Posted on the 3rd February 2010

(We have been flooded with articles and documentation about this topic.  Members from Caledon and Greyton to Swellendam have expressed concern about EIA's on wind farm jumping up all over the show.  The most upsetting is such a study for a birding hot spot such as the farm Nacht Wacht outside Bredasdorp.  We hereby publish a selection of articles on the negative impact that wind farms could have on bats in view of giving visitors a better understanding of the problem at hand.  Right at the bottom we give referals to a variety of links for those wanting to read more about the topic.  - Ed.)

Wind turbines threatening bats survival

Dated 28 August 2008

Washington - Wind turbines pose a greater danger to bats than birds as the power generators produce a sudden drop in air pressure that causes the nocturnal animal's lungs to burst, a study has found. While the turbines' blades may endanger birds, Canadian researchers found that 90 percent of bats found dead at wind farms had suffered internal hemorrhaging caused by the drop in air pressure, a condition known as barotrauma. Only about half of the migratory bats showed any evidence of direct contact with the blades, said the study published in the August 26 edition of the journal Current Biology. Bats, which emit a sonar-like sound to detect objects, rarely collide with man-made structures, the researchers noted. "An atmospheric-pressure drop at wind-turbine blades is an undetectable - and potentially unforeseeable - hazard for bats, thus partially explaining the large number of bat fatalities at these specific structures," said Erin Baerwald of the University of Calgary in Canada. "Given that bats are more susceptible to barotrauma than birds, and that bat fatalities at wind turbines far outnumber bird fatalities at most sites, wildlife fatalities at wind turbines are now a bat issue, not a bird issue." Birds have more rigid lungs than bats that allow them to more easily withstand sudden drops in air pressure. The lungs of bats are balloon-like, with two-way airflow ending in thin flexible sacs surrounded by capillaries. A drop in air pressure can cause the sacs to expand too much, making the capillaries explode, the researchers said. Bat deaths caused by wind turbines could have far-reaching consequences, the researchers warned. While bats can live for 30 years or more, most only produce one or two pups at a time and not necessarily every year. "Slow reproductive rates can limit a population's ability to recover from crashes and thereby increase the risk of endangerment or extinction," said Robert Barclay of the University of Calgary. Their deaths could also affect ecosystems on the bats' migration routes as they eat thousands of insects, including many crop pests, every day, the researchers added.

Wind Turbines

Do wind turbines affect bats?

The following is the Bat Conservation Trust's Position Statement on wind farms, wind turbines and microturbines:

BCT supports the development of sustainable energy but, in line with the Eurobats resolutions, stresses that it is imperative that the possible harmful effects on bats and other wildlife (both direct and indirect) are taken into account before deciding on the siting of wind turbines, large and small.

The discovery of dead bats and birds underneath wind turbines in the US and in mainland Europe has led to concerns that research into the siting of these structures is not sufficiently rigorous, and that some have been erected on migration routes of bats and birds.

The siting of turbines may be an issue for bats in the UK, not only because of the risk of direct collision if turbines are placed on migration or commuting routes, but also because of displacement from foraging habitat. The positioning of mid-sized wind turbines in hedgerows is also a concern.

Microturbines are a relatively new technology. However, BCT already has anecdotal evidence of bat mortality caused by microturbines. BCT opposes the move to make the installation of these small-scale household wind turbines permitted development (ie not requiring submission of a planning application). Microturbines can be freestanding or placed on buildings, boats or road signs.

BCT would like to see monitoring undertaken at existing wind turbine sites and monitoring of all new turbines, whether large or small. We would also urge that full impact assessments of the potential effect on bats are undertaken, and for post-installation monitoring to be made a planning condition. BCT hopes that future updates of BWEA's guidance on wind farm development and nature conservation will reflect the need to consider bats in the planning of wind farms.

BCT would welcomes the decision by Defra, the British Wind Energy Associatoin (BWEA) and Countryside Council for Wales (CCW) to fund a study to determine whether British bat populations are at risk from onshore wind turbines.

Bats and wind turbine research

In March 2009 Defra commissioned the University of Bristol and BCT to deliver Phase 1 of a research project on bats and wind turbines: 'Determining the impact of wind turbines on bat populations in Great Britain'. This initial phase established what information and research is currently available on bats and wind turbines , and developed a research protocol to be taken forward into Phase 2. Phase 2 of the project is planned to commence in July 2009 and will comprise a three-year project gathering data on bat activity and bat fatalities at wind farms in England, Scotland and Wales.

Click on the following document to read the report from Phase 1 of this project (PDF file):

Determining the impact of wind turbines on bat populations in Great Britain Phase 1 Report

Microturbine issues

BCT has concerns about how bats interact with microturbines, particularly in light of the government's wish to make microturbines permitted development to increase their use. Microturbines may be attached to buildings, boats, or freestanding. We have information that bats have been killed by microturbines, but we do not understand how they interact with microturbines, whether they are attracted to them in some way, or whether they cannot 'see' them. This is an area needing more research, and is something we are promoting with our work on bats and the built environment. BCT would like to see research into the development of 'wildlife friendly' turbine designs that discourage collision by bats and birds.

Siting of microturbines is extremely important. Careful checks of the subject building and surrounding buildings must be made before installing a turbine to avoid proximity to roosts and bat flyways; turbines close to roost accesses could have devastating effects on the colony size when bats are leaving and returning to the roost. Turbines causing bat mortality should be resited because of the legal protection afforded to bats.

Click on the following documents to see BCT's response to the English Government's 2007 consultation Permitted Development Rights for Householder Microgeneration (PDF files):

BCT has also responded to the equivalent Welsh Assembly Government consultation, and will be responding to the equivalent Scottish Government consultation.

Microturbine research Scientists at the University of Stirling are conducting the world's first study into the effects of micro-turbines on birds and bats. Micro-turbine owners are invited to take part in the study by completing an online questionnaire:

Recent research (2009) by Long et al published in the Proceedings of the Institute of Acoustics has investigated the
interactions between bat echolocatio pulses and moving microturbine blades.

Country Guardian was founded in 1992 to oppose wind farms in unspoiled rural areas of the U.K. Their web site is at It includes a thorough summary of the case against industrial wind power, many views from people alarmed at and who have experienced the destruction wrought in the name of going green, and links to other groups fighting industrial wind installations. National Wind Watch is a U.S. coalition founded in August 2005. Their web site, containing key documents, a resource library, a daily news feed, FAQs, their own publications, and links to affiliated organizations, is at More than 300 groups around the world are listed at A good series of newsletters is produced by Views of Scotland and available at

For information specific to off-shore siting of wind towers, which raises many issues not covered above, see and, and For example, Greenpeace has been at the forefront of opposing the U.S. Navy's use of low-frequency sonar, because of its disruption to wildlife, particularly whales. At the same time they are at the forefront of promoting off-shore wind power plants, which produce low-frequency noise that has been measured at well over 100 dB, louder than the noise from an oil-drilling platform. The Daily Mirror (U.K.) reported on June 6, 2005, that scores of baby seals on Scroby Sands off Great Yarmouth have been found dead -- born dead or abandoned by their mothers. Staff at the wildlife hospital involved say the wind facility there is to blame. Save our Sound, and SafeWind, and WindStop were founded to organize opposition to a very large wind power project between Cape Cod and Nantucket Island off the coast of Massachusetts.

A selection of a few more of the many opposition sites:

The industry and government voices mentioned also can be found on line: the American Wind Energy Association at, the British Wind Energy Association at, the Danish Wind Industry Association (in English) at (they have an excellent guide to how it all works), FPL Energy at, the California Energy Commission at, the U.S. Department of Energy at, the U.K. Department of Trade & Industry at, Enxco at, and the National Wind Coordinating Committee at Windpower Monthly has a web site at that includes abstracts of many of their articles.

Manufacturers of large wind turbines include GE in the U.S. ( and Vestas in Denmark ( The GE site includes many pictures of their installations. Specifications for several models from these and other companies are collected at

An example of the controversy of wind farms in wilderness and rural areas, in particular the "Northeast Kingdom" of Vermont in the U.S., is documented in the archives of The Caledonian-Record newspaper, which you can search by
clicking here. [Click here, here, and here for good letters. Click here for a very good editorial from another Vermont newspaper.] The Burlington Free Press has compiled much of what it has published on the issue at The Kingdom Commons Group opposes industrial wind plants in this region. Others in the area are the Lowell Mountain Group, Ridge Protectors, and, just over the border in New Hampshire, Citizens for the Protection of Gardner Mountain. The Glebe Mountain Group opposes development in the south central Vermont township of Londonderry. Their web site contains an extensive list of on-line resources. Groups and individuals from around the state have organized Vermonters with Vision. Click here for an excellent letter from Kansas about the corporate piracy behind large-scale wind development.

For continuing notes on the issues raised in this paper, see the "
Out of Kirby Mountain" web log.

On this site:
PDF version of this paper (68 KB)
a concise version of this paper
a really concise version of this paper
electricity consumption in wind turbines
analysis of electricity production and use
report of technical problems of wind power in German grid
explanation of why wind turbines cause the use of more conventional fuel
photos of wind facilities in California and Germany
analysis of CO2 savings, by John Etherington
wind generation in Intergovernmental Panel on Climate Change analysis of CO2 mitigation
pictures showing size of industrial turbine towers
specifications of popular industrial wind turbines
photos of turbine towers being constructed
areas covered by some facilities
U.S. Fish and Wildlife Service recommendations
report of ill effects in Kewaunee County, Wisconsin
essay examining the case for wind, from the Protect Rural Scotland Party
letter to The Caledonian-Record (St. Johnsbury, Vt.), by Bill Eddy
letter to The Caledonian-Record, by Bill Klein
letter to the Burlington (Vt.) Free Press, by Eric Rosenbloom
editorial by the Burlington Free Press
letter to The Wichita (Kan.) Eagle, by Gaylord Dold
notes on some surveys about wind farms
report on the poor record of the Searsburg, Vermont, wind plant
comments about proposed East Haven, Vermont, wind project and projects in Vermont in general
letter to the Manchester (Vt.) Journal, by Hugh Kemper, and response by Andrew Perchlik
outline of large wind projects targeting Vermont and vicinity
response to criticism by Mark Diesendorf
"Questioning the faith of wind power," by David Roberson -- an environmentalist view
"Industrial wind, corporate vandalism," by Joanna Lake -- a progressive view
"Big money discovers the tax breaks for wind energy," by Glenn Schleede -- a fiscal conservative view



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