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Power Stations

How does a Power Station Generate Electricity?

Some power stations use a primary energy source to
heat water. Fossil fuels, nuclear power, geothermal energy
and biomass are all used to boil water to make steam
which turns a turbine. When the fossil fuel is natural gas,
some power stations don't boil water to make steam
but directly use the hot burnt gases to turn the turbine.

What is a Turbine?

A turbine, like a windmill, has a number of blades which
rotate when a liquid or a gas (for example steam)
is forced through it under pressure. Large cooling towers
then condense the steam back into water. The
water is recycled, reheated and turned back into steam.

The rotating turbine is connected to a generator
which produces electricity with an alternating current.
A bigger generator producing more electricity
uses more primary fuel per second. The electricity
produced is put through a step up transformer
and it is then transmitted across the national grid.

Some renewable energy sources do not heat water
(see above) but turn a turbine directly. Hydroelectric power
and tidal power use falling water to turn the turbines.
Wind power uses wind turbines to turn small generators.

Solar power generates electricity directly from sunlight
or from the heating effect of sunlight that has
caused air to move. The moving air turns turbines.

The following pages give the advantages and
disadvantages of these processes. We can not rely on
just one way of generating electricity. To make sure
that we have enough electricity all the time we need it,
we must use a variety of ways to generate electricity.

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