Global energy resources
Renewable vs non-renewable
A renewable resource is replenished as quickly as it is used and will not run out. A non-renewable resource is finite and will eventually be exhausted.
| Renewable | Non-renewable |
|---|---|
| Wind, solar, hydroelectric, tidal, wave, biomass, geothermal | Coal, oil, natural gas, nuclear (uranium) |
Note: nuclear fission fuel is finite, but it has a low CO₂ output during operation.
Pros, cons and environmental impact
| Resource | Pros | Cons / Environmental impact |
|---|---|---|
| Coal | High output, reliable, cheap | High CO₂ + SO₂; mining destroys habitat |
| Natural gas | Reliable, less CO₂ than coal, fast on/off | Still releases CO₂; methane leaks |
| Oil | Reliable, energy-dense | CO₂; oil spills; finite |
| Nuclear | Low CO₂; high reliable output | Long-lived radioactive waste; high build cost; accident risk |
| Wind | No CO₂, free fuel | Intermittent; visual / habitat impact on birds |
| Solar (PV) | No CO₂, decentralised | Intermittent; low UK winter output; rare-metal mining |
| Hydroelectric | Reliable, fast response, no CO₂ | Reservoirs flood habitat; expensive |
| Tidal | Predictable, reliable | High build cost; estuary habitat impact |
| Biomass | Renewable if replanted; carbon-cycle balanced | Releases CO₂ when burned; land vs food |
| Geothermal | No CO₂, reliable | Site-limited (volcanic regions) |
Trends
Globally, electricity demand is rising as populations grow and economies industrialise. Most countries are gradually replacing fossil fuels with renewables to reduce CO₂ emissions and meet climate targets (UK target: net zero by 2050).
Reliability
A reliable source generates on demand all year round. Wind and solar are not reliable in isolation — they need either storage (batteries, pumped hydro) or back-up from gas / nuclear.
Cost considerations
- Capital (build) cost.
- Running cost (fuel, maintenance).
- Decommissioning (especially nuclear).
- Externalities (climate, health) — increasingly priced via carbon taxes.
OCR exam tip
When asked to evaluate a country's energy mix, give: one renewable advantage, one non-renewable advantage, one environmental disadvantage, and a comparative conclusion — that 4-step structure routinely scores 4/4.
AI-generated · claude-opus-4-7 · v3-ocr-combined-science-leaves