Wind Power's Foe: Wind Noise

As wind farms get built closer to where people live, the downsides to the massive installations get a lot more attention. Well, at least from nearby residents, who discover that the giant blades and turbines are neither silent nor particularly lovely to behold.

A small town on an island off the coast of Maine has sowed the wind and is now reaping the whirlwind. When three windmills, each with a 1.5 megawatt turbine built by General Electric Co. (NYSE:GE), went into production, residents immediately got more noise than they bargained for.

The state’s compliance limits call for no more than 55 decibels during the day and 45 decibels at night. According to tests run by the state, the sound levels at the wind farm are higher than 45 decibels at night, but no specific number was given.

A library, where patrons whisper, might generate about 30 decibels of ambient noise. That hum from your refrigerator racks up 40 decibels. A dial tone on your phone puts out about 80 decibels. So, 45 decibels is really pretty darn quiet.

However, it only takes a change of about 5 decibels to make a noticeable change in ambient sound levels. A rise of 10 decibels is double the noise. So if the wind farm is generating, for example, 50 decibels at night, that could be pretty loud.

But residents say they were told that ambient sounds would cover up the noise. That ambient sound is now the volume of the argument between the wind company and the residents.

Paul Ausick