1. The larger the area, the greater the resistance and will be easily destroyed when a hurricane occurs. And the greater the resistance, the higher the energy loss.
2. The blade is one of the highest costs in the entire windmill, which can save costs.
3. Based on the blade length of 34 meters, when the wind is strong, the blade tip speed exceeds the speed of sound, causing some special air waves. I am not an expert so I cannot explain it more clearly.
4. It seems that the 120-degree angle is also good for stress.
The installation and transportation costs of 2-blade blades are lower than those of 3-blade blades. In addition, the tip speed ratio of the 2-blade is higher than that of the 3-blade. If it is used to generate electricity, the speed increase ratio of the gearbox is smaller than that of the 3-blade, so the cost of the gearbox is less.
ps
The hub structure of the 2-blade is special, with a seesaw structure, and the fatigue problem is more serious than that of the 3-blade. So each has its pros and cons.