Have you ever wondered how green
wind energy really is, especially when you see those vast piles of wind
turbine blades dumped in landfill? Social media and articles
like this one from Bloomberg have raised this question, casting doubts
on the sustainability of wind power. Some people are saying it's
actually horrible for the environment. Today
we're going to tackle this issue head on. We'll examine why recycling wind
turbine blades is such a challenge, focusing on the materials
and manufacturing methods involved. Then we'll scrutinize the current
recycling methods and discuss what needs to change
for blades to be effectively recycled. We'll also evaluate the efforts of wind
turbine manufacturers and composite material suppliers towards this goal. I'm Rosie Barnes. Welcome to Engineering with Rosie. I'm an engineer with a Ph.D. in wind
turbine blade design and years of experience working for a wind
turbine blade manufacturer. So I think I am pretty well placed
to answer the question of today's video. Why are wind turbine blades
so hard to recycle? First,
let's put wind turbine waste into context. Most parts of a wind turbine are made from steel, copper and concrete,
and they're recyclable. However, the blades
made mostly of fiberglass and sometimes carbon fiber, present
a unique recycling challenge. this challenge is shared
with other products made of composite materials
like boats, cars and airplanes. And in fact, wind turbine blades account for only about 5
to 10% of global composite material use. Very early in this YouTube channel,
I made a video on wind turbine blade waste and did some rough calculations that showed
that if I were to get all my household electricity from wind over 20 years,
my share of composite material waste from that would be less than the composite
waste from my mountain biking habit. "My mountain bike is German and it has more
composite materials in it than a German's share of wind turbine blades
over twenty years of electricity use." So all that is to say that, yeah, the problem is overstated
and it's overblown. However, blade recycling is still an issue
that ought to be addressed, even if it's not the largest
environmental issue we face compared to, oh say, climate change
caused by burning fossil fuels. And now it is a reality that wind turbine blades going into landfill, create
a really bad vibe surrounding wind energy. And the general public does
want this solved. So what would it take
to stop blades going to landfill? And why aren't we already doing it? Understanding
the structural design of wind turbine blades is key to grasping
why they pose a recycling challenge. You can picture a wind turbine blade
as a giant cantilever beam, much like a diving board. It's fixed at one end
and free at the other. A 30 meter long blade, which is small by
today's standards, has to be able to withstand extreme gusts of wind that exert
nearly 200,000 Newtons of force. That's equivalent to the weight of
about four African elephants. These blades must be incredibly stiff
to avoid bending into the tower
and extremely strong to resist breaking. And at the same time, they need to be light enough for the tower
and bearings to support them. The key
to being able to achieve this remarkable combination of stiffness,
strength and light weight lies in fiber reinforced materials
like fiberglass and carbon fiber. These materials contain fibers
that are very strong because they are too thin to contain any
defects, but they are floppy like a rope. Then the fibers are contained in a resin,
which is not particularly strong or stiff on its own. But the resin keeps
all the fibers in place. Once you put the fibers in resin
and the resin cures, fibers can't fly past each other anymore. And so the composite material becomes very stiff and strong
in the direction of the fibers. the composite structure
allows for a high degree of optimization, concentrating the stiffness and strength where it's needed
most while keeping overall mass down. When manufacturing wind turbine blades,
the orientation of fibers is crucial. Most fibers align along the blade
length, ensuring strength and stiffness where it's needed,
and they need to be continuous. So wind turbine blades are made
in a single piece, layering dry glass fabric in a mold and infusing it
with resin under a vacuum. Once that resin cures, you're left
with a very durable structure. These plants need to withstand exposure
to the elements for 20 or 30 years. The fact they can do
that is a great engineering feat, but their incredible durability
also makes them hard to recycle. As we move on to recycling,
you need to keep in mind that the features making these blades robust also
make them tough to break down and recycle. Photos of wind turbine blades in landfill look terrible, and the idea of recycling
gives off a very nice vibe. But let's dive a little bit beneath
appearances and vibes. What does recycling actually mean? It's not as straightforward
as you might think. Is burning material for energy recovery
considered recycling? What about shredding
the blades to use them as filler for low value materials
where structural integrity isn't crucial? Does that count as recycling? Recycling options
like these raise questions about sustainability
and environmental impact. For instance, burning blades releases CO2. Recycling plastics often uses more energy
than producing from virgin materials, and using shredded materials as filler
wastes those amazing structural properties that we just discussed. The ideal recycling scenario would involve
recovering glass and carbon fibers and usable resin
to create similar or new products. And it would save energy,
CO2 emissions and money along the way. But that is incredibly hard,
and it's not what the majority of today's blade recycling projects
that you hear about are even attempting to do. Let's talk in a bit more depth about fiber
reinforced composite materials to find out why. Remember that fiberglass or carbon
fiber are a combination of two elements The fiber and the resin bonded
tightly together. The key to recycling composites is separating those two components
without destroying them. the resin is a type of plastic
and on a molecular level, it's composed of long polymers that slide
past each other when in liquid form and they solidify upon curing. You might be thinking that recycling
plastics is a straightforward process. We do it all the time, right? PET bottles are recycled
into new bottles or into new products such as trendy workout
gear or durable outdoor furniture. yet. This method can't be used for wind
turbine blades. Due to the distinct nature
of the resin involved. The resin used in
these blades is a thermoset which, unlike Thermoplastics, undergoes
a permanent chemical change upon curing. The change is similar to cooking an egg. Once the egg is fried or hard boiled,
it cannot revert to its raw state. The polymers in thermostats
form a complex cross-linked network when they're cured, and those links
can't be easily broken down again. That makes them impossible to melt down
and reshape like them in plastics which behave more like spaghetti. thermoplastic polymers don't crosslink,
they just tangle. and they're easily untangled and reshaped
when they're heated. This distinction between thermosets and thermoplastics is a key factor in the difficulty of recycling wind
turbine blades. Just jumping in here to let you know
that I'm going to be at Everything Electric Australia in Sydney
this February 9th, 10th and 11th, which will be a great opportunity
to meet up in person. It's a fantastic event for anyone
interested in the future of transport and home electrification. I'll be hosting four sessions on Friday,
February 9th on EV myth busting, discussing what's next in the energy
and transport transition, exploring the best opportunities
to decarbonize business and exploring
the next wave of new battery chemistries. And you'll also be able to find me on Saturday,
walking around, checking out the latest electric cars and listening
to some of the other amazing speakers. You can use my exclusive discount code,
EEROSIE to get 20% off your tickets. The organizers actually pass on all of
those ticket sales from this code to me. So by using this code, you're not only getting a great deal, but you're also directly supporting
Engineering with Rosie, which I thank you for. So are you ready to join us at Everything
Electric Australia? Grab your tickets
now using the link in the description and remember to use my discount code
to support the channel. I can't wait to see you there. Let's move on now to the different methods
we can use to recycle wind turbine blades. The first and simplest method is to creatively repurpose
turbine blades for new uses. Given their size and durability, blades
can be cut up and used for applications like bike shelters
and playground structures or whatever. Every time someone makes something
like this, it always gets widely shared. People go nuts for this stuff, but there are over a million wind
turbine blades in the world today. Do we realistically want a million wind
turbine blade shaped bridges? I mean, I love wind energy
way more than the average person, but I don't want every bike, shelter
and playground in the world
to look like a hunk of wind turbine blade. I don't really think that's
a scalable solution. So let's move on to more versatile
recycling methods. Shredding is a key method in recycling
wind turbine blades. It involves breaking down the blades into smaller, more manageable fragments,
which can be used in applications where the demanding structural integrity
of the original blade isn't required. For example, the shredded material
can be incorporated into products like decking materials, vehicle
dashboard, or even for 3D printing. you can also use shredded wind turbine
blade materials in cement production. This process has a dual purpose. The organic content of the blades
is recovered as energy, while the mineral fraction becomes
integrated into the cement clinker. One tonne of blade
waste can cut CO2 emissions by 110 kilos, and save 461 kilos of raw materials
compared to the standard cement manufacturing process. Pyrolysis is an advanced recycling method
for wind turbine blades that involves heating the material between 4-7 hundred degrees
Celsius in a low oxygen environment. This process chemically decomposes
the resin into simple substances and allows for the recovery of fibers
which can then be reused in structural applications. But the fibers strength is reduced
by as much as 50% after being heated. So you can't easily make new wind
turbine blades out of the recovered fibers as they're no longer strong enough. Other downsides to pyrolysis
include high energy use and CO2 emissions, and you don't recover the resin while the methods mentioned so far, offer
valuable ways to reuse composite materials, they generally lead
to a lot of degradation, limiting the materials used in structural
and demanding applications like new blades. So now let's move on to more advanced
recycling methods, where the goal is to be able to reuse the fiber and or resin
in structurally demanding uses. There's a two pronged approach
to this occurring in industry now. One, designing new blades
that are easier to recycle, and two, coming up with ways we can reuse fiber
and resin from existing blades. To the extent that you could make
new blades from those recovered materials. remember earlier we talked about how easy thermoplastics
are to recycle versus thermosets? If we could make wind turbine blades
using thermoplastic resins, the task of recycling
would be so much easier. Thermoplastic resins
can be melted away from fibers and then recombined into new blades while
preserving their structural properties. This approach won't help recover materials
from existing blades, but could make future blades
fully recyclable. The challenge is that thermoplastic resins
usually have much lower structural properties than Thermosets, but there has been progress
recently in a few projects working on new types of thermoplastic
resins and new structural design and manufacturing methods to create fully
recyclable thermoplastic blades. Recently, LM Wind Power, who I used to work
for, has manufactured the second ever recyclable blade using Arkema
as ilium recyclable thermoplastic resin. The blade is 77 meters long, so similar to most onshore
wind turbine blades and its shear web. That's the structural component inside
the blade that holds the two shells apart. They made that using recycled resin. This blade has already completed
static testing where the blade is exposed to extreme loads and it will undergo
fatigue testing over the next few months. In the second prong of blade recycling efforts,
new recycling methods for existing blades. There's a lot of progress here
too, in higher tech versions of all the standard recycling processes
that we covered earlier, there is advanced mechanical recycling. One example of this is Regen fiber who are able to convert
decommissioned blades into reusable materials for the concrete,
mortar and other industries. And they can also break blades down
into little pencil like pieces that function like a mini rebar
in applications like road construction. There is also advanced pyrolysis,
such as the multi-stage process that Ryan Ginder from the University of Tennessee discussed
with me in one of the very early videos on this channel. by carefully controlling the temperature
of the pyrolysis process, the structural properties of the recovered
fiber can be maintained much closer to the virgin material. the recycled glass fiber can be made
into nonwoven fabrics, continuous textile yarns, automotive sheet molded components
and plastic injection molding pellets, besides pyrolysis, There are other forms of chemical recycling
being applied to wind turbine blades. Solvolysis involves dissolving polymers
in a solvent where controlled temperature and pressure conditions
facilitates the breakdown of the polymer matrix, allowing for the separation
and recovery of fibers and resins. Wind turbine manufacturer Vestas
is working on commercialization of a sylvolysis recycling process
as part of a collaboration called Circular Economy
for Thermoset Epoxy Composites or Cetec. Together with two Danish universities
and epoxy resin supplier Olin, they produced a large scale proof of concept in early 2022,
but have been quiet since then. So I'm not totally sure how the scaleup
is going in terms of technology maturity. It's way behind the mechanical and pyrolysis processes
that we discussed earlier. However, if it's successful, it will be a way to recycle epoxy resin,
which the other methods aren't. That would be halfway to the holy grail
of wind turbine blade recycling. The ability to recover both resin
and fiber for reuse and new blades and the other half
may have actually already been achieved. While I was researching for this video, there was an announcement
by Decom Blades. They have produced recovered fibers
that can be used to make new blades. They used pyrolysis to separate
out the glass material from old blades and then grind that into a powder
which can be melted to produce new fibers. And they actually did this at 3B's
glass fiber manufacturing plant in Norway
last September. They say they can replace up
to 5% of virgin glass. Yeah,
that doesn't sound like a lot, does it? However, because these days
there are a lot more new blades being made than old blades
being decommissioned. Substituting 1 to 5% of raw
materials in new blades is actually enough to make use of all the current
number of decommissioned blades. It'll be decades
before the number of retiring blades catches up, with the number of new blades
being produced. And by then other methods will
hopefully have progressed to the point where most of that can be covered by
recycling. That is a nice, uplifting way
to finish this video, isn't it? Perhaps
uncharacteristically optimistic for me. Sorry, but I'm not going to end like that. I have made it
most of the way to the end of this video without addressing the biggest problem
of all with wind turbine blade recycling and that is why do we even want to recycle
wind turbine blades? Did you notice
how complicated all these processes are? and the closer we get to the Holy Grail
of recycling old wind turbine blades into new wind turbine blades, The more complicated it gets, the more processes are needed
and the more transport between facilities. How much energy do you think that uses? Well, it turns out it's a lot. this question was addressed
in a 2018 study by Liu at al, which found that the energy
needed to process one kilogram of wind turbine blade waste was 0.26
mega joules to put blades in landfill. That's a little under point one kilowatt hours and around 20 mega joules
for the various chemical processes. that's nearly 100 times more energy
for advanced recycling compared to simply landfilling Incineration with energy recovery
generates rather than consumes energy. However, it releases CO2 in the process. So only really a good outcome
if it's replacing a fossil fuel energy source
such as in a cement kiln, or if it includes carbon capture,
which so far it does not. Let me just add in lest This get taken out of context. Even the most energy intensive recycling
process is only using about as much energy as the blades would have produced
in a few days during the operational life. So we are not anywhere near the level
where you could say that recycling blades uses more energy
than the turbine ever generated. not that that is going to stop anyone
from trying to claim that. But if you want to minimize energy use
and emissions from a decommissioned wind turbine blade, don't transport it
anywhere, don't process it, and definitely don't take carbon atoms that are currently
bound up in the resin and liberate them to form CO2 in the atmosphere
by burning them without carbon capture. But end of life, energy
use and emissions aren't the only concern. The full lifecycle matters. This was the topic of another recent study
by Diez Canemaro and Mendoza. If you consider the whole life of the wind
turbine blade, then using recycled materials in new blades
will offset some of the energy and emissions
needed to produce virgin materials. The more that can be recovered
and the better its quality, the less virgin materials are needed. this study found that Sylvolysis
even though it has a second highest emissions
from end of life processing, it emerged as the most effective
in terms of circularity and full lifecycle CO2 emissions,
significantly outperforming other methods such as pyrolysis and landfilling,
and with potential to improve further. If the process can be developed
to improve material quality of the recycled material
and if efficiencies can be maintained as the process is scaled from where it is
now and basically in the lab up to commercial scale. So yes, I do think the situation
is looking pretty positive overall. The only downer
left is the issue of cost, which no one likes to talk about, and it's really hard to estimate
for something like sylvolysis anyway. That still needs to be scaled a long way. Will we be happy to pay more for recycled
or recyclable wind turbine blades? Cynically, I would say probably not
unless regulations force it, which they may soon. I think the biggest driver for the wind turbine manufacturers
is those images of blades going into landfill have really captured
the attention of the general public. It's just not a good look
And I have discovered that it's not really a winning tactic
to try to explain that Landfilling Blades is actually a decent environmental outcome
if you look at the issue logically. So I'm looking forward to watching
progress on the issue of blade recycling. Over coming years
I think we will see this problem solved. The videos on this channel are all
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and I'll see you in the next video
