Offshore Wind: Applying Circular Economy Principles to Wind Power Infrastructure

Wind power is often seen as inherently sustainable. But as the industry scales, new questions emerge about materials, design, and what happens to wind turbines at the end of their life.

In this episode, Intertek experts explore how circular economy thinking is reshaping wind energy, from the use of low-carbon and recycled steel to advances in recyclable turbine blades and the role of artificial reefs in supporting marine biodiversity. The conversation looks at how innovation, engineering, and circular design can help the wind sector reduce environmental impact while building long-term resilience.

Speakers:

• Richard Sargeant- Subject Matter Expert for Offshore Wind, Intertek
• David Muil- VP ATIC Sustainability, Intertek Business Assurance

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Transcript

David Muil | 0:10
Welcome to Intertek Sustainability Podcast, where we typically explore how innovation, assurance, and most importantly, circular thinking.

Richard Sargeant | 0:13
Yep.

David Muil | 0:27
Are starting to shape the future of global industries. Today’s episode, we’re going to focus on a sector at the heart of the energy transition, and that’s wind power. And more specifically, kind of peel back that onion a little bit, go down another layer.

David Muil | 0:44
And talk about how the circular economy is redefining the materials and technologies behind it.
So when wind power is often seen as inherently sustainable. Of course, we see these out in the fields, in the water, and we think this is perfect. But as the industry starts to scale and new challenges, new challenges will emerge.
What’s happening? We have to ask the question: what happens to wind turbines at the end of their useful life?

So, for instance, towers made from thousands of tons of steel and blades built from complex fiberglass composites are now reaching that decommissioning stage in the life cycle. If we don’t address this, we risk replacing one sustainability challenge with, quite frankly, another one, and who knows which one is better.

So this is really where circularity comes in. And in this episode, I wanted to talk a little bit more about circularity and wind energy, and how it applies, and try to give you some examples.

Then we’re going to talk about three items here. First of all, recycled steel. Steel is obviously one of the most recycled materials in the world, but using verified low-carbon recycled steel in wind towers and components has a big potential.

Second, we’re going to dive in a little bit into the whole area of adhesives engineered for bonding. So glue, adhesives, and bonding agents, and what do we do with these things at the end of their useful life?

And finally, a very interesting topic, the creation of artificial reefs, and how that impacts biodiversity and sustainability initiatives globally.

So today I’m joined by Richard Sargeant once again, Global Manager, Offshore Wind, and our technical expert. So welcome, Richard, and why don’t we jump right in with some of your insights on these three areas that we’re starting to see some movement or increased focus on, starting with recycled steel.

Richard Sargeant | 2:57
Yeah, thank you for the introduction. It’s always nice to talk to you about these topics. Green steel is a fascinating subject, and obviously, as developers and operators are both sort of morally and also legally obliged to look at their carbon footprint, looking at the steel used in the foundations is an obvious place to start.

So I recently learned that Orsted, which is obviously a leading offshore wind developer, has an agreement with a German steel producer. I think the company is called Dillinger, to use lower-emission steel plates in the manufacture of the monopile foundations for its projects, including the huge development pipeline they have in the North Sea here in Europe. And deliveries of those are supposed to start from 2027 to 2028.

This is a great example of a developer working closely with a steel producer to lower their carbon footprint. And also, they’re not the only ones doing it. Looking at RWE and the Thor offshore wind farm, this is something that’s planned in Denmark. It’s a pioneering project using a number of advanced engineering sustainability features, including reduced-carbon steel towers for 36 of its turbines, and these are obviously huge structures.

RWE is also constructing other projects like the Sophia and the Nordsee cluster wind farms using these same advanced materials. So yeah, it’s fantastic to see two of the leading developers, two of the biggest developers in offshore wind in the world, embracing green steel now. So yeah, this should make a huge difference.

David Muil | 4:40
Yeah, so that’s interesting. So obviously, they looked at the life-cycle assessment of a wind tower itself and realized that a lot of the opportunity existed in reducing the amount of carbon and then finding a solution with this low-carbon steel. I’m assuming that the low-carbon steel is every bit as structurally sound as the initial design intent of the steel they had used in the beginning, correct?

Richard Sargeant | 5:10
Yeah, correct. It’s fascinating to look at the design parameters, taking into account also the geotechnical challenges that occur in these instances. Because it’s very easy to over-engineer a pile, particularly if you’ve got a monopile with a colossal amount of steel in it, depending on where in the world it’s going to go and what the seabed conditions are actually like.

So it’s easy to overspend on these things. And then embracing green steel, recycled steel, or low-carbon steel, for example, it forces the engineers and the developers to look at the amount of material used and run some fairly advanced computational calculations to ensure that the stress cycles that these foundations will see in operation can be withstood using the materials that they’ve actually got. I didn’t explain that very well. A typically rambling answer from me. You get the idea.

So yeah, it’s not only the steel used, but it’s matching it up not only to the tensile strength and the sharp end tests and some, but also how it will work when it’s in the seabed. And the seabed is a variable as well. So it’s not just, is this steel tough enough. There’s more to it than that.

David Muil | 6:11
Yeah, thank you.

Richard Sargeant | 6:30
So yeah, it’s a fascinating engineering challenge.

David Muil | 6:32
Interesting stuff. All right, let’s switch gears to adhesives and engineered bondings. And you know, this one’s very important as well because not just offshore wind or wind energy, but the automotive world’s grappling with this right now at the end of life cycle of a vehicle.

For example, the amount of components that are put together via bonding agents make the reintegration of the materials in the circular approach almost prohibitive because you destroy everything with the glue.

And even in other areas, there’s a fascinating video on YouTube with a company called Interface. And Interface went through this challenge with carpets, bonding agents on carpets. Well, what do you do at the end of a life cycle with carpets? So they got rid of these things.

How are adhesives and these bonding agents impacting life cycle over time in the wind world, Richard?

Richard Sargeant | 7:41
Yeah, it’s a good question. We’ve all seen ugly pictures of old wind turbine blades being put into landfill, which is pretty shocking. And you know, offshore wind or wind energy in general has enough sort of ill-educated detractors without giving them the ammunition to argue, in this instance correctly, that burying stuff in the ground is not very environmentally responsible.

And as you point out, yeah, the adhesives used in the blades are at the heart of this. So at the back end of last year, I was at the Husum Wind show in Germany, and I saw a recyclamine-based epoxy system developed by a company called Connora Technologies.

And this technology uses a specific amine curing agent in the epoxy adhesive. Now this stuff allows the cured thermoset epoxy to be broken down into a reusable thermoplastic material, and more importantly, the original reinforcing fibers, which are typically glass or carbon, by immersion in a low-pH solution at an elevated temperature.

So you can actually separate these now, which is not something that’s been widely done before, certainly not in wind.

And the good news is that the big boys have actually picked up on this. So Siemens Gamesa, for example, has successfully implemented these materials to create the world’s first fully recyclable wind turbine blades. And these are planned for use in the Sofia offshore wind farm here in Europe.

So it’s gone from a very difficult technical challenge into implementation in a very, very quick phase. And it’s wonderful to see these large companies looking at what’s going to happen to these blades because they’re designed to last for 25, 30 years or more. So they’re really looking way down the road here at their environmental responsibility in the future.

So yeah, some very interesting tech coming through now in that area.

David Muil | 9:43
Wow, that’s amazing. I mean, obviously there’s such a push to start thinking in this space that we never did before, right? And certainly thinking about these natural resources and resources we already have put value into, how do we extract more value without going back into the earth, right? And then adding to the carbon as well.

So this is brilliant stuff. But it’s just amazing how many of these examples are coming out of every industry.

I think the other area I did want to touch on, only because I find this fascinating and the potential of this, is the artificial reefs. And how does wind energy, circular economy, how does that fit into the whole concept of these artificial reefs?

Richard Sargeant | 10:41
Yeah, there have been some really fascinating initiatives in this area. Just before I kind of get into the meat of that, I’ve seen some of the major developers running competitions where they look at how they can boost marine life around the foundations of their turbines, particularly with moored, so floating offshore wind turbines now, which is sort of the next generation of technology that people are exploring and trialing.

Some of these are now actually coming into operation. You’ve got a lot of mooring lines, and what do you do with them? How do you ensure that you’re supporting biodiversity?

It’s also a nice foil against objections from the planning phase, from fishing communities, because they often rightly complain that their livelihoods are threatened. So it’s important to boost that marine scenario where possible.

In a specific case here, one of the world’s largest artificial reefs has actually been installed at a wind farm. This is at the Rampion offshore wind farm in the UK. And it’s pretty innovative.

This has 75,000 specially designed reef cubes placed at the bottom of each turbine. And these cubes are made of low-carbon concrete, because obviously concrete is a fairly carbon-intensive material to produce. And they’ve got holes placed in them and are designed specifically to encourage marine life and marine growth.

So these things are bursting with life. And it’s part of a nature-inclusive design project, which is designed not only to support marine life, but also to protect the turbine from long-term erosion as the seabed moves around.

So it serves not only an ecological benefit, but also an engineering benefit as well, because it protects the structure. And again, it’s great to see these reef cubes being used. And I’m pretty sure we’ll see them used elsewhere in the world as well, not just at the Rampion wind farm.

David Muil | 12:47
So that would mean that these reef cubes would stay attached to the piling for life, for whatever we leave the piling or the base in. And if it’s in the ocean, obviously we leave it in for life, right?

Richard Sargeant | 12:55
Yeah. I mean, they’re designed to last for the duration of the wind farm. So most wind farms have a design life of something like 25 years, and ideally longer.

And obviously some wind farms now are coming towards the end of their life offshore. So we’re looking at how to repower them and how to basically get more energy out of existing structures that have already had a carbon footprint required to install them.

But yeah, these cubes are designed to last as long as the wind farm does. And they look, when you see them, like they’re dumped ad hoc, but they’re not. They’re placed in a very specific place to discourage scour, or to mitigate against the risk of scour, which is obviously seabed movement forming pits around the foundation and weakening the structure.

But they’re designed in such a way that each cube attracts marine life and becomes a haven for fish and other species. So yeah, it’s a very interesting application. It’s really cool stuff.

David Muil | 14:02
Yeah, that’s interesting. Well, again, the one thing that I absolutely know for sure is that I don’t know enough, because I learn so much on each of these podcasts.

Richard, we’re out of time, and I did want to thank you once again. And I think based on the feedback we’re getting from a lot of folks, this whole circular approach and management concepts, these ideas are very inspiring.

And I think we need to consider additional podcasts as we move down the road, because it’s really what people want to learn from. And you can actually take that thinking and move it into different spaces, right? It’s not just wind farms.

So thank you so much for joining me today on this podcast. Always a pleasure, always interesting. And I always learn, which is the most important thing for me. So thank you, Richard. Really appreciate you.

Richard Sargeant | 14:51
How wonderful. Very nice to spend time with you. I hope people have learned a little bit, and I’m learning too. So yeah, it’s nice to talk. Thank you for your time.

David Muil | 15:00
Thank you, and until next time, we’ll see you then. Take care. Bye-bye.

Richard Sargeant | 15:03
Bye-bye.