EDEXCEL IGCSE / CERTIFICATE IN PHYSICS 4-4 Energy Resources and Electricity Generation Edexcel IGCSE Physics pages 150 to 159 June 17 th 2012 Content applying.

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