Generating Electricity (WJEC GCSE Physics): Revision Note

Generating Electricity in Fuel Based Power Stations

• Fossil fuels, such as coal and oil, are used to produce energy on-demand when energy is needed

• This is done by: 

  • Burning the fuel to heat water

  • The water boils creating steam

  • Steam is forced around the system and this turns a turbine

  • The turbine turns coils in a magnetic field in the generator

  • This generates electricity

• The electricity is transferred to the National Grid through a step-up transformer and is carried by electrical lines

• The steam within the turbine will cool and condense and then be pumped back into the boiler to repeat the process

A Coal Powered Thermal Power Station

The structure of a coal-fired thermal power station

• The energy transfers taking place in this process are:

  • Chemical energy is released from the fuel when it is burned and is transformed into thermal energy in the water

  • As the steam turns the turbine, energy is transformed into kinetic energy in the turbine

  • As the turbine turns the generator, energy is transformed into kinetic energy in the generator

• All thermal power stations generate electricity by heating water to turn a turbine

• The only difference is the type of fuel used

• The majority of power stations in the UK use gas because this is the cleanest of the fossil fuels (less polluting)