Flashcards
AQA Phyisics Unit 1 Part 4 - Generating Electricity
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- 14 - Generating Electricity4.1 - Fuel for electricity
- Electricity generators in power stations are powered by turbines which is driven by steam turning the turbine around
- Coal , oil and natural gas are burned in fossil fuel power stations
- Nuclear fission is when nucleus of uranium atom is unstable and splits in two, releasing energy
- Uranium and plutonium are fuels used in nuclear power stations. More energy is released per kg from uranium or plutonium than from fossil fuels
- Biofuels are renewable sources of energy. Methane and ethanol are examples of biofuels which can be used for power stations
- Biofuels produce carbon dioxide but its safe for the environment as the carbon dioxide levels are balanced as plants absorb CO2 and then release the same amount of energy when burned - 24.2 - Energy from wind and water - Energy from wind, waves or tides can produce renewable energy as the natural resources can never be used up - Wind turbine is an electric generator on top of a tall tower - Waves produce electricity from a turning floating generator - Wave power requires cables and buildings on the coastline that connect to the electric grid and can spoil some areas of the coastline. - If tidal patterns change from the floating generator it can harm habitats of marine life and birds - Hydroelectric power is generated by rainwater collected in reservoirs or lakes which flow down mountain slopes that drives turbines producing electricity in the electricity grid at the foot of the hill - Tidal power is where tidal power stations traps high tide and uses it to produce electricity4.3 - Power from the sun and the Earth
- Solar cells are flat solid cells that convert solar energy directly into electricity
- Solar heating panels se the Sun's energy to heat water directly
- Solar power towers are used to generate electricity and uses 1000's of flat mirrors which reflect sunlight into a large water tank at the top of the tower
- Geothermal energy comes from energy released by radioactive substances deep inside Earth
- Heat flow from underground is called ground heat which can be used to heat water with long lengths of underground pipes
- Water pumped into hot rocks underground produces steam to drive turbines that generate electricity - 34.4 - Energy and the environment - When no renewable resources are burnt they produce carbon dioxide and sulfur dioxide - Carbon dioxide released from fossil fuels cause global warming - Sulfur dioxide can cause acid rain which harm limestone statues and buildings - Sulfur is removed before the fuel is burned - Carbon capture storage is used to stop CO2 emissions and to store old oil and gas fields - Nuclear power fuels produce radioactive waste and have advantages and disadvantages - Advantages of nuclear power: no greenhouse gases produced more energy produced compared to fossil fuels - Disadvantages of nuclear power: Used fuel rods contain radioactive waste which must be stored safely for centuries If a explosion at a nuclear reactor happens radioactive material could be released harming areas for many years- Renewable energy sources affect wildlife and plant life. They have many advantages and disadvantages.
- Advantages of renewable energy:
Never run out
greenhouse gases or acidic rain is produced
radioactive waste isn't produced as waste products
Can be used where connection to the national grid is uneconomic
- Disadvantages of renewable energy:
Wind turbines produce a whining noise which upsets locals
tidal barrages affect river estuaries and habitats of wildlife and plants
hydroelectric schemes use large reservoirs which affect the local wildlife and plants
Solar cells cover large amounts of land to generate large amounts of power - 44.5 - The National Grid - The national grid provides electricity to homes and other buildings from power stations - Transformers also are used and there's two types of transformers. Step up transformers and Step down transformers - Step up transformers are used to raise the voltage and lower the current. Mostly used near power stations - Step Down transformers lower the voltage and raise the current. Mostly used at homes or other buildings - High grid voltages reduces the amount of energy lost and makes the system more efficient-Electricity pylons are objected by people as the cause health problems and destroy landscapes
- Pylons also are used as an alternative to underground cables as they are less expensive, easy to repair and easy to position - 54.6 - Big energy issues - Gas fired power stations and pumped storage stations can meet variations in demand - Renewable energy resources are unreliable. The amount of electricity generated depends on conditions - Nuclear, coal and oil power stations can meet base load demand - Nuclear power stations, fossil fuel power stations using carbon capture and renewable energy are all likely to contribute in future energy suppliesEnd of this section
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- GCSE Physics Flashcards on AQA Phyisics Unit 1 Part 4 - Generating Electricity , created by azini on 11/06/2015.
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