Ice Man wrote:AEI Special Report: Wind energy noise impacts
March 14, 2008 by Acoustic Ecology Institute
Summary:
This document authored by Acoustic Ecology Institute provides a comprehensive overview of noise issues pertaining to utility-scale wind energy development. This AEI Special Report will be continually updated, incorporating new research, more recent reports, and suggestions/comments from readers. Planned topics to be added over time include: effects of noise on wildlife and habitat, h*r* wind energy, and the health effects of chronic noise exposure.
--------------------------------------------------------------------------------
INTRODUCTION
Wind energy has long been a favorite of many environmental advocates. No carbon emissions, utilizing a free resource without depleting it in the least, even the potential for distributed generation rather than distant centralized power plants: for many of us, wind was the cleanest of green power sources in our dreams of the energy future.
In recent years, as wind turbines have grown from the small backyard kits that the truly committed built in the 70's, the reality has made those dreams become less certain. Modern wind turbines are massive structures, hundreds of feet tall, and often constructed in large wind farms that in effect industrialize rural landscapes, from the rolling grassy hills of California, to the vast rangeland of Texas, to ancient ridgelines in the Appalachians, to the commons in rural England. While the trade-offs may be worth it in some areas, the downsides have become more apparent. Resistance to wind farms is often belittled as NIMBY-ism (Not In My Backyard); but at the same time, proponents often slip into oversimplifeid WARYDU rhetoric (We Are Right; You Don't Understand). If we are to forge a reliable energy future that is respectful of both the environment and the rights of neighbors, we'll need to move past knee-jerk reactions on both sides, and develop best practices that can ensure that the landscape and local residents don't become long-term casualties of today's "Klondike Wind Rush."
This AEI Spotlight Report will focus specifically on the noise impacts of wind turbines and wind farms. However, it is worth mentioning some of the other concerns that rural residents have raised about the sudden appearance of industrial wind farms in their communities. Besides the visual blight, which many residents are, in the end, willing to accept as a tradeoff for producing clean energy, the most common argument against wind energy is that wind farms are notoriously inefficient, rarely achieving even half their rated capacity, due to fluctuating winds. A more important long-term issue, still flying mostly under the radar, is that lease agreements between land owners and power companies can be full of holes, raising the very real specter of ridge lines and rangelands becoming, over time, abandoned junkyards of massive metal hulks, rusting and disintegrating for decades.
It is entirely possible that ongoing technical innovation, combined with closer legal scrutiny, can overcome these issues. Similarly, noise impacts are not necessarily deal-killers for wind energy, as long as developers are honest about what is likely to be heard and continue to work diligently to investigate the aspects of wind turbine noise that are still not fully understood. Continually improving turbine design will likely mean that tomorrow's turbines are not as noisy as today's. Local residents should be sure that their fears are not based on others' experiences with older turbines, and wind energy advocates must be diligent in not glossing over potential noise impacts. With continual incorporation of best technology and best practices in siting, wind energy need not be stymied by noise issues. However, with noise impacts gaining more public credence, it is clear that the current boom in wind farm development could well backfire, for both the industry and a clean energy future, if the current generation turbines are sited too close to residences. The Altamont Wind Farm in California, shortsightedly built on a major raptor flyway in the early years of industrial wind development, has rippled through the years as a poster child for the bird-killing power of wind turbines, despite widespread understanding that it was an exceedingly bad siting decision. Similarly, many noise complaints today seem to be coming from people whose homes are on the near edge of fairly loose siting guidelines (within 500 meters in many cases, and often much less). If the thousands of windfarms likely to be built in the coming decade are placed too close to homes, the industry will be faced with an echoing chorus of complaints and resistance for years to come, even if it manages to invent much quieter machines. Better to be conservative, accepting the fact that even occasional atmospheric effects should be factored in to siting decisions today, so as to build a reservoir of good will, rather than a rising tide of complaints.
A key point is made in a study completed in 2007 by the National Research Council, the research arm of the National Academy of Sciences, which found conflicts are widespread because of a fundamental reality of wind power. The environmental costs -- visual impacts, noise, landscape and wildlife disturbances -- are primarily felt by those near the wind farm. The benefits, however (reduced global warming emissions and other air pollution, less dependence on foreign oil and less mining and drilling) are felt more on the regional or national scale. "Benefits and (costs) don't necessarily affect the same people," said David Policansky, who directed the study. "If you talk to a national representative of an environmental organization, it's quite likely that person will be in favor. Whereas, when you talk to a local representative, it is more likely that person will be opposed to some local project."
This AEI Special Report is designed to provide a layman's introduction to the types of noise produced by wind turbines. It is not our intention to over-emphasize noise complaints, but rather to provide information that can foster informed conversation about any specific wind farm proposal. A recent UK government survey suggests that only about 20% of wind farms tend to generate noise complaints; the question is, what are the factors in those wind farms that may be problematic, and how can we avoid replicating these situations elsewhere? [more ...]
Editor's note: The full document can be accessed by clicking on the link below.
Web link:
http://www.acousticecology.org/srwind.html 
I knew there was a blade manufacturing issue but where was the maintenance issue at one of Gamasa's Wind Farms?