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GMP reports on Kingdom Community Wind sound levels

26 February 2013

COLCHESTER, VT…. Green Mountain Power today filed with the Vermont Public Service Board the results of its first monitoring of sound levels in the communities surrounding the Kingdom Community Wind farm in Lowell.
      
The results of the continuous monitoring showed that the project met the standards required by the Vermont Public Service Board (PSB) for all but two brief isolated time periods. The PSB requires that sound outside nearby homes not exceed 45 decibels, which is generally the background sound of a library.
              
“We were pleased to demonstrate results that show the actual sounds from the wind turbines are what we expected from our modeling,” said Dorothy Schnure, GMP corporate spokesperson. “Sound monitoring will occur at four locations for at least a two week period every season for two years.”
      
The first round of testing was conducted between Dec. 6, 2012, and Jan. 15, 2013. The monitoring records sound when turbines are operating as well as periods when the turbines are shut down in order to accurately measure background noise. Under the monitoring plan approved by the PSB, two different methods are being used to analyze sound levels. An independent third party reviewed the data collected and verified that it was sufficient to make a determination of compliance.
      
Turbine noise never exceeded the standards at any of the sites by the first method of analysis, and under the second method the turbine noise was above the PSB standard at one of the four monitoring sites for less than two hours out of the 703 hours tested. In this limited instance, the sound was measured at 45.3 decibels, or 0.3 decibels above the standard. Sound levels never exceeded 45 decibels at the other three sites under either method of analysis.
      
The report also indicates that at one site there were prominent discrete tones during two of 82 separate measurement periods, each period lasting one hour. There were no prominent discrete tones at the other three sites and the tones never occurred after the initial two testing days. The next testing phase, which is already underway, will help determine whether the tones were an isolated early operations incident and whether on-going turbine maintenance has eliminated the tone.
      
The second phase of testing began February 19 and will run at least two weeks.

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About Green Mountain Power
Green Mountain Power (www.greenmountainpower.com) generates, transmits, distributes and sells electricity in the state of Vermont. The company, which serves more than 250,000 customers, has set its vision to be the best small utility in America. 


Contact: Dorothy Schnure, Green Mountain Power,
Desk: (802) 655-8418, Cell: (802) 324-4418
Dorothy.Schnure@greenmountainpower.com