Energy sources can be described as renewable and non-renewable.
Renewable energy sources are those which are continually being replaced such as energy from the sun (solar) and wind. Other examples are:
- Tidal and wave energy
- Hydroelectric energy (water running down hill)
- Biomass energy (using plant and animal waste as a fuel)
- Geothermal energy (using heat en energy from beneath the surface of the earth)
If an energy source is being used faster than it can be replaced (for example coal takes millions of years to form) then it will eventually run out. This is called a non-renewable energy source. Examples of non-renewable energy are:
- Nuclear energy