Why is there only one set of blades per wind turbine?

In summary, the conversation discusses the issue of maximizing the efficiency of wind turbines and the potential for tying multiple towers together to spread out the force from the wind and dynamic load. It is also mentioned that wind turbines experience varying levels of stress due to gusts and eddies, leading to the idea of using a flexible flag pole structure. However, it is noted that it would be impossible to tie the towers together at the top due to the need for rotation. The conversation also mentions the potential for higher blade speeds and the current tallest installed turbine in the UK at 640 feet.
  • #1
Infinitybyzero
33
3
I'm a civil/structural engineer and I was just recently thinking about one of the biggest issues for maximizing the efficiency of a wind turbine - the structure itself. The mega turbines that engineers want already have foundations of titanic proportions because as we all know, flag pole structures require a hell of a lot to keep them upright and stable. So my immediate thought in response to this is: can you allow for higher blade speeds and larger blades if you perhaps tied 4 towers together? I'm wondering if there would be a cost savings on the overall structure if you could take advantage of spreading out the overturning force from the wind and the dynamic load from the turbine on the turbine structure over a frame rather than just a cantilevered column.
 
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  • #2
I only discovered this the other day, but the load on a wind turbine is far from consistent. Wind contains gusts, eddies and probably other turbulences with a wide range of frequencies. The guy I was talking to was describing a project to dynamically adjust the pitch of the blades to reduce stress on the gearbox that was happening from one side of a rotation to the other.

Bearing that in mind, I think a flag pole structure might provide flex to help even out the force on the turbine and generator components.
 
  • #3
It would be impossible to tie the towers together at the top because they have to rotate depending on the wind direction.
 
  • #5
I think the UK currently has the largest installed turbine at 640 feet with each blade 262ft long. However I read something about a turbine in development that's over 900ft tall.
 

1. Why can't there be more than one set of blades on a wind turbine?

Having multiple sets of blades on a wind turbine would be inefficient and could potentially create structural issues. The wind would have to be divided between the sets of blades, reducing the amount of energy that each set can harness. Additionally, having more blades would increase the weight and stress on the turbine, potentially leading to mechanical failures.

2. Can't more blades increase the energy output of a wind turbine?

While it may seem logical that more blades would result in more energy production, there are diminishing returns. The drag created by each blade reduces the efficiency of the turbine, so adding more blades would not necessarily result in a significant increase in energy output. In fact, most wind turbines are designed with the optimal number of blades for maximum efficiency.

3. Why do some wind turbines have different numbers of blades?

The number of blades on a wind turbine can vary depending on the desired energy output, wind conditions, and design preferences. Some turbines may have two or three blades, while others may have up to six or more. The number of blades is carefully chosen to balance efficiency, cost, and structural considerations.

4. How do wind turbine blades capture energy from the wind?

Wind turbine blades are designed with a curved shape called an airfoil. This shape allows the wind to flow over and under the blade, creating an area of low pressure on top and high pressure on the bottom. This pressure difference causes the blades to rotate, which in turn drives the turbine's generator and produces electricity.

5. Can wind turbine blades be replaced or upgraded?

Yes, wind turbine blades can be replaced or upgraded if needed. Over time, wear and tear from wind and weather can cause blades to become less efficient, and they may need to be replaced. Additionally, advancements in technology may lead to more efficient or durable blade designs, and older blades can be upgraded to improve the performance of the turbine.

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