Page 23 - Volume 9, Issue 3

WIND TURBINE NOISE
Nancy S. Timmerman
25 Upton Street Boston, MA 02118
The Wind Turbine Industry in the USA
“Acknowledge the problem
In 2011, a private study was com- missioned to determine why there were At the present time (2013), Vestas, and work to eliminate it.” so many strong complaints about the loss of well-being and hardships experi- Gamesa are involved in supplying the machines for enced by people living near large industrial wind turbines
Siemens, General Electric, and
the production of electricity from the wind. In the United States, there has been a production tax credit for sustainable energy. This credit has encouraged investment in wind farms in the United States. According the the American Wind Energy Association’s Annual Report for 20121, cumu- lative wind generating capacity in the United States was 60 GW (gigawatts). Some 13,131 MW (megawatts) were installed in 2012. The top states by installed capacity were Texas, California, Iowa, Illinois, and Oregon. That installed capacity represents about 3.5%2 of the electrical generation in the United States.
Massachusetts — Falmouth
In the Commonwealth of Massachusetts, where the author lives and works, the debate about wind turbine noise has been in the press. Paralleling the national practice, the state government has been encouraging the use of renewable energy, including wind, for at least the past five years. One project which has caused considerable trouble is located in Falmouth, Mass., on Cape Cod.
The story of the wind turbines in Falmouth is taken from a report at the end of April, 2013 in the Boston Business Journal3. There are, at this time, three wind turbines in Falmouth: Wind 1, Wind 2, and Notus. They are 1.65 megawatt turbines which the Massachusetts Technology Collaborative (MTC) bought in December 2005 for $5.3 mil- lion using the state’s rate-payer-funded renewable energy trust fund. The goal was to speed up the shipment of the tur- bines, which were in high demand at the time, to the Town of Orleans. But the Orleans project fell through in 2007. The MTC tried to use them in Fairhaven, but there was a legal challenge, and in Princeton and Gloucester, but Vestas wouldn’t approve the locations. By mid-2008, the MTC had put the turbines up for sale. The windmill parts sat unused at facilities in Texas and Canada. In 2009, the Town of Falmouth voted to purchase Wind 1 to save on electric costs at its power-hungry sewage treatment plant. At the town meeting, there was near-unanimous support to purchase the turbine. The town subsequently bought Wind 2, a similar turbine, from Vestas. A Falmouth landowner bought Notus from MTC, and installed in it a nearby industrial park. When Wind 1 started spinning in March 2010, complaints from the neighbors soon started. The nature of the complaints includ- ed unexpected amount of noise leading to sleeplessness, headaches, and other problems. The Town believes it would have been better served by a smaller turbine, and/or a quieter blade technology.
4
operating in Falmouth, Mass . The work has also been pre-
sented at Inter-Noise in New York City in August 2012. The study focused on whether or not there was infrasonic and low frequency noise from Wind 1, a municipally-owned Vestas V82. By March of 2011, the Falmouth town selectmen volun- tarily decided to curtail Wind 1 operations when hub wind speed exceeded 10 m/s. Since the study was performed after that, the work focused on the nearby Notus. The work was performed in the Spring of 2011 and reported in December 2011. Of note in the study was:
The investigators were surprised to experience the same adverse health symptoms described by neighbors living at this house and near other large industrial wind turbine sites. The onset of adverse health effects was swift, within twenty minutes, and persisted for some time after leaving the study area. The dBA and dBC levels and modulations did not correlate to the health effects experienced. However, the strength and modulation of the un- weighted and dBG-weighted levels increased indoors consistent with worsened health effects experienced indoors. The dBG-weighted level appeared to be controlled by in-flow turbulence and exceeded physiological thresholds for response to low-frequency and infrasonic acoustic energy as theorized by Salt. The wind turbine tone at 22.9 Hz was not audible yet the modulated amplitudes reg- ularly exceeded vestibular detection thresholds. The 22.9 Hz tone lies in the brain’s “high Beta” wave range (associated with alert state, anxiety, and “fight or flight” reactions). The brain’s frequency follow- ing response (FFR) could be involved in maintain- ing an alert state during sleeping hours, which could lead to health effects. Sleep was disturbed during the study when the wind turbine operated with hub height wind speeds above 10 m/s. It took about a week to recover from the adverse health effects experienced during the study, with lingering recurring nausea and vertigo for almost seven weeks for one of the investigators...
The research is more than just suggestive. Our experiencing of the adverse health effects reported by others confirms that industrial wind turbines can produce real discomfort and adverse health impacts. Further research could confirm that these ill effects are caused by pressure pulsations exceed- ing vestibular thresholds, unrelated to the audible
22 Acoustics Today, July 2013