Based on cost-performance ratio.
As the blades increase, although the wind power utilization rate increases, due to the Bates limit, the wind power utilization rate can reach 59% . It is difficult to improve by adding more blades. At present, the effect of 3 blades can already reach 50%, so there is no need to add more blades. And 3 blades are more balanced than 2 blades and single blades.
An increase in the number of blades will also increase material costs and make hub design more difficult.
So, taking into account profitability, current horizontal axis wind turbines are all three blades.