Short Notes (Energy)

Non-Conventional Sources Of Energy:
Non-conventional sources of energy are those sources of energy which are not in common use at this time but are being considered or explored to bring to routine use in the future. With the exhaustion of conventional sources of energy the search for non-conventional sources of energy have been intensified.
Conventional sources of energy are coal, gas, oil, wood and nuclear fuels. These sources are in routine use nowadays.
Non-conventional sources of energy are solar energy, geothermal energy. Wind energy, tidal energy and ocean thermal gradient.

Solar Energy:
The energy of the sun is called solar energy. It has been estimated that on the average 180,000 kilowatts solar energy is falling per square kilometre of the earth. Solar energy is utilized in two ways.
A solar furnace contains thousands of mirrors to focus the sun rays. In this solar heater produces heat used in industry or houses. The heaters heat up water or air. Solar energy can also be used indirectly. Solar cells made up of panels of semi-conductors (usually silicon) are used which when illuminated by sun generate electricity. These kinds of cells have frequently been used in space probe. They have not become popular in domestic side due to high cost.

Wind Energy:
Energy obtained from wind by using wind mills is called wind energy. The wind rotates generated which produce electricity.
Previously wind mills were used for grinding grains. The rotating wings of a wind mill can be attached to a magnet which gives an electric current with rotation. Low power, high cost and uncertainties of weather had not made power generation through wind power.

Geothermal energy:
Heat energy obtained from the hot molten metals inside the earth crust serves as the source of thermal energy. This type of energy is present in the form of hot water and steam. Geothermal electricity plants change the geothermal energy into electricity. Hot water of springs is being used for power generation particularly in USA, Italy, and Japan etc. furthermore; hot springs are used as geysers for heating the houses.

Nuclear Energy:
The most concentrated form of energy is in the atomic nuclei. This energy can be released by the processes of fission or fusion.
Fusion reactions have been producing electricity in commercial quantities for about 30 years. In Pakistan we have got only one fission nuclear reactor located at Karachi which generates 137 megawatt of power to meet ur future domestic and industrial needs, we will have to generate electricity from nuclear plants using (Uranium U-235) and plutonium s fuel.

Tidal Energy:
Energy which is obtained through the tidal waves of the sea is called tidal energy. Tidal waves of sea strike the shore constantly. These waves are used to run electric generators which produce electricity. The kinetic energy of the tides is also used to produce other forms of mechanical work. Tidal power station traps high tides behind a barrage. The water flows through turbines.