Today, we’re going to check out windmills, one of the most common generators of wind energy on the planet! A basic windmill normally has a number of aerodynamic blades on it that are shaped in such a way that they can catch the wind when it blows. These are attached to a central hub on the windmill, allowing the blades to start turning by using the power of the wind.
Modern windmills (some people call them wind turbines) are a little bit more complicated. They normally have three blades as this is thought to be the most efficient, while most tend to rotate clockwise – this is not to say that there aren’t windmills out there with more or less than three blades that rotate anti-clockwise!
The most recently designed windmills are computer-controlled and the role of this computer is to keep the windmill facing the wind so that it catches each strong gust or air and keeps turning. In times of storm or extremely strong winds, there may be too much energy for the windmill to harness, so the computer will position the windmill in a position to let the wind pass without catching it. To do this, the computer keeps an eye on the direction and speed of the wind using instruments that are on top of the windmill and pitches (twists) the windmill according to what is most suitable.
Once the windmill catches the wind, it creates something called rotational energy which makes the blades spin around. The blades are connected to a generator that can then convert the mechanical energy (energy generated from the spinning blades) into electrical energy, which is of course, electricity! Some windmills are fixed speed machines, meaning the blades rotate at the same speed regardless of how fast the wind is blowing. Others are variable speed machines, which rotate at whatever speed the wind blows them. Windmills develop green energy which is then passed through underground cables that go to local energy grids, eventually powering your home!
Watch the video to become an expert on wind turbines.
In some countries, electricity is not easily available and so there are many basic, daily actions that take a lot off effort to complete without the help of electricity. Imagine not being about to turn on a light to read or work at night time. Imagine not being able to charge a computer or cook on a stove top. The video below is about William Kamkwamba from Malawi, who used his own ingenuity to build a windmill and in turn create electricity to help build a better life for his family. This is a fantastic example of how windmills can be used as a source of energy, and also how important invention and creativity can be to us all: