The wind whistles in your ears and nose, but the wind turbine stands there completely unmoved. This can have very different reasons.
It seems absurd at first: although the wind is blowing hard, the wind turbines stand still in the landscape instead of turning. Aren’t these the perfect conditions to produce a decent amount of electricity? But it’s not that simple: There are various reasons why the rotor blades don’t move.
If the wind blows too strongly, a wind turbine can suffer damage, for example to the rotor blades or to the generator that converts the movement of the rotor blades into electricity. The manufacturers specify the wind speed at which the system should be shut down for each model individually. The parking speed is usually 25 meters per second – that corresponds to wind force ten, i.e. a severe storm.
Power grid can be overloaded by wind
In storms or strong winds, however, wind turbines can also be switched off in order not to overload the power grid. The wind turbines could then produce so much electricity that distributors, transformers or electrical devices would be damaged – or the grid would collapse completely and there would be a widespread power failure. As a rule, however, conventional power plants are initially throttled on windy days in order to utilize the power of the wind.
Another reason for shutting down a wind turbine can be the sun. If, for example, a settlement in the vicinity of the turbine should not get more than half an hour of rotor shadows per day, the turbine will switch off automatically as soon as the shadow continues to fall on this area. The system can use its position and the position of the sun to calculate where your shadow will fall.
Wind strength can vary greatly
Other reasons for a wind turbine to come to a standstill are maintenance work or wind speeds that are too low. A constant wind speed of around three meters per second is ideal for most wind turbines to keep their blades constantly turning and generating electricity. However, the wind conditions can differ greatly even within short distances, so that one wind turbine rotates quickly, but the next one is much slower.
There can also be major differences between the wind strength on the ground and that at the height of the rotor blades – the subjective impression of calm can be deceptive. There are now wind turbines with a hub height of 140 meters, up there the wind can blow strongly, even if you don’t feel it much directly above the ground. Conversely, a strong wind around the nose does not mean that the wind strength is sufficient for electricity production.
