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

Pros and Cons of Offshore Wind Farms

  • While the tower is around 3 miles north of Cleveland's shore, a viable wind farm would need to be at least 6 times farther out in Lake Erie. The wind monitoring tower measures the speed, direction, and height of Lake Erie's wind to determine if wind power generation on the lake is economically viable. (Photo courtesy of Lisa Ann Pinkerton)

Proposals for offshore wind farms, from the coasts of Texas to New England have the potential to generate more electricity than land turbines do. Lisa Ann Pinkerton reports these projects face various hurdles to becoming reality, but they’re not completely insurmountable:

Transcript

Proposals for offshore wind farms, from the coasts of Texas to New England have the potential to generate more electricity than land turbines do. Lisa Ann Pinkerton reports these projects face various hurdles to becoming reality but they’re not completely insurmountable:


Over the past few months, whenever the weather is favorable, Aaron Godwin of Green Energy Ohio rides a power boat several miles out into Lake Erie. Out on the on the city of Cleveland’s century old water intake structure he’s built a tall wind monitoring tower.


“The upper part of the tower is about 168 feet above the water, so we’re measuring at about 30, 40 and 50 meters, and dual instrumentation at each level, anemometers that measure wind speed and vanes that measure direction.”


Godwin’s got almost a year of wind data and today he’s installing a small wind turbine to confirm what he’s discovered: that the lake’s wind is roughly twice as strong as wind on land. So to Godwin offshore wind farms are inevitable, especially since 75 percent of the nation’s energy use is near coastal cities.


However, proposed projects everywhere face a number of hurdles. One of them is bird and bat migration. Some land turbines have killed creatures that flew too close. But in Denmark, where offshore wind is 15 years old, extensive water foul surveys show little change in bird behavior. Charlotte Boesen is an environmental planner for Dong Energy in Denmark.


“These birds, they do fly around the wind farm. They do not like flying over land you can say and maybe they in some sort they perceive the turbines or wind farm as a similar object.”


Even so, no wind project in the US will ever get off the ground without a full assessment of potential wildlife impacts. That’s why 60% of Lake Erie has already been ruled out by a preliminary study conducted by the wind consulting firm AWS True Wind. Its Executive Director Bruce Bailey says that leaves most of eastern Lake Erie still available, with the best wind about 15 miles northwest of Cleveland.


“That’s where the strongest winds would be found. With water depths still being under say 70 feet.”


Bailey adds the shallow depth of Lake Erie combined with its solid lake bottom and fresh water makes it more friendly to offshore wind generation than oceans.


“You wouldn’t have to deal with the corrosion or the extra cost to safeguard your hardware from corrosion if you’re sighted in a fresh water lake.”


Bailey adds designing against hurricanes makes ocean projects more expensive. On the flip side, Lake Erie’s been known to freeze.


“There are ways to deflect the ice from actually pushing too strongly against or lifting out a turbine foundation. Some of them have already been deployed already in offshore projects in Northern Europe, and some of them are located in locations where you might even get icebergs.”


Another concern is whether these turbines will ruin the natural beauty of America’s Coastlines, even though on the horizon a turbine might only look a big as a thumbnail. Walt Musel of the US Department of Energy says this worry is unfounded.


“It’s worth noting there are no projects in the United States, so most people who object to offshore wind have never seen one.”


Fifteen years ago, projects in Denmark faced the same prejudice. Today tourists rent boats to go see them.


Above all, perhaps the largest impediment to offshore wind power is its high cost. Installation in water is expected to be double the cost of on land construction. However, once farms are producing power, electricity companies are open to buying it.


Out on Lake Erie, Aaron Godwin is packing up his tools for the day. He says there is an up side to those high capital costs. He says in the future, turbines will be so large it’ll make more sense to manufacture the parts locally, giving America’s manufacturing industry a ray of hope.


“Energy is a guaranteed growth market. Wind power is the fastest growing energy sector in the entire world. Why would you not want to get involved in that guaranteed growth market? It just does not make sense.”


Godwin says if the US can clear these hurdles of public perception, engineering, and environmental impacts, he thinks the US economy might find a pleasant surprise: consistent, green energy, built and harnessed off the blue coasts of America.


For the Environment Report, I’m Lisa Ann Pinkerton.

Related Links

Wind Power Expands With Deregulation

According to the Worldwatch Institute, wind power is the fastest
growing energy source in the world – growing at an annual rate of 22%.
Here in the U-S, the Midwest accounted for most of this country’s wind
energy growth. The Great Lakes Radio Consortium’s David Hammond reports
that energy deregulation is fueling much of this development: