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Wind Energy
Introduction
Wind is not treated in any detail in Greek mythology. However, in a very
general sense, mythological winds are referred to in two principal ways: as
male gods who engage in humanlike activities and are also the winds them-
selves, and as nonhuman entities that can be conned in a bag. There are
also the three principal winds: Zephyros (the west wind), Boreas (the north
wind), and Notos (the south wind).
In a technical sense, wind can be dened as air in motion. It can be pro-
duced by the uneven heating of the Earth’s surface by energy from the sun.
Since the Earths surface is made of very different types of land and water,
it absorbs the suns radiant energy at different rates. Much of this energy is
converted into heat as it is absorbed by land areas, bodies of water, and the
air over these formations.
As noted, the Earth is not uniformly heated by the sun, in that the poles
receive less energy from the sun than the equator. Along with this, dry land
heats up (and cools down) more quickly than do the seas. Solar insolation
causes temperature difference driving forces between the equator and the
poles. These create a global atmospheric convection system reaching from
the Earths surface to the stratosphere, which acts as a virtual ceiling. On a
local scale, the warm air over the land expands and rises, and the heavier,
cooler air over the water rushes in to take its place, creating winds.
Wind power is the conversion of wind energy into a useful form of energy.
This is accomplished by using wind turbines to make electricity, windmills
for mechanical power, wind pumps for water pumping or drainage, or sails
to propel ships. The total amount of usable power available from the wind
is estimated to be considerably more than present human power use from
all other sources [1]. For example, planes traveling from west to east use jet
stream winds to increase groundspeed. Thus, transcontinental airline times
are usually shorter west to east and longer east to west. However, airstreams
within a few hundred feet of the ground are of primary importance to
ground-based wind energy systems.

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