- "The process was very pleasing"
There is a practical need to prevent collisions with birds and wind turbine blades in the offshore wind farms. Five years ago, a system to cover the need was just a dream. But when there is a need, a will, and a university – there is also a way.
In 2015 Juha Niemi, 57, was teaching electrical engineering and ICT at the university of applied sciences when a fellow professor Juha Tanttu from Tampere University inquired if Niemi would like to find out an automatic way to identify and monitor varieties of birds and their movements in the area of Pori offshore wind park and to make his doctoral dissertation for DSII (Doctoral School of Industrial Innovations, managed by Tampere University and Tamlink Ltd.) out of it.
The main reason for that was to both monitor and to prevent bird collisions with the wind turbine blades in offshore wind farms. The environmental license of the first Finnish offshore wind park obliges that bird behavior will be monitored in the vicinity of the wind turbines. The authorities have announced two key bird species for particular monitoring in the area: the white-tailed eagle (Haliaeetus albicilla) and the lesser black-backed gull (Larus fuscatus fuscatus).
That is why Niemi was asked to develop a unique system that could automatically find out what kind of birds fly in the area, at what times, and which seasons. The aim was to monitor and to warn the system about possible bird collisions. The research was done in collaboration with Suomen Hyötytuuli Oy, which was the first Finnish wind power production company to build an offshore windpark.
"The difficult part was that I needed to start from scratch", Niemi ponders.
"There were no existing systems for this kind of use."
The main thing was that the system should recognize different bird species. As Niemi had been enthusiastic about birds and birdwatching already from the 1970s, birds were the easy part of his dissertation. Niemi was finding out different ways to identify the birds and ended up with identification by form and color.
"Monitoring the birds by human resources would be expensive and inefficient."
The system designed by Niemi consists of a DSLR camera and a radar, which came from a Dutch manufacturer, Robin Radar. The birds are detected by the radar which sends the coordinates to the steering system of a camera, and the camera shoots a series of photographs. The system uses a bird picture database for identification. Input data of the system consist of digital images. All images for training the system have been taken manually at the test location in various weather conditions.
"The system works very well. We can easily monitor birds and their behavior in an area."
Of course, the camera cannot shoot the pictures at night or in difficult weather conditions. Infrared light could be an option, but the problem is that its range does not reach very far.
"Birds don’t fly in winter nights that much, but they fly a lot during summer nights and migration."
Bird collisions are not very common in Finland
The collision of birds and wind turbine blades was a big concern in Finland, but during the research, only one single collision of bird and blade was witnessed.
"That collision happened during a heavy fog. Big birds like swans and the white-tailed eagle (Haliaeetus albicilla) are in the most danger, as they might not notice the convergent blades on time. Seagulls mostly just play in the wind with the turbine blades."
Niemi mentions in his dissertation that the estimated numbers of bird collisions in foreign studies lie between 0-68 birds per turbine per year. He also mentions that most of the studies have been conducted in the onshore environment and therefore cannot be applied directly to the offshore environment.
"Those statistics don't apply at least to Finland. I guess in other countries, like Spain, Netherlands, Portugal, German and Scotland, with different bird species the risk is higher. These countries also have a much stricter permit requirements."
When the system has identified the bird from 600 meters, the turbine could be turned off or slowed down when the bird is 300 meters away. Also, the angle of the blades could be adjusted to prevent the collision. The problem is that the technology of wind turbines gets worn out if the turbines get stopped too many times. That is why different deterrent measures need to be found out.
"One challenge also is that birds, like other animals, get quite easily used to noises and lights which could be used as deterrent measures. Especially the nesting birds which get acquainted with these measures won’t be afraid of them anymore for longer than two weeks max."
The prototype system was tested in Tahkoluoto offshore wind farm on the Finnish west coast, Pori for two years, but not continuously.
Future as monitoring service for organizations and companies
Due to climate change, there is a need to produce electricity more sustainably. Using wind power is an excellent option, but the process of establishing new wind power plants is very long and difficult with strict environment studies and permissions which could take years to induce. That is where this new innovation can be of use too.
"In other countries, it’s much more difficult to have permission to start a wind power plant."
That is why Niemi, now a postdoctoral research fellow, in collaboration with Tampere University and other organizations is now developing a new service that could either offer help monitoring the birds in a territory planned for a new wind turbine plant or sell the system for organizations to use.
"We could do both – sell the system but also offer the monitoring as a service. The radar technique used in this system is quite pricy, so maybe it’s not for smaller companies, Niemi notes."
Right now, Niemi and his associates are planning a startup and they are looking for business partners, funding and they also need the radar company to be involved, Niemi sums.
Studies in DSII
Niemi notes that he enjoyed his time and its activities in DSII. During his career as a teacher, he had supervised many final assignments, so the journey of his dissertation was a bit different than generally.
He applies that if you do your studies in Tampere, there are many interesting courses you can choose from – though he accomplished his studies in Pori unit.
Niemi was very active in participating different meetings and roundups in Tampere. He says that he made new connections and networking with different people useful for his project.
"I enjoyed my research. The dissertation seemed like an extra by-product for this pleasant project, Niemi states."
You can read Juha Niemi's dissertation here.