
Fifteen out of the facility’s 103 turbines were outfitted with Bat Deterrent Systems. A 5.0 m/second cut-in speed curtailment was simultaneously applied at the deterrent-equipped turbines.
There are several bat species present at Pilot Hill, including multiple migratory tree species. The testing revealed a significant reduction of 72% with Silver-haired Bats, 71% with Hoary Bats, and 94% with Big Brown Bats. Eastern Red Bats proved harder to deter, with 58% reduction in mortality for the two treatments together.
The Pilot Hill trial was preceded by a two-year study at the Los Vientos Wind Energy Facility in Texas, which saw an overall reduction in bat fatalities of 54%. NRG’s Bat Deterrent System is currently only available in North America. The company plans to hold trials of the technology in Europe in 2019.