[cdn-nucl-l] Wind power not all pleasant breezes

["Adam Mclean" <adam.mclean@utoronto.ca>]

Posted in the Globe and Mail on November 9, 2004 and at:
http://www.theglobeandmail.com/servlet/story/RTGAM.20041109.wwind1109/BNStor
y/specialScienceandHealth/
See all of Canada's wind farms here:
www.canwea.ca/en/CanadianWindFarms.html
And the PNAS wind study is available here:
www.pnas.org/cgi/reprint/0406930101v1.pdf

Adam

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Wind power not all pleasant breezes 

Wind turbines tower over an employee at the McBride Lake Wind Farm southwest
of Fort Macleod, Alta. The site is Canada's largest single-site wind farm.  
 
A cool if not quite cold wind is blowing over the ballyhooed environmental
benefits of a big shift to wind power.

A group of Canadian and U.S. scientists reported Tuesday that computer
simulations show that a large-scale use of wind farms to generate electrical
power could create a significant temperature change over Earth's land
masses.

While the precise tradeoff between the climate changes from wind farms
versus that from carbon-based power systems is still a matter of contention,
the fact that wind power isn't climate neutral leaps out of the simulations.

“We shouldn't be surprised that extracting wind energy on a global scale is
going to have a noticeable effect. ... There is really no such thing as a
free lunch,” said David Keith, a professor of energy and the environment at
the University of Calgary and lead author of the report, which appeared in
the Proceedings of the National Academy of Sciences.

Specifically, if wind generation were expanded to the point where it
produced one-10th of today's energy, the models say cooling in the Arctic
and a warming across the southern parts of North America should happen.

The exact mechanism for this is unclear, but the scientists believe it may
have to do with the disruption of the flow of heat from the equator to the
poles.

Depending on how much energy is ultimately generated by wind power, the
study's simulations say these changes could range from one-third of a degree
to 2 degrees Celsius.

One unexpected finding to the study is that the hotter temperate zone/cooler
Arctic effect exists in the simulations if the wind farms are concentrated
in a few spots or scattered across the world.

Prof. Keith and others involved in the study strongly caution, however,
against an anti-wind-power reading of their work.

“This is really a ‘but, yes' article,” says Stephen Pacala, a professor of
ecology at Princeton University, who is a co-author of the paper.

The “but” is the fact that wind farms would alter the climate, the “yes” is
the paper's preliminary estimation that if wind power produced one-10th of
today's energy, its climate-altering effects would be only one-fifth that of
the carbon dioxide it would replace.

But there may also be a “yes, but” lying in the future.

Prof. Keith argues that the paper is so ringed with uncertainties that one
cannot rule out scenarios where at some size wind farms might cause more
climate ill than good.

Specifically, the new paper's simulations do not include any of the
jaw-dropping calculations of the local temperature effects of large-scale
wind farms that appeared last month.

Dr. Pacala's then-graduate student Somnath Roy and others reported that
simulations of a wind farm in Oklahoma with 10,000 windmills could increase
temperatures by upward of 2C for several hours in the early morning. These
findings mirror an actual but previously ignored temperature rise that U.S.
government meteorologist Neil Kelley observed at an actual wind farm in
California in 1990.

The mechanism for local temperature changes are the vertical eddies that
behemoth windmills – these monsters can be 30 stories tall and have turbines
that spin at 400 kilometres an hour – would generate.

These local temperature shifts occurred because eddies heated, dried and
lifted ground air.

Even before publication, the new paper has been intensely controversial.

Joseph Romm, a former acting assistant secretary of energy for the United
States Department of Energy, wrote a blistering critique of early drafts in
which he pointed out that carbon dioxide-induced global warming might cause
a complete shift in the world's climate, whereas wind power would raise
local temperatures only.

The scientists involved in the PNAS paper spent 1½years rewriting it.

“The first version of the paper caused a lot of outrage, and we are trying
to pull our punches and not to draw conclusions,” Prof. Keith said.

Nonetheless, Dr. Keith says that after a rumour about his findings got out,
he was contacted by a group fighting the establishment of a wind farm in
Cape Cod in Massachusetts.

Wind power's proponents are cautiously optimistic that all climate changes
will prove minor when compared with the sea level rises, crop failures, and
disease spread that have been linked to the continuing use of carbon based
energy sources.

“It seems to me this is an area that requires further research to see if
there is a problem there ... although there doesn't seem to be anything in
the paper itself that leads you to that conclusion,” says Robert Hornung,
president of the Canadian Wind Energy Association.