Nordic innovations in developing “bird radars” can reduce the disturbing impact wind turbines have on bird nesting and feeding from the operating noise and the blade movement, as well as the risk of birds flying into the blades.
The same radars not only produce a safer environment for birds but also provide an enormous amount of valuable objective data on bird numbers and their movements, which can now be used by researchers.
The impacts depend on the size and number of wind turbines and the the distances between them, their technical solutions, geographical location and shape of the surrounding terrain, as well as on the composition of bird species in the region.
A bird radar has been installed in the first offshore wind farm in Finland at a wind farm near Pori in Finland (see https://hyotytuuli.fi/en/). It collects data about the behaviour and number of birds and has been developed with the Dutch Robin Radar and the University of Tampere.
The radar can also stop a turbine for a few minutes when a bird of an endangered species is flying towards it. The birds are happy, so are the wind farm owners!
Radar observations carried out in Tahkoluoto have indicated that birds do not fly right past the wind turbines even if the birds have previously used that particular route.
No changes have been observed in the total number of flights or in the direction where birds set off from nesting islets for hunting and where they are feeding. All in all, the impacts of wind turbines on birds would seem to be small and less than predicted.
Bird monitoring studies
The recent summary study of bird monitoring covering several years was completed in 2019. The monitoring was carried out during spring and autumn migration in the area of onshore wind farms on the North-Eastern coast of Finland. This area has many wind farms and is an important bird migratory route.
Migratory birds appear to avoid wind farms, meaning that wind farms have a low impact on birds in nationally important migratory routes. No changes resulting from wind farms were detected in the location of resting and feeding areas. Agricultural activities carried out there have a bigger impact on birds.
Furthermore, when wind turbines are spaced far apart it appears that they do not disturb bird movements.
Based on implemented studies, the number of collisions of birds with wind turbines has remained clearly lower than estimated in the project planning stages and in environmental impact assessments (EIA). Actual verified collisions have mainly taken place among local species.
The studies were published in the BirdLife Finland yearbook 2018, and articles on the subject have been published in Finnish in the Tuulivoima online magazine.
Bird radars are a powerful tool for conducting risk analysis and environmental impact assessments (EIAs) for wind farm operators. Over time, the technology gathers scientific data on bird movements within the area in great detail.
A recent study carried out by The Norwegian Institute for Nature Research (NINA), revealed how painting turbine blades black can help to deter birds from colliding with wind turbine blades. Sweden’s Vattenfall has been testing this solution that is achieved by reducing motion smear. Motion smear is a visual phenomenon that occurs when an object is moving so fast it appears to the eye like a near-invisible blur. Researchers suspected that this phenomenon made it harder for birds to see wind turbine blades, especially the tips, increasing the chances of collision.
NINA painted a single blade of four turbines black and left four unpainted. Bird strikes were reduced by 70%. More testing is needed to prove the effectiveness of this method conclusively, but the initial results are certainly promising.
For the record a company in Portugal called Strix has also been involved in Bird Radar development. STRIX is a leading company providing environmental, social and sustainability consultancy and technical assistance services and products. They have also been doing innovative development work with their “Bird Tracker” (see https://www.strix.pt/index.php/en/birdtrack ).
Photos: Robin Radar & DWE
