Chapter 24 Energy Conservation
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Iowa, Minnesota, New Mexico, Oregon, Texas,
Washington, and Wyoming. You may see
a large number of wind turbines grouped
together in one location, Figure 24-20. Those
areas have the favorable wind conditions
needed to generate electricity. There are large
spaces between the wind turbines because the
rotating blades change the airfl ow to a turbu-
lent pattern for a short distance. If the next
turbine is too close, it will be less effective in
generating electricity. Proper spacing and dis-
tance between each unit is therefore necessary
to allow the wind to recover its normal pat-
tern and for the turbine to be effective. These
groups of wind turbines are called wind
farms or wind plants.
Wind turbine costs
The cost of the wind farms includes
acquiring the land, laying a foundation,
building the tower, assembling the parts, and
maintaining the equipment. Many times a
developer will buy or lease land from a farmer
or other landowner on which to build the
wind turbines. The landowner may receive a
one-time payment, a percentage based on the
wattage produced, or a fi xed amount per year.
The electricity produced by wind turbines
is not usually fed directly into a home. DC is
produced as the blades turn. If a home is in
a remote area, its electricity may be produced
by a dc wind turbine. For most wind turbines,
however, dc is fed into an inverter and
converted to ac. The ac is then used on-site or
fed into the electrical grid. The landowners
have a contract with the power company, and
they may be credited for the electricity the
turbines on their property put into the grid.
Advantages and disadvantages
There are some sources that say we could
generate over 10 trillion kWh of electricity
every year with wind turbines alone. That
is more electricity than is used in the entire
United States. The major problems with wind
turbines, however, are their cost and the fact
that the wind does not blow all the time. The
wind cannot be forced to match the energy
demand and will not always blow the most at
the time of day when demand for electricity is
Figure 24-20. Lake Benton, Minnesota wind farm is built along a windy ridge.