Not to be confused with free-standing mini wind turbines, which are
dealt with separately. Micro
wind turbines have been used successfully for many years in
applications such as boats, caravans and other places where no fixed
electrical supply is available. These generate DC power
suitable for battery charging and the majority of portable
appliances and tend to be located in windy areas, free from
obstructions. Recently attempts have been made to apply the
same technology with turbines mounted on buildings (to save the cost
of a free-standing tower) and using inverters to convert the DC to
AC power suitable for connection to the consumer unit in a home
(grid-parallel operation). In this configuration the turbines
are subject to the very turbulent wind conditions and low wind
speeds typical of the urban environment, so that the turbines
continually "hunt" to find what little wind is available and do not
stabilise for long enough to produce a great deal of useful power.
In addition the requirement for power electronics to synchronise
with the mains supply has led to additional inefficiencies, so much
so that, in some cases, the inverter losses exceed the useful
electricity generated.
The force of the wind on the turbine
causes considerable noise and vibration which can be amplified by
the structure and, in a few cases, the force exerted by the turbine
on the building to which it is attached has led to structural damage
to the wall. One major supplier recently recalled their
products after components became detached in strong winds.
Monitored trials to date have
demonstrated poor performance in urban conditions. Rural
locations with free-standing products may perform better. |