March 12, 2019 | Michael Krueger, Science Sceptical blog
A new study finds that around 1,200 tons of insects are killed p.a. by wind turbines in Germany alone.

In Germany, there are currently around 25,000 wind turbines installed. For some years now, it has been known that they do not provide environmentally friendly electricity, as countless birds and bats are killed by their rotor blades. But that is not all.

Wind turbines for power generation should actually produce more electricity with increasing wind strength. However, this is exactly what they often do not do, which has confused experts for years. The puzzle could already have been solved in 2001 thanks to a new study: dead insects that stick to wind turbines should be responsible for the low yield.

This was reported by a Dutch-Danish team of scientists as early as 2001 in the issue of the British journal Nature: “Insects can halve wind turbine power”, Nature 2001.

Burst insects rough up the surface

At low wind speeds, burst insects start to accumulate on the leading edges of the rotor blades, the authors explain. At strong winds, the air flow can be torn off due to the now rough surface – the electricity generated drops rapidly.

Such power losses – in some cases up to half – have been noticed, for example, on California wind farms. The reason was unknown until then.

However, with specially developed reflectors glued to the rotor blades, experts were able to directly observe the effects of dead insects 20 years ago.

The “bee dying off”

Currently, the “great insect dying off” and “bee dying off” is on everyone’s lips. However, neither the Greens, nor the environmental NGOs, nor the Federal Environmental Agency are addressing the insects killed by the rotor blades of wind turbines, let alone field studies are commissioned. The media is also not interested in the topic.

However, some scientists have long suspected that insects could be attracted to wind farms due to the color of the rotor blades, the heat given off by the turbines and the flashing lights on the wind turbines.

The scientists also know that turbines cause a reduction in wind speed at the hub level and cause turbulence. The turbines cause changes in wind, precipitation, temperature and evaporation. Studies have been able to prove such environmental influences up to 20 km away from a wind farm site.

A recent study by the Deutsches Zentrum für Luft- und Raumfahrt (DLR) “Interference of Flying Insects and Wind Parks” concludes that 24,000 tons of insects per summer could pass through the German wind farms with a total of 25,000 wind turbines. That would be about a ton of insects per wind turbine. 5% of the insects could fall victims to the turbines. So 1,200 tons of insects in total, or 50 kg of insects per wind turbine.

The DLR study further concludes that this could be relevant to the survival of insect populations within 15 years, especially for insects flying in the appropriate altitude range between 20-220 meters altitude. This is what most insects do!

Regardless, the topic will not be further discussed and silenced. So also last night in the public German TV channel ARD.

Full story (in German)