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Print 38 comment(s) - last by The Raven.. on Nov 4 at 10:28 AM


  (Source: Treehugger)
Raising the cut-in speed to 11 mph could result in as much as a 93 percent reduction in bat-turbine related deaths

Wind power has become an important competitor in the race for clean energy, but like many newer developments, it needs some work. One issue associated with wind power is bat and bird-related fatalities due to the spinning blades of the turbines. However, researchers may have solved this problem with a slight change in speed

Edward Arnett project leader from the Bat Conservation International in Austin, Texas, along with John Hayes, co-author of the study from the University of Florida, have studied bat fatalities associated with wind turbines and concluded that altering the speed slightly would reduce a large percentage of these deaths.

Wind turbines within the United States are programmed to start producing power when wind speed reaches 8 or 9 mph. The speed at which wind turbines begin producing power is the cut-in speed, and those with a low cut-in speed tend to run more often than those with a high cut-in speed because they begin running at lower speeds in the first place. 

Arnett, Hayes and their research team recorded bat fatalities while observing 12 out of 23 turbines at the Casselman Wind Project in Somerset County, Pennsylvania. They stayed for 25 summer and fall nights in 2008 and 2009 (because wind speeds are low this time of the year), and found that the less time a wind turbine is running, the better because bats cannot be harmed by blades that aren't in motion. Following this logic, Arnett suggests raising the cut-in speed of wind turbines to 11 mph, which would result in a reduction of bat fatalities by approximately 44 to 93 percent and an annual power loss of less than one percent. 

"This is the only proven mitigation option to reduce bat kills at this time," said Arnett. "If we want to pursue the benefits associated with wind energy, we need to consider the local ecological impacts that the turbines could cause. We have already seen a rise in bat mortality associated with wind energy development, but our study shows that, by marginally limiting the turbines during the summer and fall months, we can save bats as well as promote advances in alternative energy."

Arnett notes that reducing bat fatalities is essential because bats help with pollination and pest management, making them an important part of ecosystem health nationwide. 

"Rarely do you see such a win-win result in a study," said Arnett. "There is a simple, relatively cost-effective solution here that could save thousands of bats. This is good news for conservation and for wind energy development." 

This study was published in Frontiers in Ecology and the Environment on November 1.



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RE: This is news?
By TheHarvester on 11/3/2010 7:55:40 AM , Rating: 3
This article might actually be useful if some context was given for the actual number of bats that were killed during the period of observation. Reducing the cut-in wind speed reduced the number of bats killed from... 3 to 1? 100 to 6? If 100 bats were dying during a summer by these things, then maybe there's something to talk about here in terms of ecological impact, but if the number of bats that died was like 10, knowing that allows us to effectively weigh the cost of a one percent loss in energy capture and decide the ten bats can snuff it and not jeopardize integrity of our ecosystems.


RE: This is news?
By Tiffany Kaiser on 11/3/2010 9:47:10 AM , Rating: 2
The study said Arnett and Hayes recorded bat fatalities for 25 summer nights and 25 fall nights in 2008 and 2009. They found at least one fresh bat carcass every night that the turbines were fully operational as opposed to when the cut-in speed of the turbines increased to 11-14.5 mph, thus running for a shorter period of time. The mortality rate was approximately 3.6-5.4 times higher with a lower cut-in speed.

These were the only figures I could dig up. Hope this helps.


RE: This is news?
By 67STANG on 11/3/2010 11:13:26 AM , Rating: 2
How is this a valid study? Bird, bats, etc. fly into objects all the time. Who's to say that if the turbines they observed were cell towers, they wouldn't have flown into them accidentally and died? I'm sorry, but this is bunk. The same people that do these studies also state that turbines kill birds, when 20x more bird deaths are caused by them flying into sky scrapers.


RE: This is news?
By The Raven on 11/3/2010 3:32:55 PM , Rating: 2
Umm... I'm not down with this hubub either, but the study is not bunk based on your objections.

quote:
The same people that do these studies also state that turbines kill birds


Your comment makes it sound like you think that since more birds are killed by skyscrapers than windmills, you don't believe that bats can be killed by windmills. Windmills do kill birds. And bats too. Unfortunately they don't kill politicians.

And if you know anything about bats it should be the fact that they are blind (hence the saying "blind as a bat"). I think it would be a piece of cake to echo-locate a stationary cell tower as opposed to a moving windmill blade.

So unless you have any other objections, this study seems just fine.


RE: This is news?
By FaaR on 11/4/2010 8:29:05 AM , Rating: 2
Bats use echo-location not because they're blind (which they in fact aren't, seeing as they got eyes), but because bats hunt at night, when there's not much light to be had to see by.

So in other words, the saying which you quote, is - like so many other sayings - nothing but a big ol' load of crap.


RE: This is news?
By The Raven on 11/4/2010 10:10:55 AM , Rating: 2
You are right. I didn't mean for the hyperbole to come off that way. But it must be noted that bats don't have great vision and certainly don't rely on it at night (which is when they are awake). And when they do use their vision, it is poor (though variances exist depending on the species).

And it should also be noted that just because an animal has eyes doesn't mean that it can see. I think moles can see (poorly) but there are other species of animals that live underground and they have non-seeing eyes. Truly blind.
I think they are caught in a point of evolution where they haven't yet "cast off" their eyes.

But my point was that a bat might have issues with these windmills due to the fact that they rely heavily on echolocation. And though they are extremely precise, that skill would be compromised if they were to locate the blades of a quickly spinning windmill.

Point is: this study isn't a "big ol' load of crap" ;-)


RE: This is news?
By The Raven on 11/4/2010 10:28:59 AM , Rating: 2
quote:
For bats, vision is important for foraging and homing, and for predator avoidance. Mesopic vision (at light levels that stimulate both the rods and the cones) is particularly relevant at dusk and dawn and on brightly moonlit nights. For flower-visiting and nectar-feeding bats like those studied here, UV vision should increase foraging success, as many flowers visited by bats show UV reflection.


http://www.sciencedaily.com/releases/2009/07/09072...

This looks like it should be the definitive word that bats aren't as blind as I thought they were.


RE: This is news?
By kattanna on 11/3/2010 11:35:22 AM , Rating: 2
http://www.theresilientearth.com/?q=content/wind-p...

quote:
While the total number of birds killed in the US each year fluctuates, Michael Fry of the American Bird Conservancy estimates that US wind turbines kill between 75,000 and 275,000 birds per year.


the article also talks about previous studies on bats

quote:
Blade rotational speed was a significant negative predictor of collisions with turbine blades, suggesting that bats may be at higher risk of fatality on nights with low wind speeds


but also this

quote:
This followed previous research that showed that bats can have their lungs ruptured from the sudden low pressure of passing turbine blades: the bats are actually drowning in mid-air. It is not necessary for the bats to collide with the turbines, bats don't even need to come in physical contact with the turbine blades. A blade passing close by is enough to be fatal—an unexpected hazard that was previously unsuspected.


its good to see more sites talk about this issue. I want to see the enery field be on a level playing field and if any other energy producer was the product of such mass death there would be howls from the econuts. yet wind has seemingly been getting a free pass, even when it comes to killing endangered species

quote:
Yet a July 2008 study of the wind farm at Altamont Pass, California, estimated that an average of 80 golden eagles were killed there by wind turbines each year.


wind power has its place, like most other forms, but it is FAR from the "magic bullet" a lot of greens think it is


RE: This is news?
By FaaR on 11/4/2010 8:32:16 AM , Rating: 2
Wind turbines should preferably be placed out at sea where winds are stronger and more prevalent than over land, or in high, mountainous regions where few birds (and virtually no bats, I presume) fly around to get killed by these things.


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