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Global
map of wind power potential
A new global wind power map has quantified global
wind power and may help planners place turbines in locations that can
maximize power from the winds and provide widely available low-cost
energy. After analyzing more than 8,000 wind speed measurements in an
effort to identify the world's wind power potential for the first time,
Cristina Archer and Mark Jacobson of Stanford University suggest that
wind captured at specific locations, if even partially harnessed, can
generate more than enough power to satisfy the world's energy demands.
Their report will be published in May in the Journal of Geophysical
Research-Atmospheres, a publication of the American Geophysical Union.
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The researchers collected wind speed measurements from
approximately 7,500 surface stations and another 500 balloon-launch
stations to determine global wind speeds at 80 meters [300 feet] above
the ground surface, which is the hub height of modern wind turbines.
Using a new interpolation technique to estimate the wind speed at that
elevation, the authors report that nearly 13 percent of the stations
they reviewed experience winds with an average annual speed strong
enough for power generation. They note that, based on their expectations
of other global areas, an even greater percentage of locations would
likely reach the 6.9 meters per second [15 miles per hour] wind speed
considered strong enough to be economically feasible.
Such wind speeds at 80 meters, referred to as wind power Class 3, were
found in every region of the world, although North America was found to
have the greatest wind power potential. The researchers also found that
some of the strongest winds were observed in Northern Europe, along the
North Sea, while the southern tip of South America and the Australian
island of Tasmania also recorded significant and sustained strong winds
at the turbine blade height. In North America, the most consistent winds
were found in the Great Lakes region and from ocean breezes along the
eastern, western and southern coasts. Overall, the researchers
calculated winds at 80 meters [300 feet] traveled over the ocean at
approximately 8.6 meters per second and at nearly 4.5 meters per second
over land [20 and 10 miles per hour, respectively].
"The main implication of this study is that wind, for low-cost wind
energy, is more widely available than was previously recognized," Archer
said. "The methodology in the paper can be utilized for several
applications, such as determining elevated wind speeds in remote areas
or to evaluate the benefits of distributed wind power."
The study also estimated the amount of global wind power that could be
harvested at locations with suitably strong winds. The authors found
that the locations with sustainable Class 3 winds could produce
approximately 72 terawatts and that capturing even a fraction of that
energy could provide the 1.6-1.8 terawatts that made up the world's
electricity usage in the year 2000. A terawatt is 1000 billion watts
( a trillion )
, a
quantity of energy that would otherwise require more than 500 nuclear
reactors or thousands of coal-burning plants. Converting as little as 20
percent of potential wind energy to electricity could satisfy the
entirety of the world's energy demands, but the researchers caution that
there are considerable practical barriers to reaping the wind's
potential energy.
Chief among those barriers is creating and maintaining a dense array of
modern turbines that would be needed to harness the wind power. Some
sources have suggested that millions of turbines would be needed to
produce an acceptable level of energy and that alternative energy
sources would still be necessary to produce power when the wind speeds
fall below a certain threshold. Creating a large field of turbines could
also be hazardous to birds and may produce unacceptable noise levels.
The current research, however, indicates that several of those
limitations can be overcome with better placement of wind turbines. The
researchers report that their study can assist in locating wind farms in
regions known for strong and consistent winds, which may help avoid some
of the problems with intermittent winds. In addition, they suggest that
the inland locations of many existing wind farms may explain their
inefficiency.
"It is our hope that this study will foster more research in areas that
were not covered by our data, or economic analyses of the barriers to
the implementation of a wind-based global energy scenario," Archer
concluded.
Source: American Geophysical Union
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