# So, why can't windmill blades be recycled? And why do they wear out in the first place? **URL:** \ **Category:** Factual Questions\ **Created:** [January 10, 2020, 3:04am UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201 "2020-01-10T03:04:33Z")\ **Posts on this page:** 11\ **Page:** 3
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [January 12, 2020, 11:16pm UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201/41 "2020-01-12T23:16:51Z")
> [@Ruken](#): > > If you want your house to bend in the wind, sure. Better than the house spinning. ---
**Author:** ![DinoR](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dinor/32/2821_2.png) [@DinoR](https://boards.straightdope.com/u/DinoR)\ **Post date:** [January 13, 2020, 1:35am UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201/42 "2020-01-13T01:35:48Z")
Both heat and UV radiation can damage the resins used in composite materials through oxidation over time. I would assume they select resins that minimize the effects for parts designed to be exposed outdoors for their entire life cycle. That doesn’t make the issue go away from we are looking at life cycles measured in decades. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [January 13, 2020, 2:59am UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201/43 "2020-01-13T02:59:22Z")
> [@kaylasdad99](#): > > Are windmill blades standardized in shape and size? . Not universally, since (1) the technology is changing so fast, (2) a blade design is specific to the tower height and the characteristic wind-speed. I imagine that when you are talking about wind farms with hundreds of towers they must pretty much all be identical. ---
**Author:** ![EdelweissPirate](https://avatars.discourse-cdn.com/v4/letter/e/8491ac/32.png) [@EdelweissPirate](https://boards.straightdope.com/u/EdelweissPirate)\ **Post date:** [January 13, 2020, 5:24am UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201/44 "2020-01-13T05:24:22Z")
> [@Squink](#): > > That depends on where one took statics and mechanics of materials. No, it doesn’t. Not even a little bit. And statics is irrelevant to this discussion. > [@Squink](#): > > I tend not to think about such things as [elastic deformation] and more about irreversible strains in wood and metal. You’re thinking of plastic deformation. Fatigue always happens in plastic deformation. It _can_ happen during elastic deformation, but it doesn’t have to. > [@Squink](#): > > You are correct in pointing out that not all strain is irreversible That’s true, but it’s not what I said. Besides, you’re conflating strain with fatigue. They’re not remotely the same. If you had retained what was taught in mechanics of materials, you wouldn’t have this problem. I wouldn’t come down on you so hard if you hadn’t done that handwaving about “this is just a question of where we draw the line.” These are not judgement calls; they’re basic materials science concepts. Birds aren’t mammals no matter where your pencil has wandered off to or what line it drew when it got there. Steel and titanium have endurance limits. Strain below their respective limits does not accumulate fatigue. Aluminum has no endurance limit, so any strain—no matter how small—adds to the cumulative fatigue in the structure. This sounds alarming, but it’s not: with proper design parameters, an aluminum structure can have an arbitrarily long fatigue life. Fatigue in composites is complicated and not fully understood, but we know enough to design reliable composite structures—at least, those of us who paid attention in class do. > [@Squink](#): > > but I expect reversibility is limited in stiff structures such as windmiil blades. Bend too far, and you will get damage. This is solipsistic. There’s nothing that won’t be damaged if you bend it too far. That’s the very definition of “too far.” ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [January 13, 2020, 11:57am UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201/45 "2020-01-13T11:57:22Z")
Whatever. We are using different sets. As ai said, my schooling was different than yours. ---
**Author:** ![EdelweissPirate](https://avatars.discourse-cdn.com/v4/letter/e/8491ac/32.png) [@EdelweissPirate](https://boards.straightdope.com/u/EdelweissPirate)\ **Post date:** [January 13, 2020, 3:55pm UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201/46 "2020-01-13T15:55:34Z")
I owe you a partial apology. My penultimate sentence was meant to read, “Fatigue in composites is complicated and not fully understood, but we know enough to design reliable composite structures.” That line instead contained a gratuitous barb that I thought I had edited out before posting. Obviously, I was wrong. I’m sorry I missed that. ---
**Author:** ![Kobal2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kobal2/32/20_2.png) [@Kobal2](https://boards.straightdope.com/u/Kobal2)\ **Post date:** [January 13, 2020, 4:04pm UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201/47 "2020-01-13T16:04:51Z")
> [@ASGuy](#): > > You pegged some of it right here. The leading edge of a blade is _always_ crashing into something: AIR. Air and air particulates slowly degrade the edge, leading to cracks and possible structural failure. I do not have a cite off the top of my head but I’ve seen YouTube video (the most reliable souce of information _ever_) showing and discussing this leading edge failure condition. Well, yeah. We call it “erosion”. It turns mountains into little rock stubs. Given time. Time, and pressure… that’s all it takes, really. I’m sure I’ve heard that somewhere 🙂 ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [January 13, 2020, 4:22pm UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201/48 "2020-01-13T16:22:26Z")
At Ep: Left hand is not working now, so I keep posts shorter than is best. No worries, NO acrimony, We Are OK. I understand your points. ---
**Author:** ![Kobal2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kobal2/32/20_2.png) [@Kobal2](https://boards.straightdope.com/u/Kobal2)\ **Post date:** [January 13, 2020, 4:33pm UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201/49 "2020-01-13T16:33:56Z")
> [@am77494](#): > > Comparing Wind power to Coal Power is apples and oranges to a certain extent. Wind mostly blows in the night (when power demand is lower) for many states. That’s interesting, I didn’t know that and it seems a little counterintuitive - it was my understanding that wind was caused by pressure differentials and interactions between cold and hot air masses - but air masses gets hot (or not, hi 1996 !) during the day when the Sun cooks this bit but not that bit and so on ; so why more wind at night ? ---
**Author:** ![EdelweissPirate](https://avatars.discourse-cdn.com/v4/letter/e/8491ac/32.png) [@EdelweissPirate](https://boards.straightdope.com/u/EdelweissPirate)\ **Post date:** [January 13, 2020, 4:42pm UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201/50 "2020-01-13T16:42:29Z")
> [@Squink](#): > > At Ep: Left hand is not working now, so I keep posts shorter than is best. > No worries, NO acrimony, We Are OK. I understand your points. Cool. I hope your hand feels better pronto. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [January 13, 2020, 6:41pm UTC](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201/51 "2020-01-13T18:41:21Z")
Round here we get 40-50 mph windstorms in day. Things calm at night. What .you get depends on topography. [Previous page](https://boards.straightdope.com/t/so-why-cant-windmill-blades-be-recycled-and-why-do-they-wear-out-in-the-first-place/846201.md?page=2)