Caledon Wind Farm

A wind farm is being planned for the Caledon area. It will comprise 150 wind turbines, between 2 – 3.6 MW each in size. The hub height will be between 80m and 100m and the turbine blade length between 40m and 58.5m. (that's about 12 storeys high!) Here is the link if you'd like to read more http://projects.gibb.co.za/Projects/CaledonWindDSR.aspx

You can also read Stuart Shearer's blog - Greytonian (http://greytonian.blogspot.com/) for extensive information about wind turbines and the plans for the Caledon Wind Farm and how you can object.

Following is an article about the effect of wind turbines on bats:

Wind turbines threatening bats survival

August 26 2008 at 03:50PM

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.

For more information on wind turbines you can also have a look at this link: http://www.aweo.org/ProblemWithWind.html