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8. Energy and Its Forms eLearn.Punjab

The shortage of fossil fuels will create serious energy problems. We must look for alternative sources
of energy that can be recovered. These sources are called renewable energy sources.
Renewable sources of energy include wood, water, wind, animal wastes, sunlight and tides of sea.

Hydro-electric Energy

The kinetic energy of flowing water is transformed into electrical energy. This energy is called as
hydro-electric energy. Dams are built to obtain this energy.
• The water required for producing hydro-electric energy is available free of cost.
• Hydal power stations do not add pollution to atmosphere.

Wind Energy

Wind has kinetic energy in it. A windmill is a machine which has blades. These blades move by the
energy of wind. In recent years, a windmill is being used to produce electricity.
A wind farm (consists of about 100 windmills) is used to generate electricity in larger amount.
• Wind energy is available without any cost.
• Wind energy does not cause any pollution.

Biogas

Biogas is a mixture of gases. These gases are formed by the decay of animal wastes and water. A
biogas plant is used to produce this gas. Biogas can be used as a fuel in homes. We can use the
remaining material as a fertilizer. The plant for biogas is also called gobar gas plant.
• Biogas is cheaper than any other fuel.
• It produces less pollution as compared to coal and petroleum.

Fig.8.13: A wind farm

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