Making Wind Energy Safer for Bats
When you think of people’s best friend, chances are you don’t think of bats. But maybe you should! Bats are one of nature’s most effective forms of pest control. They gobble up nocturnal insects, help farmers save money on pesticides by eating bugs that damage crops, and important food crops like bananas, cocoa, and agave (the key ingredient in tequila) rely on bats for pollination.
So bats are good for people. Wind energy is good for people, too. But is wind energy good for bats? The answer is yes, with an asterisk. Using wind energy reduces greenhouse gas emissions, which is good for bats, and it appears that wind energy doesn’t present a risk to most bat species. However, at certain times of the year, some species of bats in some regions are prone to having fatal interactions with wind turbines. Researchers have been trying to understand why certain bat species are at risk, and several hypotheses are being tested. “We need to think about bats not as a monolithic group, but rather as individual species, or similar species that share characteristics,” explained Dr. Amanda Hale, Associate Professor of Biology at Texas Christian University. “It would be a mistake to attribute the behavior of one bat species to all bat species of the same type.”
One thing is clear: to operate wind energy that is safer for bats, collaboration on assessing the risk and developing and applying solutions is key. And that collaboration is happening, with new data analysis tools and exciting technological advancements underway.
“Climate change is one of the greatest threats facing bats today,” said Dr. Cris Hein, former Director of the Wind Energy Program at Bat Conservation International. “We are concerned about the potential population-level impacts of wind energy development on some species, but at the same time, we recognize that wind energy presents one of the best hopes for reducing greenhouse gas emissions from power production. So we’re very focused on collaborating with others to find ways to make wind energy safer for those species of bats for which turbines are a problem.”
Diving into the Data
The AWWIC database has been an important new step for improving of understanding why bat fatalities occur near and around wind farms. The first formal report based on AWWIC data, AWWI’s Bat Technical Report, confirmed that 72% of all recorded bat fatalities at wind farms were concentrated among just three species of migratory tree bats, and that the incidence of fatalities varied substantially by region. By providing a better representation of the shape of the problem and revealing its complexity, the report has yielded valuable insights, setting the foundation for understanding which species are at risk, where, and why.
Collaborating to Protect Bats
“An unexpected silver lining to this situation is that wind energy has benefited bat research,” reflected Dr. Hein, former Director of the Wind Energy Program at Bat Conservation International. “When people started trying to understand why and how bats were interacting with wind farms, it became clear that there were a lot of knowledge gaps. We have learned a lot more about bats as a direct result of the resources that have been put toward trying to solve these problems, and that learning continues.”
Stakeholders from the scientific, wind, and conservation communities have come together to tackle the problem head on. The Bats and Wind Energy Cooperative (BWEC) formed in 2003 for the express purpose of understanding the reasons behind turbine-related bat fatalities. Bat Conservation International is a founding member of BWEC.
AWWI actively partners with BWEC to evaluate innovative technologies and strategies to help minimize bat-wind interactions. The goal of these efforts is to find solutions that will enable wind power to continue to expand and flourish while having the least possible impact on affected species of bats.
Defenders of Wildlife is also deeply involved in work to minimize the impact of wind energy on affected bat populations. “AWWI has played a vital role as a convener,” explained Joy Page, Director of Renewable Energy & Wildlife at Defenders of Wildlife. “First and foremost, they’ve gotten everyone working on this issue together and talking, which is invaluable. They also disseminate information, which is tremendously helpful. And perhaps most importantly, they’ve done an incredible job of creating platforms for cooperation that enable stakeholders to leverage funding and other resources to advance critical research. The solution to this challenge and a strong future for these bats depends on this collaboration.”
Making Wind Farms Safer for Bats
The potential for wind farms to harm bat populations is something the wind industry takes very seriously. Some, like Duke Energy, have even hired “bat men and women” to focus specifically on making wind farms safer for bats. While research to understand why bats are attracted to turbines continues, it appears that wind speeds below about 7 meters per second tend to be more problematic for bats, probably because both bats and their invertebrate prey are more likely to be flying and to come into proximity with turbines when wind speeds are slower.
In response, the wind industry has experimented with curtailing turbines at low wind speeds. While this method has proven effective at reducing fatalities, blanket curtailment is inexact and results in significant production losses. A more targeted approach is smart curtailment, which entails stopping the turbines at a wind farm when bats are most likely to be at risk. Developers of smart curtailment strategies and systems are collaborating with AWWI and other partners to evaluate these approaches, and a new funding opportunity from the U.S. Department of Energy will support this testing.
Several other technologies and strategies that could help detect or deter bats to help reduce and avoid bat mortality at wind farms are being developed and evaluated as well. For example, companies such as NRG Systems and GE have developed ultrasonic acoustic deterrent devices – which are designed to be mounted on wind turbines and deter bats with high frequency noise – and partnered with consultants, academic researchers, and BWEC to further develop and evaluate these devices.
Investing in Solutions
Finding solutions to protect bats is one of AWWI’s highest priorities. AWWI works closely with stakeholders across multiple sectors to explore and develop novel approaches, and we evaluate new technologies through the Technology Innovation program. The wind industry shares this commitment to developing effective methods of reducing risks to bats. “We want to make our wind farms as safe as possible for bats and other wildlife,” said Jenny McIvor, Vice President of Environmental Programs, Compliance and Permitting at MidAmerican Energy Company. “We start by doing what we can to avoid impacts, and then we seek to minimize any impacts we cannot avoid. Technologies that can augment or enhance our risk minimization strategies will definitely continue to be of interest.”
We’re still learning why, when, and which species of bats interact with wind farms, but significant time and resources are being devoted to answering these questions and understanding how to protect and conserve one of people’s best friends.