RLB_UK_Riders_Digest_2013

UK CONSTRUCTION INFORMATION
Wind Turbines
What is it?
The UK is the windiest country
in Europe with an average wind
speed of 6m/s. However most
housing is in sheltered areas, so
average wind speed will be about
3 or 4m/s. It is recommended
that an average wind speed of
5m/s second is needed for a
turbine to be viable. Even though
turbines are multi directional,
wind in towns is often affected
by turbulence, the wind in one direction may fall below 3m/s
leaving the head turning aimlessly trying to find wind, leading
to a decreasing life expectancy of the turbine. Wind increases
with height, with a rooftop being the ideal place to place a
turbine, however this may lead to added structural costs. A
wind turbine will generate noise typically 2 or 3 decibels above
the background noise, so proximity to living spaces should
be avoided. A turbine moving in fast winds is likely to cause
resonance through the building.
How does it work?
Wind turbines convert the power in the wind into electrical
energy using rotating wing-like blades which drive a
generator. They can either be connected to the national grid
to export electricity, used directly for electricity or used to
charge batteries for on-site use.
Turbines can range from small domestic turbines producing
a single Kilo Watt of energy to large offshore turbines with a
capacity of 5MW and a diameter of 100m.
While horizontal axis wind turbines (HAWTs or ‘propeller
type’) are the most common, there is growing interest in
vertical axis wind turbines (VAWTs) particularly in urban
locations where they are thought to be able to cope with
more turbulent winds.
Turbines can be free standing mounted on a tower, mounted
on a building structure or in the case of new buildings it also
possible to integrate turbines within the buildings structure.
Wind velocities are the key factor in the location of wind
turbines. Care must be taken with site selection, particularly
for larger turbines. A feasibility study should take into
account wind speed and turbulence and constraints such
as radar stations, airports, landscape designations and
proximity to special wildlife areas or bird migration corridors.
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