Document No. 1112M001 Revision 1.8 Date: June 2013
41
Annexure 2: Choosing a Site (Courtesy of BWEA)
The output from a wind
turbine is highly sensitive
to wind speed. It is
essential that turbines
should be sited away from
obstructions, with a clear
exposure or fetch for the
prevailing wind. Wind
speed also increases with
height so it is best to have
the turbine high up, and
most small turbines have
towers much higher
relative to their diameter
than large ones.
It is generally agreed that
the ideal position for a
wind turbine generator is a
smooth hilltop, with a flat
clear fetch, at least in the prevailing wind direction. The wind speeds
up significantly near the top of the hill and the airflow should be
reasonably smooth and free from excessive turbulence. Excessive
turbulence causes fatigue damage and shortens a turbine's working
life.
In practice, especially for very small machines that need to be located
near to the user, ideal siting will not be easy. As far as possible though,
keep away from local obstructions such as large trees and houses, or
use a taller tower to ensure that the turbine is well above the
obstructions.
Before considering the installation of a wind turbine the potential site
should be assessed. Initial indications of wind strength and direction
can be obtained by observing the deformation of vegetation and trees,
