Altamont Wind Turbines Bad for Bats?

Better for birds -- but bogus for bats.

The wind turbines at Altamont Pass between the San Ramon and Central valleys are getting a makeover. Many of the 40-year old windmills that capture the pass's famous gusts to be replacing with fewer, much-larger structures.

This will be better for birds: about 10,000 raptors like hawks and falcons are killed every year by some of the 2,000-plus turbines. By 2015, all those will be shut down, and in their place, 125 newer, bigger windmills -- 262 feet tall to the blade's hub, but 428 feet tall to the tip of the blade -- are expected to cut down on birth deaths by 80 percent, according to the East Bay Express.

But the new and improved windmills could be deadlier for bats, the newspaper reported -- and all thanks to a lawsuit brought by environmentalists.

Five chapters of the Audobon Society as well as Californians for Renewable Energy sued NextEra, a Florida-based company that operates the turbines, over the bird deaths. The resulting settlement will lead NextEra to replace the turbines, but does not take into account bats, according to the newspaper.

A 2007 study that examined bat deaths at wind farms around North America said that "bat fatalities increased exponentially with tower height."

The problem is that bats are dodgy: their small corpses are eaten by scavengers, so scientists can't know how many bats are being killed. The wind turbines also turn on at nine miles per hour of wind, and bats do better when turbines don't turn on until there's wind between 11 and 15 miles per hour.