For the first time, an onshore wind farm has triggered calls for caution from marine mammal protection organizations.  The 2500-acre, 56-turbine wind farm will be built along a steep shoreline that funnels nutrient-rich waters from Antarctica to the surface, spawning a dense aggregation of phytoplankton and krill. Along the coast of Isla Grande de Chiloé, blue whales and right whales gather from January to April to feast on this abundance; blues come as close as 400m to shore, and rights have been seen only 5m offshore.

Environmentalists, including local organizations like Santiago’s Centro de Conservación Cetacea, and international voices such as the Whale and Dolphin Conservation Society have raised dual concerns, regarding construction of a new port to bring construction materials to the site, vastly increasing ocean noise from ship engines in this relatively acoustically pristine area, and possible disturbance or even displacement of animals due to noise from pile driving during construction and airborne wind turbine noise during operations. Even the International Whaling Commission’s scientific committee has called for “the urgent development of an environmental impact assessment in this region and to reconsider locating the wind farm towers further away from coastline.”

The importance of the feeding ground to southern hemisphere blue whales, combined with having 40% of the turbines right along the shore, raise the question of whether the ongoing blade noise will keep whales at a distance; there is some evidence that airplane overflights cause whales to move away, and the sound levels of the turbines will be similar to a small plane. Whether whales might be able to move a small distance away and still find enough krill is the big question. Chile’s environmental authorities approved the project in August after requiring a simple environmental declaration, rather than a detailed impact study; the Chilean Supreme Court is hearing a lawsuit from opposing groups, and will make a decision in the next few months.

National Geographic News has a good, detailed article on these questions.

An article in the Independent this week details the steps taken by four English wind farms to reduce noise experienced by neighbors.  In each case, the wind farm operator made changes in at least some turbines’ operation, including slowing them down or shutting them off when the wind hit certain speeds or came from directions that heightened the problems.

Research summary of Francis, C.D., Ortega, C.P., Cruz, A. 2011. Noise pollution filters bird communities based on vocal frequency. PLoS ONE 6(11):e27052.

An ongoing research project in New Mexico continues to shed more detailed light on the question of how moderate human noise affects nearby wildlife.  In a study design that effectively separates out the impact of the noise from other habitat disruption effects, Clint Francis and his colleagues are finding that some species are displaced, while others seem to thrive in areas with coalbed methane compressor stations creating noise around the clock.  The most recent paper to be published by Francis et al finds that species that sing at lower frequencies are most likely to avoid the noisy areas, while those who vocalize at higher frequencies are more apt to be unaffected or even thrive.

While this research studies an area with oil and gas development noise, it’s likely that similar effects would occur in and near wind farms, which also produce predominantly low-frequency noise. And, as the authors note to conclude their paper: “At the community-level, we must still determine whether noise is an agent of ecological filtering for other taxa that rely on acoustic communication.”

Rather than doing the full AEI lay-summary of the most recent paper, I want to point you to the great summary already written by Caitlin Kight, biologist who studies the effects of anthropogenic disturbances on animals; it was recently featured on her Anthrophysis blog.

Town officials from Mount Pleasant, Wisconsin recently visited a wind farm in Brownsville in order to listen and take sound measurements of turbines similar to three being proposed by a local plant that aims to generate all its energy needs on site.

What they heard reassured them, after hearing noise concerns from some local residents. “At 800 feet, measurements came in at 46 – 47 decibels, and at 1,200 feet it was less than 40 decibels, ” said Planning Director Ron Meyer. By comparison, he said a passing car on the paved road came in at 62 decibels. Even within a thousand feet, they could sometimes not hear the turbines spinning.

Of course, any quick visit to a wind farm offers just a snapshot view (or listen). In many cases, neighbors’ noise issues occur mainly in particular atmospheric or wind conditions, so the question becomes how common these above average noise events are. Stable sound-reflecting air layers above the turbines, high levels of turbulence in the air hitting the blades, and wind speed differences from the bottom to top of the blades are all factors that tend to contribute to higher or more intrusive noise levels. And, night time noise tends to be a bigger issue than day time; even moderate noise levels can become the loudest sound heard out a bedroom window at night.

Still, it’s good to get out there and get a sense of what may be heard near the proposed turbines.  Unfortunately, no residents were able to join the town officials on this trip, though they were invited. It’s hard to know what degree of investigation will really give a complete picture of what may be experienced by people near the plant; spending a few nights in Brownsville might help.  More generally, many towns considering wind project siting questions would be well served by a series of well-designed survey projects around wind farms, which might best capture the range of experiences at existing wind farms.

A couple living roughly 5000 feet from a proposed 5-turbine wind farm has appealed the project’s approval by the town of Clifton, Maine, citing quality of life concerns due to the likelihood that they will hear the turbines from their home and farmlands. “Our land is our home. We work here. We farm here. We recreate here and we restore our souls here,” said Peter Beckford.  Beckford and his wife Julie run an organic flower business on a sixty-acre property, which also includes several small cabins where farm apprentices and other visitors live.

The proposed wind farm, on Pisgah Mountain, was designed to include 4000-foot setbacks from homes, but the Beckfords say that their cabins and other buildings used for their business were improperly excluded as protected or occupied structures when the setback was applied.

The Beckford’s challenge is notable in that it is making a quality of life argument that audible turbine noise is an inappropriate addition to the local soundscape.  The appeal rests on several permitting issues, including the outbuilding distance and other aspects of the town’s planning process, but their statements indicate that the turbine noise is the crucial issue for them.  Their challenge is perhaps the strongest expression yet of the feeling by some rural residents that any noise intrusion is unacceptable; several more cautionary acousticians have recommended noise limits, at least at night, of 30-35dB, and setbacks of a mile to a mile and a half, in acknowledgement that any turbine noise readily audible above quiet rural background sound levels will trigger significant annoyance in some neighbors.

Most previous challenges of wind farm approvals have attacked siting standards that placed turbines much closer than a half mile, or noise standards that could allow intrusive sound levels (15dB or more over ambient) at some or many homes. In saying that three-quarters of a mile is not far enough away, the Beckfords are standard-bearers for rural residents who want wind farms to be far enough away to be effectively inaudible. For people living deep in rural areas, it’s an understandable desire; some towns have have banned tall industrial turbines altogether, to assure local soundscapes will remain unblemished.  Other towns, aiming to be somewhat more welcoming to wind projects, have set half-mile to 4000-foot setbacks in order to reduce the severity and frequency of noise intrusions. Time will tell whether new wind farms built with these larger setbacks will be more easily accepted by rural communities.

A wind farm in South Australia has been shutting down 16 of its 34 turbines at night since last December, after a nearby neighbor complained of noise keeping his family awake at night.  This week, the state Supreme Court affirmed that the wind farm was breaking its noise limit, due to a tonal noise component, and sent the issue to the Environmental Resources and Development Court for adjudication.

The neighbor, Bill Quinn, said his mother and sister, who live near the existing turbines, had been in “absolute heaven” since the decision was made to shut the turbines down at night. A spokesman for AGL Energy said that “We understand that one of our neighbours has been inconvenienced and we apologise. We want to be a good neighbour and we’re committed to working with local communities and taking any concerns that they have about our projects seriously.” AGL is working with the turbine supplier on a “permanent acoustic treatment” to dampen tonal noise.

Several Australian states have recently moved to increase setbacks from new wind farms.  In Victoria, the Baillieu government has announced strict regulation of wind farm developments, including a minimum 2km (1.25mi)  distance from houses. In NSW, Premier Barry O’Farrell has indicated he intends to introduce similar laws. South Australia’s guidelines limit noise to 35dB in areas “primarily intended for rural living” and 40dB elsewhere, while providing for agreements with landowners to allow higher sound levels.

Town votes in Riga, Michigan, and Rumford, Maine have both adopted wind farm siting standards that are somewhat more cautionary than most. Riga township  voted 440-236 to uphold an ordinance that establishes setbacks of 4x turbine height (1200 or so feet) from non-participating property lines, and sets a noise limit of 40dB at night and 45dB during the day.  The distance setback shouldn’t be an issue for developers (1200-1500 foot setbacks are typical of many wind farms), though the night time noise limit could make it difficult to site turbines closer than a third to half mile from homes. It wasn’t clear from initial press reports whether the Riga ordinance provides an option for neighbors to sign waivers allowing closer siting or higher noise levels.

Meanwhile, the third time was the charm in Rumford, where two previous proposals went down to defeat, one for being too stringent (including setbacks of a mile), and the next for not protective enough (the sticking point likely being a 45dB night time noise limit).  The current proposal garnered overwhelming support, winning by a margin of 1137-465, and includes a 40dB night/50dB day noise limit, along with a 4000-foot setback from non-participating neighbor property lines.  Neighbors can, however, sign a Mitigation Waiver agreement to allow closer siting.

Conversely, in New Hampshire, Read the rest of this entry »