Turbine Blades Painted to Prevent Bird Collisions


Electric power company PacifiCorp is studying bird safety in Glenrock, Wyoming, by painting wind turbines blades black to observe any potential reduction in collisions.

According to PacifiCorp at the project launch, 36 different turbines have been coated to analyze how the painted blades affect fatality rates for eagles, other nonnocturnal birds and bats.

About the Project

A recent report from the Wyoming Public Media states that animals such as owls, turkey vultures and golden eagles are consistently colliding with the human world.

Wyoming is reportedly an important area for many of these species, especially golden eagles, as tens of thousands live there year-round. The state is also a huge migration corridor between Alaska and Mexico.

At the Teton Raptor Center in Wilson, Wyoming, veterinarians, avian scientists and volunteers have been treating birds for accidents often caused by crashes into infrastructure. Conservation Director Bryan Bedrosian stated that wind energy growth has become a threat for a species that have typically been “at the top of the food chain.”

“They've never had to look over their shoulder. So if they're up soaring looking for prey, they're never looking over their shoulder for something else to come get them,” Bedrosian said. “When they don't see that turbine blade going at 180 miles an hour, that could potentially hit them.”

The turbine blades reportedly kill hundreds of thousands of birds and bats a year, though scientific estimates vary. However, those numbers are reportedly still less than threats like power lines, cars, buildings and even house cats.

One of the largest wind farms in the continental United States is also reportedly being built in Wyoming, with some of the strongest wind resources in the region.

According to PacifiCorp, experts thought that both eagles and diurnal non-eagle birds could see the new painted blades better, resulting in higher turbine avoidance.

The study initially began with news of recent research in Norway, which found an almost 72% decline in turbine blade-related bird collisions from painting one turbine blade in black.  

“This is an extraordinary partnership of scientists, federal regulators, wildlife managers, a nongovernmental organization, academia, developers and utility companies working together to find solutions to reduce the impacts of critical electric infrastructure on birds,” said Travis Brown, Director of Compliance and Permitting for PacifiCorp.

Painting blades is thought to visually disrupt what often may appear to the bird as a uniform airspace, making the turbine more visible and helping trigger avoidance behavior.

According to PacifiCorp, bats have different visual and auditory understandings of their surroundings while flying, so the study also used a second hypothesis that bats would not see the painted blades and there would be no change in bat collision fatalities at turbines with painted blades.

The researchers are reportedly using human and canine tracking to count collisions, and will continue to do so for several years. Senior scientist with the Renewable Energy Wildlife Institute Shilo Felton explained that it was a good opportunity to study the statistical viability of paint as a solution.

“Wildlife conservation doesn't happen in a vacuum. We have to consider how we as humans interact with wildlife and how we can address those challenges so that humans and wildlife can coexist,” Felton said.

Felton also stated that utility companies have also tried stopping the turbines from spinning when birds are around, but that required detection using complicated technology or human spotters on the landscape. Additionally, it was deemed to be inefficient.

“Curtailing turbines is generally very effective because you've stopped the turbine from moving. But it also results in lost energy production,” Felton said. “That lost energy has to be made up somewhere to meet our energy demands as people.”

This is reportedly only the beginning of the research process for painted blades, as there are still some unanswered questions, including:

  • Do North American birds see turbines the same way as European ones?
  • Will the general public have an issue with new black blades?
  • Are there energy or engineering concerns with black turbines compared to white ones?

But Jona Whitesides, a spokesperson for PacifiCorp, stated that the company believes it is worth learning more due to the economic and conservation benefits it could provide for the company.

“Of course this is exciting, because it's something new. Something that's never really been tried,” he said. “If it is viable, it definitely could be one of those solutions that could be rolled out nationwide.”

Researchers reportedly expect to have conclusive results from the Glenrock study later this decade. They explained that they plan to compare their data with similar experiments happening around the world, including at wind farms in South Africa, Sweden and Spain.

The study is reportedly being supported through a public-private partnership that includes:

  • U.S. Geological Survey;
  • Renewable Energy Wildlife Institute;
  • U.S. Fish and Wildlife;
  • Invenergy;
  • U.S. Department of Energy;
  • NextEra Energy Resources; and
  • Oregon State University.

PacifiCorp stated that there has been widespread support in the U.S., as evidenced by this study by PacifiCorp and its partners, to replicate the Norway study with more treated turbines to confirm if similar results can be reached at other sites.

In 2021, the Oregon state legislature reportedly asked Oregon State University to find a project that would evaluate the effectiveness of painted blades on wildlife collisions.

“The timing of the legislature’s interest and the engagement of PacifiCorp could not have been better. We have a diverse and well-rounded scientific team tackling this important question, and OSU is proud to be a partner,” said Christian Hagen, associate professor at Oregon State University.

Norway Study

The study in Norway was published back in 2020, finding that bird death from collisions with turbine blades dropped by 71.9% when one of the blades was painted black, compared with unpainted blades at the same wind farm.

The study, which began in 2013, was conducted at the Smøla wind farm, along Norway's west coast. When completed in 2005, the 68-turbine wind farm was one of the largest onshore facilities in northern Europe, according to Bård Stokke of the Norwegian Institute for Nature Research, one of the study's lead authors.

Over 10 years, trained dogs found nearly 500 dead birds at the base of turbines, killed by collision with blades or with the towers. Researchers began looking for ways to reduce collisions and looked to a 2002 University of Maryland laboratory study showing a single black blade could reduce bird impacts.

According to the research, birds appeared to be more aware of what's happening to their right and left when flying through a perceived open-air space, such as a wind farm. The blurred motion of moving wind blades directly in front of them doesn't appear as an obstruction, causing them to fly into the blades or towers.

But, when researchers at the Norwegian Institute for Nature Research and the Lake Ånnsjön Bird Observatory in Sweden painted a single black blade out of three on a rotor, it created a visual smear that the birds perceived as an obstacle, driving them away.

While this notion wasn’t unknown to other researchers at the time, including in the United States, Garry George, Director of the National Audubon Society's Clean Energy Initiative, said that the study had moved the research forward.

At the time of the report, the wind industry killed roughly 250,000 birds annually in the U.S., according to Fish and Wildlife Service estimates. While this only represented 0.01% of human-caused bird death, advocates said the cost-effective measure should be repeated at scale and replicated to look at the impact.


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