In a recent research published in the Ecology and Evolution journal it was found that painting a wind turbine’s blade black would reduce the number of bird collision cases at wind farms by up to incredible seventy two percent.
Onshore wind farms are noticeably commercially effective in the long-term however sometimes they are being criticized by eco-activists for cases of negative impact for fauna.
The present investigation brings to light the real reasons behind bird collision enabling wind turbine developers and operators to mitigate collision risks by a very slight adjustment.
Generally, the risk of bird collision with a wind turbine’s blade is rather low. To find out how many birds get killed by blades, the research team focused on the Smola, one of the largest wind farms in Norway consisting of 68 turbines.
In 2013, four wind turbines in the Smola got one blade painted black. The research team led by Dr Roel May, who had counted 82 bird deaths due to collision with wind turbine blades during his research in 2006-2016, examined the results of the colour change and found out that the number of bird collisions has reduced by 72%. At the same time the researchers stress out that bird deaths were observed only on eight wind turbines over the same area so the research findings should be carefully reviewed.
Dr Roel May, Senior Researcher at the Norwegian Institute for Nature Research in Trondheim, says, “Collision of birds, especially raptors, is one of the main environmental concerns related to wind energy development. In Norway, 6-9 white-tailed eagles are killed annually within the Smøla wind-power plant. One of the mitigation measures we tested was painting one of three rotor blades black. The expectation is that this design reduces so-called motion smear, making the blades more visible to birds.”
Practically, the research concept is based on laboratory experiments carried out in the US in the past twenty years.
The testing has shown that after they painted one blade black, the number of bird collision cases has significantly decreased, however the finding needs to be tested on more sites to be recognized officially. The research team plans to test wind farms in the Netherlands and in South Africa for these countries have a large volume of wind farms set up in different environmental conditions.
Noteworthy, wind turbines vary greatly in size and blade type. The specified Smola wind farm is a set of big horizontal-axis wind turbines spread out over a territory of 18 square kilometers. When it comes to other types of horizontal axis wind turbines, the figures may be different.
Grigory Levkovets, the Chief Executive Officer of Estonia-based Tbhawt Manufacturing wind turbine manufacturing company, says: “Big attention should be paid to every wind turbine design specifics, how big the wind turbine is, how fast the blades rotate, what area attracts collisions the most. All such factors should be researched for each wind turbine type because in some cases painting one blade black might appear insufficient, or even unnecessary.”
“Our wind turbines are manufactured after the Darrieus wind turbine design with its own advantages and specifics. We are strongly concerned about the environmental impact of technology to nature and do our utmost to create the best, custom development plan for our clients with minimum risk to birds and wildlife in general,” he noted.
Mr Levkovets adds: “Painting a blade black is a very cost-effective way to save bird lives, and I agree with the researcher Dr Roel May that the painting should be made right prior to construction. In this way the developer would save a lot of money, rather than think of options of how to paint a massive blade after it’s up and running.”