Editor's note: This commentary is by Willem Post, a retired engineer, who now writes about energy issues, currently specializing in energy efficiency of buildings and building systems. He is a founding member of the Coalition for Energy Solutions.
[I]n violation of Act 250, Vermont has been shamelessly trashing its pristine ridge lines with 500-foot tall, environmentally destructive, noise-making, property-value-reducing, health-damaging wind turbine plants that produce unsteady, grid-disturbing, variable, intermittent (i.e., non-dispatchable) energy at a cost of about 10 cents/kWh (with subsidies), and about 15 cents/kWh (without subsidies).
The passing of a rotor blade past the mast creates a burst of audible and inaudible (infrasound) sound of various frequencies, base frequency is about 1 Hz, similar to a person’s heartbeat, and the harmonics, at 2, 4 and 8 Hz, are similar to the natural frequencies of other human organs.
Infrasound interferes with the body’s natural biorhythms, and likely causes adverse health impacts on nearby people and animals, including DNA damage to nearby pregnant animals, and their fetuses, and newborn offspring.
Because infrasound travels long distances, a buffer zone of about 1 mile (1.6 km) would be required to reduce these adverse impacts on people. However, roaming animals would continue to be exposed. See Link.
1) Poland is considering a proposed a law with a 2.0 km (1.24 mile) buffer zone between a wind turbine and any building. That means at least 65 percent of Poland would be off limits to wind turbines. Most future wind turbines plants likely would be offshore.
2) Denmark has a buffer zone of four times total height of wind turbine, about 4 x 500 = 2000 feet, about 0.61 km (no exceptions), and it also has a requirement noise cannot exceed:
• For dwellings, summer cottages, etc.: 39 dB (wind speeds of 8 m/s, 18 mph) and 37 dB (wind speeds of 6 m/s, 13 mph)
• For dwellings in open country: 44 dB (wind speeds of 8 m/s) and 42 dB (wind speeds of 6 m/s) Link
For both categories of areas, the mandatory limit for low frequency noise is 20 dBA, which applies to the calculated indoor noise level in the 1/3-octave bands 10-160 Hz, at both 6 and 8 m/s wind speed. The purpose of the regulation is to ensure neither the usual noise, nor the low frequency noise, will annoy neighbors when the wind turbines operate. Link
The below regulations describe the methods and time periods over which sounds are to be measured.
On page 4, paragraph 5.1.1 mentions averaging over various periods. Only the worst average readings of a period are to be considered for compliance.
On page 4, paragraph 5.1.2 mentions a 5 dB penalty must be added to the worst average readings for a period for clearly audible tonal and impulse sounds with frequencies greater than 160 Hz, which would apply to wind turbine sounds.
“If the perceived noise contains either clearly audible tones, or clearly audible impulses, a 5 dB annoyance penalty shall be added to the measured equivalent sound pressure level”
On page 6, paragraph 5.4 mentions limits for indoor A-weighted low frequency noise 10-160 Hz, and G-weighted infrasound 5-20 Hz. The 5 dB penalty does not apply to low frequency and infrasound noises, i.e., 160 Hz or less. Link, pages 3-4.
In many cases, a proposed wind turbine plant would not be approved, because of the 5 dB annoyance penalty. The noise of wind turbines varies up and down.
The sophistication and detail of the Danish wind turbine code, issued in 2011, is light years ahead of the Public Service Board code. To compare the Danish noise code with the Vermont code is like comparing apples to watermelons.
NOTE: At 800 uPa (micropascal) the SPL = 20 log (800/20) = 32 dB; at 1600 uPa, 38 dB; at 3200 uPa, 44 dB, where 20 uPa, the reference pressure, is the lowest SPL the human ear can sense.
The new Danish regulations on noise from wind turbines underestimate the indoor levels of low-frequency noise, mainly due to the use of too large sound insulation numbers of houses for frequencies above 63 Hz. As shown in below links, the new Danish regulations (issued 2011) are therefore inadequate to protect the nearest neighbors from annoying low-frequency noise. Link. Link. Link.
As a result of those requirements, onshore, about 278 wind turbines were added and 255 decommissioned, during the past four years; the new rules were in effect January 2012.
Assuming 278 x 3 MW (new) – 255 x 0.51 MW (old) = 874 – 131 = 703 MW added during the past four years, 703/3096 (end 2011) = 22.7 percent MW growth.
Offshore increase was 400/1271 = 45.9 percent, during the past four years. Offshore is growing twice as fast as onshore. By law, offshore wind turbines must be beyond the horizon, i.e., at least 10 miles from shore. Link. Link.
3) Vermont’s wind turbine code calls for 45 dB, averaged over one hour (no distinction for daytime and nighttime), as measured at a nearby residence. Vermont’s code has no required buffer zone, and no required infrasound limit, and no 5 dB annoyance penalty.
Ever-present, irregular, randomly occurring noises, with higher dB values, say up to 51 dB, can occur, during that hour, but the “averaging over one hour” makes these noises disappear; hence the reason for Denmark having a 5 dB annoyance penalty.
It is the ever-present randomly occurring, audible and inaudible peaks that are most annoying, and they occur mostly at night. These noises adversely affect the health of nearby people. As a minimum, they deprive nearby people from getting a good night's sleep to recover from the prior day and to get ready for the next day.
4) The sophistication and detail of the Danish wind turbine code, issued in 2011, is light years ahead of the Public Service Board code. To compare the Danish noise code with the Vermont code is like comparing apples to watermelons. Denmark has been a leader in wind power for at least 40 years.
The PSB did not need a “learning curve” four to five years ago. It could have copied major parts of the Danish code to bring its code to where is actually protects nearby Vermonters. Link.
Denmark holds infrasound is harmful to health of nearby people and animals. Therefore it has an infrasound requirement in its wind turbine code. The PSB is still in denial.
Vestas, a Danish conglomerate that supplied the Lowell wind turbines, would never get a PSB-type noise code in Denmark, and soon also in Poland. New Hampshire and Maine have lower dB levels than Vermont. Vermont is lagging regarding protecting its people!
It is an outrage for the PSB, Department of Public Service, et al. to claim these environment-destroying, wind turbines are a public good for nearby Vermonters, especially when they knew these sound outcomes before the Lowell turbines were erected, according to various acoustics engineers, who testified during PSB hearings, and who reviewed my article.
It is hypocritical for GMP, Blittersdorf, et al. to crow, with straight faces, about being in “compliance” with the shabby PSB wind turbine noise code. They, and the wind turbine vendors wrote, and the PSB, after meaningless “hearings,” adopted that code four years ago. DPS Commissioner Chris Recchia, et al. actually defend it.
That code is not worth the paper it is printed on. The rewriting of that code, to protect Vermonters, is long overdue.
Vermont’s wind turbine saga further deceives and burdens already hard-working, struggling, over-taxed Vermonters, who are forced to swallow such shenanigans (poor Vermont saving the world?), and to endure the shame of the largest EB-5 fraud in the U.S., while trying to make ends meet in a near-zero-real-growth Vermont economy, with near-stagnant real household incomes, reduced by increased taxes, fees and surcharges, year after year.