The generator generates the electricity when there is enough wind to turn the blades. The directional system swings the horizontal axis machines in line with the wind. The protection system protects against damage in extremely high winds. The tower raises the turbine up so that it can capture the higher wind speeds, and avoid the turbulent air, which is close to the ground. The tower also eliminates resonance between the frequency range of the rotating blades and the resonant frequency of the tower.
Variability comes into play a lot in wind turbines.
This variability is the greatest challenge to the economic use of wind power. Wind is not around all the time in every place, just as it is not sunny all the time in every place. The only fix for this is the storage mechanisms, which can store the excess energy we get when it is super windy or to be used when it is not windy at all. That is the only solution. Well, the future looks very optimistic.