A Safe Space for Bats: New NRG Systems Technology Protects Bats at Wind Farms
Thursday, April 18, 2019
Posted by: Jeff Couture
Globally, bat populations are in decline. According to Bat Conservation International, the International Union for the Conservation of Nature has deemed 22 bat species as “critically endangered,” meaning they face an imminent risk of extinction. Fifty-six other bat species are endangered and more than 100 are considered vulnerable.
There are numerous reasons for recent downturns in bat populations, including habitat reduction and white-nose syndrome, a fungal disease that has wreaked havoc on hibernating bat populations in North America. Bat fatalities are also occurring at operating wind farms. Although the underlying causes of bat fatalities at wind turbines remain unknown, the wind energy sector has made bat conservation a top priority.
The wind industry has been diligent in its search for solutions, with curtailment taking the lead as the most widely used tactic to reduce bat take at wind farms.
“More than anything, wind industry professionals are passionate about the environment,” said Tim Hayes, the Environmental Director at Duke Energy. “We go to work every day driven by a mission to reduce the impacts of global climate change and we certainly do not want to do that at the expense of biodiversity. While curtailment is an effective method for reducing bat take, it is important to find a balance between producing renewable wind energy and sustaining the environment.”
In 2015, NRG Systems, Inc., a Vermont-based company that designs and manufactures technologies for all stages of wind and solar development, began developing an ultrasonic Bat Deterrent System. The goal was to create a tool for minimizing bat take at turbines without affecting energy production.
NRG’s deterrent system is based on “jamming” the echolocation capabilities of bats, which they rely on for communicating, foraging, and orienting themselves. When switched on, the Bat Deterrent System emits an ultrasonic acoustic field in the same range as bats’ natural calling frequencies. This interferes with their ability to receive and interpret their own echolocation calls, which creates disorienting airspace that is difficult to navigate. By jamming their echolocation systems in such a way, bats are discouraged from entering the treated airspaces and roosting location, effectively pushing them out of dangerous territories such as the rotor-swept area of a wind turbine.
NRG’s Bat Deterrent System features multiple Bat Deterrent Units (BDU), which are the ultrasonic speakers mounted to the outside of the nacelle, as well as a Deterrent Unit Controller (DUC), which tells the speakers when to turn on and off and provides information to the SCADA system.
The Bat Deterrent System has been trialed at several wind farms across the United States and Canada. In December 2018, NRG released the results of a two-year test at the Los Vientos Wind Energy Facility, a Duke Energy-owned wind farm in Starr County, Texas. The results showed that the system reduced overall bat fatalities at the wind farm by 54% during the second year of testing, proving that the technology is an effective tool for reducing mortality of certain species of bats caused by wind turbines.
Read more at Windpower Engineering & Development