GREAT FALLS — An operations center in California can shut down wind turbines 1,200 miles away in Montana in fewer than 30 seconds when the flight patterns of golden eagles and other raptors indicate a potential collision in the making.
The quick response is possible because of tracking radar, “detect and deter” cameras and human spotters called “bio-monitors” deployed at Rim Rock Wind Facility in Montana’s Glacier and Toole counties.
Greg Copeland of San Francisco-based NaturEner USA, the owner, says the combination of technology and trained avian biologists form a tiered alert system that’s proving to be effective, so far, at preventing the turbine blades from striking birds.
“We think this three-layered system provides the best kind of protections that have been deployed anywhere in the United States,” Copeland said.
The 189-megawatt wind farm with 126 turbines is Montana’s largest.
It’s located near the Kevin Rim, a series of sandstone cliffs 20 miles northwest of Shelby.
Golden eagles, ferruginous hawks and other species nest in the rocky outcroppings, and the U.S. Fish and Wildlife Service and Montana Audubon previously have raised concerns about the location of the wind facility in prime raptor habitat.
The wildlife conservation system “without a doubt” is saving birds, Copeland said. Other wind facilities are using individual forms of technology, or a human monitoring component, to protect birds, Copeland said. NaturEner’s integration of multiple forms of technology with human expertise, in a layered strategy, makes its eagle protection efforts stand out, he said.
“It’s a real aggressive approach to protecting avian species,” Copeland said.
Brent Esmoil, deputy field supervisor for the U.S. Fish and Wildlife Service, said NaturEner has submitted an eagle conservation plan to the agency but it has yet to review it and provide comments.
Montana Audubon likes what it has seen, said Steve Hoffman, the bird conservation organization’s executive director.
“They’re working hard in this and they’re taking their responsibility of being an environmentally conscious energy company quite seriously,” Hoffman said.
Montana Audubon encourages wind companies to build wind farms at sites without large concentrations of birds or migratory pathways.
Hoffman adds NaturEner has gone “above and beyond” in its efforts to reduce the possibility of bird strikes at Rim Rock and has been willing to share information including when “a raptor gets sliced and diced.”
Since the wind farm became operational in October 2012, two raptor fatalities have been documented, Copeland said. That is “an extraordinary number” compared to higher figures documented at 20 wind farms in similar raptor habitat in the Pacific Northwest, he said.
One of the birds found dead at Rim Rock was a goshawk, an old-growth forest species that likely was migrating through, and the second a ferruginous hawk.
Two kinds of marine radar systems from different manufacturers are being tested at the wind farm.
Each system has detailed acquisition and tracking software that can hone in on birds 5 to 7 miles away from the wind farm, Copeland said. Radar dishes send out signals and feedback dishes capture the return signals.
“So that gives you a pretty good view of activity that could be taking place quite a distance from the wind farm,” Copeland said.
Radar has been deployed with limited success at other wind farms, but units elsewhere have been placed in the interior of wind farms, which can lead to interference, Copeland said. At Rim Rock, the radar units are situated outside of the turbine field, which Copeland said seems to have solved the “clutter” issue.
Biologists, called “bio-monitors,” are the second layer of protection.
During the day, armed with high-resolution spotting scopes and stationed at three different locations, they observe raptors to gather information for a habitat-use study. Eight people have been hired to do the work.
“Literally they sit out there on a particular location and search the sky for their entire shift,” Copeland said. “Believe it or not, there are people who love that.”
If the bio-monitors — or radar — identify a raptor at risk because of its flight pattern, satellite phones are used to call in a turbine shutdown order to the operations center in San Francisco.
Turbines are being shut down every other day or so because of approaching raptors, but shutdown orders could become more infrequent in the future, Copeland said. That’s because bio-monitors currently are being told to be particularly conservative in estimating flight distances as they learn more about raptor flight patterns in the area.
Turbines at the wind farm are divided into zones, each with four to eight towers. When a shutdown order is called in, it’s for a particular zone. The impact of the shutdowns on power production is limited because of their surgical nature, Copeland said.
The quickest a turbine operating at full speed has been powered down was 21 seconds, Copeland said. Turbines remain down for a few minutes up to 30 minutes.
The last line of defense is cameras mounted on the turbines with software that can visually acquire avian targets and track them. If raptor approaches within 200 meters, it triggers a high frequency noise and flash of light meant to drive them away.
A policy also is in place in which specific turbines that pose the highest risk to birds are shut down during certain times of the year when the wind directions tend to push birds toward those turbines.
“We’re not doing it because of any regulator banging on our heads,” said Copeland, adding the company is committed to conserving wildlife, particularly as a “green” company.
But in taking the steps, the company also is trying to eliminate the potential for raptor fatalities thus reducing the risk of enforcement action, he added. The U.S. Fish and Wildlife Service enforces federal laws protecting eagles and migratory birds.
Copeland said the same kind of technology could be implemented at other wind farms, giving the work at Rim Rock added significance.
The cost of purchasing and then maintaining the radar units alone for five to 10 years will be about $750,000.
Monitoring has shown that raptors do not utilize the footprint of the wind farm 90 percent of the time, Copeland said.
Hoffman said the death of one golden eagle is significant because the birds can live as long as 25 years and usually produce one young a year.
Seven pairs of golden eagles nest around Rim Rock, Montana Audubon’s Hoffman says.
Today’s wind turbine blades are larger and slower than earlier versions, making strikes less likely, Hoffman said. But the blades on newer towers still turn at 200 mph at their tips, he said, and raptors are susceptible to being struck because their eyes are focused on the ground.
“Raptors are always looking for food,” Hoffman said. “They’re not looking for potential objects striking them.”