2. 2
Generators
Use energy to generate electric currents.
A moving magnet pushes the electrons along a
wire.
The energy used to move the magnet is carried by
the electric current.
magnet
Coil of wire
torch
bulb
3. 3
The inventor of the generator
Michael Faraday 1791-1867
invented the generator in 1831.
4. 4
What do we need to make a generator
for a power station?
• Strong magnets
• Lots of wire
then lots of
energy
to turn the generator.
5. 5
• Generators in
power stations supply
electricity to factories,
homes and schools.
• These generators are
in power stations
• and are huge!
Factories, homes and schools
need huge amounts of energy
6. 6
Generators in power stations are
very, very big
Huge generators
need huge amounts
of energy.
The energy turns
the generators.
The electric
current carries the
energy to where it
is needed.
Size of a person
7. 7
How can a generator be turned?
Source
of
steam
Turbine
Steam can be used
to turn a turbine
to turn the generator.
9. 9
How can water be heated to make steam?
Old way:
Burn coal
The smoke is dirty and pollutes the
atmosphere.
Also produces lots of carbon
dioxide which is a green house gas –
heats up the Earth.
Newer way:
Burn gas
Gas is cleaner than coal but still makes
lots of carbon dioxide
Eventually the world will run out of coal and gas.
10. 10
Steam from nuclear energy
Nuclear reactors can be used
- to split atoms
- to release energy
- to boil water
– to make steam
- to turn the generators.
+
splits to give
This does not cause pollution
but some waste is
very dangerous and has to be
handled very carefully.
11. 11
Steam from the Earth
70000 C
5000 C
- giving energy
to generate
electricity.
In some countries there
are hot rocks close to the
surface of the Earth.
12. 12
Energy from the Earth
In some countries
energy from the Earth
can be used
to boil water
to turn generators.
This does not cause
pollution
and will not run out. NREL geo pacific gas and electric
But is not an option in the UK !
It would need very very deep holes!
13. 13
Electricity from waste
Vegetation and animal dung give off energy as
they rot. This can be used to heat homes and
greenhouses directly.
Also waste can be burned
- to boil water
- to make steam
- to turn generators.
The process uses up waste.
But produces carbon dioxide.
14. 14
How else can we turn a generator
without polluting the Earth?
Use flowing water.
Hoover Dam in USA – 220m high
top of dam
15. 15
Hydroelectricity
Running water turns the generator
(Tennessee Valley Authority)
Water
from a
mountain
lake
Does not pollute the atmosphere.
The dam must be high in mountains.
16. 16
Waves
Energy from
waves can be
used to turn
generators.
We have lots
of waves in the
seas around
the UK.
Does not cause pollution.
There are more problems to solve.
17. 17
We can make a windmill
When you blow
the windmill it
turns.
The moving air
pushes the blades
round.
What happens
if you blow
harder?
18. 18
Wind can turn generators
Now modern wind turbines
are used to turn
generators.
Do not pollute the air.
Wind is not used up.
But sometimes the wind
does not blow.
Many years ago
windmills were used to turn
mill stones to grind grain.
20. 20
Solar cells
Use solar cells to change the energy in sunlight
into electricity
parking meter
Solar
cells
traffic
sign
– no generator needed
- needs lots of sunlight.
21. 21
The space station has huge
solar panels
The framework is 109 metres long.
NASA
The
International
Space Station
uses solar
panels to
collect energy,
making it
possible for
scientists to
live on board
and do
experiments.
22. 22
Fusion
Makes the Sun shine.
Scientists are finding ways to get huge amounts
of energy.
when small atoms join together,
energy is given out
– like in the Sun.
Will not run out.
Does not pollute the air.
The future? Not possible for another 20 years!
+
gives
23. 23
Fossil fuels
Coal - pollution
Gas - pollution
Oil - pollution
Renewable sources – do not run out
Hydroelectricity – needs mountains
Wind - only works when wind blowing
Waste & rotting vegetation – greenhouse gases
Sunlight – best in sunny countries
Geothermal – only in countries with hot springs
Waves – small scale only – so far
Energy from nuclear reactions
Fission – waste needs very careful handling
Fusion – waste less dangerous
will not run out - but very difficult !
Energy Sources:
24. 24
Re-cap
• A generator generates an electric current
by moving magnets near a coil of wire.
• We need a source of energy to turn the
generator:
Burn fossil fuels?
Nuclear reactions?
Renewable energy?
• You will have to choose !
