Energy resources: renewable vs non-renewable
A renewable resource is replenished as fast as it is used. A non-renewable resource takes far longer to form than humans take to use it.
Non-renewable
| Resource | How energy is released | Issues |
|---|---|---|
| Coal | Burning to heat water -> steam -> turbine | High CO_2, SO_2 -> acid rain |
| Oil | Burning, fuels transport, heating | High CO_2, oil spills |
| Natural gas | Burning, less CO_2 than coal | Methane leaks (potent greenhouse gas) |
| Nuclear | Fission of uranium-235 -> heat | Radioactive waste, expensive plants |
These provide reliable, high-output power but produce greenhouse gases or hazardous waste and will run out.
Renewable
| Resource | How it works | Strength | Weakness |
|---|---|---|---|
| Solar (PV) | Photons knock electrons free -> current | No emissions, modular | Intermittent (weather, night) |
| Wind | Blades drive a generator | Cheap once installed | Intermittent, visual/noise impact |
| Hydroelectric | Falling water drives a turbine | Reliable, high output | Floods land, ecosystem damage |
| Tidal | Tides flow through underwater turbines | Predictable | Few suitable sites |
| Wave | Wave motion drives a generator | Coastal regions | Storms damage equipment |
| Geothermal | Heat from hot rocks underground | Constant supply | Limited to volcanic regions |
| Biofuels | Burning crops / waste | Carbon-neutral if regrown | Land used for food crops |
Trends in the UK and globally
UK electricity in the 2020s: decreasing coal (now under 2%), rising wind (~25%), gas still dominant (~40%), nuclear ~15%, solar/biomass making up the rest. Globally, fossil fuels still supply ~80% of total energy demand, though renewable share is rising rapidly.
Why move to renewables?
- Reduce CO_2 emissions and slow climate change.
- Reduce dependence on imported fuels.
- Avoid running out of finite resources.
WJEC exam tip
When asked to compare two resources, structure your answer by criterion: cost, reliability, environmental impact, lifespan. Avoid one-sided answers — most renewables have downsides too.
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