Massive rural wind farms are soaring symbols of America’s
renewable energy future, but ecoconscious urban dwellers might
wonder: How can I get in on the action? After all, the wind roars
through downtown concrete canyons, and in many blustery towns, wind
is a cheaper renewable source than solar power.
New ways to catch the breeze are in the works. Towering masts
and propellers don’t always fit in dense metropolitan areas, much
less in backyards, so developers are pursuing everything from
‘micro windmills’ that can be retrofitted onto existing homes and
businesses to wind-harnessing ‘energy skin’ for building
exteriors.
In Guangzhou, China, the proposed 69-story Pearl River Tower
looks like a United Nations building with two horizontal
creases-mechanical floors bent inward to funnel winds through eight
interior turbines. At the Lilliputian end of the scale,
Arizona-based Southwest Windpower makes a minitower that produces
about two-thirds of a home’s power and costs about $9,000 with
installation. California-based AeroVironment-which designed the GM
vehicle canonized in the recent film Who Killed the Electric
Car?-will soon sell turbines that resemble box fans and are
designed to line the roofs of big-box stores and distribution
centers. At least three companies tout a helical design they say
better captures capricious urban winds.
There is a reason this breezy dreamscape is still on the verge:
The urban environment is less hospitable to wind power. Nearby
buildings create turbulence that cuts turbine efficiency, and some
turbines cause vibrations that buildings can’t handle (as well as
noise that neighbors can’t stomach). Because of these and other
limitations, urban wind power won’t be a silver bullet but rather a
portion of the energy mix-single-digit percentages, according to
most experts.
Still, it’s suddenly a hot commodity. Southwest Windpower has
sold farmers and sailors small-scale wind generators for 20 years
but found a new market when turn-of-the-millennium technology
better connected turbines to homes on the power grid. As Southwest
prepared to ship its Skystream 3.7 turbines this fall, some
customers told company cofounder Andy Kruse, ‘I don’t care how much
it costs, I just want one.’
The Skystream, a three-blade turbine atop a 35-foot pole,
produces about 400 kilowatts a month in 12-miles-per-hour average
winds (a speed reachable in most of the Midwest, Southwest, and
coastal areas). The propellers hum along at under 45 decibels-quiet
enough to keep the neighbors happy. The unit requires half an acre
of unobstructed land, making it a product only an urban area’s
sprawl zone can love-but a lot of people live in suburbs and
exurbs, and green power generated there bypasses the nation’s
brittle, maxed-out power grid, where 9.5 percent of power is
literally lost in transmission.
The Pearl River Tower’s convex skin will funnel winds in a way
that produces 15 times the energy of free-standing turbines, claims
its architect-engineering designer, Chicago-based Skidmore, Owings
and Merrill. The funnel-dappled exterior is Pearl River’s sexiest
visible feature, but Roger Frechette, the firm’s director of
mechanical, engineering, and plumbing, says wind is just one of 28
efficiency and renewable strategies and will generate less than 10
percent of the building’s power.
Pearl River has its doubters. Paul Gipe, a wind advocate, says
the wind power component ‘is unlikely to ever be done, and if it’s
done, it will be removed in one or two years.’ He predicts that
engineers won’t master internal vibration and cost challenges, and
he points to Freedom Tower, the 1,776-foot-high World Trade Center
replacement that initially included wind power, which was later
removed. That building was also designed by Skidmore, Owings and
Merrill.
Such turbulence may represent growing pains rather than snake
oil. ‘Many states offer incentives for solar or small wind,’ notes
Southwest Windpower’s Kruse, ‘but before you qualify, you have to
go through rigorous testing by a third party saying this product is
going to work.’
Gipe sees more potential in smaller-scale urban wind farms that
have already sprung up within municipal borders. Atlantic City
debuted a five-tower complex this year. Just up the coast from Cape
Cod’s controversial ‘Cape Wind’ project, the 11,000-person Boston
suburb of Hull, Massachusetts, gets 13 percent of its electricity
from two towers and will be 100 percent wind-powered after four
more are built.
Grabbing urban wind may be less about flashy innovation than
about applying concepts proven elsewhere, Gipe says. ‘Just like
Europe has done for 20 years,’ he notes, ‘American harbors and
piers should be covered in wind turbines.’
