Energy ResourcesOxford AQA IGCSE Physics: Revision notes
Section 1
Why do we choose particular fuels?
Fuels are stores of energy. Which fuel is chosen for a given job depends on:
- Ease of storage (e.g. a liquid fuel is easier to store and transport than a gas)
- Energy content (how much energy is released per kilogram)
- Safety (flammability, toxicity, ease of handling)
When a fuel is used, some energy is always transferred to the surroundings rather than doing the intended useful job — some fuels achieve this more efficiently than others.
Section 2
What energy resources do we use nationally and globally?
A wide range of energy resources is used on a national and global scale, including fossil fuels (coal, oil, gas), nuclear fuel, and renewables (wind, solar, hydroelectric, wave, tidal, geothermal, biofuel).
Choosing between them has implications for society, including:
- Renewability — fossil fuels and nuclear fuel are non-renewable and will eventually run out; renewables will not
- Environmental impact of extraction (e.g. mining, drilling), use (e.g. carbon dioxide emissions, air pollution) and disposal (e.g. nuclear waste)
Evaluation questions want a balanced answer — always weigh an advantage against a drawback, e.g. reliability versus environmental cost, rather than listing facts on only one side.
Section 3
What are the main renewable energy technologies?
| Resource | How it generates electricity | Advantage | Drawback | |---|---|---| | Wave power | floating devices move up and down with waves, driving generators | no fuel cost, no emissions | unreliable (depends on sea conditions), can disrupt shipping/marine life | | Solar power | photovoltaic cells convert sunlight directly into electricity | no fuel cost, no emissions, works on a small or large scale | only generates in daylight, output depends on weather | | Geothermal power | heat from underground rocks heats water/steam to drive turbines | reliable, low emissions once built | only available in certain geological locations |
Must Know
- Fuels are chosen based on ease of storage, energy content and safety
- Some energy is always transferred to the surroundings when a fuel is used; efficiency varies between fuels
- A range of resources (fossil, nuclear, renewable) is used nationally and globally, with different renewability and environmental impacts of extraction, use and disposal
- Wave power: uses wave motion, unreliable but no emissions
- Solar power: uses sunlight directly, only works in daylight
- Geothermal power: uses heat from underground rocks, reliable but geographically limited
That's the notes covered.
Carry on to the next subtopic.