Wind energy


  • Air in motion is called wind. Contrast in temperature causes pressure difference which generates wind. Energy derived from wind velocity is wind energy.
  • It is a non-conventional type of energy which is renewable with suitable devices. This energy can be used as a perennial source of energy.
  • Wind energy is obtained with the help of wind mill. The minimum wind speed of 10 km/hr is considered to be useful for working wind mills for agricultural purpose.
  • Along the sea coast and hilly areas, wind mills are likely to be most successful in Karnataka, Maharastra and Gujarat State.

Function of wind mill

  • Wind mill extracts energy from the wind and produces mechanical energy. This energy may be converted into electrical energy.
  • A minimum wind speed of less than 10 km/hr is not suitable to operate a wind mill on economical basis .

Types of wind mill

  • Wind mill may be of two types :
    • Horizontal axis rotor
    • Vertical axis rotor

Horizontal axis rotor

  • Horizontal axis (or wind axis) rotor is an unit whose axis of rotation is parallel to the direction of the wind. This rotor has three types of blades :
    • Multiblade unit
    • Sail type unit and
    • Propeller type unit.
  • Multiblade type rotor
    • It is very widely used in wind mills. It has usually 12 to 20 blades fixed over it. The blades are made by suitably shaping the metal sheets. It runs at speed of 60 to 80 revolutions per minute .
  • Sail type unit
    • It has three blades made by stretching out triangular pieces of canvas cloth. It runs at 60 to 80 revolutions per minute.
  • Propeller type unit
    • It has 2 or 3 aerofoil blades and runs at speeds of 300 to 400 revolutions per minute.


  • Wind power has many advantages:
    • Zero pollution
    • Provides extra income for rural farmers by renting land for turbines
    • Creates more jobs per GW of electricity generated than coal power stations
    • Renewable source of electricity
    • Sustainable source of electricity
Last modified: Wednesday, 3 August 2011, 8:38 AM