Wind energy is generated from the kinetic energy of wind. As the sun unevenly heats the Earth, it causes air movement and wind. Wind energy can be harnessed and used to do mechanical or electrical work. Historically, windmills were used to lift water or grind grain, now large wind turbines in wind farms are used to generate electricity on a commercial scale. While renewable, wind energy has limitations in requiring sufficient wind speeds and backup power sources during periods without wind.

1. ZEPHYR
Noun: a soft gentle breeze

2. INTRODUCTION
The unequal heating
of the landmass and
water bodies by solar
radiation generates
air movement and
causes wind to blow.
This kinetic energy of
the wind can be
used to do work.

3. WHAT IS WIND ENERGY?
• Wind energy is the kinetic energy
possessed by the air due to its velocity.
• It is a renewable source of energy.
• It can be utilized for performing
mechanical and electric works.

4. USES OF WIND ENERGY
1. Wind energy was harnessed by windmills in past to do
mechanical work. For eg. in a water lifting pump, the rotatary
motion of windmill is utilised to lift water from a well.
2. These days, wind energy is also used to generate electricity.

6. WINDMILL
• It is a machine which
converts the kinetic energy
of the wind i.e. wind energy
into electrical energy.
• It essentially consists of a
oooo similar to a large
electric fan that is erected
at some height on a rigid
support.
• To generate electricity, the
rotatar motion of the
windmill is used to turn the
turbine of the electric
generator.
Chesterton Windmill, Warwickshire

8. WIND ENERGY FARM
• The electric power output of a single
windmill is quite small and cannot be
used for commercial purposes. Therefore
a large number of windmills are erected
over a large area.
• A cluster of windmills is called a wind
energy farm.
• The combined energy output of all the
windmills generate electricity which is
used on commercial scale.

9. A wind farm: a cluster of windmills over a large area

10. MERITS
• It is an environment friendly and efficient source of
renewable energy as no fuels are burnt to generate
electricity.
• It requires no recurring expenses for the production
of electricity.
• Wind turbines require less space than average power
stations.

11. LIMITATIONS
• Wind energy farms can be established only at those places
where wind blows for the greater part of the year. The wind
speed should also be higher than 15 km/h to maintain the
required speed of the turbine.
• There should be some back-up facilities (like storage cells) to
take care of the energy needs during a period when there is
no wind.
• Establishment of wind farms require large area of land. The
initial cost of establishment of wind energy farms is quite high.
• The tower and blade need high levels of maintenance as
they are exposed to the vagaries of nature such as rain,storm
and cyclone.