What
is a wind energy turbine?
Wind
is a form of solar power that can be managed and reaped
into wind energy. The flow of wind is motion energy. And
this motion energy is harnessed into mechanical energy
by wind energy generators. Wind energy turbines are
specialized wind energy generators that generate
electricity by harvesting the wind resource. Being the
most modernized technique of generating electricity,
wind turbines are used majorly these days. Wind is a
kinetic energy formed due to the uneven heating of
earth’s surfaces due to its irregularities, rotation of
the earth and the scratchy heating of the atmosphere by
the sun’s rays. The water bodies and vegetative covering
also contribute to the differential heating. Thus there
is a constant temperature difference between the earth’s
equator and its poles. This temperature difference
causes wind flow from the cooler areas to the
comparatively hotter regions of the earth. This wind
flow is a kinetic energy in itself which is further
regenerated into electricity by a wind energy
converter.
Wind
Energy Turbines: types and
functions
Wind
energy turbines are broadly classified into two
varieties namely, the horizontal-axis type and the
vertical-axis type. The classification is based on the
orientation of the axis around which the turbine
rotates. The horizontal wind turbine rotates around a
horizontal axis and is the common variety largely used
to generate electricity. A horizontal-axis turbine
mainly consists of a rotor shaft, two or three blades
and an electric generator. The blades are pointed in the
direction of the wind. The movement of the blades moves
the shaft mechanically and the generator connected to
the shaft uses this mechanical energy into electricity.
Thus the electricity produced is directly proportional
to the speed of wind, rather the speed of the propeller
blades. Some advanced wind energy turbines use a gearbox
to turn the slow rotation of the blades into a faster
rotation to ensure an efficient driving of the
electrical generator. Wind turbines that are mounted on
a high tower, say hundred feet capture the most energy
as the wind at such a height is less turbulent and much
faster.
Turbulence
is usually produced behind a wind turbine tower and that
is why the turbine is normally pointed upwind of the
wind tower. To prevent the wind turbine blades from
being pushed into the tower by heavy winds, the wind
turbine blades are usually made very stiff. Besides, the
blades are tilted a little up and placed wide apart in
front of the tower to prevent forcing into the wind
turbine tower. The downwind type is also built as they
do not require the additional mechanics for holding the
blades in the direction of the wind. In high wind,
however, the wind resistance is reduced due to the
fatigue failures thus pulling down its efficiency. The
horizontal-axis wind turbines can again be divided into
3 subtypes like the 12th century windmills, the 19th
century windmills and the modern wind turbines, the last
one being the most evolved and modernized device.
Vertical-axis
wind turbine has the main rotor shaft vertically
oriented. Thus this turbine does not require to be
pointed in the direction of wind to be effective. This
is a big advantage in areas where wind direction is
variable and unpredictable too. Wind from different
directions is easily and efficiently utilized by the
vertical-axis wind turbines. Besides all these
advantages the vertical-axis wind turbine has some basic
limitations (cannot be installed on high towers due to
the huge size) which clearly discourage the large scale
usage of this device to generate electricity.
Advantages
and disadvantages of wind energy
turbines
Wind
energy turbines have proved themselves to be quite
rewarding in generating electricity. The tall tower
bases help capture high winds that ensure a high power
output. Also since the modern technology helps control
the angle of the turbine blades remotely thereby
increasing the control over the same, the turbine can
collect the most wind energy. The wind energy turbines,
though are basically useful to the whole world, still
pose some issues in their operations. The transportation
of the huge blades (around 90 meters long) is a serious
issue. The tall towers require huge, expensive cranes
for their installation which is again a botheration. The
tower construction required is just huge to bear the
loads of the gearbox, generator and heavy blades. Also
the avian mortality (bats and birds being killed while
flying into the rotors) and noise pollution issues
(generated by the rotor blades) along with the visual
impact (the huge machinery that block the view of the
landscape) cannot be ruled out at all. Despite all the
pros and cons the wind energy is an asset being a
renewable resource that is clean and pollution
free.
