One of the more recent things I’ve seen on social media is an image showing a huge windmill blade being buried in a landfill. The accompanying text says that decommissioned windmill blades cannot be recycled and can only be disposed of when they can no longer enjoy the breeze.
This is posted as a “gotcha” for those who say that wind power is the solution to our fossil fuel dependency. It turns out that wind power isn’t so environmentally great after all! Ha ha!!
So, what’s the deal. Why can’t windmill blades be deconstructed when they can no longer work on a windmill? Can’t the carbon fiber at least be chipped into gravel for roads, landscaping, or whatever? Can they at least be broken up to make them easier to dispose of? And, to me, the big question: Why do windmill blades need to be replaced anyway? Absent some external factor like something crashing into them or being damaged by weather, why would they not last for a very long time?
Apparently, it’s not that you can’t, it’s that it’s not necessarily easy, as per this NPR article. (Also, it says that they aren’t carbon fiber, but a mix of resin and fiberglass.)
So what makes them be decommissioned? The NPR article doesn’t get into why these blades are waste in the first place. Why do they wear out? How long does a windmill, from support structure to turbine to hub to blades last?
A broken turbine blade is catastrophic. If a blade breaks off of a wind turbine, it may crash into something or someone—at the very least, it’s a threat to neighboring turbines. But the big deal is that the other two blades are now unbalanced, and they’ll tear the whole thing apart.
Because the magnitude of the risk is so high, operators tend to err on the side of replacing blades. Carbon fiber and fiberglass are both fairly notch-sensitive, so a nick can turn into a crack quite quickly. When a crack is detected, the cracked blade gets replaced immediately.
Neither carbon fiber nor fiberglass are easily recyclable. You can absolutely cut up carbon and glass fiber composites and use them in other things, but that can be labor-intensive. You can also heat the pieces until the resin cools off, leaving the bare fiber. That fiber can then be chopped and used to as fill for injection-molded plastics. But that’s not really a high-value commodity, so it’s not like there’s a ton of money to be made there.
Cured carbon fiber and glass fiber composites are also incredibly abrasive to cutting tools, so you really need to break down turbine blades with a grinding blade. This creates a ton of carbon and silica dust; it’s not a clean process, and the people doing that work need respirators and other PPE (personal protective equipment).
All that said, that Facebook stuff is pretty deceptive. As Rukeyser pointed out, serious analyses account for the costs and benefits over a full lifecycle. That Facebook post is propaganda.
Yeah, it seems a pretty strange argument against wind power. I mean, wind turbine blades are not exactly going to account for a very large proportion of materials going to landfill. And I’m sure there’s plenty of stuff in coal-fired power stations that can’t be recycled. (Not least the coal…)
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.
They’re flexing constantly. Brend stuff enough and it’ll fail. Also, bald eagle beaks are hard. So is dust.
But from talking to a guy at NREL a few months back, it sounds like turbines are often retired early if a sufficiently better turbine is available. IIRC the nacelles are often resold.
Also to add : Although the blades are spinning slowly, due to the size of the blades the tip of the blade is almost at the speed of sound (Mach 1). This high speed results in much higher damage.
Everything wears out eventually, including coal plants. If we started avoiding anything that could break or wear out, we’d be back to living in caves and even then our stone tools would break or wear out.
The goal isn’t perfection. The goal is improvement.
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.
Wind is certainly a great renewable energy source, but with current technology (and to a foreseeable future), it requires energy demand to be fulfilled by FOSSIL fuels viz-a-viz coal and oil and gas, when wind is not producing.
The greatest bottleneck or drawback to renewable power is not recycling issues or environment or the like. The greatest challenge is energy storage (battery technology).
I knew I wasn’t the only nasty one here. Do you have a specific question that I could stick in GQ or GD? Or I can just dump some stuff in MPSIMS and see where it goes.
yeah, this. carbon-fiber and glass-fiber reinforced plastics are generally used with a catalyzed resin; a form of plastic which is created via a chemical reaction. Polyester resin or some kind of epoxy are common. They don’t melt like a thermoplastic, so it’d be impractical to separate it from the reinforcing glass or carbon fibers. the best you could probably do is shred it and use the pieces for filler for something.
Are windmill blades standardized in shape and size? ISTM that where sufficient identical EOL blades are available, they could be tessellated and bonded together for use as pre-fab building components.