Energy Resources: An Overview Revision Notes | GCSE AQA Higher Physics

1. Why Energy Resources Matter

Every time you switch on a light, charge your phone, or travel in a car, you're using energy that came from somewhere. But where exactly? The UK gets its energy from a mix of sources - some will last forever, others are running out fast.

This isn't just about science - it's about your future. Energy choices affect electricity bills, climate change, and even international politics. Countries go to war over oil, but no one fights over wind or sunlight.

Understanding energy resources helps you make sense of news headlines about fracking, nuclear power stations, and wind farms. More importantly, it explains why governments are desperately trying to move away from fossil fuels.

2. The Energy Resource Toolkit

Earth provides us with a range of energy resources. AQA lists fossil fuels, nuclear fuel, bio-fuel, wind, hydroelectricity, geothermal, tides, the Sun and water waves. If you split fossil fuels into coal, oil and gas, that gives ten named sources. Each source has different strengths and weaknesses, so the best choice depends on the job being done.

Coal burns hot and was Britain's main energy source for centuries. Oil is liquid gold - perfect for transport because it's energy-dense and portable. Natural gas burns cleanly and heats most UK homes.

The renewable sources work differently - they harvest energy that is constantly being replenished. The Sun provides solar energy, wind harnesses moving air, and hydroelectricity uses falling or flowing water. Geothermal taps Earth's internal heat, while tidal and wave power use ocean movements. Naming the Sun explicitly matters because it appears directly in the AQA specification list.

Here's where students often get confused - let's clear this up now:

3. The Three Energy Jobs

Every energy resource on Earth does one or more of three jobs: generating electricity, powering transport, or providing heating. But not all energy sources are good at all three jobs.

Electricity Generation: This is where we have the most choice. Coal, gas, nuclear, wind, solar, hydroelectric, geothermal, tidal and wave power can all generate electricity. The power station converts the energy source into electrical energy that travels through the National Grid to your home.

Transport: This is trickier. Most transport runs on oil-based fuels (petrol, diesel, jet fuel) because they're energy-dense and easy to store in tanks. Bio-fuels can substitute for these. Electric vehicles use electricity (which could come from any source), but batteries are heavy and take time to charge.

Heating: Natural gas heats most UK homes through boilers and radiators. Coal used to be common for heating. Wood (bio-fuel) still heats some homes. Electricity can provide heating, but it's expensive. Geothermal directly heats buildings in some countries.

Notice the pattern: oil dominates transport, gas dominates heating, but electricity generation uses everything. That's because electricity is versatile - it can be made from any energy source and used for almost anything.

4. The Renewable vs Non-Renewable Divide

The most important classification in energy is renewable versus non-renewable. This determines whether we can keep using an energy source forever or whether it will eventually run out.

Non-renewable sources took millions of years to form and cannot be replaced on human timescales. Fossil fuels formed from ancient plants and animals. Uranium formed in dying stars billions of years ago. Once we've used them up, they're gone.

Renewable sources are constantly replenished by natural processes. The Sun shines every day, wind keeps blowing, rivers keep flowing, and plants keep growing. We can harvest their energy without depleting the source.

But here's what catches students out: renewable doesn't automatically mean unlimited. A hydroelectric dam can only generate as much electricity as water flows through it. Solar panels don't work at night. Wind turbines stop when the wind stops blowing.

The advantage of renewables isn't that they're always available - it's that they'll still be available in 100 years' time. Fossil fuels won't.

5. Comparing Energy Resources in Action

Let's see how different energy sources stack up for the three main uses. This is where the real-world trade-offs become clear.

Worked example: Comparing Energy Sources for Electricity Generation

A country needs to choose between coal, nuclear, and wind power for a new power station. Compare their suitability.

1. Coal: Burns 24/7 when fuel supplied Nuclear: Runs continuously for months Wind: Only when wind blows (intermittent) — Reliability means consistent power output
2. Coal: Must buy coal continuously Nuclear: Uranium lasts years in reactor Wind: No fuel needed (wind is free) — Running costs vary dramatically
3. Coal: High CO₂ emissions, air pollution Nuclear: No CO₂, but radioactive waste Wind: No emissions, but visual/noise impact — Each has different environmental trade-offs
4. Coal: Moderate setup cost Nuclear: Very high setup cost Wind: High setup cost per turbine — Initial investment varies significantly

Answer: No single 'best' choice - depends on country's priorities (cost, environment, reliability). Most countries use a mix of sources.

For transport, the comparison is simpler but changing fast. Oil-based fuels (petrol, diesel) currently dominate because they're energy-dense, quick to refuel, and work in existing engines. But electric vehicles powered by renewable electricity are growing rapidly.

For heating, natural gas wins in most developed countries because it's efficient, relatively clean, and the infrastructure already exists. But heat pumps (running on electricity) are becoming popular as electricity gets cleaner.

6. Exam Success: Energy Resources Questions

Energy resources questions appear in every GCSE science exam. Here's how to tackle them like a pro and avoid the common traps.

Command word mastery: 'Describe' means state what happens without explaining why. 'Explain' means give reasons using scientific principles. 'Compare' means give similarities AND differences.

Common exam traps: Students often say nuclear power is renewable (it's not - uranium runs out). They confuse tidal power (renewable) with wave power (also renewable) - both are correct but different. They forget that bio-fuel is renewable because new plants can be grown.