Rick James, acoustic engineer, responds to Mass. wind turbine noise study, 2km minimum setback necessary to protect people

I have worked for many people who have severe response to wind turbine sounds. Most are within 1 mile of the nearest turbines, but some are at much greater distances.  In 2008 George Kamperman and I applied standard acoustical principles to wind turbine noise to set criteria for siting wind turbines while protecting public health.  We did not want to use setback distances because the required setbacks are a function of how many turbines are contributing to the sound immissions at a residence as well as the type and size of the turbines. But, after reviewing the sound studies for many of the participants in Dr. Pierpont’s research we did conclude that a setback of at least 2km (1.25 miles) was appropriate to protect the majority of people for the more common arrangements and types of turbines at that time.  Now with the turbines being 2.5 MW and higher in energy output and also producing more infra and low frequency sound one might argue that the setback distance needs to be revisited.  Based on increased infra and low frequency noise this setback should increase for larger wind turbines if those are the only factors.  However, there are other factors that make a 2km minimum setback a hurdle for developers that have nothing to do with noise.

I have several clients who live more than 2km from the nearest turbine who have problems. Some have been discussed in this email thread and other are participating. When I look at their situations, based on both on site tests and familiarity with where homes are located I conclude that had there been a 2km setback requirement in their community the turbines would never have been allowed in the first place.  Thus, I would argue for a consensus on a minimum setback of 2km, not because it is safe for all, but because it is more easily supported in a public forum as being reasonable.  2km does not appear to be a “0” tolerance position.  5km or 10km does. We do not regulate other pollutants to a “0” risk level because it becomes too hard to justify the broad impact of such limits.  We might want “0” heavy metals in our drinking water, or “0” NOx in our air but it may not be possible to get enough support to do it. The same applies to noise from wind turbines.  If we have to pick a distance for setbacks instead of evaluating each project for noise impacts (which is my preference), we need a limit that protects most people and includes some mechanism for those who are more sensitive to be relocated at the cost of the utility operator.  This would greatly alter the dynamics of a new project.

I like the concept of requiring all residents within the setback distance to agree to the project that I understand is being used in parts of Australia (Victoria?).  If someone refuses to sign off, the developer can choose to either not build the project, relocate turbines, or to make some financial deal with the people who refuse to sign.

For example, my clients in Wisconsin understood that a large setback was needed but did not think they could get political support for 2km.  They used maps of the state’s better wind regions to determine that if the setback was only 1800 feet there would be no place in the State that could host wind turbines in any significant numbers without running into someone else’s property.  Since the economy of wind energy requires a large number of turbines to support the cost of substations and other infrastructure this rather small setback rules out any large scale projects. I see the 2km setback minimum in the same light.  It may not be completely protective but it will force wind energy developments in areas with even moderate population densities to address the concerns of local residents before getting a permit to build and operate.  That might be sufficient until the industry dies for the many other reasons why wind turbines are not a good way to produce renewable energy.

We do not need a zero tolerance solution just one that is effective in separating people from turbines. We do need one that forces the industry to deal honestly and fairly with people living in established communities instead of what is happening now.

The Massachusetts Study is a step backwards.  I noticed while reading it that many important references were not included and even those that were, like Dr. Salt’s recent research, were not given appropriate weight.   None of the panelists tried to contact any of the people who have publically complained. Old papers from non-medical and non-independent sources, such as some by Leventhall, are given undue weight.  It was a poorly conducted literature review designed to support a political position and not to present an unbiased summary of current evidence.  For that I would look to the recent paper (January 2012) by Barbara Frey and Peter Hayden “Wind Turbines and Proximity to Homes: The Impact of Wind Turbine Noise on Health.”  Although not a  literature review, I also have a paper in an upcoming issue of the Bulletin of Science, Technology and Society, titled: “Wind Turbine Infra and Low-Frequency Sound: Warnings Signs That Were Not Heard” that debunks much of Leventhall’s work for the wind industry and explains how other sources of dynamically modulated infra and low frequency sound have been identified as the cause of similar symptoms in the past.

Rick James
E-coustic Solutions

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