Mystery: this is why the windmills in Zoetermeer are shut down during a storm

You might think that storms like Eunice or Dudley actually generate some energy at the windmills in Zotermeer. Nothing could be further from the truth, because the mills are shut down in strong winds. How hard must the wind blow for the windmills to be shut down? And why is that anyway?

On Friday, February 18, Storm Eunice rages across the country, a slightly more powerful version than its predecessor Dudley. In our province of South Holland, code red was issued due to a severe storm.

Not built on

The more wind, the more energy? No, unfortunately that’s not how it works with windmills. In the Netherlands they are not built for storms, because they do not occur here very often. A windmill can therefore also get too much wind in its blades. There are windmills that can withstand a big storm, they are specially designed for it. Near Zoetermeer, the Siemens windmill along the A12 is one of the best known.

Wind force 10

“The wind turbines run best at wind force 5 to 6 and are stopped when the wind blows very hard,” says wind energy expert Vermeulen in an interview with Fidelity† The limit is approximately at wind force 10, then the wind blows too hard and the mills are shut down. Above wind force 10, the risk of short circuit, wear and other damage increases.

Software determine when the blades should be switched off. They go into rest position and turn at the right angle so that the wind slides past them. When the wind drops below force 10 again, the turbines start to rotate again. This Friday there was a good chance that this happened at the windmills near Zoetermeer because storm Eunice had peaks up to wind force 11.