Geoscience Reference
In-Depth Information
associated with wind turbines is that they are useless if the
wind does not blow. In order to reach maximum efficiency,
wind speeds
≥
10 mph are required for long periods of time.
As a result, many parts of the world are not suitable for de-
veloping a sustainable wind-energy program. In the United
States, for example, the southeastern part of the country is
poorly suited for wind energy, as are significant parts of the
American West. Much of the Midwest is also less than ideal
(Figure 6.26).
On the other hand, many parts of the country, such as
the Great Plains and along many mountain ranges, are ex-
cellent places to develop wind energy. Efforts are currently
underway to dramatically increase wind energy production in
these favorable areas. This upturn in wind energy production
is part of a global pattern that accelerated in the first decade
of the 21st century. Between 2005 and 2010, average annual
growth of the industry was about 27%. As of 2011, over
200,000 wind turbines have been installed around the world,
with Europe being a focus of rapid growth. In Denmark, for
example, 28% of the nation's electricity is produced by wind.
Within the United States, the number of units recently sur-
passed 50,000. The high potential for growth in the industry
is nicely exemplified within the state of Kansas, where about
1.2 GW (gigawatts) of energy production has been installed.
Estimates indicate, however, that about 952 GW of power
generation is possible. Continued development of this energy
source could bring thousands of jobs to the area and billions
of dollars in economic development. Farmers and ranchers
also benefit because they lease the ground on which turbines
are installed, resulting in a steady stream of supplemental
income for them.
To maximize the production of wind energy in these
places, extensive wind farms are being developed throughout
much of the central United States. A variety of incentives are
in place to build these complexes, including tax credits and
government subsidies. The world's largest wind farm is the
Horse Hollow Wind Energy Center in north central Texas
(Figure 6.27). This facility contains over 400 turbines spread
over 190 km
2
(73 mi
2
) and generates enough power for about
220,000 homes per year. Similar large wind farms occur else-
where in the Great Plains, as well as California, which now
ranks second behind Texas as the leading producer of wind
energy in the United States. An interesting development to
continue watching is the Cape Wind project off the coast of
Cape Cod, Massachusetts. In November 2008, voters along the
south shore of the state approved a nonbinding ballot to allow
the construction of 130 large turbines far offshore. A local
historic preservation group attempted to block construction,
however, because the complex would be built in Nantucket
Sound, which they claimed to be environmentally sensitive.
In 2011, the Massachusetts Supreme Court ruled that devel-
opment of the complex could proceed, and a purchase agree-
ment between the group and the Massachusetts Department
of Public Utilities was subsequently signed in November,
2012. As a result, installation of wind turbines could begin
sometime relatively soon.
Figure 6.25 A Dutch windmill.
Windmills like this one were
first built in the Netherlands in the 12th century to grind flour and
pump water from swampy areas.
windmills were developed in northwestern Europe to grind
flour and pump water out of low-lying areas. Many such
windmills still dot the landscape in Holland (Figure 6.25).
Wind energy was the power source behind the great sail-
ing voyages, such as those by Magellan and Cook, during
the Age of Exploration that set the stage for the mod-
ern world.
Given increasing demands for electricity and for renew-
able, clean sources of energy, wind power technology has
advanced dramatically in the past 30 years. This shift began
with the development of the modern wind turbine in the early
1980s following the oil shortages of the 1970s. Like the wind-
mills of old, modern wind machines use large blades that slow
wind speed and collect kinetic energy. As the wind flows over
the top of the curved blade, it causes lift and a turning motion
that spins a drive shaft connected to a turbine. This turbine
generates electricity. To give you an idea of how much energy
a turbine can produce, consider that a 5 megawatt turbine can
produce more than 15 million kilowatt hours (kWh) of elec-
tricity in a year, which is enough to power more than 1400
households.
What are the pros and cons associated with wind energy
production? On the positive side, wind energy is a clean and
an efficient way to produce electricity. Unlike coal power
plants, it produces no greenhouse gas emissions and thus
does not contribute to climate change. Some problems do
exist, however. The blades of wind turbines can strike migra-
tory birds, and turbines can be damaged by strong storms
and by lightning. To some people, wind turbines are aes-
thetically unattractive and are too loud, although quieter tur-
bines are currently being developed. The biggest problem
