Statement on Painting Wind Turbine Blades

A recent study suggests that painting one blade on a wind turbine black may reduce bird mortality. But more studies are needed before this finding can be considered a definitive solution.

Creative and scientifically tested measures are needed to reduce the threat renewable energy infrastructure, such as wind turbines, can pose to wildlife. Photo: Niek Goosen

(September 3, 2020, Washington, DC) A recent study (July 2020) from a wind energy facility in Norway found that painting one blade on a wind turbine black significantly reduced bird mortalities due to collisions. This is a positive finding. However, only four of 68 turbines in the facility featured the black blade. American Bird Conservancy (ABC) hopes that future, larger studies elsewhere bear out the same results so this can be applied more broadly.

“This is a good start in identifying additional ways to reduce the threat of wind turbines to wildlife,” said Joel Merriman, ABC's Bird-Smart Wind Energy Campaign Director. “That said, it's too soon to bill this as a proven technique to minimize bird mortality at wind energy facilities. We're seeing many people refer to this paper as if it's a proven method, rather than what it is — an encouraging starting point for further study.

“Above all, siting turbines away from high bird-use areas remains the best way to reduce bird mortality,” he added.

The study was conducted over an 11-year timeframe. Searches for bird carcasses were conducted for 7.5 years before the turbine blades were painted black to gather baseline data, and for 3.5 years after the blades were painted. The researchers used trained dogs to find bird carcasses, a commendable element of study design given that dogs find considerably more birds than human searchers. However, as the authors themselves acknowledge, the small sample size of four turbines being painted black substantially limits the application of this study.

“Unfortunately, even though wind turbines enable production of carbon-free energy, they are not free from environmental impacts,” said Merriman. More than half a million birds are killed by wind turbines in the U.S. each year. Considerable effort has been expended seeking ways to minimize these impacts through smart wind facility siting, technology, and mitigation. Above all, siting facilities in low-risk areas is of paramount importance.

It's also important to consider whether this technique could be widely deployed. For example, in the U.S., current Federal Aviation Administration standards require that turbines be painted white or light gray to increase their visibility in daylight hours. Painting turbines another color could raise aviation safety concerns.

“This pilot study is a great start,” said Merriman. “American Bird Conservancy is very supportive of such innovations and hopes that further, similar studies are conducted. Different colors, patterns, or less-conspicuous approaches like using UV-reflective paint could also be promising ways to reduce bird mortality and move a step closer to making wind energy development bird-smart.”

With the recent legal opinion that reinstates bird protections under the Migratory Bird Treaty Act, the wind industry now has an increased incentive to study these kinds of innovations. Hopefully this will be seen as a great opportunity to come up with a proven long-term solution expanding on the current study, as well as investigating improved turbine designs and other potential remedies.

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Media Contact: Jordan Rutter, Director of Public Relations, 202-888-7472 | jerutter@abcbirds.org | @JERutter
Expert Contact: Joel Merriman, Bird-Smart Wind Energy Campaign Director | jmerriman@abcbirds.org

American Bird Conservancy is a nonprofit organization dedicated to conserving birds and their habitats throughout the Americas. With an emphasis on achieving results and working in partnership, we take on the greatest problems facing birds today, innovating and building on rapid advancements in science to halt extinctions, protect habitats, eliminate threats, and build capacity for bird conservation. Find us on abcbirds.org, Facebook, Instagram, and Twitter (@ABCbirds).