National and global energy resources: describe the main energy sources available

The idea

You need to give a clear account of the main energy sources used for electricity generation and transport, including fossil fuels (coal, oil, gas), nuclear fuel, biofuels, wind, hydroelectric, tidal, wave, solar, geothermal and water waves. For each, state whether it is renewable or non-renewable and outline how it is used. For example, in a gas-fired power station, burning natural gas transfers chemical energy to thermal energy in steam, which turns a turbine to generate electrical energy. In a hydroelectric scheme, gravitational potential energy of stored water transfers to kinetic energy as it flows downhill, turning turbines. You should also describe patterns of use, such as the global reliance on fossil fuels and the growing contribution of renewables.

What earns the marks

• Name at least four main energy sources, including at least two fossil fuels and at least two renewables.
• State correctly whether each named source is renewable or non-renewable.
• Describe the energy transfer for one named source, for example chemical to thermal to kinetic to electrical in a coal-fired station.
• Describe how a named renewable source is harnessed, such as solar cells transferring light to electrical energy directly.
• Describe a national or global pattern, such as fossil fuels supplying most global electricity or renewables growing in use.

Common mistakes and how to put them right

• Treating 'energy source' and 'fuel' as identical.

  Put it right: Wind and solar are energy sources but not fuels because they are not burned.

• Describing nuclear power as burning uranium.

  Put it right: Nuclear fuel undergoes fission, releasing thermal energy without combustion.

• Omitting the final electrical transfer.

  Put it right: A full chain for a power station ends with kinetic energy in the turbine transferred to electrical energy by the generator.

Exam tips

• Learn a concise energy transfer chain for each major source so you can write it quickly and accurately.
• If asked to 'describe', give a continuous account rather than a bullet list of unconnected words.
• Use comparative language such as 'more reliable than' or 'less polluting than' when describing patterns of use.