform, owners and operators, as well as, People who are looking to develop projects
Alex Byrne: [00:07:57] when, when a new project is getting built, we can also do an assessment of the lightning exposure that project is going to experience, so that can help inform.
budgeting. we can forecast what we expect the lightning damage to look like at the site. Now it might be different because like different lightning protection systems work differently. but the risk assessment is something that can be valuable, because not all sites are the same. They won’t all experience the same amount of lightning
Matt Malkin: [00:08:27] damage.
Allen Hall: [00:08:28] Part of that effort, Alex is that there’s this just take there’s Virgin ground out there. And we’re going to put some wind turbines on this site. Are you pulling lightning data off of Vaisala or the national lightning detection network? And then. Once you put up these big, tall, 500 foot turbines out there, do you predict that’ll change the lightning environment?
Or is there data that you’re trying from previous history that you know, that this is what the impact is going to be when you put these big towers out in the middle of this field?
Alex Byrne: [00:08:57] Great question. Yeah. so when there’s you, maybe you have flat farm lands and yeah, we’ll look at the lightning data that stark lightning data from that area.
And it’s collected by the national lightning detection network. Which is run by Vaisala as you mentioned. So we get that data from Vaisala and yeah, assess, how much, what the severity is for that site, but then as you say, but turbines – they are gigantic structures. and they are going to impact the lightning environment.
We do have experience looking at that. So looking at lightning data before and after wind farm is built, and we have some sense for how it, how the presence of turbines impacts lightning, but definitely want to impart on your listeners that lightening is a very random process. there’s a lot of unknowns about it.
There’s a lot of unknowns about the interaction between lightning and wind turbines. So none of it is, it’s hard facts, hard science. there’s a lot that we will be able to estimate and give indications of but a lot of it, we just have to wait and see what happens.
Dan Blewett: [00:10:04] Gotcha. And is this where.
Your field performance assessment comes in because it sounds like when there’s a new project and you guys are consulting for them, that you will do like an initial assessment. Is that right?
Alex Byrne: [00:10:17] Yeah, so we can assess the field performance at any point. So we use the same approach, whether the turbines are in the ground or not, whether they’ve been operating for a year or 10 years, but the longer the operating history, the more certainty that we have
on the outcome of the results. So if doing an assessment before any turbines have gone in the ground, or just for asking and trying to give an indication of what we expect to see as far as lightening damage goes Once the turbines are in the ground and they’ve been operating for some time, then we can look at the actual lightning, environment, how much lightning the turbines have experienced over the number of years that they’ve been operating.
Yeah. And then from that, estimate how much damage you would expect given fully functional lightning protection system? And if the lightning protection system, wasn’t doing a great job, then you’d see more damage. Then that calculation would show. And that can give you a direction to go for figuring out why you’re seeing that damage.
Allen Hall: [00:11:19] So
is there a generic rule of thumb, based on the country or location, is it regionalized in terms of the quantity of the lightning strike or even the amplitude or action integrals or all those sort of lightning parameters? How do you break that down? Because it seems like every part of the country is just a little bit different.
And, Iowa Is different than Texas and Texas is different from California and California is different than Italy. How do you do all that? how do you aggregate that data?
Alex Byrne: [00:11:48] Yeah. Yeah, it’s a good point. yeah. And there’s localized effects too. So you might know what the lightening environment is in Texas, but then once you put your wind farm in place in Lubbock, then you know, you might see very different lightning exactly.
In that specific location. So when we do our assessment, we collect data from that exact location where the turbines are and no more, no less. so I think that’s a really important aspect of it. that said we’re not lightning scientists – we’re engineers. and so what we know is mostly from the research that the lightning PhDs out there have done and what we’ve observed, but, it does seem like there’s some standard characteristics of lightning.
and some parts of the world that will vary, but in general, you can expect to see a certain distribution of characteristics of lightning, across different sites. the exception. Yeah. The exception to that is that the intent, the frequency. Of the lightning varies a lot by location and you can look at maps of frequency and see how that varies across the world.
And those tend to be fairly, be consistent. Like you mentioned, you have some coastal areas, Italy, Japan, Florida, you just get a lot of lightning there.
Matt Malkin: [00:13:16] I had a thought there, Alex, as you were talking, it is true. I, as you said, the lightning flash density varies geographically. One thing that we’ve seen recently, which is very interesting is in a couple of very low flash density, geographic areas.
We’ve seen some very significant strikes to wind turbines. And very interesting, and this has been several points around the globe where we might normally have, one flash per square kilometer, per year, something like that, very low flash densities yet.
We’re seeing. some significant, lightning events. And so it is, but I say individual events. maybe the overall flash density is not changing, but we are seeing instances where turbines gets struck and damaged. And so what’s going on there? to me, that’s interesting from a number of angles, but one is related to tall structures, like wind turbines and the nature of lightning.
And Now we understand that very tall structures are struck almost exclusively by upward lightning. Whereas shorter structures below say 60 meters or so are struck almost exclusively by downward lightning and the lightning directionality matters because the characteristics of that lightning are different.
And the resulting damage modes to this, to the object that they hit are also different. And so the case of. Upward lightning and wind turbines. there can be a lot of charge transferred, in those upward lighting events. And that can have some specific damage modes. There’s a lot of heating involved in that type of event.
In addition to that upward lightning can be very challenging for lightning location systems to see it in cases where there’s a continuing current phase, only of the lightning event, there’s just basically DC content. And that there’s not a lot of the, the high frequency content that the sensors, the ground based sensors anyways, are looking for, in lightning events.
That makes our job interesting. So you may have a damaging lightning event that a there’s no record of it based from the ground based sensors. That’s a particularly interesting topic. And I think one that we’re going to start to see more of as tip heights – so that’s the hub height of the turbine
plus the length of the blade – goes, go up, which seems to be the trend. And it doesn’t seem to be stopping.
Allen Hall: [00:15:34] Yeah, there’s very little data, Matt. I think you’re right about that. That there’s very little data about height versus lightning strikes. When the empire state building was built back in the twenties, there was GE had performed a lot of research on the top of, of the empire state building and were measuring, lightning strike data.
And they realized a lot of the lightning strikes were upward. And then, but in terms of like power generation equipment, we’ve never been to those heights before and didn’t rely on it. if the empire state building got struck, nobody really cared. But if our wind turbine goes down, when we start to really care about it, and I think you’re right about that, there is some effect about as we get bigger and the diameters get bigger, where we’re changing the way we’re changing the environment.
It’s a weird way to think about it, but we’re actually. Changing the way electricity works in the cloud because we’re creating these really darn conductive things. and I’m not sure if it’s all height related or combination of height, plus some environmental changes that are happening on top of it. Or in some cases it seems like the number of turbine seems to affect the weather pattern a little bit.
Any sense of, as we go bigger, what we’re going to see, are we going to see more of this sort of continuing current positive lightning strikes, upper triggered strikes as we get bigger, which is where we’re going right now with some of these GE blades and the Haliade, and some of these turbines are just getting
enormous.
Matt Malkin: [00:16:52] Yeah, that’s right. The turbines are continuing to grow. It is my sense that we will begin to see a higher fraction of events that strike turbines as upward, in the upper direction, just because of the height, as far as a sort of, a couple of your other comments, the environment, having some, influence there, if that’s possible.
I don’t know if the number of turbines is affecting that or not. I think that’s a very challenging question to answer.
Alex Byrne: [00:17:20] The other
interesting question is whether or not the rotating nature of the turbine has any impact on it. We do have some curious behavior lightening around wind turbines that doesn’t seem to be mimicked with just tall towers.
So there’s some indication that it’s the rotating nature of the turbine though. I don’t think that is perfectly well understood yet. And there’s some. Speculation, I guess that shutting down out a wind farm when a particular storm comes through, might reduce the damage that on the turbine.
Dan Blewett: [00:17:53] There have been any studies done with say the Redwood forest? If we’re talking about really tall non rotating objects, I wonder if there’s been anything done there where they say, hey, this is comparable and to height to too many of these wind turbines, but they don’t seem to have the same lightning environment.
Alex Byrne: [00:18:10] I don’t know the answer to that question. I know that there’s lighting measurement on various tall, towers, like communication towers and yeah. Then there’s rocket triggered lightning. They do a lot of those experiences or, but yeah, they’re all a little different than wind turbines.
And then the other thing to note is just that historically we have not done a great job of math sharing lightning on wind turbines. So as Matt mentioned, Yeah. We typically rely on the lightening location system that National, the NLDN that we talked about earlier, national lightning detection network, to give us data about lightening, but that night, or we’ll typically only give you the peak amplitude of the lightning flash or stroke.
And it, it doesn’t give any of the other characters of lightning. So there are multiple characteristics that represent the whole time wave form of the lightning events and peak current is only one of them. So typically, that’s all we have and sometimes we don’t even have one that if the lightning location system doesn’t capture the damaging strike. So to compare, we’re seen on wind turbans to what we’re seeing on towers is a little difficult just because we don’t know the distribution of the rise time of the total duration, total charge transfer of specific energy.
And, we’re also a little bit in the dark on what’s happening with those upward events, just because they’re not captured as much in the lightning location systems.
Matt Malkin: [00:19:46] Yeah,
I think that there is ample room for the industry to measure lightning strikes to turbans and it’s, to me, this is a very exciting and interesting area where there could be so much more development.
there’s various sensors out there that could be mounted in the blades. They could be mounted at the base of the tower that could potentially provide that full current time wave form. For lightning strikes that hit the turbine. And that is very useful information.
Allen Hall: [00:20:16] That circles back around again.
Does that our issue right now is that we have IEC specifications for qualifying wind turbine blades and testing wind urbine blades. But then we have a separate issue, which is one, the lightning varies across the world. And, but also as we get taller, we’re seeing effects that we wouldn’t have otherwise recognized.
I know on the aircraft side we have the same issue, where we’re seeing different kinds of strikes. As we start to instrument, aircraft and wind turbine towers that we’re starting to record some of the data and starting to scratch our heads and say, wow, a lot of the data we took almost literally a hundred years ago.
80 years ago in terms of towers, isn’t maybe as accurate as what we can measure it out, or now we’re recording. We can record every strike. And I think you’re right. as an operator, just measuring a couple of turbines would be a huge impact into future development projects because as your field performance assessments or putting together that history, having some of that real data can make the next generation wind turbines, just a lot more resilient to lightning strikes.
Alex Byrne: [00:21:22] Yeah, I think you’re making exactly the right points there Allen, and our longterm objective should be as an industry to get more knowledge about how lightning is interacting with wind turbines so that we can get better at protecting these turbines, especially as yeah, they’re getting taller and we’re expecting to see more and more lightning and possibly more severe.
there’s no way to get better at that without the data. so yeah, we absolutely have to start measuring data on wind turbines.
Dan Blewett: [00:21:58] All right. So Matt, we’ve been talking a lot about, the need for measuring all these strikes upward versus downward. So you said you’ve seen the lots of the mechanical damage. that’s like very much in your wheelhouse. we’ve talked a lot about like the overall picture a little bit, but how bad is this issue of lightning damage right now?
Where’s it coming from. and is there anything that makes, we’ve talked a little bit about it, but anything that makes lightning’s interactions with wind turbines, especially unique?
Matt Malkin: [00:22:25] Definitely. Let’s walk through it when lightening attaches to a wind turbine. there’s two essential functions that the lightning protection system on the turbine provides.
The first is to get the lightning to attach to what’s called the receptor, which is an appropriate point for the lightning to attach to. And then once that’s happened, the lightning needs to be safely conducted to ground. What we see in terms of damage is first when lightning attaches somewhere else, other than a receptor.
And so you get the lightning puncturing through the fiberglass shell of the blade and attaching to, for example, the down conductor, that the, the cable that’s inside the blade, directly, rather than attaching to the, to the receptor. Or you may see lightning attached to structure with inside the blade.
And that typically happens, more frequently with carbon fiber structure, which is partially conductive and that attachment, that can do that damage to the carbon fiber itself. It can do damage to anything that the lighting passes through. There’s also damage done during the conduction phase.
And so that can be, heating that results in, the shells of the blades opening up. So the trailing edge of the blade can split at the tip. You can have arking inside the blade between the down conductor and conductive components within the blade. you can have, arking, if there’s a broken cable down conductor cable or a gap, you can have arking there as well.
which leads to again, to, potentially to damaging the typically fiberglass laminates within the blade. Yes, there’s various damage modes that can occur. the, the impact of this financially, it can be very significant for a project. So you can have a, a bad lightning season.
And, I’m aware of a large project they budget a million dollars a year for lightning damage repair. Wow. Yeah. This is a huge problem. As far as the uniqueness of lightning. And damage to wind turbines, wind turbines are unique structures they are not steel telecommunications towers.
they, the blades are typically manufactured of fiberglass, sometimes carbon fiber. so they’re, they’re glass reinforced plastic and they are not as that again, they’re not as robust as a steel tower. and so they are sensitive to lightning damage.
Dan Blewett: [00:24:47] So, say in year one and they take 10 lightning strikes, just throwing out a random number.
they might not have to repair any of those 10 that year. So what’s the difference between short term damage. And I assume there’s probably a lot of longterm damage that when you’re talking about heat transfer with an, a blade, some of these laminates probably take five, 10 years. Sometimes, maybe to start to really show the effects.
Matt Malkin: [00:25:11] Great question, there’s so sometimes the lighting damage is obvious, right? You need to, it’s very clear that you need to shut down the turbine until a repair can be done at other times. Lightning damage on the surface anyways, may look not that bad. So you may continue to run the turbine, keep an eye on it.
And then other times, the damage may not look so bad on the surface. But underneath the structure that matters, there may be initiation site and, wind turbines see a very, high fatigue environment. And under that fatigue environment, that damage can progress and grow and become critical.
So there’s a lot of uncertainty when it comes to assessment of damage to blades in particular. and
Allen Hall: [00:25:54] Matt, that he component, I think is where people get lost in this and the fatigue environment that you’re in. Because Dan was saying, what we have seen a lot of is like the split trailing edges, which may not happen, but immediately during the lightning event and maybe another month or two, after that, where just the fatigue starts to split the split the blade.
And internally too, we’ve seen a lot of damage internally that has completely heat-related to Coulombs from the lightning. So the long duration currents heating up the down conductor, mostly the receptor blocks in there, whether it just, or just getting physically hot and for most cases it wouldn’t matter.
But yeah. the resin systems and the resin systems that most blades use are not really high temperature resin systems. Like we would typically use and other things, they tend to be low temperature, 250 cure kind of things. so the, if you get anywhere near 150, 180 degrees or 200 degrees locally, you can really deform those structures.
Locally. And the fatigue seems to take over time. Is this, is that’s what we’re seeing. Are you seeing that similar thing where the lightning strike itself? It happens, but there’s not an immediate walk for that, but it’s sometime later that it’s that sort of accumulated damage that happens.
Matt Malkin: [00:27:10] That’s a good question. And I, it really varies again. I think you get both, I think you get immediate effects. and then you also do get some instances where the damage will progress over time and, we’ve seen that. And it is an ongoing challenge being able to properly identify and categorize damage that due to lightning con blades. this, I think this will continue to be a challenge for the industry.
Dan Blewett: [00:27:35] So Alex, on the data analytics side. if you’re trying to track – Hey, this turbine took a couple of strikes. Is there any way you can then say, all right, we’re going to monitor it or will you see something happen with the data where you say, okay, it seems like something’s internally wrong with this blade.
what can data do to forecast or to see into the future or just track some of these lightning strikes over time.
Alex Byrne: [00:27:59] Yeah. It’s a great question. And we get asked that a lot. Yeah, it would be ideal if we had some data source where it could just ping you and say, there’s something going on with this blade.
As the blades get larger, they do get better instrumentation. It gets more sensors on the blades that might be able to help with that. But the typical blades we’re working with today, they’re not well instrumented. And so the information that we get from typical data streams, just isn’t sufficient to indicate anything about blade health.
there’s a lot of questions we get. if lightning damages the outside of the blade, wouldn’t you see that show up in the performance of the turbine, because now the airfoil is compromised. So it’s not capturing the same power and we should, you see a decrease in power and you should be able to tell us like that blade,.
that should go – you should go inspect that blade and in theory, that is true. Another, I think that we do a poor job of measuring his wind at sites. You really need to know what the wind speed is to know if the power is degraded or not. So I would say that. To get there, to get to work from where we are now to being able to identify damage through data.
You either need to get a little better when measurements or we need to get better blades, sensor measurements. And I think we’re going in that direction more for the ladder for the blade sensors. A common way to identify whether or not a blade or a turbine should be inspected after lightning storm.
It’s just to look at the lightning data. I think that’s pretty typical as we’ve already mentioned lately and location systems, don’t capture all the lightning. So that’s gonna, it’s gonna miss stuff, with some regularity, but it, it’s the best I think we have right now. So you look at the lightning data, you say.
There were some strikes close to this, the natural, but not triggering. You go out and look at them and that’s an acceptable approach for what we’ve got to work with right now.
Matt Malkin: [00:29:52] And this is, I would like to put in another plug there for on-turbine lightning measurement devices. just from an operational standpoint at a project, if you wanted to target your inspections after a storm, if you had data from the, you would know which turbines had been struck and you can then go out and look at those turbines in some detail.
Dan Blewett: [00:30:12] So speaking of, going out and inspecting the damage, I assume there’s like a spectrum, right? So there’s probably strikes that cause very little damage that maybe never needs to be repaired or maybe way down in the future. And there’s some that probably needs to be taken care of right away.
A, can you speak to the, sort of the range on that spectrum and B how do you know the difference, especially if there’s internal, if there’s internal damage.
Matt Malkin: [00:30:37] That’s a great question. And it’s super relevant for so many projects, right? There is that spectrum of small instances of damage all the way to, very severe damage, right?
Typically damage is categorized. So you might have category one damage, which is quite light and you can continue to operate that. and then you re that range goes all the way to say category five, which would be catastrophic. And it’s somewhere in between is where it gets interesting. What do I do with my category three damage?
And there are different strategies for managing damage. Different operators have different ways to do it. There is no universal sort of categorization system. As an aside, I am working on a project with the Electric Power Research Institute – EPRI – to develop a recommended practice around this damage categorization for blades.
Your question has a subtlety to it that I think is very challenging to answer. And that is what about. The effects on the internal structure of the blade. And this is something that is very difficult to know. Internal inspections of blades are a great thing. And I think that they’re not done frequently enough.
They are time consuming. they require some special, knowledge in terms of confined space entry from the people doing the work and they, they, while they’re a good information source, they’re also. Limited, You may, a visual inspection, either the inside or the outside of the blade, can’t see everything.
And, there’s, I think there’s limitations to what we can know about the extent of damage due to lightning events.
Allen Hall: [00:32:14] Matt, how critical is that as you’ve gone from fiberglass blades to carbon fiber, carbon fiber spar caps.
Matt Malkin: [00:32:21] Good question. I think that, carbon fiber or in general is less tolerant of flaws than fiberglass.
And, if a flaw is initiated, a flaw is present because of damage due to lightning, that can be more critical on the other side. carbon fiber is more challenging to repair. there’s, I think a. And importance in understanding what the damage extent is in carbon fiber blades, perhaps a greater importance than with, with fiberglass, please.
Allen Hall: [00:32:55] Yeah. Yeah. And I think you raised a good point there. Repairing damage on the outside of the blade can be relatively easy, but if you have spar caps, bar web damaged carbon fiber damage internally that’s is that even possible to repair?
Matt Malkin: [00:33:10] It is. Yep. It is possible. It’s costly. The blade may need to be removed from the turbine repaired on the ground.
Re-installed rather than say an up-tower repair. That’s one of the challenges, one of the general challenges of blades is that they are difficult to access. That challenge does not go away with lightning related damage
Allen Hall: [00:33:29] In internal damage. How do you even know too, especially when you get to these larger blazer, a lot of carbon fiber on the spars.
How do you know to even check internally? Is there any triggers that happen that say we need to go inside and look.
Matt Malkin: [00:33:43] That’s a good question. Typically internal inspections are, time-based, they’re done on a, every several years. I do think that in the, in some instances, if there known damage modes, then than you might, that might trigger internal inspections, right?
if there is, some external indication that might suggest that further. Internal looks are advised then. Yeah. You’d want to do that. So
Allen Hall: [00:34:10] yeah, at that point you would provide an invaluable service just because you have the history of different, a lot of different blades. And so you would know that we have seen this sort of issue on other blades.
So we need to go look here and that history is really invaluable. Isn’t it?
Matt Malkin: [00:34:24] Sure. Yeah, there’s a lot of experience, Alex and I get exposed to a lot of, different turbine and platforms, we see damage across, different projects around the world and, that helps inform our perspectives on, whether, what advice we provide to clients.
do we think this is severe or not? there’s a lot of judgment involved there.
Allen Hall: [00:34:43] So when we go off and we qualify a new blade design, we do lightning testing per the IEC, 61400-24. And there’s different lighting protection levels there, but essentially we’re going to put 200,000 amps and 10 megajoules into that blade.
And we’re going to see how its responses. Now, one of the things that. I think gets overlooked a little bit is the post-test inspection structural of the blade from the electrical engineers perspective we look at it like, yeah, all right. The energy went in, the energy, went out and from what we can tell electrical speak, it looks like the blade is fine.
How important is that 1 – the post-test inspection of the blade structural inspection is done to see if there are those sort of fatigue points that we just created and the blade. And then how does that data then translate over to performance in the field? So if I know a blade has quote unquote, pass the IEC test, does that translate into success in the field or is it still unknown?
Matt Malkin: [00:35:43] Yeah, let me hit that a couple of key points there. Great questions. I think that, first of all, typically full-scale blades or, the full blade is not tested in the lightning lab. What will happen for the, the high voltage leader attachment test, which is checks the lightning will be directed to a receptor rather than somewhere else in the blade that’s done with the outer portions, just the tip of the blade.
I’ll say, I don’t know, 10 meters or five meters of the tip portion of the blade. And then the, some of the other tests are done again with just pieces of the blade, the down conductor, our various connections. And it’s very rare that a full blade would be brought into a lightening lab and tested.
So I think that it’s not, necessarily even possible to do a post test inspection if you haven’t tested that full blade. Yeah, so very, I think there’s a lot of room there for improving, how we do lightening tests, but really the laboratory of the real world is where we get our test data.
it’s when you get the turbines out there, they’re operating and we see what happens,
Dan Blewett: [00:36:48] Speaking of which do you see any new challenges now that we’re getting more? Floating offshore, wind farms and larger ones off shore, is there a significantly different lighting environment out there, way out in the ocean compared to here.
I mean, we talk about, we did a show about floating wind turbine tech a couple of episodes ago, and. there’s a lot of engineering that goes into it, but we’ll see if those structures hold up in 10 years in the high seas. There’s still just a lot of, like you said, the real world lab.
but do you see any challenges with offshore versus onshore?
Alex Byrne: [00:37:21] Yeah, I think offshore has its own unique challenges. The lighting environment is different than on shore, and it’s a lot harder to get data off shore. The lightening location systems are, mostly capturing lightning that’s occurring onshore.
So to start with, we just don’t have that much information going into the building of a new project. and then, Matt talked about challenges with blade repairs, unsure, like lowering a blade to the ground to do repair, like offshore your costs. Shoot way up, to repair these things. So is that much more important than the lightning protection system works?
It’s that much more important to do measurements on turbines, to know when you need to go out and identify damage. And then decisions around when and how the repair are going to be a lot more complex because you need to take into consideration more weather conditions, access, limitations, and, of course higher costs.
yeah, it’s a big challenge. We’re grappling with Stella as an industry.
Allen Hall: [00:38:24] So as we do more and more offshore wind turbines and the floating wind turbines and everything gets bigger and bigger. How important then is it to really instrument the turbines? is it just exponentially more important to do it?
Just because we don’t have the lightning detection, the network really accurately out there.
Alex Byrne: [00:38:43] I think so. yeah, we were hammering on that point, but, as the turbines get bigger, they get more valuable per turbine and so putting one sensor on it is going to start to make a lot more sense, especially as you’re talking about these 10 megawatt turbines and bigger, it’s, the cost per megawatt, then just as small for a sensor like that.
And it’s just going to start making a lot of sense. And the value is across, multiple aspects from deciding when to inspect, understanding the lightning itself, understanding, how many times a turbine or blade got struck. I keeping track of that lifetime impact of. Of lightning on the blades just can’t emphasize enough how important that’s already is and will continue to become moreso .
Dan Blewett: [00:39:35] all right. So you both penned an article for ran on wind power engineering.com earlier this summer called lightening wind turbines and force measure a risky mix. So we’ve been talking a lot about maintenance and about sensors and about, just getting data. And, but let’s talk about what this means for the wind farm owner, because obviously at the end of the day, they need to make good financial forecasts and they want to make sure that, damage is covered under warranty.
I’ll toss us up to you first, Matt. if I’m buying a wind turbine, is there a specific language that I should include in the contract? And I know, force majeure has been one of those sort of contentious contract language pieces, but what should I be trying to get in my contract to help protect my investment?
Matt Malkin: [00:40:30] Great question. Yeah. The force majeure has its place. if a tornado hits your turbine, that’s force majeure events, right? In the case of lightning though turbines have a lightning protection system that is engineered to protect against a certain level of lightning, which is governed by the IEC-44 standard.
Now I think that it is reasonable that if lightning is within the capability of the lightning protection system, that lightning should not necessarily cause catastrophic damage to a turbine that wouldn’t result in say, an uninsurable event. I think that in the contracting phase, when commercial contracts are being developed, either it’s like a turbine supply agreement or a, say a service and maintenance agreements, those types of commercial
documents between a purchaser and a turbine and vendor, In those documents. I, from my perspective, lightning should not automatically be considered a forced measure event. And it certainly some lightning it should, right. Lightning that’s far outside of the capability of the lightning protection system.
Again, I think that’s reasonable, but I think that in the case of, of lightning. There ought to be a closer examination of, of whether or not the lighting protection system should or should not have, safely protected the turbine from the event. So that’s, typically commercial agreements consider lighting force majeure, and then the industry
has just been proceeding that way. and I do think that, that is probably time to shift the industry away from that and that could have some beneficial effects that can have the effect of us pushing through towards better understanding of lightning and its interaction with wind turbines, driving better designs for lightening protection systems.
Okay. and, improvements in the standard, those kinds of things. So I think there’s a lot there, at that could be driven by the content of commercial agreements.
Allen Hall: [00:42:27] how much influence do the land owners have? So the adjacent communities play into that because there seems to be a number of organized efforts, not huge, but there are local organized efforts that are concerned about blades breaking and lightning strikes and that sort of thing.
the sort of the overall pressure on the industry to, provide a really stable lightning protection systems seems to be growing and growing. As particularly in United States as the wind turbines get larger distribution. I think that the money is going to be the key point here and insurance companies obviously have a big say and into what manufacturers do.
Have you seen that sort of change? I think I seen better lightning protection systems and I saw 10 years ago
Matt Malkin: [00:43:12] in general, lightning protection systems do a pretty good job, I think that if blade failures are very rare events and blade failures due to lightning are even rarer know, on top of that.
I think that the risk associated with these events is low. I, again, I do think that there is there’s different ways where we can push on this force measure clause and having that sort of changed. I think having underwriters and insurance policy writers.
Influenced the content of those contracts, potentially other stakeholders like landowners. Although I think that the, I don’t know much about the interactions between landowners and developers, but, it seems to me like, yeah, that’s possible, that they could influence, influence those discussions.
Allen Hall: [00:43:57] Yeah. And so I’ll give you the comparison in the aviation world. So first powered flights, 1903, we had lightning strikes, airplanes. Prior to world war II, pretty commonly. And in terms of the nation, or we started putting in essentially laws didn’t happen until late or mid 1960s. After we had a series of commercial accidents that were just visible to the public, there were large press events and it.
pushed the federal government to do something. are we in that sort of phase right now where we don’t have federal requirements to provide lightning protection systems to some level, does it even need to go that far? Or is the industry going to be able to self regulate?
Matt Malkin: [00:44:40] Good question. I think turbo manufacturers themselves have an incentive to, have their turbines run great and not be damaged by lightning.
So there, I think that there’s always going to be good efforts within terms of manufacturers to have high performing lightning protection systems. I suppose that, the, as the industry evolves that, and as you say, terms become more widespread. There could be an increasing role in, either at any level of government and in the regulation of turbines, turbine design, that type the thing.
but I think we’re alone way from the extent to which there’s interaction between the government and, and the aviation industry. So
Dan Blewett: [00:45:21] I want to jump back to the contract language. So on your article, you mentioned that there were a couple of factors that they should consider when drafting their contracts.
So number one, lightning damage, not being a force majeure event by default. Number two, a clear definition of function. Impairing damage. number three, consideration of uncertainties, with possibility or possible adjustments of assigned responsibility between the manufacturer of the turbine and the owner.
and lastly, a path for dispute resolution such as like a mediator. So can you talk through those a little bit more and elaborate a little bit for me?
Alex Byrne: [00:45:59] Yeah, I think the, once you take out the forced measure language, or once you say not all lightnings force majeure by name, his first major, you introduced some new challenges and the new challenges.
How do you know how severe the lightning was? How do you know what actually caused the damage? if you have it all lightning is force majeure. it’s easier, But it might not be very fair, then lightning protection system is designed and certified to protect the turbine to a certain level of lightning.
And so if it’s the turbine’s getting damaged at less severe lightning, then that should be okay. The OEM service provider’s responsibility. but yeah. So as you read from the article, the complications do arise of figuring out was it lightning within or outside of the design limits? so that’s a typical definition for other types of force majeure.
If you have, wind conditions that are outside the design elements that might be considered force majeure. Lightning. It should be the same – if it’s outside the design limits of the lightning protection system, that should be conserved for some mature, but then we get back to our earlier conversation.
We don’t have good measurements as of late me of all of the printers. Sometimes, let me location system doesn’t even measure the damaging strikes. So how do we know if it was within or outside of those design limits. And the answer is, we either. We either use, on turbine measurement systems we’ve been talking about or use probabilities and that’s an acceptable way to go.
We do know the typical frequency distributions of the design parameters, and so we can make educated guesses about it and we can put statistics around those educated guesses. What we need to have in the contract language is clear definitions around how those probabilities are used. So if we’re able to calculate the likelihood that the design limits were exceeded the contract needs to say, at what point does the responsibility go to the owner versus the operator, or the service provider?
Or is there a split contribution?
Dan Blewett: [00:48:15] Yeah, that makes sense. Because like you said, it seems Hey, all lightening is force majeure, therefore its just, if they take that clause away, it’s gonna force everybody to make a lot of really strong standards to say, okay, this is where we cover it. This is where you cover it.
And, yeah, it seemed like there was like a lot of insurance and just legal paperwork, right?
Alex Byrne: [00:48:37] Yeah. Yeah. And the, what we wouldn’t want to see is. The force majeure clause removed and not, and what goes in its place, not being clear, precise enough.
Dan Blewett: [00:48:48] So do you have an idea about, where, that limit would be?
is it a certain amount of Coulombs or kill the amps or what, Allen, I’ll throw this to you. what do you think like a lightning strike looks like that’s well, beyond the limits of a
Allen Hall: [00:49:02] LPS. Oh, the LPS has, are designed today to take 200,000 amps little over and, 10 million Action integral or mega joules per Ohm.
I
Matt Malkin: [00:49:13] think really good question. I think that if any, one of the design parameters are exceeded, an argument could be made that. That lightening event that exceeded that design parameter was outside of the capability of the LPS, because the LPS is only designed to be able to handle so much. yeah, just again, like Alex was saying with wind conditions, right? let’s say the termin saw extreme wind event and it was the turbulence that was too high rather than the wind, the mean wind speed that was too high. And they, you could still make the argument that wind event exceeded the capability of the turbine.
At least to the 2010 version of the dash 24 standard there is really no, Restriction on how many times the lightning protection system can get hit. there’s certainly, there’s discussion around erosion of receptors, which makes sense, right? Like you want to be able to replace, components that have eroded or melted, because of numerous strikes.
so you know, that lightening protection really system really needs to be able to handle, Oh, what we collectively, as an industry decide are the limits of its capability, for the life of the turbine.
Allen Hall: [00:50:17] Yeah. I agree with that. I was just trying to relate that, strikes that are above 200,000 amps are
relatively rare and 10 megajoules per ohm are again, relatively rare, tend to be positive strikes. So there, I think the thing that we’re seeing, maybe just, maybe it’s a US based thing that we aren’t seeing such super strikes so much as show that repetitive nature and you’re right – the IEC spec does talk about repeat strikes and replacing components that are going to be.
Likely erosion, like the receptors are going to get eroded. that all makes sense to me. I think what we’re concerned about is that accumulative effect, because now we are triggering a lot of these strikes and we don’t really. I have a really hard number on how many strikes we’re likely to take.
And I think that could be an argument made from the manufacturer’s perspective that, we designed our system to take, say it’s a hundred strikes. And for whatever reason where we put this wind turbine, it’s taken five hundred. I think because it’s not described very well in the IEC document, I think that’s an area of concern and I don’t think there’s an answer for it, but I think that’s where probably a lot of the discussion will end up.
It’s just on the repeatibility and the number of strikes.
Alex Byrne: [00:51:26] I think that’s a good area of maybe research out there. I don’t know that the industry has grappled with it yet, but I agree that there’s some indication that the number of strikes has an impact on how well the blade’s able to handle additional strikes.
And maybe at some point that will be a part of the standard.
Allen Hall: [00:51:46] Yeah, we certainly have a lot of data and you’re probably at the forefront of it. All of this data, Alex, is that you have a sense of how many strikes these turbines are taking on. And as an industry, I know we’re going to make that cycle around again, where we’re going to be coming back to that UC spec and opening it up again.
And do we start putting in requirements that say, all right, we need to do repeat strike testing. We need to look at. So the likelihood of taking 50, a hundred strikes, how do we even evaluate it in the laboratory? Because that’s a thing we don’t do today. So there’s a lot of complexities, but as you were talking about earlier, one, the force majeure seems to be a big driver here, but to just the lack of data is really an area we should focus on today.
If we can.
Dan Blewett: [00:52:29] So as we start to wrap up here, let’s talk about the future a little bit. So are there any trends or any, new recommendations or technologies you’d like to see becoming standard or just the industry going towards in general? Alex, I’ll throw this to you first. what do you think about the future of, of lighting protection in the wind industry?
I think
Alex Byrne: [00:52:49] the main thing we need to do as an industry is understand the interaction of lightning with wind turbines better. There isn’t enough information out there about the actual field experience. So more measurements, more data, more analysis, and then being just being open to the fact that it’s an evolving science and the lightning protection systems are evolving.
As the turbines are getting bigger they’re getting hit more and possibly with higher intensity lightning, losing blades is a, it’s a very high profile event for the industry and it threatens our credibility. not to mention it’s very expensive. Across the board. I think it’s a really important issue.
It should be getting a lot of attention. and, and yeah, I’m excited to see where it goes in the next few years.
Matt Malkin: [00:53:40] I would add to that, again, as we’ve said that I think that there’s a lot of room on the contracts side for evolution, of the language and the contracts to handle, lightning as an event.
And again, as we’ve talked about to not consider. Automatically all lightning as force majeure. and I think when you couple, as Alex was saying, the sort of increasing size of turbine is increasing. I it’s, the sort of dollar per megawatt, value here. I think that the contracts should keep up with that and they should, the contracts, the content of the contracts should match the risk levels that we see here.
So again, I think there’s room for evolution in the standards and, certainly in the technology that we use, for measuring lightning and for protecting ourselves against
lightning.
Dan Blewett: [00:54:34] All right. Alex and Matt, thank you guys so much for being here. This was a really detailed awesome talk. I know Allen loves geeking out a lightning whenever he gets a chance. So yeah, it’s a real treat for him, especially, but all of us here, so Alex, thank you so much for coming on the show. Really appreciate it.
Alex Byrne: [00:54:50] Thank you both. Yeah, it was a real pleasure talking with both of you
Dan Blewett: [00:54:53] and Matt.
Thank you again. I appreciate your expertise. Yeah, I
Matt Malkin: [00:54:58] really enjoyed the conversation and thank you very much for inviting us and having us on.
Dan Blewett: [00:55:03] Alright, well, we’re going to wrap up today’s episode of uptime. If you’re new to the show. Welcome. If you’re a regular here, thank you for your continued support.
Please subscribe to the show and leave a review on iTunes, Spotify, or wherever you listen to podcasts. Don’t forget to check out the Weather Guard Lightning Tech YouTube channel for video episodes, full interviews and short clips from each show. For Allen and all of us at Weather Guard stay safe and we’ll see you next week.
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