So in my pinball-like movement around the internet, caused by my searches, and friends’ emails, I stumbled across Discovery UK video about problems with the composite blades that make up modern wind turbines. That is a long, but professionally done video. The only problem is the Pollyanna view of the people talking in the video.
It seems that the engineers didn’t think wear and tear on wind turbines would be an issue when they were built. Someone in that video even says that they thought wind turbines would be maintenance-free once installed. (That is spoken like someone who never got outdoors on the water.)
Salt spray. Hail storms. Particulate matter in the wind. All that combined with the fact that the blades are moving at about 150 MPH or better, means that the leading edges are going to deteriorate.
They talk about “poor performance” in the Discovery UK video, but I can’t help but wonder if unbalanced blades, and the resulting strain on drive shafts doesn’t account for at least some of the Wind Turbine failures you can see in videos everywhere. Aside from blade failures (which can be spectacular) there are number of fires that seem to break out in the hub of the turbine. Some of them are spectacular as well. (Glass reinforced plastic can burn really well.)
So after seeing the Discovery UK video at the top, where there was an “Up Next!” selection from YouTube that included turbine failures, I went looking. And it wasn’t hard to find problems.
But I’ll control myself and only talk about one. One. Incredibly. Stupid. Problem. Galled stainless steel fasteners. (OK, I won’t be able to limit it to one issue.) How galled fasteners may affect wind-turbine O&M.
Standard stainless steel bolts and fasteners have a tendency to gall under certain conditions because of their specific properties. Thread galling can occur with standard fasteners when pressure and friction cause the bolt threads to seize to the threads of a nut or a tapped hole.
Severe galling, known as “cold welding,” can also cause the two surfaces to fuse together. This makes the joint impossible to remove without cutting the bolt or splitting the nut.
That article is clearly from a management perspective, but it is from last month, and in an “engineering” publication. And it must be news to someone, unless they are just really desperate for articles.
Now I’m not an engineer. I have a degree in mathematics and I spent most of my career doing Information Technology stuff. Well, and managing people. But even I know that galling is a problem. Which is why there are anti-seize compounds. And more expensive anti-galling fasteners. I haven’t found examples of stainless bolts being driven into tapped holes in aluminum structures, but I wouldn’t be surprised to find that done either. In a salt-water environment, that kind of thing (which I have seen done) doesn’t work out in the long run.
I haven’t seen mention of stress fractures in the stainless. They probably won’t show up for a bit. I have seen a 1/2 inch by 3 inch piece of stainless so riddled with fractures that my friend was able to break it into 2 pieces by hitting it on his thigh. Sailboat fittings can see a lot of stress, but probably not as much as you find on a turbine hub, 300 feet in the air, off the coast of Scotland.
Oh, and those damaged blades, which apparently need to be replaced every 10 years or so, can’t be recycled. Sioux Falls landfill tightens rules after Iowa dumps dozens of wind turbine blades.
This year, 101 turbine blades have been trucked to the city dump. But with each one spanning 120 feet long, that’s caused officials with the landfill and the Sioux Falls Public Works Department to study the long-term effect that type of refuse could have on the dump.
Then there are the complaints about turbines on the great lakes suffering leaking gearboxes and dumping a not insignificant amount of used oil into the water.
Environmentally responsible engineering, apparently carried out by people who don’t have much experience with the environment.