Researchers at Oregon State University are working on a system that could potentially save the lives of thousands of birds killed every year by the spinning blades of wind turbines.
The system — which detects not only when a bird hits one of the giant blades, but also what species of bird — marks a step forward in protecting some animals from what is otherwise considered to be a key piece of environmentally-friendly energy production.
Critics of the turbines have pointed to deaths of bald and golden eagles, both of which are protected under federal law, as a fundamental problem with the huge turbines. The towering propellers can stand 300 feet tall and have blades with twice the wingspan of a Boeing 747. At their tips, the blades can be moving at 200 mph, said study author Roberto Albertani.
"If a turbine strikes a generic bird, sad as that is, it's not as critical as striking a protected golden eagle, which could potentially trigger down time in turbine operations and losses in revenue, and most important the loss of a member of a protected species," Albertani, a mechanical engineering professor at OSU, said in a statement.
There are more than 50,000 wind turbines in use across the U.S., according to American Wind Energy Association, with more than 1,800 in Oregon alone. A study published in 2013 found that wind turbines were responsible for more than 500,000 bird deaths, including 83,000 raptor deaths.
The new system, the development of which was supported by the U.S. Department of Energy, uses a vibration sensor at the base of the blade, an acoustic sensor on the generator housing and a camera on the base of the tower.
In practice, researchers hope that the camera will be able to detect when a bird is approaching, determine what type of bird it is and, if it is one that is under federal protection, the computer would trigger a deterrent in the form of a brightly colored facsimile of a person designed to play into an eagle's aversion to human beings.
To test the system, Albertani and his team, which included biologists from the U.S. Geological Survey, used a compressed air launcher to fire tennis balls at wind turbine blades equipped with the sensors.
"General results from 29 field tests with blade strikes showed positive detection and confirmation 14 times," Albertani said. "This study demonstrates the feasibility of an impact detection system based on vibration sensors."
When a strike is detected, video recordings of the moment of impact can be analyzed to determine exactly what hit the blade.
"It is strongly believed the success rate can be significantly increased," Albertani said.
-- Kale Williams
kwilliams@oregonian.com
503-294-4048