Why do wind turbines pitch their blades?

In summary: You are correct that the capacity factor is low, meaning that the turbines don't operate at the designed wind speed that often.
  • #1
Ian231
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TL;DR Summary
Wind turbines seem to pitch their blades to protect the generator. Why don't they get a bigger generator instead?
Hi all.

I'm new to this forum and to wind turbine technology in general, and I watched one of these one-minute videos explaining why wind turbines pitch their blades but it doesn not make sense to me. Why don't you just get a bigger generator? You'd get more energy for the same blades, same tower, same location, etc. Or am I missing something?

Here's the video, in case my explanation does not make sense.



Thanks,
Ian
 
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  • #2
Optimization. Turbines are designed to work with the expected wind, using larger generator that would be used just for few days a year is not economically viable.
 
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  • #3
Your comment makes it sound like you are focused on what is called "feathering" of the blades when the wind is too strong.

You are correct that putting on a bigger generator might keep the speed down even when the wind is strong. However there are other stresses and forces that increase with more wind and more power generated. The short answer is that something may break -- structural failure.

Even things that don't rotate at all get blown down by strong winds.
 
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  • #4
anorlunda said:
Your comment makes it sound like you are focused on what is called "feathering" of the blades when the wind is too strong.

You are correct that putting on a bigger generator might keep the speed down even when the wind is strong. However there are other stresses and forces that increase with more wind and more power generated. The short answer is that something may break -- structural failure.

Even things that don't rotate at all get blown down by strong winds.
So, if I understood you correctly, my 'same blades, same tower' was actually wrong: you could get more energy by putting a bigger generator, but you'd need to change the structure so it can handle higher stresses and forces. Did I get it right?
 
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  • #5
Borek said:
Optimization. Turbines are designed to work with the expected wind, using larger generator that would be used just for few days a year is not economically viable.
Ok, that's quite interesting. I guess wind turbines do have a quite low capacity factor, which (if I undersand correctly) shows that they don't operate at the designed wind speed that often
 

Related to Why do wind turbines pitch their blades?

1. Why do wind turbines have blades that can pitch?

Wind turbines have blades that can pitch, or rotate along their axis, in order to optimize their performance and maintain stability in changing wind conditions. This allows the blades to adjust their angle and direction to capture the maximum amount of wind energy.

2. How do wind turbines determine when to pitch their blades?

Wind turbines use sensors and control systems to constantly monitor wind speed and direction. When the wind changes, the control system sends a signal to the blades to adjust their pitch accordingly. This process is automated and occurs in real-time.

3. Can wind turbines pitch their blades too much?

Yes, wind turbines can pitch their blades too much. If the blades are pitched too far, they can stall and stop producing energy. Additionally, excessive pitching can put strain on the turbine's components and lead to mechanical issues.

4. What happens if the wind is too strong for the wind turbine's blades to pitch?

If the wind is too strong, wind turbines have safety mechanisms in place to protect themselves. This can include feathering the blades, or turning them parallel to the wind, to reduce the amount of force on the turbine. In extreme cases, the turbine may shut down completely to prevent damage.

5. Do all wind turbines have blades that can pitch?

No, not all wind turbines have blades that can pitch. Some smaller or older turbines may have fixed blades that cannot adjust their angle. However, most modern turbines have pitch control systems to optimize their performance and improve their efficiency.

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