Wind power will worsen climate, scientists find
(NaturalNews) A massive switch over to wind power may actually be worse
for global climate systems than current catastrophic levels of
greenhouse gas emissions, according to a study conducted by researchers
from
Harvard University and published in the journal
Environmental Research Letters.
"People
have often thought there's no upper bound for wind power - that it's
one of the most scalable power sources," said researcher David Keith, an
international policy expert on climate technology.
But the new atmospheric modeling study found that assumption to be wrong.
The
problem is that the energy that windmills "harvest" has to come from
somewhere, and where it comes from is the wind's velocity: simply put,
the wind blowing through a windmill slows down. This drag, or "wind
shadow," is a critical component of wind farm design, as it means that
windmills cannot be placed too close to each other and still remain
effective.
The new study found; however, that it's not just
windmills that have wind shadows - wind farms cast their own, larger
shadows, made up of the interactive effect of all the individual
windmills. And that means that wind farms cannot be placed too close to
each other, either. And the more wind farms you build, the more shadows
you create, until you are actually altering wind patterns on a planetary
scale.
"One of the inherent challenges of wind energy is that as
soon as you start to develop wind farms and harvest the resource, you
change the resource, making it difficult to assess what's really
available," Adams said.
In practical terms, the study found that
although prior studies have estimated the generating capacity of wind
megafarms at two to seven watts per square meter, the wind shadow effect
actually limits their capacity to only 0.5 to one watt per meter.
Worse than carbon dioxide?The findings have major implications for wind power both as a viable energy source and as a climate-friendlier one.
"It's clear the theoretical upper limit to
wind power is huge, if you don't care about the impacts of covering the whole
world with wind turbines," Keith said. "What's not clear ... is what the
practical limit to wind power would be if you consider all of the
real-world constraints."
"You'd have to assume that wind turbines
need to be located relatively close to where people actually live and
where there's a fairly constant wind supply, and that they have to deal
with environmental constraints. You can't just put them everywhere."
"The
real punch line," he said, "is that if you can't get much more than
half a watt out, and you accept that you can't put them everywhere, then
you may start to reach a limit that matters."
And one thing is clear: putting wind turbines "everywhere" would be devastating for our planet's
climate systems.
"My
guess, based on our climate modeling, is that the effect of that on
global winds, and therefore on climate, would be severe - perhaps bigger
than the impact of doubling CO2," Keith said.
Source:-
http://www.naturalnews.com/039575_wind_power_climate_carbon_dioxide.html