Health effects of noise from wind turbines
Work and recommendations of ANSES
ANSES has undertaken several scientific expert appraisals on the potential health impacts of noise from wind turbines. In 2006, the Agency received a first formal request from the Ministries of Health and the Environment to conduct a critical analysis of the report published by the French National Academy of Medicine recommending that the most powerful wind turbines (of greater power than 2.5 Megawatts) be placed no nearer than 1,500 metres from residential areas due to the noise pollution generated by these structures. In the conclusions of its first expert appraisal report published in 2008, ANSES stressed the need to study appropriate distances for wind turbines on a case-by-case basis, particularly with modelling methods taking local configurations into account.
Following various complaints from residents living near wind turbines, the Ministries of Health and the Environment submitted another request to the Agency in 2013 in order to assess the potential health effects of infrasounds and low-frequency sounds emitted by wind farms. To date, while assumptions on the mechanisms of health effects still remain to be explored, a review of the available experimental and epidemiological data does not give adequate scientific arguments indicative of health effects for local residents specifically related to their exposure to inaudible sound emissions from wind turbines (infrasounds in particular). The current state of knowledge therefore provides no justification for extending the scope of health impact studies on noise from wind farms to issues other than those related to audible noise, for which the effects are confirmed, complex and documented.
The share of renewable energy sources is constantly rising in France and worldwide. This tendency is primarily the result of a desire to diversify energy sources and thus lessen our dependence on fossil fuels, while also reducing emissions of greenhouse gases.
Following the publication by the French National Academy of Medicine of a report whose aim was to assess the impact of the operation of wind turbines on human health, in June 2006 the Agency received a formal request from the Ministries of Health and the Environment to analyse the Academy’s recommendations, in particular the recommendation to keep a systematic distance of 1,500 metres between wind turbines and residential areas. In its Opinion associated with this expert appraisal (published in 2008), ANSES underlined the risk of overestimating or underestimating the acoustic impact of setting a systematic distance and recommended establishing this distance on a case-by-case basis by means of an acoustic study taking local conditions into account.
In 2011, the French regulations relating to wind turbines were amended with the classification of wind farms in the regime of Classified Installations for the Protection of the Environment (ICPE, Ministerial Orders of 26 August 2011). This regulatory framework provides for a minimum distance of 500 metres from the first home, in addition to limit values for noise exposure (noise emergence) to be taken into account to establish actual distances (exceeding 500 metres in practice) on a case-by-case basis, after undertaking a noise impact study.
Despite the growing interest in renewable energy, there is widespread public concern about the possible impacts of wind farms on the environment and human health. In particular, many residents living near current or future wind farm sites complain about the audible noise generated and are also concerned about the potential role of infrasound and low frequencies emitted by wind turbines in the occurrence of certain health effects.
In this context, the Agency received a formal request from the Ministry of Health and the Ministry of the Environment in 2013 to undertake an expert appraisal on the potential health effects of low frequencies and infrasound from wind farms. To do so, a Working Group of experts in the areas of acoustics, metrology, epidemiology and health risk assessment was set up by the Agency in 2014.
The Working Group conducted a review of the scientific literature on auditory and extra-auditory health effects, enabling it to update current knowledge, and was also able to document levels of noise exposure near wind farms. In addition to taking into account data from the scientific literature on exposure to infrasounds and low frequencies from wind farms, ANSES commissioned noise measurement campaigns (including low frequencies and infrasounds) in the vicinity of several wind farms. In addition, its analysis of the regulatory standards in force in European countries showed that this issue is taken into consideration in a variety of different ways within the European Union.
The current situation and recommendations
In response to the formal request received from the Ministries of Health and the Environment, a Report and an Opinion were produced and published by ANSES in March 2017. They reported on the current state of development and outlook of the wind turbine sector at global and national levels, and gave a review and comparison of the various regulatory frameworks around the world. This review showed that there are no harmonised standards in the European Union specific to noise from wind turbines. The expert appraisal work also identified the state of controversy around the installation of wind turbines and the various stakeholders involved.
Levels of noise from wind turbines were assessed by means of a measurement and modelling campaign. The measurement campaigns undertaken during the expert appraisal enabled the noise emissions from three wind farms to be characterised, showing the emission of infrasound (sound below 20 Hz) and low-frequency sounds. Only very high intensities of infrasound can be heard or perceived by humans. At the minimum distance (of 500 metres) separating homes from wind farm sites set out by the regulations, the infrasounds produced by wind turbines do not exceed hearing thresholds. Therefore, the disturbance related to audible noise potentially felt by people around wind farms mainly relates to frequencies above 50 Hz.
In conclusion, the Agency states that the available data do not provide adequate scientific arguments indicative of health effects related to exposure to noise from wind turbines. Current knowledge of the potential health effects of exposure to infrasounds and low-frequency noise provides no justification for changing the current limit values or for extending the spectrum of noise currently taken into consideration.
However, the Agency recommends, with regards to studies and research:
- verifying whether or not there is a possible mechanism modulating the perception of audible noise at intensities of infrasound similar to those measured in residential areas;
- studying the effects of the amplitude modulation of noise on the disturbance felt;
- studying the assumption that cochleovestibular effects may be responsible for pathophysiological effects;
- undertaking a survey of residents living near wind farms enabling the identification of an objective signature of a physiological effect.
Regarding information for local residents and the monitoring of noise levels:
- enhancing information for local residents during the construction of wind farms and participation in public inquiries undertaken in rural areas;
- systematically measuring the noise emissions of wind turbines before and after they are brought into service;
- setting up, especially in the event of controversy, continuous noise measurement systems around wind farms (based on experience at airports, for example).