Zephyr, Boreus, … and their leader Aeolius are represented in statues as chubby-cheeked boys puffing and blowing their amusement or their anger. Today we know that the wind is not caused by unpredictable and easily-offended gods, but quite simply by non-uniform heating of the surface of our planet by the sun, creating zones of different pressures and temperatures: anticyclones for areas of high pressure, depressions for low pressure. Since pressure naturally seeks to become the same throughout the system, masses of air move from anticyclones towards depressions. The deeper the depression, the stronger the wind that is created.
Global planetary winds from the tropics to the poles, regional winds from the sea to the land, winds from mountain tops towards the valleys … there is no lack of variety! Wind is perhaps the form of energy that is the most evenly distributed throughout the world, with the exception of the equatorial zones.
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It has also been used since very early times: we think the first sailing boats appeared 5000 years ago. Today the ancient uses for the wind have become rather outmoded. Windmills are a little quaint, navigation by sail and derivatives such as windsurfing are reserved for leisure activities and the small windmills with multiple vanes dotted around the countryside, pumping underground water, are giving away more and more to motorised pumps. The modern use of wind as an energy source is epitomised by the tall wind turbines that are “flowering” in “farms” in areas where the wind is frequent and reasonably strong. They are used to produce electricity.
How does a wind turbine work? And what is the importance of wind energy today?
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