Demand for renewable energy, including wind power, is expected to continue to grow both in Canada and globally for the foreseeable future. The wind energy sector in Canada has grown at an ever-increasing pace since the 1990s, and Canada is now the fifth-largest market in the world for the installation of new wind turbines. As the sector grows, the wind turbines being installed are getting more powerful. The first megawatt-scale turbines were installed in Canada in 2004, with 3 megawatt models arriving in 2008; larger models up to 7.5 megawatt are currently being tested internationally. To produce this power, turbines have also increased in size. As wind turbines become a more common feature of the Canadian landscape, this new source of environmental sound has raised concerns about potential health effects on nearby residents.
Determining whether wind power causes adverse health effects in people is therefore important so that all Canadians can equitably share in the benefits of this technology.
THE CHARGE TO THE PANEL
In response to growing public concern about the potential health effects of wind turbine noise, the Government of Canada, through the Minister of Health (the Sponsor), asked the Council of Canadian Academies (the Council) to conduct an assessment of the question: Is there evidence to support a causal association between exposure to wind turbine noise and the development of adverse health effects?
The Charge also includes the following sub-questions:
- Are there knowledge gaps in the scientific and technological areas that need to be addressed in order to fully assess possible health impacts from wind turbine noise?
- Is the potential risk to human health sufficiently plausible to justify further research into the association between wind turbine noise exposure and the development of adverse health effects?
- How does Canada compare internationally with respect to prevalence and nature of reported adverse health effects among populations living in the vicinity of commercial wind turbine establishments?
- Are there engineering technologies and/or other best practices in other jurisdictions that might be contemplated in Canada as measures that may minimize adverse community response towards wind turbine noise?
The Panel defined health in a way that is consistent with the World Health Organization’s concept of health: “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity” (WHO, 1946). The Panel interpreted noise to include both objective measures of acoustic signals in the environment (sound), as well as subjective perceptions of sound sensations that are unwanted by the listener (noise). As there are a variety of wind turbines available worldwide, with differing sound characteristics, the Panel focused specifically on the type that constitutes almost all of the installed turbines in Canada: modern, three-bladed, tower-mounted, utility- scale (500 kilowatt capacity or more), upwind, horizontal-axis wind turbines that were land-based.
THE PANEL’S APPROACH
To respond to the Charge, the Panel used an evidence-based approach to identify and review relevant research. First, the Panel identified more than 30 symptoms and health outcomes that have been attributed to exposure to wind turbine noise, based on a broad survey of peer-reviewed and grey literature, web pages, and legal decisions.
Empirical evidence related to any associations between these health outcomes and exposure to wind turbine noise was then collected from several sources, including peer-reviewed journal articles, conference papers, and grey literature. More than 300 publications were found through a comprehensive search, and these were narrowed down to 38 relevant studies related to the health effects of wind turbine noise. The body of evidence concerning each health outcome was appraised and assessed according to Bradford Hill’s guidelines for causation, and summarized using standard terms adopted from the International Agency for Research on Cancer (IARC).
Based on its expertise and review of empirical research, the Panel made findings in the following areas:
- Acoustic characteristics of wind turbine noise;
- Evidence of causal relationships between exposure to wind turbine noise and adverse health effects;
- Knowledge gaps and further research; and
- Promising practices to reduce adverse community response.
Other aspects of the Charge, such as the prevalence of adverse health outcomes in Canada, could not be answered because of a lack of data.