A non-renewable energy resource is one that is used faster than it is formed. Once consumed, it cannot be replaced within a human timescale.
Fossil fuels
Coal, oil and natural gas are fossil fuels. They formed over millions of years from the remains of plants and animals buried under heat and pressure.
How they generate electricity:
Fuel is burned to heat water. The steam produced drives a turbine, which turns a generator to produce electricity.
| Stage | Process |
|---|---|
| 1 | Burn fuel (chemical energy to thermal energy) |
| 2 | Heat water to produce steam |
| 3 | Steam drives a turbine (thermal to kinetic) |
| 4 | Turbine turns a generator (kinetic to electrical) |
Nuclear fuel
Uranium (or plutonium) undergoes nuclear fission in a reactor. The energy released heats water to steam, which drives a turbine and generator (the same process as fossil fuels from stage 2 onward).
Nuclear fuel is non-renewable because the supply of uranium is finite. However, a small amount of nuclear fuel releases a very large amount of energy.
Advantages of non-renewables
- High power output: a single power station can supply a city.
- Reliable: output is not affected by weather.
- Fossil fuel stations can increase output quickly to meet demand.
Disadvantages of non-renewables
- Fossil fuels produce carbon dioxide (greenhouse gas), contributing to climate change.
- Coal and oil also release sulfur dioxide and particulates (air pollution, acid rain).
- Nuclear: risk of radioactive waste, long storage required, decommissioning is expensive.
- Finite supply: coal, oil, gas and uranium will eventually run out.
Common errors and how to correct them
Saying nuclear power stations produce carbon dioxide. Nuclear fission does not produce CO2. The environmental concern for nuclear is radioactive waste, not greenhouse gases.
Confusing fission and fusion. Nuclear power stations use fission (splitting heavy nuclei), not fusion (joining light nuclei).
How to apply this in an exam
Distinguish between fossil fuel and nuclear energy sources. When comparing, address carbon emissions, reliability, waste products and supply separately.
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