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EDEXCEL IGCSE / CERTIFICATE IN PHYSICS 4-4
Energy Resources and Electricity Generation
Edexcel IGCSE Physics pages 150 to 159
June 17th 2012
Content applying to Triple Science only is shown in red type on the next slide and is indicated on
subsequent slides by ‘TRIPLE ONLY’
Edexcel SpecificationSection 4: Energy resources and energy transfer
d) Energy resources and electricity generation
understand the energy transfers involved in generating electricity using:
• wind
• water
• geothermal resources
• solar heating systems
• solar cells
• fossil fuels
• nuclear power
describe the advantages and disadvantages of methods of large-scale electricity production from various renewable and non-renewable resources.
Red type: Triple Science Only
Renewable and non-renewable energy sources
A renewable energy resource is one that will not run out.
Renewable energy sources do not produce radioactive waste, greenhouse gases or acid rain.
Examples include wind, hydroelectric, wave, tidal, solar and geothermal.
Fossil fuels such as coal. gas and oil as well as uranium are non-renewable energy sources.
Wind power
Wind is used to rotate a turbine (the blades) which turns an electrical generator.
A wind farm
Energy changes:
kinetic
to electrical
ADVANTAGES • Renewable energy source• No greenhouse gases• No acid rain• No radioactive waste• Inexpensive to build• Short start up time
DISADVANTAGES• Unreliable – needs wind!• Best used in places where
they will often be regarded as unsightly
• Many turbines are needed to produce the same energy of a small thermal power station
• Noise• Danger to wildlife
TRIPLE ONLY
Hydroelectric powerFalling water is used to drive a turbine which rotates an electrical generator.
Energy changes:
gravitational potential
to kinetic
to electrical
Hydroelectric power station
ADVANTAGES • Renewable • No greenhouse gases• No acid rain• No radioactive waste• Short start up time
DISADVANTAGES• Very limited locations• Wildlife affected• Expensive to build
TRIPLE ONLY
The Hoover Dam near Las Vegas
Wave power
Waves can be used to drive an electrical generator.
Energy changes:
kinetic
to electrical
ADVANTAGES • Renewable • No greenhouse gases• No acid rain• No radioactive waste• No land needed• Short start up time
DISADVANTAGES• Unreliable• Can only be used in areas
with suitable waves• Prone to storm damage• Many needed to produce
the same energy of a small thermal power station
• Danger to shipping
TRIPLE ONLY
Tidal powerMoving water caused by the tides is used to drive a turbine directly which rotates an electrical generator.
Energy changes:gravitational potentialto kinetic to electrical
Tidal power station at La Rance, Brittany
Tidal power station
ADVANTAGES • Renewable • No greenhouse gases• No acid rain• No radioactive waste• Short start up time
DISADVANTAGES• Very limited locations• Wildlife affected• Expensive to build
TRIPLE ONLY
Proposed Severn Estuary Tidal Power Scheme
Geothermal energy
In some volcanic areas hot water and steam rise to the surface. The steam can be tapped and used to drive turbines. This is known as geothermal energy.
Energy changes:
thermal (heat)
to kinetic
to electrical
ADVANTAGES • Renewable • No greenhouse gases• No acid rain• No radioactive waste• Short start up time
DISADVANTAGES• Very limited locations• Expensive to build
TRIPLE ONLY
Solar heatingHeat energy from the Sun is focussed onto pipes containing water. The water boils producing steam. The steam is then used to drive turbines which turn electrical generators.
Energy changes:thermalto kinetic to electrical
ADVANTAGES • Renewable • No greenhouse gases• No acid rain• No radioactive waste
DISADVANTAGES• Sunshine needed and so best in desert regions
• Can only be used during the day
• A large amount of land is needed to produce a significant amount of energy
TRIPLE ONLY
Solar cells
Electricity produced directly from the Sun’s radiation.
Energy changes:
light
to electrical
ADVANTAGES • Renewable • No greenhouse gases• No acid rain• No radioactive waste• Instant start up time
DISADVANTAGES• Unreliable in the UK! –
sunshine is needed for solar cells
• Can only be used during the day
• Only 10% of solar energy is converted into electricity by solar cells
• Many cells needed to produce a significant amount of energy
TRIPLE ONLY
Fossil fuelsFossil fuels include coal, oil and natural gas.
They have been formed in the ground from dead vegetation and tiny creatures by a process that has taken millions of years.
When burnt the heat energy produced is used to produce steam. The steam is then used to drive turbines which turn electrical generators.
Energy changes:thermalto kinetic to electrical
Coal-fired power station
Problems with fossil fuels
Burning coal, gas and oil produces carbon dioxide. This is a greenhouse gas which causes global warming.
Fossil fuel burning can also produce sulfur dioxide gas. This can dissolve in water and produce acid rain which causes damage to forests and buildings. Modern power stations remove most sulfur dioxide producing compounds before burning.
Fossil fuels are not renewable. They are running out. Estimates vary between 50 to 200 years to when we will need to find alternative sources of energy.
An effect of acid rain
TRIPLE ONLY
ADVANTAGES • Concentrated energy source
• Reliable energy source• Can be built anywhere• No radioactive waste
DISADVANTAGES• Non-renewable• Produces greenhouse gases and contributes to global warming
• Produces acid rain
TRIPLE ONLY
Nuclear powerNuclear power stations use a certain type of uranium to produce heat energy.
This heat energy is used to produce steam. The steam is then used to drive turbines which turn electrical generators.
Energy changes:nuclearto thermalto kinetic to electrical
uranium fuel rods
A nuclear reactor
Problems with nuclear power stationsNuclear fuel (uranium) does not produce greenhouse gases and it generates 10000 times more energy per kilogram than fossil fuels.
However:
Nuclear waste is radioactive and may have to be stored safely for thousands of years.
Although safe in normal operation, accidents can release radioactive material over a large area. The area around Chernobyl in Ukraine has been closed off since 1986. The destroyed Chernobyl
nuclear reactor
TRIPLE ONLY
ADVANTAGES • Concentrated energy source
• Reliable energy source• Can be built anywhere• No greenhouse gases• No acid rain
DISADVANTAGES• Non-renewable• Radioactive waste• Expensive to build• Technology is related to that needed to make atomic bombs
TRIPLE ONLY
Electricity generation pie-chart
Most of our electricity is generated by burning fossil fuels (74% according to the pie chart opposite)
Nearly 20% is nuclear
Less than 5% is currently generated using renewable sources.
Choose appropriate words to fill in the gaps below:
Most of our electricity is produced by thermal __________ stations. These use the _______ produced by burning _____ or the fission of __________ to generate electricity.
The heat produced is used to change ________ into high pressure steam. This steam is used to turn a _________ which in turn _________ an electrical generator.
Over _______ of our electricity is generated by using thermal power stations.
fuels uranium
turbine
rotates
water
heat
power
WORD SELECTION:
90%
fuels
uranium
turbine
rotates
water
heat
power
90%
Online SimulationsThe Greenhouse Effect - PhET - Just how do greenhouse gases change the climate? Select the level of atmospheric greenhouse gases during an ice age, in the year 1750, today, or some time in the future and see how the Earth's temperature changes. Add clouds or panes of glass. BBC AQA GCSE Bitesize Revision: Generating electricity - Fossil Fuels Generating electricity - Nuclear Fuels Generating electricity - Wind Energy Generating electricity - Water Energy Generating electricity - Geothermal Energy Generating electricity - Solar Energy Generating electricity - Comparing sources BBC KS3 Bitesize Revision: Non-renewable energy Renewable resources Saving energy
Energy Resources and Electricity Generation Notes questions from pages 150 to 159
1. (a) Explain the difference between a renewable and a non-renewable energy source. (b) Give three examples of each.
2. Briefly describe how the following energy sources can be used to produce electricity: (a) wind; (b) water; (c) geothermal; (d) solar; (e) fossil fuels and (f) nuclear.
3. For each source listed in question 2 give two advantages and two disadvantages of their use in generating electricity.
4. Answer the questions on page 159.5. Verify that you can do all of the items listed in the end of
chapter checklist on page 159.
TRIPLE ONLY
Energy Resources and Electricity Generation Notes questions from pages 150 to 159
1. (a) Explain the difference between a renewable and a non-renewable energy source. (b) Give three examples of each.
2. Briefly describe how the following energy sources can be used to produce electricity: (a) wind; (b) water; (c) geothermal; (d) solar; (e) fossil fuels and (f) nuclear.
3. Answer questions 1, 2 and 3 on page 159.
DOUBLE SCIENCE ONLY