Harvesting wind power is a fast-growing form of alternative energy technology, and U.S. interest in the wind industry is growing, as we work towards diversifying our energy grid. New turbines are being erected across the nation, and the prospects for using wind to supplement our power supply are positive.

As with any form of technology, there have been, and will be, some collateral damage to wildlife and the environment. Although the effects of reducing oil consumption should outweigh the detrimental impact of wind turbines in the long term, researchers strive to minimize immediate negative effects as much as possible.

One issue that has been raised in the conservation community is that the turbines pose a threat to flying animals, with special attention to birds and bats, which have been shown to suffer significant mortalities on wind farms, especially for migratory tree-roosting bat species. Significant losses among populations of endangered species such as the Indiana bat and the gray bat.

A recent paper in PLoS ONE reports evidence that electromagnetic radiation from human sources-such as air-traffic control and weather radar-can deter bats from approaching the turbines, reducing mortalities (Nicholls and Racey 2009). The study involved experiments conducted in Britain, in which radar antennae were mounted in bat foraging areas. The authors measured both bat foraging activity (determined by detecting the foraging calls the bats use to locate prey) and insect abundance in the radar zones and in control areas without the radar emissions. Both rotating and fixed antennae were used, and fixed antennae were divided into two treatments with different emission pulses.

Results showed that the electromagnetic signals did indeed deter bats within 30 m of an antenna, although it did not entirely cease foraging activity in the area. The most effective treatment was the fixed antennae with a medium pulse rate (1200 Hz). Insects did not seem to be affected, however, as no significant difference in insect abundance was detected between experimental and congrol zones.

(Table 3. Statistical significance of differences in bat activity between control and experimental trials (*) denotes a significant result for both corrected PBonferroni (P values×number of comparisons) and uncorrected P-values.)

Although details of technical aspects such as optimal pulse rates, wavelengths, and orientation will still need to be refined, this study suggests that there are ways to mitigate bat mortalities on wind farms. Electromagnetic pulses that decrease foraging activity in the vicinity of wind turbines can substantially reduce mortalities. It will be interesting to follow the story and see if strategic location of wind farms near radio towers or other background emitters can reduce the costs and effort needed to set up these deterrent systems.

This issue also raises questions as to how the electronic signatures of our modern lives-our cell phones, wi-fi, microwaves, remote controls, radio, satellite TV, etc-are affecting the organisms around us. Studies suggest that sonar and oil drilling affect the behavior and health of marine mammals, and it seems that similar studies on volant animals would be interesting.

This could have applications for both conservation and human health, as we are by no means immune to our own radiation. (You can find information on radiation from various cell phone models here, if you are concerned). This is not to say that the paranoia about cell phone signals and other electronics causing cancer are anything to become upset and lose sleep over (I am not promoting the radiation hysteria! Some people take these worries to an extreme, but, as with anything, moderate and reasonable caution is warranted). This will definitely be an interesting line of study to follow, and hopefully research studies such as the one by Nicholls and Racey will help to mitigate impacts as we seek to progress with our energy technologies.

Nicholls, B., & Racey, P. (2009). The Aversive Effect of Electromagnetic Radiation on Foraging Bats—A Possible Means of Discouraging Bats from Approaching Wind Turbines PLoS ONE, 4 (7) DOI: 10.1371/journal.pone.0006246