What is it?
Wind is created by the uneven way the Sun heats the Earth’s atmosphere. Winds blow wherever warmer air in the atmosphere rises due to the fact that it is less dense than surrounding cooler air. When cooler air rushes in to fill the partial vacuum (low pressure) that is what we know as wind.
Prevailing winds in the UK are from the south-west but when a low pressure weather system comes off the Atlantic onto land it can bring rain as well as strong winds from any direction.
How is it used to generate electricity?
The blades of a wind turbine work in the same way as an aeroplane's wings. When air flows around an aeroplane's wings, it creates low pressure above that lifts the aeroplane. Similarly, when air flows around the blades of a wind turbine, it creates low pressure that turns it round. The blades are linked to a generator, and as it rotates it generates electricity.
Where can you find it?
Anywhere it is windy. These tend to be hilly areas or offshore.
Advantages and disadvantages of using wind energy to generate electricity
• Once the wind turbine is built, running costs are very low
• It does not produce any carbon dioxide, which contributes to the greenhouse effect
• The land occupied by a wind farm can still be used for farming
• Wind is a renewable source so it will not run out
• Wind farms are safe and easy to build
• We cannot control when the wind blows. Wind turbines shut down in very strong or very weak winds
• They can only be built in certain areas. These areas need to be windy places, usually hilly areas or coasts
• Not everyone likes the appearance of wind farms
How many wind farms in the UK?
Over 135 wind farms in the UK generating over 1900MW in total, of which over 20 are greater than 25MW each.
How much does it cost to produce?
Electricity from a large-scale onshore wind farm costs 4.2-5.2p p/kWh. It costs 6.2-8.4p from an offshore wind farm.
What is the carbon cost?
Wind power does not produce any carbon dioxide.
There is huge potential for development of wind power in the UK. The British Wind Energy Association estimates that wind power could supply 3.3 million homes in the UK by 2010 which is 8% of total UK demand.
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