Where does energy come from?
There are different Useful supply or store of energy. in the world and the amount of The capacity for doing work. stored by them varies greatly. For example, the nuclear energy within 1 kg of uranium contains a very large amount of energy, but the The energy stored by an object lifted up against the force of gravity. Also known as GPE. stored by many thousands of tonnes of water held back by a dam contains less.
Renewable or non-renewable?
Renewable resources are replenished either by:
- human action, eg trees cut down for bio-fuel are replaced by planting new trees
- natural processes, eg water let through a dam for Electricity that is generated by the movement of water. is replaced through the The continuous movement of water on, above and below the Earth.
A non-renewable energy resource is one with a Something that has a limited number of uses before it is depleted. For example, oil is a finite resource. amount. It will eventually run out when all reserves have been used up.
Different energy resources
The table below shows the main features of the most common energy resources used around the world today.
| Energy resource | Energy store | Renewable? | Uses | Environmental impact |
| Fossil fuels (oil, coal and natural gases) | Chemical | Non-renewable | Transport, heating, electricity generation | Releases CO2 (causes global warming) |
| Nuclear fuels | Nuclear | Non-renewable | Electricity generation | Radioactive waste (needs to be disposed of safely) |
| Bio-fuel | Chemical | Renewable | Transport, heating, electricity generation | 'Carbon neutral', so low impact |
| Wind (offshore and onshore) | Kinetic | Renewable | Electricity generation | Takes up large areas that could be used for farming, some people say windmills spoil the view |
| Hydroelectricity | Gravitational potential | Renewable | Electricity generation | Habitats are flooded when dams are built |
| Geothermal | Internal (thermal) | Renewable | Electricity generation, heating | Very low impact |
| Tides | Kinetic | Renewable | Electricity generation | Habitats are flooded when tidal barrages are built |
| Sun | Nuclear | Renewable | Electricity generation, heating | Solar photovoltaic panels sometimes take up land that could be used for farming |
| Water waves | Kinetic | Renewable | Electricity generation | Very low |
| Energy resource | Fossil fuels (oil, coal and natural gases) |
|---|---|
| Energy store | Chemical |
| Renewable? | Non-renewable |
| Uses | Transport, heating, electricity generation |
| Environmental impact | Releases CO2 (causes global warming) |
| Energy resource | Nuclear fuels |
|---|---|
| Energy store | Nuclear |
| Renewable? | Non-renewable |
| Uses | Electricity generation |
| Environmental impact | Radioactive waste (needs to be disposed of safely) |
| Energy resource | Bio-fuel |
|---|---|
| Energy store | Chemical |
| Renewable? | Renewable |
| Uses | Transport, heating, electricity generation |
| Environmental impact | 'Carbon neutral', so low impact |
| Energy resource | Wind (offshore and onshore) |
|---|---|
| Energy store | Kinetic |
| Renewable? | Renewable |
| Uses | Electricity generation |
| Environmental impact | Takes up large areas that could be used for farming, some people say windmills spoil the view |
| Energy resource | Hydroelectricity |
|---|---|
| Energy store | Gravitational potential |
| Renewable? | Renewable |
| Uses | Electricity generation |
| Environmental impact | Habitats are flooded when dams are built |
| Energy resource | Geothermal |
|---|---|
| Energy store | Internal (thermal) |
| Renewable? | Renewable |
| Uses | Electricity generation, heating |
| Environmental impact | Very low impact |
| Energy resource | Tides |
|---|---|
| Energy store | Kinetic |
| Renewable? | Renewable |
| Uses | Electricity generation |
| Environmental impact | Habitats are flooded when tidal barrages are built |
| Energy resource | Sun |
|---|---|
| Energy store | Nuclear |
| Renewable? | Renewable |
| Uses | Electricity generation, heating |
| Environmental impact | Solar photovoltaic panels sometimes take up land that could be used for farming |
| Energy resource | Water waves |
|---|---|
| Energy store | Kinetic |
| Renewable? | Renewable |
| Uses | Electricity generation |
| Environmental impact | Very low |
Comparing resources
Power stations that use Natural, finite fuel formed from the remains of living organisms, eg oil, coal and natural gas. or nuclear fuel are generally considered to be very reliable sources of energy, although there could be shortages in the supply of these types of fuel caused by social or political factors. These two types of energy resource provided approximately half of the country’s electricity in 2023. They operate almost continuously. When additional power is needed, gas power stations are often used because they are able to start generating electricity very quickly.
The fuel for nuclear power stations is relatively cheap, but the power stations themselves are expensive to build. It is also very expensive to dismantle, or decommission, old nuclear power stations at the end of their useful life and the highly radioactive waste needs to be stored for thousands of years before the natural activity will reduce to a safe level.
Renewable energy resources are providing an ever-increasing proportion of the UK’s electricity: 46% in 2023, which is more than the energy obtained from fossil fuels (37%). Some renewables are very reliable, eg tidal energy is predictable because of the Moon causing the tides. However, other renewable energy resources are not as predictable on a short-term timescale. For example, on a cloudy day the output from a solar PV farm will be reduced, and if the wind speed is too low, output from a wind farm will be reduced.
Renewable resources have no fuel costs, but the equipment used can be expensive to build.
