Why do Wind turbines have three blades?
Why on earth do all wind turbines have exactly three blades? ship propellers can manage with two – and one would immediately think that 4 or 5 blades would catch even more wind and therefore provide even more power.
The 3-blade horizontal axis wind turbine is the most advantageous option, in several technical and operational aspects: weight, stability, balance, performance, and costs.
In fact, wind turbines with fewer blades perform better at low rpm, are lighter,produce less noise
and last longer.
More expensive to make power with more blades
Wind turbine blades are the most expensive part of the wind turbine.
Yes, the turbine would produce slightly more power with more blades, but it would be more expensive to produce because more blades must be used for each turbine
It is also not worth having one or two blades, because they both provide less power and wear the turbine harder than three blades.
Why 3 blades
A wind turbine with three blades is aesthetically more pleasing than a similar wind turbine with two blades.
Three blades provide even pressure – and the most money for the owner. When you have two blades, you don’t have as bad a pressure, but still one blade up and one blade down with less pressure.
The counter pressure is therefore not as hard at the bottom as the pressure at the top. If, on the other hand, you have one blade up and two down – i.e. three blades in total – then it is smoother
Problems with only single-blade wind turbines
You can make a wind turbine with one blade, but then the blade has to be roughly three times wider in order to extract as much energy from the wind as possible.
Another problem for turbines with one blade is that the wind blows more the higher up you go.”
“If you only have one blade, it will exert great forces on the tower when it points upwards – and less forces on the tower when it points downwards, where there is less wind.
Such a skewed load means that most parts of the turbine actually have to be comparatively stronger to support one blade rather than three.
Problems with two-bladed wind turbines
Two blades make wind turbines ‘blink’.
A two-bladed wind turbine acts like an optical lighthouse. When the blade is in a horizontal position, it fills up a lot purely visually, and when the blade is in a vertical position, it ‘hides’ along the tower.’
“That way it ‘blinks’ and it seems more restless and disturbing than the three-bladed version. But it is now probably the overall economy that has made the three-bladed wind turbine dominant
