Wind power continues to be a viable source of renewable clean electricity production. Eventually, it could meet 35% of global power needs. To achieve such a level of electricity generation from wind power, some problems will need to solved along the way. Bird deaths from collisions with wind turbines is a problem — and the size of the problem appears to be a matter of perception. A relatively tiny portion of annual bird deaths are caused by wind power farms. (Cats kill far, far more each year, for example.) Still, if it’s possible to reduce the relatively tiny number of bird deaths resulting from wind power turbine collisions, it would be beneficial to wildlife to do so. To that effect, researchers in Norway studied a potential method to reduce these collisions. Dr. Roel May, a senior researcher from the Norwegian Institute for Nature Research in Trondheim, answered some questions about their study for CleanTechnica.
Why did you want to study bird fatalities from collisions with wind turbine blades?
Between 2006-2011 (BirdWind project) we studied the effects wind turbines had on birds at the Smøla wind-power plant, looking into flight behavior, population effects, and collision risk. After having studied the mechanisms why birds collided, we wished to test various promising mitigation measures to reduce such negative impacts on birds (INTACT project). Both the mentioned projects were funded by the Research Council of Norway, as well as the wind energy industry and the regulator.
How many wind turbines in your study had one blade painted black?
Four turbines were painted; the experiment also included four neighboring control turbines.
A 70% reduction in bird fatalities is a very significant decrease. Do you think it could be replicated at other wind power sites?
Yes, it clearly can and should be replicated elsewhere to see to which extent the findings might be species- and site-specific. There is interest to do so in South Africa and in the Netherlands.
In your study period, there were no white-tailed eagle carcasses found after the turbine blade painting. Is there a reason that painting one blade in a turbine might be effective in preventing collisions for them in particular?
This is difficult to prove given the limited number of eagle collisions at these turbines. However, statistically it was unlikely that we did not find any after painting. Although only few turbines (4) were painted, the experiment did cover a multiple-year timeframe.
How long does it take to paint one turbine blade black and how much does the process cost in electricity production when the turbine is not operating? Or are there off-peak production times when turbines are not spinning when the painting can take place?
In our case the blades had to be painted when on the hub. This had to be done by certified personnel rappelling down from the hub. This meant it had to be done during days of no/little wind. It took therefore several weeks before the work was done. When implemented, it will obviously be preferential to do this when the blades are still on the ground of at the factory.
Can new wind turbine blades be painted black before turbines are installed at sites to decrease bird strikes?
How long did your study run, and what was the total number of bird fatalities during that period?
From the beginning of 2006 until the end of 2016, rendering seven and a half years before and three and a half years after treatment. Throughout the wind power plant, 9,557 turbine searches have been performed in the period 2006–2016, whereby 464 carcasses have been recorded. At the eight study turbines combined, 1,275 individual turbine searches were performed, during which 82 carcasses were found (including 40 willow ptarmigan not included in the study).
Why paint only one of the three blades in each turbine black?
As explained in our article, it clearly states that we followed the design that performed best in reducing motion smear, as investigated in a laboratory setting in the USA in the early 2000s.
Will you do more studies involving the use of black paint on turbine blades?
We do not have any plans at the moment, no.
Are wind turbine industry leaders or government regulators paying attention to your research?
I hope so. In Norway both the industry and authorities co-funded our research and are familiar with the results. Also the article is at the moment receiving much attention internationally.