2. Energy and the Sun
The Sun is the original source of most energy resources.
Plants store the Sun’s energy through photosynthesis.
leaf
caterpillar
bird
fox
Plants are eaten by animals, which are then eaten by other animals, so the energy is passed on.

3. Energy resources from the Sun
The energy in all these energy resources originated from the Sun.
coal
oil
wind
biomass
natural gas
food

4. Non-renewable energy resources
Oil, coal and natural gas are examples of fossil fuels. They were formed from biological deposits over the course of millions of years.
oil
coal
gas
Photo credit: © 2008 Jupiterimages Corporation
The amount of fossil fuel on Earth is limited. Once fossil fuels are used they cannot be replaced and will eventually run out, so they are called non-renewable.

5. Coal formation

6. Early stages of oil and gas formation
Oil and gas are also biological in origin. Millions of years ago, tiny animals lived in the sea. Like today, their ecosystem was dependent on heat and light from the Sun and photosynthesis by plants.
When they died, the animals fell into mud and sand at the bottom of the sea, but did not rot away.
Over millions of years they were buried deeper by the mud and sand.

7. Later stages of oil and gas formation
The temperature and pressure (caused by the weight of the sediments and deep burial) changed the mud and sand into rock, and the dead animals into crude oil and natural gas.
The oil and gas is extracted from the seabed or under the ground, by drilling oil wells.
Photo credit: © 2008 Jupiterimages Corporation
Oil wells drilled at sea are supported by oil platforms.

8. Fossil fuels summary

9. Generating electricity from fossil fuels

10. Labelling parts of a power station

11. How is electricity generated?

12. Environmental effects of burning fossil fuels
Using fossil fuels to produce electricity has consequences for the environment.
Burning some fossil fuels creates chemicals like sulfur dioxide, which cause acid rain.
Burning fossil fuels also produces carbon dioxide which is released into the atmosphere.
Photo credit: © 2008 Jupiterimages Corporation
Carbon dioxide is a greenhouse gas.

13. Environmental effects of burning fossil fuels