Wind Power Point
Teacher Script
Slide 1
Wind comes in many forms – a hurricane on the
coast, an arctic front, a summer breeze… Wind
energy does not pollute and thus, wind energy
reduces carbon dioxide omissions that cause global
warming.
As long as the wind blows, energy from the wind is
created. Wind is considered an inexhaustible
(renewable) resource.
Slide 2
The entire Earth experiences winds, but some places
have stronger and more consistent wind than others.
How Does Wind Form…
• The rotation of the Earth (Coriolis effect):
– The Earth spins about 1000 mph at the equator
– The spinning of the Earth causes the atmosphere to spin
along with it in a curved path
Slide 3
The Coriolis effect is caused by the rotation of the
Earth. Because the earth is solid and the atmosphere
is gas, the atmosphere spins at a different speed and
along curved paths.
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…How Does Wind Form?
• Differences in temperature:
– Angle of sun rays are greater towards poles (less heat at high
latitudes)
– Warm air from the equator moves towards the poles and cool
air from the poles moves towards the equator
– Mountains day: cool air on top, warm air below
night: cool air drops, warm air rises
– Large bodies of water (cooler than land in day)
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Slide 4
In warm areas, air molecules spread apart. The
separation of air molecules is called a low pressure
system. Cooler (denser) air rushes towards the mass
of warmer air. Once the cool air molecules fill the
spaces between the warm air molecules the
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temperature stabilizes and it becomes a high
pressure system.
This cycle occurs on a large scale with cool air from
the poles moving towards the equator and heating,
and then the air moves back toward the poles. The
air is cooler at the poles because the angle that the
sun’s rays strike the Earth is greater (less heat per
area). Sun rays are more direct at the equator (more
heat per area).
The same cycle occurs on a smaller scale in areas
with mountains or large bodies of water. The air on
top of a mountain is cooler in the day than the air in
the valley below. At night, the cool air on top of the
mountain drops while the warm air rises and cools –
the cycle repeats.
During the day, the air above the water is cooler
than the air over the land causing the winds to blow
towards the water. At night, the land and air cools
causing the wind to blow from the water to the land.
Slide 5
A wind vane measures the direction wind blows.
One example is the common “rooster” wind vane
sometimes found on country barns.
Wind Instruments
www.sendweathervanes.com
Wind Vane
www.process-controls.com
Cup Anemometer
www.process-controls.com
Ultrasonic Anemometer
A cup anemometer measures the wind velocity.
The cups capture pockets of air thus rotating in a
circular motion. The number of revolutions per
minute (rpm) relates directly to the wind velocity.
An ultrasonic anemometer measures the wind
velocity in a three-coordinate system (U-V-W).
The ultrasonic anemometer makes measurements
almost instantaneously. The approximate cost is
$5,000.
Slide 6
When scientists are looking for a good place to
build a wind farm, there are a few general principles
they go by.
Windy Site Locations
• Wind speeds increase with
altitude:
– Hills are better than depressions
– Tall towers are better than short towers
– Flat coastlines are better than steep
cliffs (turbulence)
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• Large bodies of water cause
wind changes:
– Offshore turbines are popular due to
stronger winds
– The cooling and heating effect of water
and land creates wind
www.windpower.org
Wind speeds increase with altitude. Wind turbines
with tall towers are generally better powered than
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turbines with short towers, although a short tower
with more wind can produce a larger amount of
energy than a tall tower with less wind.
Hills are typically better than flat land. When a hill
is too steep or there are steep cliffs in an area, the
wind’s directional flow gets interrupted and
turbulence (rough air) is created (i.e. turbulence on
an airplane). Wind turbines do not work well in
areas with high turbulence because it can cause
wear-and-tear and damage turbine parts.
Wind turbines are being placed off the coastline in
European countries. Coasts provide a reliable
source of strong winds due to the cooling and
heating effect of water and land. Flat coastlines are
better suited to wind farming than coasts with cliffs
or hills because of turbulence.
Slide 7
Turbulence
Causes of Turbulence: Buildings, Steep Cliffs, Trees …
Turbulence is created by objects disrupting the flow
of wind. In the picture above, the building and
vegetation block the flow of wind causing air eddies
to form. The magnitude (strength) and direction of
the eddies vary thus creating wind turbulence.
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