Wind Farm Noise Management Based on Determinants of Annoyance

Wind energy in Europe is aimed to grow at a steady, high pace. Wind turbine noise is an important issue for residents. Environmental noise management aims to reduce the exposure of the population, usually based on acoustics and restricted to a limited number of sources (such as transportation or industry) and sound descriptors (such as Lden). Individual perceptions are taken into account only at an aggregate, statistical level (such as percentage of exposed, annoyed or sleep-disturbed persons in the population). Individual perceptions and reactions to sound vary in intensity and over different dimensions (such as pleasure/fear or distraction). Sound level is in fact a weak predictor of the perceived health effects of sound. The positive or negative perception of the sound (source) is a better predictor of its effects. This article aims to show how the two perspectives (based on acoustics and on perception) can lead to a combined approach in the management of environmental sound. In this approach the reduction of annoyance, not primarily of level, is the main aim. An important aspect in this approach is what a sound means to people: does it lead to anxiety or worry, is it appropriate? The available knowledge will be applied to wind farm management: planning as well as operation.

The effect of wind turbine noise on polysomnographically-measured and self-reported sleep latency in wind turbine noise naïve participants

Study Objectives Wind turbine noise exposure could potentially interfere with the initiation of sleep. However, effects on objectively assessed sleep latency are largely unknown. This study sought to assess the impact of wind turbine noise on polysomnographically-measured and sleep diary-determined sleep latency compared to control background noise alone in healthy good sleepers without habitual prior wind turbine noise exposure. Methods Twenty-three wind turbine noise naïve urban residents (mean±standard deviation age: 21.7±2.1 years, range 18-29, 13 females) attended the sleep laboratory for two polysomnography studies, one week apart. Participants were blind to noise conditions and only informed that they may or may not hear noise during each night. During the sleep onset period, participants were exposed to counterbalanced nights of wind turbine noise at 33 dB(A), the upper end of expected indoor values; or background noise alone as the control condition (23 dB(A)). Results Linear mixed model analysis revealed no differences in log10 normalized objective or subjective sleep latency between the wind turbine noise versus control nights (median [interquartile range] objective 16.5 [11.0 to 18.5] versus 16.5 [10.5 to 29.0] minutes, p = 0.401; subjective 20.0 [15.0 to 25.0] versus 15.0 [10.0 to 30.0] minutes, p = 0.907). Conclusions Although undetected small effects cannot be ruled out, these results do not support that wind turbine noise extends sleep latency in young urban dwelling individuals without prior wind turbine noise exposure.

Perceptions of Wind Turbine Noise and Self-Reported Health in Suburban Residential Areas

Wind turbines play an important role in the worldwide mission of producing renewable energy. The development toward integrating large-scale wind turbines in the urban environment has raised concerns over the noise impacts on urban residents. While most of the existing studies on wind turbine noise (WTN) have focused on rural settings, this paper investigates the relationship between WTN, noise perception and self-reported health of people, and controlling for background characteristics of the residents in urbanized areas. Questionnaire surveys were carried out around three suburban wind farms in the UK with 359 respondents. A-weighted sound pressure levels of WTN were predicted using noise mapping, for the most exposed façade of each dwelling of the respondent. The dose-response relationship was found between WTN and annoyance, moderated by age and degree of education. WTN was associated with some aspects of self-reported health, including raised health concerns, having headaches, nausea, and ear discomfort, but was not related to sleep disturbance directly. Noise sensitivity, attitudes to wind energy, and visibility of the wind turbines were found to significantly influence self-reported health. By employing a second variant of the questionnaire with the research aim masked, this study also addressed the focusing effects induced by the questionnaire design. The significant differences in the reported adverse health between questionnaire variants implied focusing bias among the sample who knew the research purpose. This elicited a methodological finding that should be noted in future research.

Computational Fluid Dynamics Analysis of Wind Lens

The wind-lens turbine consist of shrouded diffuser which increases the wind speed at rotor, developing electric power even in low speed wind. Energy crisis is one of the major problems facing the countries globally. One of the methods to overcome energy trouble is to use the energy available efficiently and also to reduce the energy that is being wasted. The fact that non-renewable sources of energy become cause of pollution and the increased ecological hazards and their rate of depletion has required to use of nonconventional and renewable sources. Therefore to adopt the methods of energy recovery is required. Energy recovery is a technique used to reduce the vitality input to an overall system by exchanging the energy from one system of an overall system to another. Wind lens turbine is the next generation small wind which can be installed anywhere. It has significant reduction in wind turbine noise, concentration of wind energy, compact and highly efficient, adaptable to the surroundings, highly safe systems and significant reduction in birds strike.

The test bench for the assessment of the impact of wind turbine noise on human performance

Among the factors related to the operation of wind farms, wind turbine noise has to be seen as a source of annoyance for both people living and working near wind farms. A method and a test bench to conduct noise annoyance tests of different types of wind turbine noise in laboratory conditions have been developed. The test bench is based on a multi-channel sound reproducing system using the DANTE network (in which digital acoustic signals are broadcast over Ethernet) and is compiled in the acoustic test chamber. The test bench consists of 19 speakers, including 17 Avantone MixCube studio monitors and 2 LS600 woofers. During the tests a study subject is assessed in terms of efficiency and performance using a computer-based ALS test from the Vienna Test System. The paper describes the test method, the test bench and the results of the pilot studies carried out to assess the impact of wind turbine noise on human performance.

Amplitude modulations increase annoyance due to wind turbine noise immission

Current literature suggests that annoyance of wind turbine noise is strongly affected by amplitude modulations (AM). A survey was carried out at five German residential study sites near wind turbines with a total of about 500 residents to study the effects of AM in more detail. Annoyance, disturbances, and the perception of wind turbine noise characteristics, including AM, were assessed. For each participant, address-related exposure to rating levels of wind turbines was estimated. Further, we carried out headphone-based listening experiments with participants from three of the five study areas and with non-exposed participants from another 'control' location. In the listening experiments, perceived annoyance was rated for varying AM and for different A-weighted sound pressure levels for a total number of 79 subjects. As expected, the results show an increase in annoyance with sound pressure level. Furthermore, annoyance increased significantly with the extent of amplitude modulations. Interestingly, annoyance showed a strong rise as soon as amplitude modulations became audible in the signal and this rise was hardly affected by the sound pressure level. In our contribution, we present comparisons of the results of the survey and the listening experiments.