A renewable energy industry expert, who wanted to remain anonymous, told MailOnline that a collapsing turbine is a ‘real rarity’, adding there ‘are more than 10,000 of them up and down the country’. He suggested the materials might have been faulty, but insisted it was ‘very unlikely to be the local wind speed’ that brought it down.
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Ok… so whenever one reads an article like this, it is ‘mandatory’ that the word ‘rare’ or ‘rarity’ show up in the first few sentences. Then it’s mandatory to make a claim of how many homes it generated power for… even though of course it generates nothing when the wind isn’t blowing. Having said that, there is not much to wonder about as far as the cause…. I can show pictures of dozens of IWTs that have failed the same way. Here are the symptoms…
- Came down in strong winds… but at a wind speed that was only a fraction of what the design wind speed is.
- There is almost no visible damage to the IWT except what happened when it hit the ground. ….case in point is that it looks like the blades were intact when it hit the ground and they crumpled on impact.
- The main tower section actually looks to have escaped relatively unscathed…. just some deformation because of the way it rolled itself over the knoll along side the road.
- It came down at about the 8 to 12 year range…. other lifespans are possible but this seems to be the most common.
- Finally… and this is the key to understanding the failure, there is a flange that has simply separated, and you can’t find a flange bolt anywhere. Neither can you find any distortion to either the top or bottom flanges.....the exception perhaps being where it hit the ground but this isn’t actually all that visible. Logically, wouldn’t one expect that as the tower toppled over, some of the bolts would hang on until it distorted the flange and perhaps ripped it apart? Why didn’t it do that? It’s as if the bolts all magically disappeared. What a lot of people don’t realize is that the flange should be as strong as the tower sections that are in between the flanges. So how does one explain that the bolts all magically disappeared?
The answer is simple… the bolts failed in fatigue. Over the years, the tower sways back in forth due to the winds. There are specific bolt installation protocols and then retightening checks… sometimes that doesn’t get done exactly right but regardless, eventually due to the cyclical loading in response to the winds, bolts develop fatigue cracks and are weakened… and then a decent wind comes along and they essentially all pop at once. The bolts failed in fatigue....what is not known is what all the mitigating factors were.
Good explanation and failure analysis. The photographs confirm your thoughts.
No flanges in sight, but the fallen tower (part) appears to have been constructed of 20-foot sections. Perhaps these towers are located near the ocean, and suffered from corrosion.
There is a huge flange pictured at the bottom, in a fun, time-lapse, build:
As for “Villagers were woken”...What happened to “awakened”?