Who Can See the Wind?
Who can see the wind? Neither you nor I
But when the leaves are trembling
The wind is passing by!
Who can see the wind? Neither I nor you
But when the trees are bending low
The wind is passing through!
by Christina Georgina Rossetti
As this children’s poem points out, the wind’s affect on the surrounding environment is a beautiful thing. But if you live near one of the many “wind farms” popping up all over the country, you may disagree. If that’s you, then “seeing the wind” means 400 foot tall wind turbines interrupting your landscape, and “hearing the wind” may mean loud “whirring” and “whoosh” sounds keeping you awake at night.
Wind power harvesting has many unintended consequences. Migratory bird patterns seem to be affected. Bats are routinely killed by the giant windmills in the sky. Many argue that the large obelisks visually disturb the landscape. Great distances from wind farms to population centers result in large transmission lines traveling great distances and costing even more. But believe it or not, the loudest group of nay-sayers is not the environmentalists or the economists; it’s the local residents who have to live near these wind farms, experiencing the sights and sounds firsthand.
Acoustically, large wind farms can cause low frequency noise issues due to the very large, and relatively slow turning, blades. This “whirring” sound is known to travel great distances and can be compared to the sound of a helicopter just starting up. Although the helicopter flies away; the wind farm is here to stay.
In contrast to the large wind turbines dotting the horizon, there are a variety of small, residential wind turbines being marketed today, including one by Cascade Engineering out of Grand Rapids, Michigan, called the Swift. These turbines generally produce very low noise levels because of their design and overall size. Although they will probably never produce all of the electricity that a single family residence requires, they do solve many of the problems that plague the multi-acre wind farms. They are compact, efficient, and cost effective.
If you are considering a wind turbine for your house or in your community, please consider the expert services of an acoustical consultant. Doing so can minimize the unintended consequences and can help ensure that seeing (and hearing) the wind remains a thing of beauty.