Thursday, March 23, 2006

More about Searsburg turbines

Tom Shea has shared more about his experience as neighbor of the small wind power facility in Searsburg, Vermont (see earlier post, "industrial droning"):

"No one I know has gotten accustomed to these monstrosities. ... I unfortunately have a clear view of these things and can hear them quite learly from inside my house. ... They have destroyed the peace and quiet that my family had enjoyed for over 40 years in this wilderness. They make noise when turning, and make really loud bangs when the turning mechanisms require work, which is just short of constantly."

Regarding the recent tearing off of half a blade on one of the machines:

"I am a chemical engineer, MIT '86. My unprofessional opinion is that there is not a chance that lightning was the cause of this failure."

Despite the company's report that lightning tore off the blade during a storm, some people have questioned that claim. For example:
I expect that the Searsburg blade was broken by a sudden gust from the side, perpendicular to the axis of rotation. In high winds the blades are stopped and turned so that their leading edges face into the wind to minimize stress. This works fine if the wind stays in line with the axis of the windmill. In the event of a sudden sideways gust, at least one of the three blades will be sufficiently vertical to be broadside to the wind and subject to severe stress. Since the blades are not turning there is little centrifugal stress on the blades to keep them straight. This means the blades can be bent to the point of cracking the inelastic fiber reinforcing, causing failure. In mountainous terrain the wind gusts are so variable in direction that this kind of blade failure is likely.
The company would rather claim lightning damage (1) because they probably have insurance against damage by lightning but not by wind and (2) because it doesn't look so good if it's the wind that damages the machines. This is at least the third blade failure at Searsburg.

And remember, these models are relatively small to those being proposed today.

wind power, wind energy, wind turbines Vermont