Learning Experience 1.3
WIND POWER
Name:
Date:
Class:
As the Sun shines on the Earth it warms the atmosphere more in some places
than others. Warmer regions in the atmosphere are less dense than
surrounding cooler areas so the warmer air rises upwards by the process of
convection. Cooler air from surrounding areas rushes in to replace the rising
warm air. This is what we feel as wind.
Because wind is caused by the Sun, wind energy is actually a form of indirect
solar power.
How does wind power work?
We use wind energy in many different
ways, from sailing boats to flying kites.
In terms of generating electricity, it
works as follows:
 the kinetic energy of the wind is
used to spin a propeller linked to
a generator
 the generator consists of a
system of magnets and coils of
wire
 when the propeller spins, it
makes the magnetic field from
the magnets in the generator
pass over the coils of wire, which
causes an electrical current to
flow.
Efficiency
A large turbine
can have an
efficiency of up to
40%.This means
that for every 100
joules of kinetic
energy in the
wind striking the
turbine blades, the turbine produces up to 40 joules of electrical energy. It is
unlikely that a wind turbine will ever be much more efficient than this. If you
think about what would happen to a 100% efficient wind turbine you can see
why. If a turbine were 100% efficient it would transform 100% of the wind's
energy into electrical energy. This means that the wind would have no energy
left once it had passed through the turbine blades and would stop moving.
This would effectively block more wind from passing through the blades and
your turbine would grind to a halt!
Eco credentials
Wind power produces zero emissions. Wind turbines do not produce carbon
dioxide and they make use of a totally renewable energy resource. Some
people have concerns about possible noise pollution and harm that turbines
may cause to local bird populations.
Source: BP’s Carbon Footprint Calculator, Fact Sheet 11: Wind Power
Use the information above to complete the activities on this worksheet.
Describe in your own words how wind energy is in fact ‘indirect solar power’.
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Draw and label a wind turbine in the box below.
How can wind power be used to create electricity?
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How efficient is a wind turbine? How come it is unlikely that a turbine will ever
be created that is more efficient than this?
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What are the environmental impacts of wind energy, both positive and
negative?
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Complete the energy transformation flow chart.
Thermal energy
from the _______
Why is the different density of hot and cold air so important to the formation
and use of wind energy?
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