Energy Resources

This lesson introduces the main energy resources used by humans for generating electricity and for transport and heating. Understanding these resources and their impacts is a key part of the AQA GCSE Physics specification (Section 4.1).

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What Are Energy Resources?

An energy resource is a source of energy that can be used to generate electricity, power transport, or provide heating. Energy resources are broadly classified as either renewable or non-renewable.

Type	Definition	Examples
Non-renewable	Resources that are used up faster than they can be replaced. They will eventually run out.	Fossil fuels (coal, oil, natural gas), nuclear fuel
Renewable	Resources that are replenished naturally and will not run out.	Wind, solar, hydroelectric, tidal, wave, geothermal, biofuel

Exam Tip: Nuclear fuel (uranium) is classified as non-renewable because the supply of uranium is finite and it is not replenished on a human timescale. Do not confuse nuclear with renewable — this is a common exam error.

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Non-Renewable Energy Resources

Fossil Fuels

Fossil fuels — coal, oil, and natural gas — were formed over millions of years from the remains of dead organisms buried under layers of sediment and subjected to heat and pressure.

Fossil Fuel	How It Is Used	How Electricity Is Generated
Coal	Burned in power stations	Heat from burning coal boils water to produce steam, which turns a turbine connected to a generator
Oil	Burned in power stations; used in transport	Same steam-turbine-generator system; also used directly in car and aircraft engines
Natural gas	Burned in power stations and homes	Same steam-turbine-generator system; also used for home heating and cooking

graph LR
    A["Fossil fuel burned"] -->|"Heats water"| B["Steam produced"]
    B -->|"Drives"| C["Turbine spins"]
    C -->|"Turns"| D["Generator"]
    D -->|"Produces"| E["Electricity"]

Advantages and Disadvantages of Fossil Fuels

Advantages	Disadvantages
Reliable — can generate electricity at any time to meet demand	Produce CO2 when burned, contributing to climate change
Relatively cheap (currently)	Produce SO2 and NOx, causing acid rain
Large existing infrastructure	Non-renewable — supplies will eventually run out
High energy density — produce a lot of energy per kilogram	Environmental damage from extraction (mining, drilling, oil spills)
Can adjust output to meet demand	Particulates released cause air pollution and respiratory problems

Exam Tip: When writing about the environmental impact of fossil fuels, be specific. Do not just say "pollution." State the type of pollution: CO2 contributes to the greenhouse effect and climate change; SO2 causes acid rain; particulates cause respiratory problems. Specific answers gain more marks.

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Nuclear Energy

Nuclear fuel (mainly uranium, sometimes plutonium) undergoes nuclear fission in a reactor. The energy released heats water to produce steam, which drives turbines and generators.

Advantages	Disadvantages
No CO2 produced during operation (no contribution to climate change during generation)	Produces radioactive waste that remains hazardous for thousands of years
Very high energy density — a small amount of fuel produces a huge amount of energy	Risk of nuclear accidents (e.g., Chernobyl, Fukushima)
Reliable — can generate electricity continuously	Very expensive to build, maintain, and decommission
Does not produce SO2 or particulates	Non-renewable — uranium supplies are limited

graph LR
    A["Nuclear fuel (uranium)"] -->|"Nuclear fission"| B["Heat energy released"]
    B -->|"Heats water"| C["Steam"]
    C -->|"Drives"| D["Turbine"]
    D -->|"Turns"| E["Generator"]
    E -->|"Produces"| F["Electricity"]

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The Role of Steam, Turbines, and Generators

Most large-scale electricity generation (except solar and direct wind/tidal) uses the same basic process:

1. A fuel is used to heat water.
2. The water turns to steam.
3. The steam drives a turbine (a wheel with blades that spins).
4. The turbine is connected to a generator (a coil of wire rotating in a magnetic field).
5. The generator produces electricity.

Component	Function
Boiler	Heats water to produce steam
Turbine	Converts kinetic energy of steam into rotational kinetic energy
Generator	Converts rotational kinetic energy into electrical energy
Transformer	Steps up voltage for transmission through the National Grid

Exam Tip: You should know that most power stations — whether fossil fuel or nuclear — use the same steam-turbine-generator process. The only difference is the source of heat. Solar (photovoltaic) panels are different — they convert light energy directly into electrical energy without steam or turbines.

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Uses of Energy Resources Beyond Electricity

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

Use	Examples of Resources
Transport	Oil (petrol, diesel, aviation fuel), biofuels, electricity (from any source) for electric vehicles
Heating	Natural gas (home boilers), oil, biomass (wood burners), geothermal, solar thermal panels

Why Are Fossil Fuels Still Dominant?

Despite the growth of renewables, fossil fuels still provide the majority of the world's energy. This is because:

• Existing infrastructure (power stations, pipelines, petrol stations) is designed for fossil fuels.
• Fossil fuels are energy-dense and can provide power on demand.
• Transitioning to renewables requires significant investment and time.
• Some renewable resources are intermittent (not always available).

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Energy Resource Summary Table