Site Selection of Wind Power Plant
Winds are caused by heating of atmosphere due to solar heating.
There are two types of wind viz. planetary winds and local winds. It has been also observed that the total wind power from free wind stream increases as the cube of the wind Therefore suitable studies are carried out for deciding the location for the wind energy conversion system (WECS). Four types of sites 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 and other considerations. Some of the important criteria for selection of site are :
- 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.
- The WECS must be located far away from cities and forests since the buildings and forests offer resistance to the air movement. There should be no tall structures in 3 km radius from the installation.
- The wind farms are located in flat open areas, deserts, seas, shores and off shores site since wind velocities are high in these locations.
Wind velocities must be measured by anemometer at several heights from the ground. The velocity of wind increases with height given by the relation :
C ∝ H1/7(Applicable in the range of 50 m to 250 m height.) This helps in selecting the appropriate height of wind tower with other design considerations of the structure design.
- 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.
- Ground surface should have high soil strength to reduce the cost of foundational.
- If small trees or vegetation exists at a particular location then it would need to increase the height of tower since any obstructions reduce the wind velocity. It causes the increase in cost of installation.
- It should be installed away from localities so that the sound pollution caused by wind mills does not affect the habitants in near areas.
- Approach roads to the installation needs to be constructed.
- It should have low land cost and near the consumers to reduce the total cost of installation and reduce the transmission losses.
- Tower design must be adequate to withstand maximum wind speeds observed in the last few years in the area of installations.
- 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.