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Navy looks to “Continuous Active Sonar” for anti-sub protection, less impact on whales

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While it looks like it’s been on the drawing board since at least 2004, today I ran across a news report on what appears to be an increasingly well-defined plan to outfit surface ships with a new Continuous Active Sonar (CAS) system.  In the face of what is perceived as an increasing threat from quiet subs, along with the increasing costs of compliance with environmental regulations that now govern current sonar systems (primarily the mid-frequency active sonar deployed on hundreds of ships, along with gradually increasing use of low-frequency active sonar on two US and a few UK ships), research and development efforts are turning toward the possibility of using a continuous, lower power sonar system to protect Naval vessels.

The sinking of a South Korean vessel, along with the embarrassing appearance of a Chinese sub that surfaced, undetected, within firing range of a US aircraft carrier group in 2006, has highlighted the gaps in detection that are inevitable using a sonar surveillance system that is only activated at times.  While none of the news or technical pages that I found specified the projected source level or frequency range of the new CAS system, one of its benefits was repeatedly claimed to be that it would broadcast at a lower power level, thus reducing impacts on marine species.  It sounds like they would trade the drawbacks of high sound levels for the different but not insignificant effects of adding more continuous background noise to the ocean environment.  One of the rarely-noted factors that may well contribute to the behavioral responses seen in reaction to the the current generation of mid-frequency active sonar is the chaotic, and quite disturbing, nature of the sound source; this is sometimes referred to as the kurtosis of the sound (how many sharp or abrupt elements there are in the sound itself, including sudden rise times rather than more rounded sine-like changes in intensity that are heard in most naturally-produced sounds).  If there is to be a new generation of continuously-broadcasting sonars, let us hope that the sounds themselves are more closely modeled on naturally-occuring sound patterns.

For more on the Continuous Active Sonar system, see:
The recent news report, about research at Alion Science and Technology in Mystic, CT
These two pages from Signal Systems Corporation, also researching the system
A recent Congressional earmark for research
This 2006 news report on a Signal Systems contract that mentions CAS
A September 2009 Navy powerpoint presentation on advanced development plans for undersea systems, which includes a slide on CAS

Ocean Conservation Research has been studying the implications of kurtosis and rise times to ocean noise sources, especially sonar.  For more, see this research page, and especially these two papers and this audio-video demonstration.

Dreaming big in offshore wind, inspired by sycamore seeds

News, Wind turbines 1 Comment »

Most of the new wind turbine designs you see floating around the tech blogosphere are oriented toward small backyard turbines, in the tens or hundreds of kW range.  So it was kind of a thrill to see this new design for a 10MW offshore turbine, partly inspired by a spinning sycamore seed:

Aerogenerator X concept

Aerogenerator X concept

After an 18-month feasibility study funded by a consortium of energy companies and the UK government, new funding and agreements are moving the project forward, with the goal of building a full-scale test version of the design by 2013 or 2014.  The current version is over 900 feet across, but half the height of vertical turbines (which would have the benefit of creating a markedly lower visual profile from shore, and even being “over the horizon” in many more near-shore locations).  The power-generating equipment sits at the bottom, rather than the top as in a tower, greatly reducing both the cost and complications of servicing. The horizontal design reduces pressure on the blades (which rotate just 3 times per minute), thus breaking through a stress barrier that will likely limit traditional turbine designs from moving much past the currently-envisioned 5MW size.  The drawback is that the lower profile will not access higher wind speeds at greater heights.

Here at AEI, we have great hopes for offshore wind, which moves the noise far from people’s homes, while tapping into a very consistent wind resource.  It’s not clear from the current news reports whether this design can be adapted to our ideal long-term scenario of floating turbine platforms (which allow deployment farther offshore in higher winds, and also greatly reduce the amount of loud construction noise, which is the primary impact off offshore wind on ocean acoustic ecology.) New conceptual technologies should always be treated as speculative, but this one does seem to be moving forward at a pretty good clip.  For more info:
Here’s the company press release, which has the most detail
And here are three blog reports on the announcement.

Falmouth followup: turbines shut down in high winds

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As noted here on AIEnews in May, a single new wind turbine in Falmouth, Massachusetts triggered noise problems for many nearby residents (12 formal complaints were filed, an unusually high number for any community, and residents of up to 45 of the 120 homes within a mile raised concerns in informal local meetings).  The town appears to have responded quickly: this news report from mid-June notes that the turbines had been shut off 39 times in the preceding month, when winds topped 22mph and noise would have been at its worst.  Both the town and a group of neighbors have hired lawyers and sound consultants to help them work through the situation; everyone spent a month discussing the nature of the noise issues as a study was designed to assess the conditions in which noise is the worst.  This recent article from the Falmouth Enterprise (sorry, no direct link found) summarizes the recent noise measurements made by both the town and residents’ sound consultants, and the first survey that recently took place.  Everyone seems to agree that the sound was much worse in its first three months of operation (March-May), when winds were higher, so it’s not altogether clear whether this survey, taken at a time when the air was quite hot and still, will suffice to answer the longer-term questions.
UPDATE: A more recent article, from the Cape Cod Times, appeared on August 1st.

Falmouth is the second small New England town to run into unexpected noise problems after installing wind turbines in an effort to reduce electric bills and contribute to a sustainable energy future in their localities. Residents of Vinalhaven, Maine are also trying to find the balance between wind energy and local quality of life; AEInews has tracked their efforts since last December. It appears that Falmouth is being a bit more pro-active, as evidenced by the quick decision to shut down turbines in high winds.  By contrast, the sound study project proceeded a bit more slowly in Falmouth, which may also be a good thing; in Vinalhaven, there was some confusion and uncertainty as a noise survey commenced suddenly this winter, without much pre-consultation with neighbors of the turbines on the design of the study or the sorts of qualitative descriptors used on the surveys (which some neighbors found did not encompass the sounds they experienced).

This is new territory for every town that grapples with it; both Falmouth and Vinalhaven are at the forefront of constructively dealing with noise issues (especially in contrast most wind projects, where the turbines are owned by large and comparatively impersonal energy companies).  As more towns and energy co-ops consider erecting small wind projects, the lessons learned in Falmouth and Vinalhaven will serve to make the process of dealing with noise issues a bit easier elsewhere.

Navy jumps on sonar EIS merry-go-round, aiming at 2014 renewals

News, Ocean, Sonar 1 Comment »

As many of you know, over the past two years, the Navy has completed its first-ever Environmental Impact Statements for mid-frequency active sonar, in concert with applying for permits to allow them to do sonar training missions in Naval training ranges off most of the coastlines of the US.  This training activity has been ongoing for decades, but after the infamous stranding event at a Bahama range in 2000, and legal pressure applied by NRDC and others, in the mid-2000’s the Navy initiated the process of complying with NEPA provisions that govern activities that may have harmful consequences for wildlife (an internal memo shortly after the Bahamas incident suggested the need to comply with NEPA, but formal compliance activities did not begin until after a 2004 lawsuit).

During 2009 and 2010, the Navy has filed its final EIS’s on most of its ranges, but the environmental compliance treadmill never really ceases, because their authorizations must be renewed every five years: this week, work began on the next round of EIS’s, aiming for 2014 deadlines by which the new ones must be finalized.  The initial scoping phase has begun for activities along the Atlantic Coast and around Hawaii and off Southern California, including some public hearings and fall deadlines for initial comments, which will inform the first Draft EIS’s for each area. The Portland (Maine) Press Herald covers the Atlantic process (and here’s a link to the Navy’s Atlantic Fleet Training and Testing EIS page) and the San Jose Mercury News chimes in on Hawaii and SoCal, which generated separate EIS’s in the initial round, but will be combined this time into a Hawaii-Southern California Training and Testing EIS.

AEI presentation: NEWEEP webinar on wind farm sound

Human impacts, Wind turbines 4 Comments »

On July 13, I was honored to be one of three presenters in a webinar sponsored by the New England Wind Energy Education Project (NEWEEP), a DOE-funded project of Wind Powering America.  Complementing the technical and regulatory information presented by Mark Bastasch and Ken Kalinsky, my presentation focused on the “qualitatitive” data that we are receiving from people living near wind farms, which can be as useful as the quantitative data coming from engineers and scientists.  The main point of the presentation was that reports in wind farm communities, as well as our best research indications, suggest that a significant minority of nearby residents—25 to 45%—are quite seriously impacted by noise issues when sound is 40dB or more (roughly within a half mile); I also included a look at interesting research into rural place identity and noise sensitivity, both of which provide some clues as to why many people find wind turbine sounds very annoying, while other neighbors are not much bothered by them.

UPDATE, 8/4: All three presentations, along with the audio of the webinar and a transcript, can now be downloaded at the Wind Powering America website: http://www.windpoweringamerica.gov/calendar_past_events.asp Scroll down to “Understanding the Impacts of Wind Turbine Sound.” Mark’s presentation is largely about measuring sound; Ken’s focuses more on regulatory approaches.

A pdf version of the presentation can be downloaded here, or you can view or download the Powerpoint version via Slideshare:

World Listening Day is this Sunday, July 18

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You are invited to participate in the first World Listening Day, which happens on Sunday, July 18, 2010. The purposes of World Listening Day are:

  • To celebrate the practice of listening as it relates to the world around us, environmental awareness, and acoustic ecology
  • To raise awareness about issues related to the World Soundscape Project, World Listening Project, World Forum for Acoustic Ecology, and individual and group efforts
  • To creatively explore phonography to design and implement educational initiatives which explore these concepts and practices

July 18 was chosen as the date for World Listening Day because it is the birthday of the Canadian composer R. Murray Schafer. Schafer is one of the founders of the Acoustic Ecology movement. The World Soundscape Project, which he directed, is an important organization which has inspired a lot of activity in this field, and his book Soundscape: The Tuning of the World helped to define many of the terms and background behind the acoustic ecology movement.

For more information see this info from the World Listening Project, download a press release that includes links to other sponsors and participating organizations, or contact: worldlistening@gmail.com

New recorder network will listen in on Gulf of Mexico ships, whales, seismic surveys

Ocean, Science, shipping Comments Off

Using the same recording units that have provided a rich stream of new data on the effects of shipping noise on whale communication off Boston, Chris Clark of Cornell is spearheading a new project to study the acoustic ecology of the Gulf of Mexico.  According to a press release from Cornell:

“The team will anchor 22 marine autonomous recording units (MARUs) to the sea floor in an arc stretching from Texas to western Florida, along the edge of the continental shelf. These units will record underwater sounds for three months before they receive a signal to let go of their tethers and pop to the surface for retrieval. After analyzing the data, the team will deliver a report to NOAA and other agencies involved in the oil leak response. The MARUs will listen for endangered sperm whales and a small population of Bryde’s (BRU-des) whales. They will also pick up sounds of fish and ship traffic. Some devices will be placed in areas apparently unaffected by the oil to collect “control” site information; others will be close to the gushing well. The goal is to document the state of the sounds in the ecosystem over an extended period of time and compare them with known information of the oil spill.

Researchers deploy recording units (Photo: Danielle Cholewiak, BRP)

Researchers deploy recording units (Photo: Danielle Cholewiak, BRP)

“This will be the first large-scale, long-term, acoustic monitoring survey in the Gulf of Mexico,” Clark said. “We can provide one more layer of understanding about this ecosystem, using sound to measure animal occurrences, distributions and communication, as well as background noise levels from shipping and weather, and perhaps visualize how these features are being influenced by the oil. The whales are like oversized canaries in the coal mine — they reflect the health of the environment they live in.”

Wind Turbine Sound webinar, Tuesday July 13

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I’ll be one of three presenters at what promises to be an informative 90-minute webinar taking place on Tuesday July 13.  It’s one of a series of wind energy programs being produced by the New England Wind Energy Education Project, a DOE-funded public information effort.  My piece will add a look at the experiential reports of wind farm neighbors, as well as the few studies we have that help clarify how common noise disturbances are around wind farms (hint: it’s much more than many people think, but also less than some believe); I also take a stab at understanding the variable responses of people hearing the same levels of sound/noise.  Joining me on the panel are Mark Bastasch, who will provide a primer on noise measurement and the sources of wind turbine sounds, and Ken Kalinsky, who will focus largely on the various approaches to regulating wind farm noise.  The three 20-minute presentations will be followed by a discussion and question and answer session that will last for roughly a half hour or so.

The webinar will take place on Tuesday July 13, from 2-3:30pm Eastern Daylight Time.  You must pre-register to receive login information.
For more information on this free webinar, see this PDF information sheet.  You can register from there by email; or, just use this email link and request registration information for Webinar #2.

India city dwellers get night time reprieve from noise

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Indian cities are renowned for their wild and exuberant variety of sounds: honking horns, bellowing loudspeakers, raucous holiday parades, and, much much more.  Now, urban areas are beginning to try to rein in the noise-making, at least at night.  A nationwide decree deems 10am to 6am as a time for quiet, during which restrictions have been imposed on the use of horns, sound-emitting construction equipments and bursting of firecrackers,” the federal environment ministry said.

Indian officials also announced noise-monitoring stations in major cities, including New Delhi, Mumbai and Bangalore, by September.  Eighteen more cities will join the system by 2011, the ministry said. “With the new system in place, a systematic national level monitoring and reporting network in the country will be available, as in case of air and water pollution.”

For more, see this CNN report.