Investigating Energy Transfers (WJEC GCSE Physics): Revision Note

Investigating Energy Transfers

• Before installing energy-saving devices in homes, it is important to be able to interpret and analyse data to help make an informed decision

• For photovoltaic cells (solar panels), the energy output depends on

  • Construction i.e. the efficiency of the panels

  • Location i.e. the average number of hours of sunshine

• For wind turbines, the energy output depends on

  • Construction i.e. the efficiency of the turbines

  • Location i.e. the average wind speed

Advantages of small-scale energy generation

• The advantages of small-scale energy generation are:

  • No carbon dioxide is produced, so there is no contribution towards global warming

  • Fuel costs are reduced, as less electricity needs to be bought from the National Grid

  • Some electricity can be sold back to the National Grid

• The advantages of roof-top photovoltaics (solar panels) are:

  • It is a source of ‘free’ electricity during daylight hours

  • In the UK, peak power outputs of 3 kW of electricity can be generated

• The advantages of domestic wind turbines are:

  • It is a source of ‘free’ electricity when the wind is blowing

  • In the UK, peak power outputs of 6 kW of electricity can be generated

Disadvantages of small-scale energy generation

• The disadvantages of small-scale energy generation are:

  • It can often provide an unreliable and unpredictable energy supply due to weather conditions

  • Some electricity needs to be bought from the National Grid when generation is low

  • Payback times can be long (>20 years)

• The disadvantages of roof-top photovoltaics (solar panels) are:

  • Some people object to the visual impact of solar panels on roof-tops

  • A large rooftop area or several panels are required to generate large amounts of electricity

• The disadvantages of domestic wind turbines are:

  • Some people object to the visual and noise impacts of wind turbines

  • Most locations are not consistently windy enough to generate large amounts of electricity