Southwestern Ontario sites part of study to reduce bat deaths 

In 2004, the non-profit, academics and wind industry representatives formed the Bat and Wind Energy Co-operative to look at the issue, and the Ontario project came out discussions Hein had with NextEra and Renewable NRG Systems.

Bats use echo location, or sonar, to navigate, orient themselves in the environment and catch prey, Hein said.

“So, we thought that if we could generate a signal that’s within their frequency range, we could essentially jam their ability to function,” and direct them away from deadly collisions with wind turbine blades, he said.

In recent years, researchers have found that some species of bats appear to be attracted to wind turbines, Hein said.

“They come and investigate them, spend some time flying around and that puts them at greater risk.”

The cooperative began looking at acoustic deterrent in 2006, working with a few manufacturers, carrying out tests and learning how bats react to the devices.

Recently, Renewable NRG Systems has made “incredible advances” in the technology and its ability to operate on wind towers, Hein said.

The devices emit sound at a frequency and intensity that is familiar to bats.

“We don’t feel like there’s any adverse affects on the bats, and we’re hoping that it keeps them out of a dangerous airspace,” Hein said.

The sounds only carry out to about the tips of the wind turbine blades, he added.

“We’re not adding any sort of audible sound to the environment that might be a problem for people.”

The aim is to make it uncomfortable for bats to be in the turbine blade airspace and “have them move on,” Hein said.

Researchers have used thermal cameras to watch bats at turbines.

“They seem interested” and will make multiple approaches instead of just flying by, Hein said.

“They don’t appear to recognize that there’s a danger, until it’s too late.”

But, because bats “are pretty smart,” it’s possible those encountering the acoustic deterrent devices could come to associate turbines with the disorienting sound and learn to avoid them, he said.

Ontario’s bats are the primary predator of insects that fly at night, including many forest and agriculture pests, according to Hein.

Bats “help farmers save billions of dollars a year in pesticides,” he said.

“That makes food cheaper and the environment safer.”

The testing at NextEra’s southwestern Ontario sites will compare bat deaths at turbines with the devices operating and without.

According to 2016 bat mortality reports posted on the NextEra website, 85 dead bats were found during monitoring at 28 turbines at the Jericho wind project. There were 37 dead bats at 11 turbines at the Bluewater project and 95 at 19 turbines at the Goshen wind centre during the monitoring.

According to the reports, none of the sites exceeded bat morality thresholds set by the province.

Wind companies exceeding the province’s threshold have to change turbine operations so the blades aren’t spinning at high rotations-per-minute when bats are most at risk, Hein said.

“That strategy seems to work consistently across facilities, and really well, at reducing bat fatalities.”

But, it comes at a cost in loss of revenue for wind companies, he said.

“This acoustic deterrent idea is a way that the turbines could operate normally, we reduce bat fatalities, and we’re hoping if it’s successful, we’ve got this win-win situation.”

The acoustic deterrent technology is being tested at sites in the U.S., as well as southwestern Ontario, and the results will be analyzed, published and peer reviewed.

“If we get nice consistent results, I think people will start to invest in this technology for use rather quickly,” if it’s also shown to be cost-effective, Hein said.

But, he added, “The results need to prove it out.”

In a letter to NextEra, Pauline Desroches, resources development section manager with the Ontario Ministry of Natural Resources and Forestry, said the ministry “supports research efforts that can help inform Ontario-specific knowledge about bats, including the development and testing of innovative approaches to mortality mitigation.”

NextEra declined to comment.