Power Stations

Power stations convert a primary energy resource into electrical energy.
Electrical energy is called a secondary energy source.
Electricity is a very useful form of energy because
it can be used to do so many different things
and it is easily transmitted over long distances.

The primary energy resources may be non-renewable, such as
fossil fuels or nuclear power,
or renewable, such as
hydroelectric, tidal, wave, wind, solar, geothermal and biomass.

Non-renewable means that there is only a certain amount of the resource.
Once it is used up, it cannot be replaced.

Renewable means that the resource will not run out.

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

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

The rotating turbine is connected to a generator
which produces alternating current electricity.
A bigger generator producing more electricity
uses more primary fuel per second.
This electricity is then put through a step up transformer
and transmitted across the National Grid.

Hydroelectric and tidal power use falling water to turn the turbines.
Wind power uses modern windmills (called wind turbines)
to turn small generators.

Solar power generates electricity directly from sunlight.

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.