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Introduction
Ocean waves are caused by the wind as it blows
across the sea. Waves are a powerful source of energy.
The problem is that it's not easy to harness
this energy and convert it into electricity in large amounts.
Thus, wave power stations are rare. |
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How it works
| There are several
methods of getting energy from waves.
One of them works like a swimming pool wave machine in reverse.
At a swimming pool, air is blown in and out of a chamber
beside the pool, which makes the water outside bob up and down,
causing waves.
At a wave power station, the waves arriving cause
the water in the chamber to rise and fall, which means that air
is forced in and out of the hole in the top of the chamber. |
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We place a turbine
in this hole, which is turned by the air rushing in and out. The
turbine
turns a generator.
A problem with this design is that the rushing air
can be very noisy, unless a silencer is fitted to the turbine. The
noise is not a huge problem anyway, as the waves make quite a bit
of noise themselves.
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Example:
| Example: A company
called Ocean Power Delivery are developing a method of offshore
wave energy collection, using a floating tube called "Pelamis".
This long, hinged tube (about the size of 5 railway
carriages) bobs up and down in the waves, as the hinges bend they
pump hydraulic fluid which drives generators.
Find out more, including an interactive model, videos and
technical details at www.oceanpd.com...
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| Example: Another
company is called Renewable Energy Holdings. Their idea for
generating wave power (called "CETO") uses underwater
equipment on the sea bed near the coast. Waves passing across the
top of the unit make a piston move, which pumps seawater to drive
generators on land.
They're also involved with wind power and biofuel.

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More
More ideas about how to extract energy from waves are
being proposed all the time. This page only shows three examples.
Once you've built a wave power station, the energy is
free, needs no fuel and produces no waste or pollution.
One big problem is that of building and anchoring something
that can withstand the roughest conditions at sea, yet can generate
a reasonable amount of power from small waves. It's not much use if
it only works during storms!
Advantages
- The energy is free - no fuel needed, no waste produced.
- Not expensive to operate and maintain.
- Can produce a great deal of energy.
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Disadvantages
- Depends on the waves - sometimes you'll get loads
of energy, sometimes almost nothing.
- Needs a suitable site, where waves are consistently
strong.
- Some designs are noisy. But then again, so are
waves, so any noise is unlikely to be a problem.
- Must be able to withstand very rough weather.
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Is it renewable? Wave
power is renewable.
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