Energy for the future Electricity Generation — Part

Energy for the future Electricity Generation - Part 2 1

Generators n Use energy to generate electric currents. n A moving magnet pushes the electrons along a wire. n The energy used to move the magnet is carried by the electric current. magnet torch bulb Coil of wire 2

The inventor of the generator Michael Faraday 1791 -1867 invented the generator in 1831. 3

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. 4

Factories, homes and schools need huge amounts of energy • Generators in power stations supply electricity to factories, homes and schools. • These generators are in power stations • and are huge! 5

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 6

How can a generator be turned? Steam can be used to turn a turbine to turn the generator. Turbine Source of steam 7

A power station electric current 8

How can water be heated to make steam? Old way: The smoke is dirty and pollutes the atmosphere. Burn coal Also produces lots of carbon dioxide which is a green house gas – heats up the Earth. Newer way: Gas is cleaner than coal but still makes lots of carbon dioxide Burn gas Eventually the world will run out of coal and gas. 9

Steam from nuclear energy n Nuclear reactors can be used - to split atoms - to release energy - to boil water – to make steam - to turn the generators. This does not cause pollution but some waste is very dangerous and has to be handled very carefully. splits to give + 10

Steam from the Earth 5000 C - giving energy to generate electricity. 70000 C In some countries there are hot rocks close to the surface of the Earth. 11

Energy from the Earth n n 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 ! n. It would need very deep holes! 12

Electricity from waste n n Vegetation and animal dung give off energy as they rot. This can be used to heat homes and greenhouses directly. Also - to waste can be burned boil water make steam turn generators. The process uses up waste. But produces carbon dioxide. 13

How else can we turn a generator without polluting the Earth? Use flowing water. top of dam Hoover Dam in USA – 220 m high 14

Hydroelectricity Running water turns the generator Water from a mountain lake (Tennessee Valley Authority) Does not pollute the atmosphere. The dam must be high in mountains. 15

Waves n n 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. 16

We can make a windmill n n When you blow the windmill it turns. The moving air pushes the blades round. What happens if you blow harder? 17

Wind can turn generators n n n Many years ago windmills were used to turn mill stones to grind grain. 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. 18

Energy from the Sun NASA 19

Solar cells Use solar cells to change the energy in sunlight into electricity – no generator needed - needs lots of sunlight. Solar cells traffic sign parking meter 20

The space station has huge solar panels The International Space Station uses solar panels to collect energy, making it possible for scientists to live on board and do experiments. The framework is 109 metres long. NASA 21

Fusion n n 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. gives + n Will not run out. Does not pollute the air. n The future? Not possible for another 20 years! n 22

Energy Sources: Fossil fuels Coal Gas Oil - pollution Renewable sources – do not run out - pollution 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 ! 23

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: Ø Burn fossil fuels? Ø Nuclear reactions? Ø Renewable energy? • You will have to choose ! 24