How wind energy is sucking the life out of our bat population 

As the United States looks to green technology to keep up with rising energy costs, wind energy has become a beacon of hope. Pennsylvania now ranks 15th in the nation in wind energy, and wind farms in our region have been honored by the U.S. Environmental Protection Agency.

But there are problems.

Even if all the wind farms in Pennsylvania were utilized, they’d still only make up for about 6 percent of needed electricity in the state. And, ironically, they also seem to be messing with nature: One unintended consequence of the installation of wind turbines has been a massive increase in bat deaths. Bats seem to be drawn to them, and scientists can’t figure out why. But they do know that the rapid decline in our bat population—which is crucial to general insect control—is really bad news.

“A high [bat] fatality rate was observed at a wind farm in West Virginia in 2003 and from that point on, we began seeing high fatality rates in Pennsylvania, Tennessee, and then different rates across the country,” says Dr. Cris D. Hein, coordinator of the Bats and Wind Energy Program for Bat Conservation International. “So it became an issue that needed to be addressed quite rapidly, as wind development grew in the early 2000s.”

Each year, an estimated hundreds of thousands of bats are killed after colliding with, and getting shredded by, wind turbines. Last year, Pennsylvania’s 420 turbines killed an estimate 10,000 bats, according to the state Game Commission. And that has left scientists with a conundrum: Between the repurcussions of global warming and the shrinking oil supply, going green is inevitable. So how do we stop the destruction of nature—the very nature we’re attempting to save?

Hein says wind farms kill most bats during migration season, from July through the end of September—“though that does vary a little bit from site to site.” He says three species of bat are most affected: hoary bats, silver-haired bats, and red bats—all of which are migratory tree bats and play a central role in the ecosystem. Especially Pennsylvania’s.

Which means their demise is really, really bad. Why, you ask? Because, if you listen to Elton John’s groovy soundtrack to 1994’s The Lion King , there’s this thing called the Circle of Life, and it exists outside the world of the animated jungle.

So, the more people build on bats’ natural habitat and shred them to pieces, the more pesticides are used to keep the bugs away from our food supply. And the more our food suffers, the more expensive it becomes.

Bat Conservation International, the U.S. Fish and Wildlife Service, the American Wind Energy Association and the National Renewable Energy Laboratory of the U.S. Department of Energy, then, formed the Bat and Wind Energy Cooperative in 2003 to develop “solutions to minimize or, where possible, prevent mortality of bats at wind power turbines.” Especially as the Nature Conservancy predicts up to 2,900 Pennsylvania turbines by the year 2030.

Hein says the organization ran into its first snag early on, when scientists realized they don’t really know why bats are attracted to wind turbines. Just that they are.

“We quite often would find bat carcasses at wind sites,” says Kim Lengel, the Philadelphia Zoo’s director of conservation and general curator. “There was concern and since then they have only gotten worse as the bat population in Pennsylvania and other parts of the country decreases.”

Now, BCI is doing studies to determine whether bats and wind turbines can co-exist peacefully.

With that in mind, the Bat and Wind Energy Cooperative commissioned a two-year study in Columbia and Schuylkill counties, in Pennsylvania, randomly selected 10 turbines in the areas and fitted them with bat deterrent devices—“an acoustic device,” Hein says, “that would generate a noise that would disrupt a bat’s ability to locate the turban plate”—to see if it made a difference.

In the first year of the study, 2009, researchers estimated 21 percent to 51 percent fewer bats were killed per deterrent turbine. The second year, twice as many hoary bats and four times as many silver-haired bats were killed per control turbines than at deterrent turbines during the trial period. It’s an area of research, Hein says, that’s ongoing.

“Bats are in a critical situation and Pennsylvania is right in the heart of it,” says Lengel. “People understand their role in the ecosystem, and whether that translates into ‘I want to spend more money on energy,’ is a different question.”

Hein says the country’s lag on going green may have an effect, too. The earth’s warming may have as of now unknown effects on the migratory policies of Pennsylvania’s bat population, too, which could change the way deterrent systems affect the creatures.

“I don’t think there’s anyone saying we can’t have a wind farm,” says Lengel, “but maybe the way we manage a wind farm and maybe change the certain times of year where you use deterrent devices and … others where you put your wind farm in some kind of stasis. I don’t think it’s saying no wind farms. But it’s knowing the future impact.”