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Energy for the futureElectricity Generation - Part 2

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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

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The inventor of the generator

Michael Faraday 1791-1867invented the generator in 1831.

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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.

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• 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

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Generators in power stations are very,

very bigHuge 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

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How can a generator be turned?

Source of steam

Turbine

Steam can be used to turn a turbine to turn the generator.

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A power station

electric current

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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.

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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 pollutionbut some waste is

very dangerous and has to be handled very carefully.

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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.

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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!

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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.

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How else can we turn a generator without polluting the Earth?Use flowing water.

Hoover Dam in USA – 220m high

top of dam

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HydroelectricityRunning water turns the generator

(Tennessee Valley Authority)

Water from a mountain lake

Does not pollute the atmosphere.

The dam must be high in mountains.

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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.

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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?

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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.

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Energy from the Sun

NASA

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Solar cellsUse solar cells to change the energy in sunlight into electricity

parking meter

Solar cells

traffic sign

– no generator needed - needs lots of sunlight.

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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.

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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

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Fossil fuelsCoal - pollutionGas - pollutionOil - pollution

Renewable sources – do not run outHydroelectricity – needs mountainsWind - only works when wind blowingWaste & rotting vegetation – greenhouse gasesSunlight – best in sunny countriesGeothermal – only in countries with hot springsWaves – small scale only – so far

Energy from nuclear reactionsFission – waste needs very careful handling

Fusion – waste less dangerous

will not run out - but very difficult !

Energy Sources:

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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 !