Aves voam sobre campo de energia eólica

New technology can save birds from turbine blades

Wind energy is one of the cleanest energy sources, but it also kills thousands of birds yearly: radar and map are the clues

Wind energy is one of the cleanest energy matrixes, as well as the one with the least environmental impacts among the most widespread renewable energy sources in the world. Still, it has some side effects, one of which is bird death. However, a new idea can change this scenario.

According to a study conducted by NBC News, there are more than 50,000 wind turbines across the U.S. Wind power now accounts for 8 percent of the nation's energy-generating capacity. The rate is increasing, and experts predict that this figure could rise to 20 percent of total American demand by 2030. In Brazil, there are 518 plants installed with productive capacity capable of meeting the demands of 22 million homes. With 13 gigawatts installed, the industry is in the eighth position in the wind energy world ranking, according to the Brazilian Association of Wind Energy (ABEEólica).

Wind power plants generate energy via wind turbines - structures more than 100 meters high with huge propellers that, powered by wind force, activate generators that, in turn, generate electricity. The problem is: with blades that reach 80 meters in length, wind turbines can cause wildlife damage and kill thousands of birds.

A study published in the Biological Conservation Journal estimates that 140,000 to 328,000 birds are killed every year in collisions with the turbines' spinning rotor blades and support towers in the U.S. The risk to birds is highest at night, when blades and towers are covered in darkness.

How can we save the birds? Radar and map are the clues

A group of researchers at Cornell University, in New York, came upon what could prove to be a simple way to protect birds from wind turbines. They developed a system called BirdCast.info, which integrates signals from a network of weather radar systems to interactive maps, helping to track birds in real time around the country.

The idea came from Doppler radar systems, traditionally used to detect weather changes. It's well-known that migrating birds are easily detected by the Doppler systems, but the weather service filtered such information and considered it noise. This new platform uses data that used to be discarded.

Bird flocks migration signals are drawn from 143 weather radar systems across the country and then sent to BirdCast.info maps in real time. Thus, wind power plant operators can monitor that information, and then stop or slow their turbines temporarily when large numbers of birds are flying through the area.

The research group at Cornell University suggested that wind power plants raise the turbines' speed above minimum level, which makes economic sense to run the turbines. Wind turbines would be stopped when there is little wind – a period when migration bird flocks are more intense and accidents in the turbines more frequent. Therefore, turbines would only work with stronger winds, that is, when weather conditions are not good for migrating bird flights, thereby reducing bird deaths with minimal impact on energy production.

According to Professor Kyle Horton, on any given night during the peak of migration - from April to May -, up to 520 million migrating birds are on the wing, in the U.S. alone. "If we're getting large pulses of migrating birds coming through on a handful of nights, then altering their strategies for just five nights, or other periods, it may have a big impact," Horton said to NBC. “We really want to see some conservation come out of this, hopefully to reduce some [bird] mortality,” he added.