There is an article in Composites World this week (9/25/2024) about a report by Clarkson’s Research that states that offshore wind energy is poised to grow substantially in the very near future. In fact, Clarkson’s reports that installed offshore wind capacity will grow at a compound annual growth rate of around 22% through 2030. That is enormous and very rapid growth. This is very much the same story that was told at the Carbon Fiber Conference last year where I gave a couple of talks – one of which was about sustainability of composites. The other one I also wrote about here a couple of times – what happened to the Titan? But this post is about wind turbine blades, so I’m not going to bring that disaster up again here – yet.
What I heard at that conference was that new installations of offshore wind were going to grow total installed capacity by an order of magnitude by 2050. I also heard that most of the new capacity was going to be large diameter turbines with blades over 100 meters long. This of course necessitates the use of carbon fiber for almost the entire blade. This is because of two things. First is the self-weight of the blade. 100+ meter long blades, even made out of glass fiber and balsa wood, are extremely heavy. The second issue is the fact that the centripetal force (tension force at the root of the blade) is so high with that length of blade that glass fiber just is not strong enough to keep the blade attached to the hub of the wind turbine. On top of that, the bending load on a wind turbine blade that long is enormous, and if glass fiber is used for what is called the “spar cap” the blades would bend back toward the tower far enough that they would hit the tower. This is called “tower strike” and it is the worst thing that can happen to a wind turbine. Basically what happens is that the blade that strikes the tower snaps off which causes an imbalanced rotor, and the whole mess goes to hell. Tower strike must be avoided at all cost. Hence, carbon fiber is the only solution that works for these enormous machines.
This story from Clarkson’s Research, a charitable or not for profit organization in England and Wales, confirms without much doubt that what I heard at the Carbon Fiber Conference last year is in fact going to come to pass. The impact of this is many-fold. First, what this will require is an order of magnitude increase in production capacity for carbon fiber within the next two decades. That in and of itself is an enormous undertaking for the manufacturers of carbon fiber. The biggest problem that the fiber manufacturers have today is that they are very near capacity for being able to make carbon fiber with the total amount of manufacturing capacity that exists worldwide. Increasing that capacity is going to require an enormous investment, and it will take time. It has been estimated that it takes about 3000 kg (a bit over 3 tons) of carbon fiber to make the blades for one megawatt installed wind energy capacity. And each wind turbine has about a 4 megawatt nameplate capacity which requires about 12 tons of carbon fiber. To meet the oncoming demand predicted by Clarkson’s for just offshore wind, we will need about 450 gigawatts of capacity or 40,000 wind turbines. These numbers add up very quickly, because the total worldwide capacity for making carbon fiber at present is on the order of 140,000 to 150,000 tons. An order of magnitude increase in manufacturing capacity for carbon fiber is not only reasonable, it is probably a bit low, because increasingly offshore wind is not the only major market for carbon fiber. There is also the upcoming hydrogen economy which requires 15,000 psi light weight pressure vessels to store the hydrogen. These can only be made using carbon fiber.
This means that what I heard and also wrote about right after that conference, as a warning to the carbon fiber manufacturers, is that they are going to have to step up the pace of building and bringing on line an enormous amount of new capacity just to meet the demand for carbon fiber from the offshore wind industry.
What this also means is that there is an enormous opportunity for the carbon fiber industry to complete the development of sources of plant-based precursors for carbon fiber – namely plant-based acrylonitrile – and also to use electricity from renewable sources for all of the process energy for their carbon fiber manufacturing plants. This means that production of fiber similar to that developed by NREL, and the fiber going into production at Syensco that was developed by Southern Research and Trillium, is going to have to be scaled up by several orders of magnitude in the very near future. This is actually in keeping with the latest trend in the renewable energy space, especially for wind turbines, because it has become recognized that the materials currently in use to make these enormous composite parts is not sustainable or recyclable. The pile of used wind turbine blades in Sweetwater Texas that I have written about a couple of times is testament to that fact.
This also means that there is an enormous opportunity for new entrants in this manufacturing space, because the current companies in the carbon fiber manufacturing business are going to struggle mightily to meet the demand just for the offshore wind energy market. This also means that these new entrants are not saddled with existing inefficient facilities that use oil or gas for process energy and petroleum based acrylonitrile as the precursors for their carbon fiber.
That is just the carbon fiber piece of the puzzle. There is also the resin systems used and the current ability of these resins to be recycled and reused at the end of the wind turbine blade’s life. That is where the recent results that came from work at NREL on development of their PECAN resin is so important. These researchers have already demonstrated not only a plant-based carbon fiber, they have also demonstrated a plant-based and inherently recyclable resin system, both of which they have incorporated into a 9 meter (~30 feet) wind turbine blade. And this blade survived all of the environmental endurance tests that NREL threw at it.
And I also just read about the “Zebra Project” that is being undertaken by LM Wind Power in Denmark. This company is the one that produced the 107 meter long wind turbine blade for GE Offshore that is the longest wind turbine blade ever made. These folks worked with a French company called Arkema that has produced a thermoplastic resin that has sufficient strength and stiffness to be used in place of standard epoxies, and is also inherently recyclable. The resin they call Elium® is an acrylic thermoplastic that can be depolymerized (dissolved) in the right mix of organic solvents and organic acids. Apparently when this resin is dissolved what you get back is both the fiber and the original monomer that made up the thermoplastic polymer. So, this resin has basically the same capacity as the NREL PECAN resin does in its ability to withstand the rigors of being the resin in a wind turbine blade, and the ability to be taken back apart when the wind turbine is done using it.
I did ask a question at the outset of this post that I believe has an answer. And that answer can only be that given the current state of the composite materials business, and the recent developments of plant-based fiber and recyclable resin, there is a very good chance that the answer to that question will be an unqualified yes. The societal changes that the world is going through, and the looming problems both of our warming planet, and the coming scarcity of fossil fuels is going to drive this renewable energy marketplace toward being truly sustainable. In this author’s mind that is a very good thing.
That’s about it for this week. I hope everyone that reads these posts enjoys them as much as I enjoy writing them. As usual I will post this first on my website – www.nedpatton.com – as well as on LinkedIn. And if anyone wants to provide comments to this, I welcome them with open arms. Comments, criticisms, etc. are all quite welcome. I really do want to engage in a conversation with all of you about composites because we can learn so much from each other as long as we share our own perspectives.
I also wanted to let everyone know that I have finished the first draft of my second book. This one is about what I have been writing in these newsletters for the last 6 months or so – sustainability of composites and a path to the future that does not include using fossil fuels for either the raw materials or the process energy to make composites. My ingoing title is “Close the Circle, a Roadmap to Composite Materials Sustainability”. I’ll keep everyone posted as this second book writing journey of mine unfolds.
Finally, I still need to plug my first book, so here’s the plug. The book pretty much covers the watershed in composites, starting with a brief history of composites, then introducing the Periodic Table and why Carbon is such an important and interesting element. The book was published and made available last August, and is available both on Amazon and from McFarland Books – my publisher. However, the best place to get one is to go to my website and buy one. I will send you a signed copy for the same price you would get charged on Amazon, except that I charge $8 shipping. Anyway, here’s the link to get your signed copy: https://www.nedpatton.com/product-page/the-string-and-glue-of-our-world-signed-copy. And as usual, here’s a picture of the book.
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