How much electricity can a wind turbine generate? This article provides a wind energy calculator that can quickly calculate the output power of a wind turbine. First select the type of turbine, including the common horizontal axis wind turbine (HAWT) and vertical axis wind turbine (VAWT), enter its size and wind speed, and then set the relevant efficiency to calculate the power generation. The solidity of the turbine is also calculated according to the chord length of the blade, which is a key factor affecting the efficiency, for users to evaluate.
Relationship between solidity and efficiency
The solidity of a wind turbine represents the ratio of the blade area to the projection of the swept area. The wider or more blades, the greater the solidity. A wind turbine with too much solidity has a large low-speed torque and is easy to start, but it is not conducive to high-speed operation and thus low efficiency. Horizontal axis wind turbines are commonly seen with slender blades for high efficiency. As for the vertical axis Darrieus wind turbine, it is often equipped with drag blades inside, or designed with large solidity (extremely wide blades or >=5 blades) to increase low-speed torque to overcome the nature of being difficult to start, but at the expense of efficiency.
New idea with excellent startability and high efficiency
The author proposes to use Magnus rotors to assist in starting the Darrieus wind turbine. The blades can maintain low solidity. The low-speed torque of the Magnus rotors is large and the cross-sectional area is small, so it does not affect the performance of the lift blade. Therefore, both startability and high efficiency can be considered. Refer to the following Film:
參考：Magnus effect and Vertical axis wind turbine。