GCSE Design and Technology AQA (8552) Unit 2: Energy Generation

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  • Created on: 14-02-19 15:19

Fossil Fuels

Fossil Fuels

  • Fossil fuels are formed from the fossilised remains of plants and animals over millions of years
  • Coal, oil and gas are extracted through mining and drilling
  • Fossil fuels are considered a finite resource as they take a few million years to form, and humans are using them significantly faster than the environment can replace.
  • They are relied upon for power generation because they are effective and they are a cheap source of energy
  • Extraction of fossil fuels can disrupt the environment, especially open cast mining.
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Energy Generation

Energy Generation

  • Fossil fuels can be burned to superheat water under pressure, which in turn, drives turbines
  • Chemical energy from fuel is turned into heat, in the form of superheated steam
  • The steam drives turbines, converting heat to kinetic energy
  • Kinetic energy drives the shaft which spins an electricity generator, converting kinetic energy to electricity
  • The electrical energy is transferred to the National Grid by pylons, where it is used.

 

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Fracking

Fracking

  • Fracking involves drilling into layers of shale rock deep in the earth to release pockets of gas
  • Water, sand and chemicals are injected into a well in order to force gas up
  • The water pressure creates fissures in the rock which open up areas with gas
  • Sand stops the fissures from closing up, and allow the gas to flow into the well pipe
  • Chemicals can contaminate nearby water tables used for drinking, and have done in the past
  • People can become ill from drinking contaminated water
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Renewable Energy Sources

Renewable Energy Sources

  • Renewable alternatives to fossil fuels include wind, solar, tidal, biomass and hydroelectric
  • These are classified as renewable as they are replaced easily without much damage to the environment

 

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Wind Turbines

Wind Turbines

For:

  • Low maintenance
  • Clean energy
  • Higher winter output
  • Low cost energy

Against:

  • Only works when windy
  • Eyesore to some
  • Hazard to birds
  • Noise
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Solar Energy

Solar Energy

  • The Sun produces a constant stream of solar energy that reaches Earth
  • In just one hour it provides enough energy to power the world for one year

 

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Photovoltaic (PV) Cells

Photovoltaic (PV) Cells

  • Light photons hit the PV cell which allows electrons to flow creating an electric current
  • PV cells are used for solar panels.

Advantages:

  • Low maintenance
  • Clean energy
  • Relatively low-cost

Disadvantages:

  • Seasonal fluctuations
  • No power generated at night
  • Complex positioning issues

 

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Tidal Energy

Tidal Energy

  • The rise and fall of the tide forces water through turbines which drive generators to produce electricity

Advantages:

  • Clean energy
  • High efficiency
  • Low maintenence

Disadvantages:

  • Construction is expensive
  • Very few suitable locations
  • Low power output compared to others

 

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Hydroelectric Power (HEP)

Hydroelectric Power (HEP)

  • Hydroelectric power is a very reliable and controllable energy source
  • The set-up costs are financially and environmentally expensive
  • Vast areas need to be flooded to create reservoirs
  • People who live locally will have to be moved to a safer location, and those who are not in danger of flooding may complain of noise
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Biofuel and Biomass

Biofuel and Biomass

  • Biofuel and biomass are created from organic matter which is burned to generate power
  • Biomass fuels include food and farm waste, compost and wood chips or compressed pellets
  • Biomass is considered to be carbon neutral as the carbon dioxide released when burnt are equivelant to the amount of carbon dioxide absorbed by the plants used to create biofuels
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Nuclear Power

Nuclear Power

  • Nuclear power accounts for over 11% of the world's electricity
  • This is not a renewable energy source as uranium supplies are limited as fossil fuels
  • Nuclear power provides an abundant, reliable supply of clean energy
  • It is unpopular with some campaigners as the nuclear waste created is dangerous and there is a risk of major catastrophe like the Fukushima disaster in Japan
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