Ocean Wind Power Maps
Reveal Possible Wind Energy Sources
(9 July 2008) Efforts to harness the
energy potential of Earth's ocean winds could soon gain an important new tool:
global satellite maps from NASA.
Scientists have been creating
maps using nearly a decade of data from NASA's QuikSCAT satellite that reveal
ocean areas where winds could produce wind energy.
The new maps have
many potential uses including planning the location of offshore wind farms to
convert wind energy into electric energy. The research, published this week in
Geophysical Research Letters, was funded by NASA's Earth Science Division,
which works to advance the frontiers of scientific discovery about Earth, its
climate and its future.
"Wind energy is environmentally friendly. After
the initial energy investment to build and install wind turbines, you don't
burn fossil fuels that emit carbon," said study lead author Tim Liu, a senior
research scientist and QuikSCAT science team leader at NASA's Jet Propulsion
Laboratory in Pasadena, Calif. "Like solar power, wind energy is green
energy."
QuikSCAT, launched in 1999, tracks the speed, direction and
power of winds near the ocean surface. Data from QuikSCAT, collected
continuously by a specialised microwave radar instrument named SeaWinds, also
are used to predict storms and enhance the accuracy of weather
forecasts.
Wind energy has the potential to provide 10 to 15 percent of
future world energy requirements, according to Paul Dimotakis, chief
technologist at JPL. If ocean areas with high winds were tapped for wind
energy, they could potentially generate 500 to 800 watts of energy per square
meter, according to Liu's research. Dimotakis notes that while this is slightly
less than solar energy (which generates about one kilowatt of energy per square
meter), wind power can be converted to electricity more efficiently than solar
energy and at a lower cost per watt of electricity produced.
According
to Liu, new technology has made floating wind farms in the open ocean possible.
A number of wind farms are already in operation world-wide. Ocean wind farms
have less environmental impact than onshore wind farms, whose noise tends to
disturb sensitive wildlife in their immediate area. Also, winds are generally
stronger over the ocean than on land because there is less friction over water
to slow the winds down - there are no hills or mountains to block the wind's
path.
Ideally, offshore wind farms should be located in areas where
winds blow continuously at high speeds. The new research identifies such areas
and offers explanations for the physical mechanisms that produce the high
winds.
An example of one such high-wind mechanism is located off the
coast of Northern California near Cape Mendocino. The protruding land mass of
the cape deflects northerly winds along the California coast, creating a local
wind jet that blows year-round. Similar jets are formed from westerly winds
blowing around Tasmania, New Zealand, and Tierra del Fuego in South America,
among other locations. Areas with large-scale, high wind power potential also
can be found in regions of the mid-latitudes of the Atlantic and Pacific
oceans, where winter storms normally track.
The new QuikSCAT maps, which
add to previous generations of QuikSCAT wind atlases, also will be beneficial
to the shipping industry by highlighting areas of the ocean where high winds
could be hazardous to ships, allowing them to steer clear of these
areas.
Scientists use the QuikSCAT data to examine how ocean winds
affect weather and climate, by driving ocean currents, mixing ocean waters, and
affecting the carbon, heat and water interaction between the ocean and the
atmosphere.
JPL manages QuikSCAT for NASA.
(source:
NASA)
