Why wind energy is not dependable?

The speed of the wind is not constant and the wind does not blow all the time. So the inconsistency in speed is not suitable for getting stable energy. It can not be controlled.
The wind turbines will not be able to generate power if the wind speed is too low (less than about 2.5 m/s), and they will need to be shut down if the wind speed is too high (greater than approximately 25 m/s).
Hence, wind energy is unreliable because it does not always blow and its speed might change quickly.