We4Ce & CNC Onsite’s Re-FIT Blade Root Repair Goes Global

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
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episode is sponsored by Weather Guard Lightning Tech. Learn
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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,