Hi Gordon:
Windfarms do shut down turbines, feather the blades, etc. when extreme winds are imminent. Not just strong winds, but a major windstorm. Small turbines theoretically could be shut down if they had the physical means, assuming a furling cable hadn’t broken for example (which they always do), and you had either some person monitoring weather in real time, ready to shut things down, or some automated system that watched the weather predictions. I furled a 10-kW turbine here a few times when extreme winds were predicted, before the furling cable broke. Still, you end up wasting productive winds if they turn out not to be extreme, then when extreme winds do arrive, your furling cable is already broken. This is the “best” 10 kW small turbine. The manufacturer tells you to just forget about fixing the cable. But the machines do not furl properly on their own, but instead cycle between overspeeding and almost stooping when sideways. Ridiculous really. But I’ve found really extreme wind events are not always predicted, but instead just productive winds are predicted, then you wake up in the morning to see your tower blown across the yard, or maybe the blades thrown a few hundred feet. And when extreme winds are predicted, they may turn out to be just productive winds instead. They don’t always get the predictions exactly right. And extrem winds can be highly localized, almost just random events. I related recently watching a tree blown down by a gust-nado in a residential neighborhood. No other tree was touched. It happened on a very calm day! We stood there in spookily calm air, looking at this very large tree just blown down and split into three pieces right in front of us, with all surrounding trees not distrubed!.
Now a windfarm does have personnel in place to shut things down if needed for some major predicted storm, which is pretty rare since the utility-scale turbines can adjust to very high winds and still keep operating. Then again in the middle of the night, for an unpredicted wind event, maybe nobody is there or able to respond quickly enough.
For small turbines, saying you will shut them down in high winds is usually just a symptom of a newbie who is unaware that your best production occurs right at the edge of when you would want to shut things down, that the actual severity of the wind may not be exactly predicted, and that being in a high wind is not the best time to try to shut down a system.
I know, I know, we’ll just shut it down if things look dangerous. Sure these “easy answers” almost always emanate from the minds of newbies who have never tried to shut down a wind energy system during a high-wind event, or don’t consider that maybe nobody will be around when extreme winds hit - vacation?. Usually it is in response to someone pointing out that they have no real knowledge of wind energy and have no means of overspeed protection in their system. I’ve heard it so many times in the last couple of decades, I’ve lost count. I’ve certainly heard it regarding AWE many times. Everything sounds easy when you don’t really have to do it, just talk about it. Picture this: Your system is making great power, but then you get a little power spike, so you shut things down. But then the wind seems to die down a little so you think “we’re wasting all this power” so you start it up again. But then the wind gets strong again so you shut it down. Over and over you keep taking off then landing, in high winds? Assuming anyone ever develops a worthwhile AWE system, it will probably need a way to respond to overspeed in real time, like ever other wind energy system…
Meanwhile, leading edge erosion happens at all wind speeds, not just in storms. Shutting down everything whenever it gets windy would really not be a good way to address leading edge erosion. It is used for protection of the whole system when major wind events are predicted, but does not work for general overspeed protection in productive winds that contain brief excursions to excessive wind speeds.
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