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AQA GCSE Physics · Topic 4.1 Energy · National and global energy resources
Physics onlyEdexcel International GCSE Physics · Section 4 Energy resources and energy transfer
Energy Resources and Generating Electricity
In this lesson you'll learn to: say what makes a resource renewable or
non-renewable, name the main ones, describe the energy transfers when each is used to
generate electricity, and evaluate one properly — advantages, disadvantages, and a
decision at the end.
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Prefer to watch? Scroll to the bottom for the video on this topic
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A video walkthrough is coming soon — it will appear at the bottom of this page
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Start here — have a play
Don't read anything yet. Click two resources — try coal and wind — and watch the table fill itself in. Switch to tick boxes to see the same six questions your workbook asks. Then try sorting all eleven into renewable and non-renewable; the one almost everybody gets wrong is in there.
Click a resource to add it to the table — click again to take it out
How the 6-mark question works. "Evaluate the use of wind turbines" never wants a list — it wants both sides and a decision. Add two resources to the table and you can see the comparison the examiner is asking you to make.
Renewable
A resource that is being replaced as it is used, so it will never run out.
wind · solar · hydroelectric · tidal · waves · geothermal · bio-fuel
Non-renewable
A resource that is used up faster than it is replaced, so one day it
will run out.
coal · oil · natural gas · nuclear fuel (uranium)
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Renewable, or non-renewable?
The catch most people fall for. Nuclear is not renewable. It gives off no CO2, which makes it sound green — but uranium is dug out of the ground and cannot be replaced, so it will run out. "Renewable" and "clean" are two different questions.
Pick a resource to follow the energy from the source to the socket
Physics With Kate · physicswithkate.com
▲ Every fact in all three tabs comes from one list, so the pros, the tick boxes and the transfer chains always agree.
Noticed there's no winner?
That is the whole point of this topic. Every resource is good at something and bad at something else, and the exam question is always asking you to weigh them up. The notes below give you the two definitions, the list you must know, and the sentence pattern that turns a list into a full-mark evaluation.
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Revision notes
What an energy resource is
An energy resource is something we take energy from to do a job — mostly to generate electricity, but also to heat buildings and to move vehicles.
Every resource is sorted into one of two groups, and the difference is simply whether it runs out.
⭐ The two definitions — learn these word for word
Renewable: a resource that is being replaced as it is used, so it will never run out.
Non-renewable: a resource that is used up faster than it is replaced, so one day it will run out.
Notice what the definitions do not mention: pollution, cost, or how clean something is. "Renewable" is only about running out. That is why the next bit catches so many people.
⚠ The trap — nuclear is NOT renewable
Nuclear power releases no carbon dioxide while it generates, so it sounds like it belongs with the renewables. It does not. The fuel is uranium, which is mined out of the ground and is not replaced — so it will run out, and it is non-renewable.
"Clean" and "renewable" are two different questions. Answer the one you were asked.
The resources you need to know
| Non-renewable | Where the energy comes from |
|---|---|
| Coal | chemical store of the fuel, released by burning |
| Oil | chemical store of the fuel, released by burning |
| Natural gas | chemical store of the fuel, released by burning |
| Nuclear fuel (uranium) | nuclear store of the fuel, released by fission |
The first three are the fossil fuels. They formed from the remains of living things over millions of years, and they are the ones that release carbon dioxide.
| Renewable | Where the energy comes from |
|---|---|
| Wind | kinetic store of the moving air |
| Solar | radiation from the Sun |
| Hydroelectric | gravitational potential store of water behind a dam |
| Tidal | gravitational potential store of water trapped by a barrage |
| Water waves | kinetic store of the waves |
| Geothermal | thermal store of hot rocks underground |
| Bio-fuel | chemical store of crops or animal waste, released by burning |
⭐ Worth knowing — the Sun is behind nearly all of them
Sunlight drives the weather, so it makes the wind, which makes the waves. It evaporates the water that later falls as the rain filling a hydroelectric reservoir. It grew the plants that became bio-fuel — and, millions of years ago, the ones that became fossil fuels. Only tidal (the Moon) and geothermal and nuclear (inside the Earth and the atom) come from somewhere else.
How a power station actually makes electricity
Almost every resource on that list ends up doing the same three things, and only the first step is different:
- something turns a turbine — steam from boiling water, or moving air or water pushing directly on the blades;
- the turbine turns a generator;
- the generator does electrical work on the grid.
So coal, oil, gas, nuclear, bio-fuel and geothermal all boil water to make steam, and the steam turns the turbine. Wind, hydroelectric, tidal and waves skip the boiling — the moving air or water pushes the blades itself.
⭐ Solar is the exception
A solar cell has no turbine and no generator and no moving parts at all. Energy arrives from the Sun by radiation and the cell transfers it electrically. If a question asks how energy reaches a solar cell, the answer is by radiation — not by heating.
Naming the transfer — the four pathways
When a question asks how energy is transferred from one place to another, it wants one of four words. Only four. Learn which is which and these become free marks.
| Pathway | When you use it | In a power station |
|---|---|---|
| Mechanically | a force moves something — work is done on it | steam, wind or water pushing the turbine round |
| Electrically | a charge moves round a circuit | the generator sending electricity to the grid |
| By heating | energy moves because one thing is hotter than another | the hot gases from the burning fuel heating the water in the boiler |
| By radiation | energy travels as a wave — light, infrared — and needs no material to travel through | sunlight arriving at a solar cell |
The two on the bottom row are the ones people swap. A quick test: if there is nothing in between, it must be radiation. There is a vacuum between the Sun and us, so sunlight cannot be travelling by heating — it is radiation. Inside the boiler the hot gas is touching the pipes, so that one is by heating.
⭐ How to write a transfer answer
Name the store, say whether it increases or decreases, and name the pathway. For example: "the gravitational potential store of the water decreases, and mechanical work is done on the turbine."
Three of those steps is normally a full 3-mark answer. Vague phrases like "the energy goes to the turbine" score nothing — the marks are in the store names and the pathway names.
Judging a resource — the six questions
Whichever resource you are given, ask the same six things. These are the tick boxes in your workbook, and between them they cover every mark an evaluate question can offer.
| Question | What you are really asking |
|---|---|
| Is it reliable? | Can we get electricity from it whenever we need it? Fuels can be burned on demand. Wind, solar and waves cannot — no wind, no electricity. |
| Does it have a high energy density? | Does a small amount of fuel give a lot of energy? Only the fuels score here, and nuclear scores highest by a long way. |
| Does it emit CO2? | Carbon dioxide is a greenhouse gas, so it adds to global warming and climate change. Say that — "it is bad for the environment" earns nothing. |
| Is it expensive to install? | Dams, barrages, nuclear stations and wind farms all cost a great deal to build. |
| Is it expensive to run? | Fuels must be bought. Wind, sunlight, water and tides are free. |
| Does it make radioactive waste? | Only nuclear. The waste stays dangerous for thousands of years and must be stored safely. |
Two of those need the reason spelling out, because that is where the mark actually is:
- Why is CO2 bad? It is a greenhouse gas → it traps energy in the atmosphere → global warming and climate change.
- Why is radioactive waste bad? It stays dangerous for thousands of years, so it has to be sealed and stored safely for a very long time.
Reliability — the one that decides everything
Electricity has to be there the moment somebody switches a kettle on. That is why the country cannot run on wind and solar alone — not because they are bad, but because they are unreliable: they only generate when the weather allows.
Three renewables are reliable, and that is worth remembering because it makes a strong exam point: hydroelectric (water is stored behind the dam and released whenever it is wanted), tidal (the tides are predictable, twice a day, whatever the weather) and geothermal (the hot rocks are hot day and night).
AQA onlyTrends in energy use. The UK has been moving away from coal and towards renewables, because we now understand the damage CO2 does and because renewables have become much cheaper. The change is slow: power stations are expensive to replace, some renewables are unreliable, and people object to new dams and wind farms near them.
AQA onlyWhy we still burn fossil fuels. Science can tell us what a resource does — but whether we use it is also a political, social, ethical and economic decision: jobs, cost, who has to live next to it, and which country controls the fuel.
Answering the "evaluate" question
An evaluate question is worth 4–6 marks and it is not asking for a list. It wants both sides and a decision. Use this shape every time:
- give two advantages, each with the reason;
- give two disadvantages, each with the reason;
- finish with a conclusion that says which matters most, and why.
That last line is the one people leave out, and it is often worth two marks on its own. It does not matter which side you come down on — it matters that you say so and justify it.
Worked examples
Evaluate the use of wind turbines to generate electricity. [4 marks]
Wind turbines release no carbon dioxide while generating, so they do not add to global warming, and the wind is free, so they are cheap to run. However, they are unreliable — when the wind does not blow, no electricity is generated — and they are expensive to install, with many turbines needed because each one produces relatively little. Overall, wind is worth using as part of a mix, but it cannot supply the country on its own because the supply cannot be relied on when demand is high.
Describe the energy transfers when electricity is generated in a hydroelectric power station. [3 marks]
The gravitational potential store of the water decreases as it falls. Mechanical work is done on the turbine, so the kinetic store of the turbine increases. The turbine turns the generator, and electrical work is done on the grid.
Describe the energy transfers when electricity is generated by a wind turbine. [3 marks]
The kinetic store of the moving air decreases. Mechanical work is done on the turbine blades, so the kinetic store of the turbine increases. The turbine turns the generator, and electrical work is done on the grid.
How is energy transferred from the Sun to a solar cell? [1 mark]
By radiation. Not by heating — there is nothing between the Sun and the cell to conduct through, and no turbine or generator involved at all.
In a fossil-fuel power station, burning fuel heats the water in a boiler to make steam. How is energy transferred from the hot gases to the water? [1 mark]
By heating. The hot gases are touching the boiler, and energy moves from the hotter thing to the cooler one. Compare it with the question above: same topic, different pathway, because here there is something in between.
A student says nuclear power is renewable because it produces no CO₂. Explain why the student is wrong. [2 marks]
Renewable means the resource is replaced as it is used and will not run out. Nuclear fuel is uranium, which is mined and is not replaced, so it will run out and is non-renewable. Producing no CO2 is an environmental advantage, which is a different question.
📘 Now do it in your workbook
Fill in the structure diagram, then tick off the six criteria for each resource and write the reasons in your own words — that is the bit that earns the marks.
AQA GCSE Physics Workbook · ENERGY · pages 15–17 Edexcel iGCSE Physics Workbook · ENERGY · pages 15–17
⬇ Free: pages 15–17 (PDF)
⬇ Free: pages 15–17 (PDF)
Get the full workbook on Amazon
Get the full workbook on Amazon
Free sample = the pages for this lesson. The full workbook covers the whole Energy topic for your board, with exam-style questions and worked answers.
✅ Can you do it? Tick as you go
0% complete🎉 Nice work! You've ticked off every objective for this spec point.
Don't forget to hit “Mark complete” at the bottom of the lesson.
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Prefer to watch? Here's the whole thing
Video walkthrough — coming soon
Everything above, explained out loud — useful for a last-minute recap, or if you'd rather hear it than read it.
Everything above, explained out loud — useful for a last-minute recap, or if you'd rather hear it than read it. The video is on its way.
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Video coming soon
The walkthrough for this lesson is being filmed and will appear right here. Until then, the notes and the free workbook pages above cover every mark.
▲ In GHL you can also use the lesson's built-in video field instead of this embed.
Now put it into practice
Watching is the easy bit. The workbook gives you the structure diagram to fill in and the tick boxes for each resource — and it is writing the reasons yourself that turns a list into a full-mark evaluation.
Watching is the easy bit. The workbook gives you the structure diagram to fill in, the tick boxes for each resource, and the energy-transfer questions on generating electricity — with worked answers at the back.
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