Renewable and non-renewable energy sources.

Wind energy:

        Moving air turns the blades of large windmills or generators to make electricity, or to pump water out of the ground. A high wind speed is needed to power wind generators effectively.

Wind pumps and generators have been used in remote areas of Australia and in other countries around the world for many years. More recently, wind turbo-generators on wind farms have been providing electricity for cities and towns in more than a dozen countries.

Hydroelectric energy:

        Hydroelectricity is produced from falling water. The movement of the water spins turbines that generate electricity. Places with high rainfall and steep mountains are ideal for hydroelectricity. Canada, Brazil and New Zealand produce most of their electricity this way.

Non-renewable energy sources:

Coal:

        Coal is a fossil fuel formed over millions of years from decomposing plants and animals. Coal is mainly burned in power stations to make electricity and as a source of heat for industry. When coal is burned it produces large amounts of carbon dioxide, one of the gases responsible for the enhanced greenhouse effect (the increase in the world's temperature due to the increased insulating effect of the earth's atmosphere).

Petroleum:

        Petroleum, or crude oil, is formed in a similar way to coal. But instead of becoming a rock, it became a liquid trapped between layers of rocks. It can be made into gas, petrol, kerosene, diesel fuel, oils and bitumen.

Gas:

        Gas is made in the same way as petroleum and is also trapped between layers of rock. Natural gas is tapped, compressed and piped into homes to be used in stoves and hot water systems. LPG (Liquefied Petroleum Gas) is made from crude oil.