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The Babylonians and Chinese were using wind power to pump water for irrigating crops 4,000 years ago, and sailing boats were around long before that.
Wind power advantages Wind power was used in the Middle Ages, in Europe, to grind corn, which is where the term "windmill" comes from.
it's working:
The Sun heats our atmosphere unevenly, so some patches become warmer than others.
These warm patches of air rise, other air blows in to replace them - and we feel a wind blowing.
We can use the energy in the wind by building a tall tower, with a large propellor on the top.
The wind blows the propellor round, which turns a generator to produce electricity.
Graphic by Will Darvill
We tend to build many of these towers together, to make a "wind farm" and produce more electricity.
The more towers, the more wind, and the larger the propellors, the more electricity we can make.
It's only worth building wind farms in places that have strong, steady winds, although boats and caravans increasingly have small wind generators to help keep their batteries charged.
The best places for wind farms are in coastal areas, at the tops of rounded hills, open plains and gaps in mountains - places where the wind is strong and reliable. Some are offshore.
To be worthwhile, you need an average wind speed of around 25 km/h. Most wind farms in the UK are in Cornwall or Wales.
Isolated places such as farms may have their own wind generators. In California, several "wind farms" supply electricity to homes around Los Angeles.
Advantages
* Wind is free, wind farms need no fuel.
* Produces no waste or greenhouse gases.
* The land beneath can usually still be used for farming.
* Wind farms can be tourist attractions.
* A good method of supplying energy to remote areas.
Disadvantages
* The wind is not always predictable - some days have no wind.
* Suitable areas for wind farms are often near the coast, where land is expensive.
* Some people feel that covering the landscape with these towers is unsightly.
*Can kill birds - migrating flocks tend to like strong winds.
*However, this is rare, and we tend not to build wind farms on migratory routes anyway.
*Can affect television reception if you live nearby.
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