renewable energy. They’re popular among power companies and environmentalists alike because they provide cost-effective electricity without releasing emissions that worsen climate change.
As with most technologies, though, they can also have environmental drawbacks. The main concern is the fact that they sometimes kill birds and bats.
Researchers estimate wind farms kill 234,000 birds and 600,000 bats in the United States each year. While still less deadly than other threats such as cell towers and cats for birds and a fungal disease called white-nose syndrome for bats, these are not negligible numbers.
In response, energy companies, researchers and entrepreneurs are searching for ways to make wind turbines safer for airborne critters. Here are three of most promising.
Perhaps the most straightforward approach to making wind farms safer for birds and bats is considering them when siting new facilities.
Many different factors go into determining where to build new wind turbines, including average wind speeds in an area, land rights, energy demand and access to transmission infrastructure. The process also includes extensive permitting that takes into account the farm’s potential impact on the surrounding environment and wildlife, as well as the concerns of the people who live nearby.
To protect birds and bats, considerations surrounding them must be an integral part of the permitting process. Wind companies can purposefully avoid known habitats, flight paths and migratory routes.
Engineers can also increase the visibility of wind turbines to prevent avian mortality. To protect eagles, for example, energy companies should keep turbines away from cliffs and hills, where eagles soar using updrafts. They could also avoid areas near caves where bats are known to roost.
Additional research on this topic could help permitting bodies and wind companies site wind farms in more ideal locations.
Technology can also play a role in protecting birds and bats from wind turbine deaths. The same Doppler radar systems we use to monitor weather can also detect migrating birds.
Researchers have begun tracking these patterns and posting maps online of migration forecasts and real-time movement. The researchers hope energy companies will use the maps to protect migrating birds.
Turbine operators could do this by monitoring the maps and, if large flocks of birds are expected to move through the area, slow down or shut down the turbines.
Even if they only do this a few times a year during migration season, it could have a substantial impact on reducing bird deaths. During a typical night during peak spring migration season, as many as 520 million birds may be in the air.
Ultrasonic acoustic determent
Another technology, known as ultrasonic acoustic determent, may help to protect bats from the dangers of wind turbines.
This approach takes advantage of the echolocation process bats use to navigate. It involves a device that continuously creates a sound with a frequency between around 10 and 100 kilohertz (kHz). This high-frequency sound “jams” the bats’ echolocation, disorients them and causes them to avoid the area. The sound doesn’t hurt the bats, but jars their senses. Researchers have likened it to walking into an extremely bright room.
The devices are still under development, and research into their effectiveness is still underway. A 2013 study, however, suggests they could reduce bat deaths by more than 50 percent.
Wind turbines have substantial environmental benefits stemming from the fact that they produce emission-free, renewable energy. They can also be a hazard to birds and bats. Energy companies and researchers are working on a range of potential solutions to this problem. If they succeed, wind energy will become an even more environmentally friendly energy source.
This is a guest post written by Megan Ray Nichols.
Megan Ray Nichols is a science writer and the editor of Schooled By Science. She enjoys discussing scientific discoveries and exploring the world around her. Follow her on twitter @nicholsrmegan.