Rooftop Wind Power

  • Power lines lead from a wind turbine placed near a coast to catch steady breezes. New designs for smaller turbines might be used in urban areas where wind is more turbulent. (Photo by Lester Graham)

The government wants 20% of the
energy generated in the nation from renewable
resources. Today, we’re at a mere fraction of
that goal. Lisa Ann Pinkerton reports experts
believe the US could get there sooner if wind power
technology can be moved successfully to where the
electricity is actually consumed, America’s
cities:

Transcript

The government wants 20% of the
energy generated in the nation from renewable
resources. Today, we’re at a mere fraction of
that goal. Lisa Ann Pinkerton reports experts
believe the US could get there sooner if wind power
technology can be moved successfully to where the
electricity is actually consumed, America’s
cities:


Right next to Lake Erie, a large wind turbine spins hypnotically in the
breeze. Its three big propeller blades provide only around 6% of
the energy consumed at the museum where it’s located, the Great Lake
Science Center. So the big turbine is mainly for educational purposes.
The museum’s Executive Director, Linda Abraham Silver says turbine
catches the steady winds off the lake:


“We don’t want turbulence, that’s right. Steady wind is what produces
the best energy and saves the gears and instrumentation inside.”


The single wind turbine stands in a wide open space near Lake Erie, but here
on the streets of downtown Cleveland, the wind is blustery and
unpredictable. These conditions are hostile to traditional turbines.
So the conventional wisdom was wind power couldn’t flourish in urban
environments… that is, until now.


“I think the problem was the propeller, not the whole idea that wind
power was somehow unable to be captured in the city. Some people even tell
you there is no wind power in the city”


Bill Becker is an urban wind developer from Chicago. He’s abandoned the three-propeller design for a horizontal one.
And it kind of looks like a metal DNA double-helix strand. He says it’s
actually two turbine designs in one so the machine can function in low and high winds. The turbine, manufactured
by Aerotecture, is a lot smaller than traditional ones so it can be mounted on rooftops. Becker’s installed 16 on skyscrapers in
Boston and Chicago. They can generate enough electricity to power two homes annually in a typical breezy day.


Becker’s not the only inventor who thinks there are better alternatives
to expansive turbine wind farms sprouting up on ridges and bluffs
across the country. And in England, the three-blade concept isn’t dead
yet.


The company Quiet Revolution has a vertical turbine with blades curving
up and down it. It creates power in even the slightest breeze, but that
power isn’t any more than Becker’s model and it costs 4 times as much.


Instead of catching open wind, in California entrepreneurs are
capturing a very specific type of wind: breezes traveling up and over
building parapets. Those are walls that extend past the roof lines of
big box retailers and factories:


“There’s a potentially great wind resource on those buildings that’s
not being tapped into today.”


Spokesman Steve Gitlin says the company AeroVironment is tapping into
this wind with systems of 15 turbines each. These futuristic rotating
fans, each about six feet tall, line the parapets of flat-roofed
buildings:


“What we’ve done is figured out there’s a unique acceleration of wind over that edge of the building
so the turbine’s designed to actually extend above and angle slightly downward
over that acceleration zone.”


The AeroVironment system is the most expensive… six times as much as the Aerotecture double-helix
design and generates slightly more electricity. It does, however, operate in very low wind, five miles per hour or less.


Ken Silverstein says this range in cost and efficiency shows the urban wind industry is
still growing. He edits Energy Biz magazine, and
adds to make an impact on the market, these turbine costs must come
down. And the government could help jumpstart the industry:


“It needs to develop, it needs to reach economies of scale so that the
technology improves, so that the costs come down and so that wind becomes more widespread than it is today.”


But Silverstein says, urban wind designs like these offers the hope
that businesses and even homeowners could capture the energy of the wind
directly on their own.


For the Environment Report, I’m Lisa Ann Pinkerton

Related Links

Wind Energy Sweeping Away Wildlife?

  • A single wind turbine can change air currents, creating dangerous winds for birds and other airborne wildlife. (Photo by Michael Tyas)

Wind energy is one of the fastest growing sources of new electricity in the United States. For some environmentalists, that’s
good news. Wind turbines don’t spew smoke into the air. There’s no nuclear by-product. But there is an environmental risk. To see it, you have to view the wind turbines through the eyes of a bird.
The GLRC’s Dustin Dwyer has more:

Transcript

Wind energy is one of the fastest growing sources of new electricity in the United States.
For some environmentalists, that’s good news. Wind turbines don’t spew smoke into the
air. There’s no nuclear byproduct. But there is an environmental risk. To see it, you
have to view the wind turbines through the eyes of a bird. The GLRC’s Dustin Dwyer
has more:


Chandler Robbins has spent a lot of time studying how birds kill themselves. He says he
would go out on windy nights to the Washington Monument in Washington, D.C. He’d
stand at the bottom of the 555 foot tall obelisk and watch the birds at the top:


“Just as they get to the tower, they just go around the edge of it and bang, the turbulence
from the winds going around the tower, sweeps those birds against the tower, and they’re
killed.”


Speaking at a conference, Robbins tells the crowd he once watched more than 500 birds
slam into the monument in one night, and that monument is standing still. Now imagine
wind turbines, some of them about as tall as the Washington Monument, with spinning
blades that reach nearly a football field in diameter.


Alex Hoar is with the U.S. Fish and Wildlife Service. He says a single turbine can now
change air currents for three acres around the turbine itself:


“So, if you put up a hundred turbines, the blades are sweeping 300 acres. So, that’s a large
space. And what we don’t know is when are birds and bats at risk.”


We don’t know because no one has really studied it. Both Alex Hoar and Chandler
Robbins say scientists know a lot about where birds take off and where they land. They
know about migration patterns, but they don’t know about what birds do, or where they
go while they’re in the air.


So, with more wind farms being built across the country, it’s not clear what affect they
might have on bird populations, but some suspect it won’t be good. Peter Kailing works
with an environmental consulting company. He recently did an environmental impact
study for a new 47 hundred acre commercial wind farm in Michigan. He says scientists
can learn a lot from the wind farms that have already been built. He says the ones that
have done the most damage to wildlife have a few things in common:


“The turbine was in a narrow valley, or a mountain-pass, or on the edge of a large
water body with steep wooded cover that was used by migrating songbirds, there’s almost
always a topographical association.”


Weather also plays a role. Peter Kailing and others say that birds tend to avoid cloud
banks by flying under them. That could put them in the path of turbine blades. So, one
way to limit damage would be to shut the turbines down on cloudy days.


Chandler Robbins says better technology could also limit damage. He says turbine blades
could be equipped with sensors:


“If a bird or a bat collided with that blade, it would set up enough vibration so that the
blade could be feathered temporarily to avoid other birds striking until the immediate
problem is over.”


Feathering essentially means that you twist the angle of the blade so that wind passes
over it, rather than pushing the blade into a spin. That way, birds aren’t sucked into it.
It’s basically the turbine’s braking system. Some say you don’t even need a sensor on the
turbine. They say engineers could monitor radar and thermal imaging. That would tell
them if any migrating birds are in the area, and if they are, feather the blades.


Of course, the absolute safest solution in the short term might be just to stop building
wind farms, but you’d be hard-pressed to find anyone who thinks that’s a good idea.
Most seem to realize that any way of making electricity will have some impact on the
environment. The question is what can be done with each of them to minimize the risk.
With wind energy, that work is just getting started.


For the GLRC, I’m Dustin Dwyer.

Related Links

Bubble Barrier Tweaked for Asian Carp

  • Scientists are always looking for a new deterrent for the Asian Carp. (Photo courtesy of the U.S. Fish and Wildlife Service)

Scientists across the region are expanding their arsenal of technology to fight invasive species. One research team hopes to use sound and bubbles to keep an invasive fish out of the Great Lakes. The Great Lakes Radio Consortium’s Shawn Allee has more:

Transcript

Scientists across the region are expanding their arsenal of technology to fight invasive species. One research team hopes to use sound and bubbles to keep an invasive fish out of the Great Lakes. The Great Lakes Radio Consortium’s Shawn Allee has more:


For years, biologists worried Asian Carp could enter Lake Michigan through a canal near Chicago. The Army Corps of Engineers is building an electric barrier at the canal to block the carp’s progress.


But researchers at Illinois-Indiana Sea Grant are devising a back-up plan. Researcher Mark Pegg says new devices could shoo fish away with bubbles and sound.


“The bubbles themselves are causing a lot of turbulence in the water that the fish don’t like. On top of that, they’re emitting a really loud noise, at least to the fish anyway, so that’s sort of a one-two punch.”


Pegg says the combination of bubbles and sound works in another way too. Bubbles actually amplify underwater noise, so sound travels further. The Sea Grant team will continue testing the devices. In the meantime though, even if it works, the project might hit a roadblock: the existing barrier program has no extra money for the system.


For the GLRC, I’m Shawn Allee.

Related Links