What is it?
Waves are the movement of water near the surface of the sea, and are created by the wind blowing across it. It is estimated that waves have a total power of 90 million gigawatts worldwide – that is a lot of energy!
How is it used to generate electricity?
There are several different ways to capture wave energy: from trapping waves to bobbing buoys. Wave energy devices can be fixed to the shoreline or placed out at sea. These are two of the devices:
• Oscillating water columns (OWCs) contain a turbine. The waves below act like a piston when they move, pushing air up and down making the turbine rotate. It is attached to a generator which produces electricity.
• Point absorbers capture wave energy as different parts of them move in sympathy with the waves. This movement can be used to pump air or liquid through a turbine, which is attached to an electricity generator.
Where can you find it?
Almost anywhere in the world. The UK has some very good places off north-west Scotland, Wales and south-west England.
Advantages and disadvantages of using wave energy to generate electricity
• It is a huge potential resource for the UK
• It is a more predictable energy source than wind
• There are no fuel costs, unlike conventional power generation
• Equipment needs to be designed to survive bad weather conditions such as storms
• There may be high maintenance costs, because the devices can be far out at sea
• There is no leading device at the moment
How many systems in the UK?
There are dozens of devices under development.
How much does it cost to produce?
It is difficult to calculate a cost for wave-generated electricity as there is still no overall agreement on the best types of generators and the best locations.
What is the carbon cost?
Wave power does not produce any carbon dioxide.
It has great potential. 3% of the UK's energy could be generated from wave power by 2020. That is almost the same as all renewable sources at the moment. It is a promising alternative.
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