How was it formed?
Most coal deposits were formed around 300 million years ago during the Carboniferous period. The world was covered in tropical forest then. In some swampy places, plants died and fell into water and mud where there was not much oxygen. This meant the bacteria that would normally rot the vegetation away could not do so. Instead, over millions of years the wood and other plant matter physically and chemically changed into coal.
How is it used to generate electricity?
Coal is burned to heat water. This produces steam which pushes against the blades of turbines, causing them to spin. The turbines are connected to generators, which create electricity.
Where can you find it?
Wales, Scotland, northern England. China, USA, India, South Africa, Australia, Russia, Poland, Columbia and the Ukraine are the major producers.
Advantages and disadvantages of using coal to generate electricity
• Burning coal is one of the cheapest ways to generate power at the moment
• Coal power stations can be built anywhere where there are good transport links and where there is a plentiful supply of cooling water
• The world has many coal reserves
• Burning coal produces carbon dioxide, which contributes to the greenhouse effect. It also produces sulphur dioxide, a gas found in acid rain
• Coal is not renewable. There are limited supplies which will run out one day
• Coal-fired power stations need huge amounts of fuel
How many power stations in the UK?
17 (100MW and above)
How much it cost to produce?
2.5p to 3p/kWh
What is the carbon cost?
Coal reserves should last until the end of the 22nd century. The existing coal-fired power stations are all quite old and most will need to close or fit new emission control equipment in the next 8-10 years.
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