Subject:- Renewable Energy Sources

Topic:- Wind Energy

Difficulty:- High

Winds are caused by heating of atmosphere due to solar heating. There are two types of wind i.e. planetary winds and local winds.

• Four types of site are considered suitable. These are :
• Plane land sites
• Hill tops sites
• Sea- shore sites
• Off-shore shallow water sites.

The main considerations in selection of site for WECS are based on its technical feasibility, economics, social environment & other considerations some of the important criteria for selection of site are.

a) Located where the high average wind velocities available are in the range of 6 m/s to 30 m/s throughout the year since power developed is proportional to cube of wind velocity.

b) The WECS must be located for away from cities and forests since the buildings and forests offer resistance to the air movement. There should be notall structures in 3 km radius from the installation.

c) The wind farms are located in flat open areas, deserts , seas, shores and off shores site since wind velocities are of high in these locations.

d) Historical data of wind mean wind speed must be collected for average velocities during the year to select the site for availability of wind velocities needed for installation of wind farms.

e) Ground surface should have high soil strength to reduce the cost of foundation.

f) If small trees or vegetation exists at a particular location then it would need to increase the height of tower since any obstruction reduce the wind velocity. It causes the increase in cost of installation.

g) It should be installed away from localities so that the sound pollution caused by wind mills does not affect the habitants in near areas.

h) The minimum wind speeds at the selected site must be higher than 3.5 to 4.5 m/s which is the lower limit at which the present wind energy conversion system starts turning. It is called as cut-in-speed. Upto this speed no power will be generated by the system.