Source: Ecologically man is only a part of energy flow in nature.Man requires energy for his daily needs.The major energy sources are fuel wood,fossils fuels such as coal, petroleum and natural gas.Apart from these,the other direct energy resources are sunlight, hydroelectric and wind power,tidal, geothermal and nuclear energy.
Energy requirement: During early stages of human civilization,the daily per capital need for energy was just 2000-4000 kilo calories.During the agricultural stage,the muscular energy of domestic animals was used for work.Today we need energy for agriculture,industry,transport, communication,comfort and defence.The per head energy consumption varies from country to country.
Depletion of fossil fuels
Today the world’s energy resources have reached critical stage.Most of the world’s human population uses fossil fuels(coal, petroleum and natural gas).The fossil fuel resources are being rapidly depleted.As a result these resources may last only another few centuries.Tge dwindling stocks of fuels has led to the search of alternate sources of energy.
Sources of energy
Some alternative sources of fuel are solar energy,hydro electric energy,Geo thermal energy,wind power,tidal energy, energy from garbage,dung energy and nuclear energy.They are generally called renewable or non-conventional sources of energy.
1)Solar energy
Sun is inexhaustible and pollution free source of energy.Solar equipments have been developed to harness sun rays to heat water,cook meals,light our houses and run certain machines.
2)Nuclear energy
It is generated by fusion of the atoms of certain elements such as Uranium-235.The processes results in the release of enormous amount of energy.Fission of 1 amu of Uranium-235 can generate energy equivalent to that obtainable from burning of 15 metric tons of coal or about 14 barrels of crude oil.
3)Wind power
It has been used for centuries to run the wind Mills for grinding grains and pump water in certain areas.But the wind does not blow with required intensity all the year round and in all areas.Therefore,wind power can be used only in certain areas and on certain days.
4)Dung energy
Cattle dung is widely used as fuel in rural areas of our country.This deprives our fields of valuable organic manure.Now cattle dung is used in biogas or gobar gas plant to produce an odourless,low pressure gas.This gas can be used for cooking and heating.The residue is used as manure.
5)Energy from garbage
The garbage of houses contains waste paper,plastics and several other materials.It can be used to produce organic manure.
6)Tidal energy
Tidal waves of the sea can be used to generate electricity.
7) Geothermal energy
In some places,the heated water comes to the earth’s surface as hot springs.It can be used for heating water and building and for generating electricity.
8)Hydro electric energy
It is produced from the kinetic energy of water falling from height.A number of power stations have been established on many rivers in our country.
Conservation of energy
The present critical energy position demands an organized effort at all levels from individual to international action.A considerable amount of energy can be saved by reducing wastage and using energy efficient devices.Following measures can help in this effort:
1) Development of technology for the use of solar energy in appliances and transport vehicles.
2) Development of efficient and smokeless chulhas or wood stoves.
3) Development of non conventional energy sources and less dependence on fossil fuels.
4)Planned programme for raising fuel wood,trees and shrubs under the control and maintenance of local communities especially in developing countries.
5) Effective use of agricultural and animal wastes to obtain biogas and manure.
6) Improvement of engine and pump designs to increase fuel efficiency.
7) Development of effective techniques to trap wind and tidal energy.
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