1.2 - Generating Electricity

• What is a renewable energy source?

  An energy source which can be replenished as it is being used up
• Four examples of renewable energy sources?

  • Wind Energy
  • Hydro-Electricity
  • Tidal Energy
  • Solar Energy
• Example of a non-renewable energy resource

  • fossil fuels
• Advantages of generating power using gas rather than coal

  • Flexible Generation: Gas power stations have short start times so they can be switched on/off more readily
  • Lower emissions of carbon dioxide
• 2 disadvantages of using renewable energy resources to generate power

  • not reliable, supply is uncertain due to external factors e.g. wind speed
  • generating power via other means is often more efficient and economically beneficial
• Environmental Impacts of burning fossil fuels

  • carbon dioxide contributes to the greenhouse effect and causes global warming
  • sulphur dioxide leads to acid rain which can damage buildings and crops
• 3 advantages of fossil fuels as an energy resource

  • reliable
  • can produce large amounts of energy for a given quantity
  • relatively abundant and cost-effective
• 3 advantages of nuclear power

  • low fuel costs
  • doesn't release greenhouse gases and doesn't contribute to climate change
  • large quantity of energy for relatively small quantity of fuel
• 3 disadvantages of nuclear power

  • nuclear fuel is a non-renewable energy source
  • produces nuclear waste which is harmful to humans + must be stored safely for centuries
  • risk of nuclear accidents - fatal consequences on humans and the environment
• what are the 2 types of transformers

  • step-up transformers
  • step-down transformers
• social factors which may deter types of energy production:

  • sound pollution
  • visual pollution
• visual and sound pollution are both disadvantages of wind farms
• what do step-up transformers do?

  • increase the potential difference (decrease current)
• Step-up transformers are used when connecting power supplies (power stations) to a power source (transmission cables)
• step-down transformers decrease the potential difference (increasing current)
• step-down transformers are used when connecting transmission cables to domestic buildings (like houses)
• Why do transmission lines transfer electricity at high potentials?

  • high potential difference results in a low current
  • over the current the less energy is dissipated as heat
  • transport is more efficient
• why does the potential need to be decreased between transmission lines and houses?

  • lower potentials are safer for domestic use and reduced the likelihood of severe electrocution
  • household appliances are designed for 230V
• efficiency = useful output energy transferred / total input energy transferred x 100
• hydroelectric power is more reliable than wind or solar energy and renewable
• wind power is relatively unreliable as it can only be used in sufficiently windy areas
• solar energy is renewable but unreliable
• Transmitting electricity at high voltages reduces the energy that is lost as heat due to the resistance of the cables.
• Which type of transformer is used to increase voltage for transmission over long distances?


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