The study investigates possible coherence of flying insect losses recently discovered in Germany and insect impingement on the rotor blades of wind turbines.
Evidence from literature confirms that migrating insects select fast air streams above the turbulent surface layer of the atmosphere for the purpose of efficient displacement to breeding grounds. Wind farm developers select sites with strong winds and install high towers with rotors just above the surface layer in order to optimize the energy output of their wind turbines. As a result of this coincidence, large numbers of flying insects can be expected in wind farms.
Model calculation of the amount of insect biomass that traverses wind rotors during operation provides a first estimate of the order of magnitude of 24,000 tons of insects crossing the German wind park throughout the summer season. Based on conservative model assumptions, five percent of the insects flying through a rotor could be actually damaged. The related loss of 1,200 tons per year since more than fifteen years could be relevant for population stability.
Species flying at critical rotor heights between 20 and 220 meters above ground level in addition to those already found within this study should urgently be identified by DNA meta-barcoding of the deposits that are regularly found on rotor blades. In addition to that, wind farms should be enabled to recognize approaching insect swarms and to react accordingly for their protection and conservation.
Table of Contents
2. Evidence of conflicts between wind farms and insects
2.1 Visible deposits of flying insects on rotor blades
2.2 Additional risk from barotrauma and partial impact
2.3 Insect migration in the atmospheric boundary layer
2.4 Species at risk
2.5 Critical periods in insect’s life
2.6 Additional hypotheses about insect attraction to wind farms
2.6.1 Wind Speed Attraction Hypothesis
2.6.2 Olfactory Attraction Hypothesis
2.6.3 Acoustic Attraction Hypothesis
2.6.4 Visible Attraction Hypothesis
2.7 Missing proof of tolerability
3. Model of jeopardized insect biomass
4. Model of damaged insect biomass
5. Discussion of results
6. First ideas for loss assessment and mitigation