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Sunday, July 24, 2011

Wind power without the drama

CalTech's experimental vertical turbine wind farm
Note how close the turbines are to each other
Emerging technologies tend to advance pretty quickly. Today’s “state-of-the-art” often becomes a faint memory as scientists and engineers improve on their designs. Wind energy is no different.
One way that wind energy could become practical in a technology-averse community like Charlestown is through new advances in the development of Vertical Axis Wind Turbines (VAWT).
Instead of tall towers and propeller blades – a vision that has caused fear and division in this town – VAWTs don’t have to be tall and lend themselves to disguise. They can be home-sized or commercial-sized yet still generate enough energy to be a useful part of an alternative energy strategy.


Since Larry LeBlanc first proposed his plan for two industrial-sized commercial wind turbines to be placed on the moraine on the north side of Route One, we’ve heard a lot of negatives about wind energy – the turbines are ugly, kill birds, drive people insane with noise and shadow flicker and are going to cause mass casualties when they topple over.
While these criticisms are generally overblown or subjective, there are certainly some negatives about conventional propeller blade commercial turbines. Near the top of the list is inefficiency. Propeller turbines need to be placed at least 30 feet higher than the tallest nearby obstruction, and when clustered, as in a wind farm, they must be spread wide apart to prevent turbulence from interfering with their functions.
Scientists at the California Institute of Technology (CalTech) and engineers working for wind energy companies around the world are working on new designs for systems that eliminate most complaints including those about efficiency.
"Wind 'farms' are still rather inefficient when taken as a whole," explains Caltech professor of Engineering and Applied Science John Dabiri. "Because conventional, propeller-style wind turbines must be spaced far apart to avoid interfering with one another aerodynamically, much of the wind energy that enters a wind farm is never tapped. In effect, modern wind farms are the equivalent of 'sloppy eaters.' To compensate, they're built taller and larger to access better winds."

Of course, once you increase the height, you run into all the concerns we’ve heard in the Whalerock debate.

VAWTs provide several immediate benefits, according to Dabiri, including effective operation in turbulent winds like those occurring near the ground, a simple design (no gearbox or yaw drive) that can lower costs of operation and maintenance, and a lower profile that reduces environmental impacts.

"With respect to efficiency issues, our approach doesn't rely on high individual turbine efficiency as much as close turbine spacing. As far as failures, advances in materials and in predicting aerodynamic loads have led to new designs that are better equipped to withstand fatigue loads," says Dabiri.

So much shorter vertical turbines, closely clustered, could allow the town to tap the wind without the need for tall propeller turbines and lots of acreage.

Vertical turbines could also provide homeowners with an efficient way to generate wind energy for home use.

Urban Green vertical turbine
15 foot tall, 4 KW rating
Companies like Urban Green Energy now sell vertical axis turbines as small as six feet tall (rated at 600 watts) to 15 feet tall (rated at 4 KW) that you can build yourself, at least theoretically. Personally, for me, the three most dreaded words in the English language are “some assembly required.” But we’re talking about an accessible technology that could be placed in your backyard or roofline.

According to most of the on-line surveys I’ve taken, based on our average household electricity usage, 4 KW would be fine for meeting our needs.

Honeywell has come up with a new design for a home-use propeller turbine – the Windtronics - that is less than six feet in diameter and can be mounted on a rooftop. It generates energy at wind speeds of as little as half a mile per hour.

These are just a couple of examples of new approaches to wind energy. I noted several others in my article about whether Charlestown homeowners can harness wind power for home use.

Various ways the Honeywell Windtronics system can be mounted
on homes or businesses
Because of the fear created by Larry LeBlanc’s Whalerock project, Charlestown has over-reacted with an anti-wind ordinance that takes a Draconian and frankly anti-environmental approach. The ordinance currently bans any and all devices that convert wind power into electricity. And even after the blanket ban is lifted, home use wind power (under 5 KW) is subject to nearly impossible restrictions.

Charlestown’s anti-wind ordinance must be changed. We need to get past the Whalerock trauma and set aside some of the ridiculous, unscientific anti-wind propaganda and look at wind power as a proven technology as well as an opportunity to wean ourselves from fossil fuels.

Author: Will Collette