National and Global Energy Resources

In this lesson you will learn about the main energy resources used to generate electricity and for heating and transport, how they are classified as renewable or non-renewable, and the factors that influence a country's energy mix. This is part of AQA GCSE Combined Science Trilogy (8464), Section 6.1.

---

Energy Resources Overview

An energy resource is a source of energy that can be used to do useful work — generating electricity, heating, or powering transport.

Energy resources are classified as either renewable or non-renewable.

Type	Definition	Examples
Non-renewable	Will run out; formed over millions of years; cannot be replaced on a human timescale	Fossil fuels (coal, oil, natural gas), nuclear fuel (uranium)
Renewable	Will not run out; replenished naturally on a short timescale	Wind, solar, hydroelectric, tidal, wave, geothermal, biofuel

---

Non-Renewable Energy Resources

Fossil Fuels

Fossil fuels (coal, oil, and natural gas) are burned to release chemical energy. In a fossil fuel power station:

1. Fuel is burned → water is heated → steam is produced.
2. Steam drives a turbine.
3. The turbine turns a generator.
4. The generator produces electricity.

flowchart LR
    A["Fuel burned"] --> B["Water boiled\nto steam"]
    B --> C["Steam drives\nturbine"]
    C --> D["Turbine turns\ngenerator"]
    D --> E["Electricity\nproduced"]

Advantage	Disadvantage
Reliable — can generate on demand	Release CO₂ → contributes to climate change
High energy density	Produce SO₂ and NOₓ → acid rain
Existing infrastructure in place	Finite supply — will eventually run out
Relatively cheap (currently)	Mining/drilling damages habitats

Nuclear Fuel

Nuclear power stations use uranium (or plutonium). Energy is released by nuclear fission — splitting atomic nuclei. The heat produced is used to generate steam, which drives turbines and generators (same as fossil fuel stations, but no combustion).

Advantage	Disadvantage
No CO₂ during generation	Produces radioactive waste — hazardous for thousands of years
Very high energy density	Very high construction and decommissioning costs
Reliable — generates continuously	Risk of nuclear accidents (though rare)

---

Renewable Energy Resources

Wind

Wind turns the blades of a wind turbine, which drives a generator.

Advantage	Disadvantage
No CO₂ during operation	Intermittent — depends on wind
Free fuel (wind)	Visual and noise pollution
Low running costs	Each turbine has relatively low output

Solar

Solar photovoltaic (PV) cells convert sunlight directly into electricity. Solar thermal panels use sunlight to heat water.

Advantage	Disadvantage
No CO₂ during operation	Intermittent — no power at night or on cloudy days
Low maintenance	Large area needed for significant output
Can be installed on rooftops	Manufacturing has environmental impact

Hydroelectric

Water stored behind a dam is released to drive turbines.

Advantage	Disadvantage
Reliable and can respond quickly to demand	Flooding of valleys destroys habitats and displaces communities
No CO₂ during operation	Limited suitable locations
Long lifespan	High initial construction cost

Tidal

Tidal barrages capture the energy of rising and falling tides to turn turbines.

Advantage	Disadvantage
Predictable — tides are regular	Very high construction cost
No CO₂ during operation	Affects local ecosystems and shipping
Reliable (not intermittent)	Few suitable locations

Wave

Wave generators bob up and down on the surface of the sea, driving turbines.

Advantage	Disadvantage
No CO₂ during operation	Intermittent — depends on weather
Free fuel	Low power output
	Difficult to maintain at sea

Geothermal

In volcanic regions, water is pumped down to hot rocks deep underground. The heated water or steam drives turbines.

Advantage	Disadvantage
No CO₂ during operation	Only available in areas with hot rocks near the surface
Reliable — not intermittent	High drilling costs
Very low running costs	Limited locations worldwide

Biofuel

Biofuels (e.g., bioethanol, biodiesel, wood pellets) are derived from living or recently living organisms. They are burned to release energy.

Advantage	Disadvantage
Considered carbon neutral (CO₂ absorbed during growth ≈ CO₂ released on burning)	Land used for biofuel crops could be used for food
Renewable — crops can be regrown	Still produces CO₂ when burned
Can be used in existing engines (with modification)	Deforestation can occur to clear land for crops

---

Uses of Energy Resources

Energy resources are not only used for electricity generation. They are also used for:

Use	Examples
Transport	Petrol (oil), diesel (oil), biofuels, electricity (from any source)
Heating	Natural gas (boilers), oil, geothermal, solar thermal, biomass

Exam Tip: AQA may ask you to identify uses of energy resources beyond electricity generation. Remember: fossil fuels are used for transport and heating as well as electricity.

---

The UK Energy Mix

The energy mix is the combination of energy resources a country uses. The UK's energy mix has changed over time:

• Coal use has declined sharply.
• Natural gas remains significant.
• Nuclear provides a steady proportion.
• Renewables (especially wind and solar) have increased rapidly.

Factors Influencing the Energy Mix

Factor	Explanation
Availability	Depends on geography — e.g., Iceland has geothermal, UK has wind
Cost	Capital cost, running cost, and fuel cost
Government policy	Carbon targets, subsidies for renewables, carbon taxes
Environmental impact	Pressure to reduce CO₂ and pollution
Reliability	Some renewables are intermittent; baseload power needs reliable sources
Public opinion	Opposition to wind farms, nuclear, or fracking

Exam Tip: AQA may give you data on a country's energy mix and ask you to describe trends or evaluate choices. Always consider reliability, cost, and environmental impact in your evaluation.

---

Common Mistakes