25,000 new wind turbines are to be built in Europe. But each turbine endangers numerous migratory birds every year. A new study by the Swiss Federal Research Institute WSL now shows how existing weather radars could solve the problem. Through targeted shutdowns, up to 90 percent of collisions could be avoided with minimal energy loss.
Around 25,000 new wind turbines are to be built in Europe over the next few years in order to achieve emissions targets. This could further increase the threat to migratory birds, whose populations are already declining sharply worldwide. However, there are currently no estimates of affected birds during their nocturnal migrations in Europe.
At the Gotthard Pass in Switzerland, the turbines switch off when a local bird radar registers many animals. However, the planned expansion of wind power in Europe would require automated and scalable monitoring methods that work on a larger scale.
Can weather radar data protect birds from collisions with wind turbines?
A team of researchers led by Silke Bauer from the Swiss Research Institute for Forests, Snow and Landscape (WSL) is therefore investigating how weather radar data can be used to prevent birds from colliding with wind turbines.
The radar systems studied typically measure precipitation intensity and cloud intensity in the atmosphere. But they also record the movements of flocks of birds and cover significantly larger areas than specialized bird radars. The researchers used this weather data as the basis for their bird protection calculations.
The corresponding data from the weather radars is available in high spatial and temporal resolution approximately every 15 minutes. According to the researchers, the recording makes it possible to track the flight movements of large swarms in real time in order to estimate the risk of collisions with wind turbines.
Analysis of data from five countries
The researchers evaluated weather radar data from Germany, France, Belgium, the Netherlands and Luxembourg for 2018. In these five countries, around 42,000 wind turbines generated around 718 petajoules of energy, equivalent to the annual production of 18 nuclear power plants.
According to the statistical analyses, on average almost 800 birds per turbine were considered endangered. The team then modeled shutdown scenarios to avoid 50 to 90 percent of potential collisions.
In one approach, the systems only stopped when the number of potential collisions per kilowatt hour of electricity generated exceeded a limit. In this scenario, operators would only lose 1.2 to 7.6 percent of annual energy production.
Cross-border regulations for bird protection
On the other hand, fixed shutdowns during the strongest bird migration or when a certain bird density occurs would lead to losses of two to 20 percent of electricity production. Since migration is concentrated in short phases, temporary restrictions on wind power production could be sufficient, according to the researchers.
However, transnational regulations and joint coordination would be necessary to protect migratory birds. The WSL calculations should therefore be expanded to cover the whole of Europe and over longer periods of time in the future. Biodiversity researcher Silke Bauer explained the intentions of the study:
Many people oppose wind turbines because they believe they kill an enormous amount of birds. I want to reconcile sustainable energy production and bird protection and show that there are strategies to reduce the number of endangered birds.
A notice: It is undisputed that birds die from collisions with wind turbines. However, the exact extent is difficult to quantify. However, since climate change threatens birds even more than wind turbines, many animal rights activists still support the expansion. In addition, the image is often distorted. As tragic as bird deaths caused by wind turbines are, far more birds die every year due to glass panes, traffic, domestic cats or power lines.
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