Any system which is capable of providing useful energy in a convenient form at a steady rate over a long period of time.
Classification of Sources of Energy
Renewable Sources of Energy
These are the sources of energy which are being produced continuously in nature. These are inexhaustible e.g., solar energy, wind energy, hydro energy, biofuels (wood, biogas) hydrogen energy from the ocean (tidal energy, sea waves energy, ocean thermal energy).
Advantage of renewable sources of energy are
- These sources will last as long as the earth receives light from the sun.
- These sources are freely available in nature.
- These sources do not cause any pollution.
Non Renewable Sources of Energy
These are the sources of energy which have accumulated in nature over a long time and cannot be quickly replaced. These sources of energy will be exhausted one day e.g., fossil fuels such as coal, petroleum, natural gas, fissionable materials. These are also called conventional sources of energy.
Disadvantages of non-renewable sources of energy are
- Due to their extensive use, these sources are depleting fastly.
- It is difficult to discover and exploit new deposits of these sources.
- These sources are the major cause of environmental pollution.
Fuel
It is a source of energy used for different household and commercial purposes. e.g., coal, LPG, biogas, CNG, etc.
Features of an ideal or a good fuel are
- It should have a high calorific or heat value so that it can produce maximum energy by low fuel consumption.
- It should have a proper ignition temperature so that it can burn easily.
- It should not produce harmful gases during combustion.
- It should be cheap in cost and easily available in plenty for everyone
- It should be easy to handle and convenient to store and transport from one place to another.
- It should not be valuable to any other purpose than as a fuel.
- It should burn smoothly and should not leave much residue after its combustion.