Where does our energy come from, and how can we use it wisely?
Compare renewable and non-renewable energy resources, and describe simple ways to save energy at home
A simple answer to the N(T) Science point on energy resources. The difference between renewable and non-renewable sources, their pros and cons, and practical ways to save energy at home.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this dot point is asking
This dot point wants you to compare renewable and non-renewable energy resources, give the advantages and disadvantages of each, and describe simple, practical ways to save energy at home. The big idea is that the energy we use to make electricity comes from different sources: some will run out one day and often pollute, while others are renewed naturally and are cleaner. Using energy wisely saves money and protects the environment.
The answer
Where our energy comes from
Most of the electricity we use is made at power stations. To make it, we use an energy resource, and these resources fall into two groups: non-renewable and renewable.
Non-renewable energy resources
A non-renewable energy resource is one that will run out one day, because we use it far faster than it can be replaced. Once it is gone, it is gone.
The main non-renewable resources are the fossil fuels: coal, oil and natural gas. They are burned to release heat, which is used to make electricity. They are non-renewable because they took millions of years to form and we are using them quickly.
Fossil fuels give a lot of energy and are reliable, working day and night. But burning them releases polluting gases such as carbon dioxide, which causes global warming, and they will eventually run out.
Renewable energy resources
A renewable energy resource is one that does not run out, because it is replaced naturally as fast as we use it. These resources are usually much cleaner.
The main renewable resources are:
- Solar: energy from sunlight, captured by solar panels.
- Wind: energy from moving air, captured by wind turbines.
- Hydroelectric (water): energy from falling or flowing water turning turbines.
Renewable resources do not run out and usually cause little or no pollution while making electricity. Their main drawback is that some depend on the weather: solar needs sunshine, and wind needs the wind to blow, so they do not always make electricity when it is needed.
Comparing the two
The simple comparison: non-renewable fuels are reliable and energy-rich but will run out and pollute; renewable sources are clean and never run out but can be less reliable and depend on the weather or location. Many countries use a mix of both.
Saving energy at home
Whatever the source, using less energy saves money and reduces pollution. Simple ways to save energy at home include:
- Switching off lights and appliances when they are not being used.
- Not leaving devices on standby, which still uses energy.
- Using energy-saving LED bulbs instead of old-style bulbs.
- Only boiling as much water as you need in a kettle.
- Using a fan instead of air conditioning when possible, and closing doors to keep cool air in.
Each of these means less electricity is used, so less fuel is burned and fewer polluting gases are released.
Examples in context
Example 1. Solar panels on a roof. Many homes now have solar panels on the roof that turn sunlight into electricity during the day. This renewable energy lowers the family's electricity bill and means the power station has to burn less fuel for them. On a cloudy day or at night, the home still draws electricity from the grid, showing solar's main weakness.
Example 2. Standby lights at night. Walk through a dark home at night and you will see tiny lights glowing on the television, the router and chargers left plugged in. These devices on standby keep using electricity for no benefit. Switching them off at the wall is a simple way to save energy and cut the bill.
Try this
Cue. State whether natural gas is a renewable or non-renewable resource, and give a reason. Natural gas is non-renewable, because it is a fossil fuel that will run out and cannot be replaced as fast as we use it.
Cue. Give one advantage and one disadvantage of wind power. Advantage: it is renewable and clean, releasing no polluting gases. Disadvantage: it only works when the wind is blowing, so it is not always reliable.
Cue. Explain how switching to LED bulbs helps the environment. LED bulbs use less electricity for the same light, so less fuel is burned at the power station and fewer polluting gases are released.
Exam-style practice questions
Practice questions written in the style of SEAB exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Original4 marksA country uses coal and solar panels to make electricity. (a) State which one is renewable. (b) State which one is non-renewable. (c) Give one advantage of using solar panels. (d) Give one disadvantage of using solar panels.Show worked answer →
(a) Solar (from sunlight) is renewable.
(b) Coal is non-renewable.
(c) An advantage of solar panels: they do not run out (sunlight is always renewed) and they do not give off polluting gases while making electricity.
(d) A disadvantage of solar panels: they only make electricity when the Sun is shining, so they make little or none at night or on a cloudy day.
What markers reward: correctly sorting solar as renewable and coal as non-renewable, one clear advantage (no pollution or never runs out), and one clear disadvantage (depends on sunshine).
Original3 marksA family wants to lower their electricity bill and help the environment. (a) Give two simple ways they could save energy at home. (b) Explain how saving energy helps the environment when their electricity comes from burning coal.Show worked answer →
(a) Any two sensible ways, for example: switch off lights and appliances when not in use, use energy-saving LED bulbs, do not leave devices on standby, use fans instead of air conditioning, or only boil the water you need in a kettle.
(b) Saving energy means less electricity is needed, so less coal is burned at the power station. Burning less coal releases fewer polluting gases, such as carbon dioxide, into the air, which helps reduce pollution and global warming.
What markers reward: two genuine energy-saving actions, and a clear link from using less electricity to burning less coal to releasing fewer polluting gases.
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