Library filed under Noise
Excessive low-frequency noise from open-cycle combustion turbine power plants has been recognized as a serious noise and vibration problem since the early 1970s. Yet, the problem still occurs, mainly because siting and specifying agencies are largely uninformed about the problem and because there are no standardized noise criteria in the U.S. to consult for guidance in avoiding low-frequency noise problems. Detailed sound pressure level measurements from five low-frequency problem sites are analyzed for support of a proposed criterion. The data are compared to noise and vibration thresholds. In addition, a small sampling of responses from residents to varied levels of low-frequency noise immissions is presented. This paper proposes a “C” weighted overall sound level criterion. The proposed criterion should be applicable to most industrial sources of steady low-frequency noise in addition to combustion turbines.
This review concentrates on the effects of low frequency noise (LFN) up to 100 Hz on selected physiological parameters, subjective complaints and performance. The abstract of the paper is provided below. The full paper can be accessed by clicking the links on this page.
The streamlined rules establish new procedures for demonstrating wind energy facility compliance with existing noise control standards. These standards are used by the Oregon Energy Facility Siting Council to evaluate the location of new energy facilities.
This is a letter written by Paula Stahl of St. George, West Virginia, about her experiences living in the neighborhood of the 66 MW Mountaineer Wind Energy Center. Formerly known as the Backbone Mountain Wind Farm, the 4,400-acre site has 44 turbines, 1.5 MW each, stretched along miles of ridgeline in Tucker and Preston counties. Ms. Stahl submitted the letter to the Berkshire Eagle and North Adams Transcript, neither of which has printed it.
They introduced the world to "environmentally friendly" energy, but now some of Europe's "greenest" countries are under pressure to backtrack on wind farms as public anger grows over their impact on the countryside.
These levels (noise) are much higher than predicted by the company.
The attached Pdf file provides a comprehensive overview of wind turbine noise related issues.
In order to study the physiological and psychological effects of infrasound on person, we have measured the changes of blood pressure and heart rate and also investigated subjective feelings of subjects exposed to infrasound.
"Wind turbines generate noise from multiple mechanical and aerodynamic sources. As the technology has advanced, wind turbines have gotten much quieter, but noise from wind turbines is still a public concern. The problems associated with wind turbine noise have been one of the more studied environmental impact areas in wind energy engineering. Noise levels can be measured, but, similar to other environmental concerns, the public's perception of the noise impact of wind turbines is in part a subjective determination. Noise is defined as any unwanted sound. Concerns about noise depend on 1) the level of intensity, frequency, frequency distribution and patterns of the noise source; 2) background noise levels; 3) the terrain between the emitter and receptor; and 4) the nature of the noise receptor. The effects of noise on people can be classified into three general categories (National Wind Coordinating Committee, 1998): 1) Subjective effects including annoyance, nuisance, dissatisfaction 2) Interference with activities such as speech, sleep, and learning 3) Physiological effects such as anxiety, tinnitus, or hearing loss"........ prepared by the Renewable Energy Research Laboratory Center for Energy Efficiency and Renewable Energy Department of Mechanical and Industrial Engineering University of Massachusetts at Amherst
"Onshore wind farms are a health hazard to people living near them because of the low- frequency noise that they emit, according to new medical studies. Doctors say that the turbines - some of which are taller than Big Ben - can cause headaches and depression among residents living up to a mile away."
Low Frequency Noise Low frequency noise is generated at very low frequencies, generally accepted to be at levels below 100 Hz and the audible range. There is presently no commonly accepted metric or standard for measurement, although several have been proposed or used in specific situations. Low frequency noise has been associated with wind turbine developments, as well as road, rail, sea and air traffic and other industrial applications such as cooling towers. It creates a large potential for community annoyance, and it is most often experienced inside of homes and buildings where resonance amplifies the sound, which is less easily heard outside. Because the frequencies are so low, the noise is often “felt” as a vibration or a pressure sensation. Reported effects include annoyance, stress, fatigue, nausea and disturbed sleep. Low frequency noise can be a factor at much greater distances from the noise source than audible noise. A case study in North Carolina in the 1980’s near a wind turbine installation documented low frequency noise problems at residences located over ½ mile from the turbine.2 While the phenomenon was originally believed to be associated with the older, down-wind designed turbines, the problem persists with newer wind farms. It has received particular attention in Denmark, and has been a topic considered in the UK, Scotland and Wales through a commissioned government project in 2001.
Plymouth GP Dr Amanda Harry has conducted her own survey on the effect of noise on people living near the Bears Down wind farm in Cornwall. Here, she reveals her findings.
3.8 Health & Safety Affected Environment, Environmental Impacts and Mitigation Measures "A number of comments submitted for the scoping process for the Desert Claim project EIS addressed concerns relating to potential health and safety issues. Specific topics indicated in these comments included certain possible hazards that are uniquely associated with wind turbines, such as blade throw and ice throw; health and safety issues associated with electrical and magnetic fields; more common hazards such as fire; and the incidence and impacts of shadow flicker, another phenomenon specific to wind turbines. Section 3.8 addresses these wide-ranging health and safety topics that have been identified as concerns for the environmental review. "
This significant research by van den Berg explains why turbine noise as far away as 1900 meters (more than 6,000 feet) is resulting in complaints by residents particularly at night. The paper concludes that noise immission predictions are not accurate and result in the understating of turbine noise levels, particularly during nighttime conditions.
Journal of Sound and Vibration "Since the start of the operation of a 30MW, 17 turbine wind park, residents living 500m and more from the park have reacted strongly to the noise; residents up to 1900m distance expressed annoyance. To assess actual sound immission, long term measurements (a total of over 400 night hours in 4 months) have been performed at 400 and 1500m from the park. In the original sound assessment a fixed relation between wind speed at reference height (10 m) and hub height (98 m) had been used. However, measurements show that the wind speed at hub height at night is up to 2.6 times higher than expected, causing a higher rotational speed of the wind turbines and consequentially up to 15 dB higher sound levels, relative to the same reference wind speed in daytime. Moreover, especially at high rotational speeds the turbines produce a ‘thumping’, impulsive sound, increasing annoyance further. It is concluded that prediction of noise immission at night from (tall) wind turbines is underestimated when measurement data are used (implicitly) assuming a wind profile valid in daytime."
Wind power is a relatively new generator of electricity in Sweden. Legislation and regulation regarding noise from wind turbines in Sweden have been discussed. Eja Pedersen at Halmstad University has at the request of the Swedish Environmental Protection Agency prepared this report as a base for further discussions on regulation and guidelines on noise from wind turbines in Sweden. The report reviews the present knowledge on perception and annoyance of noise from wind turbines in residential areas as well as in recreational areas. It also summarizes regulations in some European countries. The author Eja Pedersen is responsible for the content of the report. Stockholm, August 2003 SWEDISH ENVIRONMENTAL PROTECTION AGENCY Report 5308
Dr. Richard Truly, Director, National Renewable Energy Laboratory Dear Dr. Truly: It has come to my attention that an employee of the National Renewable Energy Laboratory (NREL), Mr. Larry Flowers: 1. Asserted, during public “forums” on wind energy held on March 25, 2003, in Ludington, Michigan, that I am in some way associated with the coal industry and, therefore, my analysis and writing concerning wind energy should not be considered credible. Over 150 people attended these public forums. 2. On March 27, 2003, distributed via email to one or more participants in the Ludington forums the attached undated, unsigned paper which questions the independence of my work, questions the truthfulness of my claim that my work on wind energy is self-financed, and makes other false and misleading statements. Mr. Flowers’ email forwarding the paper includes the following statement: “MI wind colleagues: here is a brief piece written in response to Glen [sic] Schleede misinformation. I suggest you distribute this to participants in the Ludington meeting…”
"This document aims to help developers, planning and enforcement authorities, other government agencies and the broader community assess environmental noise impacts from wind farms. The core objective of these guidelines is to balance the advantage of developing wind energy projects in this State with protecting the amenity of the surrounding community from adverse noise impacts. Wind farms need specific guidelines because wind turbines have unique noise generating characteristics and the environments surrounding wind farm sites usually have low ambient noise."