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Wind towers generate noise in addition to power

I have been a summer resident of Barton with a house on the eastern shore of Crystal Lake for more than 50 years. While I’m not an expert on wind-generated power, I am an electronic engineer and have worked in research and development for more than 35 years, so I am a capable interpreter of technology.

The common belief is that wind generators contribute to the common good. That they supply power that is emission free; that they reduce this country’s dependency on coal, gas, oil, and nuclear powered generation plants; and that they reduce emissions of undesirable gases and particulates. Like most people, I assumed that this was a good tradeoff; add 1,000 megawatts of wind generation capacity and subtract 1,000 megawatts of traditional generation capacity.

But it is a naive view. There is a huge base of installed wind-generated power capacity worldwide that has been operating for many years. Many of the fundamental lessons of wind power have already been learned.

In 2004, E.ON Netz, the transmission manager for about a third of Germany’s transmission facilities or grid, released a report on wind generated power. At the end of 2004 there was 16,394 megawatts of wind generation capacity in Germany, the largest of any country in the world.

The report referred to two major studies in Germany that reached essentially identical conclusions: Wind power in 2004 contributed 8 percent of its installed capacity (that of all generating facilities running or not) to base load capacity (that of generating facilities running year round). Projecting to the year 2020 and assuming an installed wind power capacity of 48,000 megawatts, the report states only 2,000 megawatts of traditional base load capacity could be replaced. That is just 4 percent.

As a justification, not only does the reduction of traditional power generation have little value, especially relative to the huge costs, it can be dangerous.

Appealing to common beliefs while brushing aside the harder reality is intended to guide people into accepting an illusion. The machines that get installed later are anything but an illusion.

Wind turbines are not like anything ever seen in the Northeast Kingdom; they are so foreign they have more in common with exotic predators last seen 65 million years ago. A wind farm is heavy industry and these turbines are nothing like the windmills on farms.

Constant wind turbine noise in your life may be part of what it means to have such a heavy industrial facility in your neighborhood. Power companies know a lot about this, but be suitably cautious about what you hear from them. Because the effects can be so serious for those who have to live with wind turbines, they have significant motivation to accept understated estimates.

Take as an example the formal engineering estimates of noise power levels for the proposed Sheffield wind farm. The estimate is based upon 26 Gamesa G87 wind turbines (since replaced by the Clipper Liberty), with a maximum height of up to 399 feet. At approximately 3,000 feet from the nearest wind turbine, the noise power is estimated to range from 30 to 40 dBA (dBA is the standard measure of noise power).

The existing Meyersdale wind farm in southeastern Pennsylvania consists of 20 NEG Micon wind turbines (now owned by Vestas) with a height of 385 feet. At about 3,000 feet from the nearest wind turbine, the noise power of this facility was measured to be 75 dBA over a 48-hour period.

The difference between the estimated and real noise power of 35 to 45 dBA is not just large, it is huge; a factor of up to about 32,000 times larger than the estimates for the Sheffield facility. The differences can not come even faintly close to being accounted for by the difference in wind turbine manufacturers. It is plain to see that there is something very wrong with these numbers. If the measurement is correct, which it almost certainly is, then the power company estimates are seriously understated.

To your ear, a 45 dBA increase will sound about 23 times louder. And what does 75 dBA mean? Well, 75 dBA is above the EPA level of 70 dBA at which it says most people can not sleep. Or, if you like something familiar, louder then a vacuum cleaner.

This is far from the simple story that proponents of wind power might have you believe. I do not wish to knock the hope of wind power. But equally I do wish people to be fully informed and understand the serious shortfall of its promise, the choices they make, and their potentially harsh consequences.

By Bill Metcalf


11 February 2007