Bird Collisions with Wind Turbines Reviewed
Daily Ardmoreite — November 20, 2013
As wind energy continues to emerge as a green energy alternative to fossil fuels, bird mortality from collisions with the turbines also is on the rise. Previous research suggests anywhere between 10,000 and nearly 600,000 fatal bird collisions occur in the lower 48 of the United States each year.
Most of these previous estimates were based on extrapolation of data from a small number of U.S. wind facilities to all U.S. wind turbines. However, researchers in Oklahoma State University’s Department of Natural Resource Ecology and Management recently shed a little more light on the subject, by reviewing studies and industry reports from 59 different wind power facilities across the U.S. Their findings were published in “Biological Conservation,” an international leading journal in the discipline.
“We estimate between 140,000 and 328,000 (mean = 234,000) birds are killed annually by collisions with monopole turbines in the contiguous U.S.,” said Scott Loss, NREM assistant professor. “We found support for an increase in mortality with increasing turbine height and support for differing mortality rates among regions, with per turbine mortality lowest in the Great Plains.”
This study evaluates only the newer monopole-style turbines and discounts the older lattice-style turbines, which are largely decommissioned in the U.S. It is often argued that the more modern turbines kill relatively few birds compared to the decommissioned turbines; however, this study suggests bird collision mortality rates at new generation monopole turbines can still be considerable. The team found, across the U.S., anywhere from roughly 2.9 to nearly 8 birds are killed per turbine each year.
“Turbine height was a strong predictor of mortality rate,” he said. “We did see some regional differences as well.”
Turbines measuring from 36 meters up to 80 meters in height, from base to hub of the blades, were used in this study. Loss said the annual per turbine mortality rates on an annual basis increase approximately 10 fold from the shortest to the tallest turbines. Read full article here…..