Could wind power ever meet the world’s energy needs?
Posted by Brad Plumer on September 10, 2012 at 3:08 pm
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Horns Rev 2, the world’s largest wind farm, 30 km (19
miles) off the west coast of Denmark (Reuters).
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At the moment, wind power
supplies about
4.1
percent of electric power in the United States. Still a bit player. Yet
there’s a whole lot of untapped wind left in the world. Wind whipping through
the Great Plains. Wind gusting off the shores. Wind circulating high up in the
sky. So what would happen if we tried to harvest
all of that wind?
We’d have enough energy to power
the world. At least in theory. A
new
study published this week in Nature Climate Change finds that there’s enough
wind potential both on the Earth’s surface and up in the atmosphere to power
human civilization 100 times over. Right now, humans use about 18 terawatts of
power worldwide. And, technically, the study found, we could extract about 400
terawatts of wind power from the Earth’s surface and 1,800 terawatts of power
from the upper atmosphere.
This isn’t what’s likely — just what’s possible. As Kate Marvel, a researcher
at Lawrence Livermore National Laboratory, explains, this paper mainly looks at
wind power’s maximum potential. “We were looking at the geophysical limits of
what the Earth could handle,” Marvel says. “We didn’t necessarily restrict our
study to what was feasible.” (Marvel co-authored the study with Ken Caldeira and
Ben Kravitz of the Carnegie Institution for Science.)
Even the most optimistic
near-term projections for wind power, however, tend to be more restrained. In
2008, the U.S. Department of Energy released a
comprehensive
report estimating that wind power could provide, at most, 20 percent of U.S.
electricity by 2030. And for that to happen, the cost of wind power would have
to keep plunging, the number of turbines built would have to steadily increase
by about 14 percent each year, and utilities would have to build new
transmission lines to accommodate the extra energy.
What’s more, electric-grid
operators would have to figure out how to juggle a power source that isn’t quite
as reliable as the coal and gas plants of old. That’s not an impossible task. As
Stanford’s Christina Archer and Mark Jacobson showed in a 2007
modeling
study of the United States, the wind is always blowing
somewhere in
the country, which means that if enough wind farms are linked together, they can
provide lots of steady baseload power. But building that infrastructure can be
difficult — Germany
is
currently struggling to upgrade its grid to accommodate a surge of new wind
and solar farms.
Rather than get bogged down in
these logistical details, however, the new Nature Climate Change paper set its
sights far higher. For one, it doesn’t just look at wind potential near the
Earth’s surface, as past studies have done. The study also asks how much wind
energy could be extracted from higher altitudes. Various companies are now
working on
designs for wind turbines that can float high in the air, on kites or
balloons. Since the wind is steadier and stronger high up in the atmosphere,
that’s a tantalizing resource — if the technology could work.
True, humans would eventually run
into a physical limit on how much wind energy could be harnessed. Wind turbines
work by creating resistance or drag, slowing the wind’s momentum. Put up enough
turbines, and the wind will slow down too much. What’s more, the change in
global circulation could, in theory, muck with the climate. (Previous modeling
studies, including one by David Keith in 2004,
had
raised the possibility that large-scale wind harvesting might alter global
rainfall patterns.)
Yet the Nature Climate Change study suggests that neither of these things
will be a problem for a long, long time. Humans could sustainably extract up to
2,200 terawatts of power from surface and atmospheric winds before bumping into
physical limits. That’s 100 times as much power as the world uses today. What’s
more, if the world ever harnessed that much wind, the temperature of the Earth
would shift by only about 0.1°C and precipitation would shift by less than 1
percent. “It’s not a big deal, basically,” says Marvel.
Marvel says the next step for this sort of research will be to restrict the
analysis to wind-turbine locations that are technically feasible. For now,
however, it’s safe to say that there’s enough wind potential to meet the world’s
demand many times over, at least in the abstract. “[I]t seems that the future of
wind energy,” the study concludes, “will be determined by economic, political
and technical constraints, rather than global geophysical limits.”
Copied from: http://www.washingtonpost.com/blogs/ezra-klein/wp/2012/09/10/is-there-enough-wind-energy-to-meet-the-worlds-needs/
p/s:I read the article without entirely understanding it.But still la i get a thing or two about it and FYI this is a copied article tau.
