Photo by Kevin Collins
Don Quixote might have been a tad afeared of California's Altamont Pass. As you approach from the east on Interstate 580, over 4,000 cagy windmills stand ready on the bright green, then dry rolling hills that hold this gateway to the Bay Area. Most of the turbines are old, and they're often idle. Built in the early '80s, the Altamont wind farm was one of first in the U.S., and it’s still one of the largest, on average producing about 125 megawatts of power—not shabby, (though, in theory, it has a capacity of 500 mw). But unfortunately, every year several thousand raptors and many more songbirds are killed at Altamont, golden eagles and warblers alike sent spiraling out of the sky by the thumping mills.
In 2007, environmentalists (including several Audubon chapters) reached a settlement with turbine operators to reduce kills by 50 percent. To help achieve the goal, the windmills have been shut down during the wintertime, but situating the turbines more thoughtfully and tweaking their design would make the bigger difference. Yesterday, an agreement of that kind was announced: NextEra Energy Resources, which owns about half the blades at Altamont, plans to replace its 2,500 turbines with fewer, but larger, more efficient rotors by 2015, or else remove them. (Additionally, the company will contribute $2.5 million to raptor habitat restoration—$10,500 for each refurbished megawatt.) The swap will be made in phases and incorporate feedback from the previous, in particular evidence of mortality among redtails, goldens, burrowing owls and kestrels. The new windmill sites will be surveyed once a month for casualties.
Biologists monitored raptors for over 700 hours recently at the nearby Vasco Caves Regional Preserve to help determine what types of airspace are favored as hunting grounds or fly zones (and for burrowing owls, nest sites). Their findings (along with other bird data from Altamont) will be used to guide Altamont’s coming installations. Abrupt shifts in elevation (like notches, saddles and benches) as well as low ravines and valleys are especially hazardous to birds: They not only attract prey, but also funnel air forcefully.
Altamont’s fatalities are part of the price we’ve paid for this early experiment in green energy, but we're learning. Certainly, we need more windmills. Oil spills apart, dirty energy sources have hidden side effects that destroy habitat, and thus birds, globally. (High rises, meanwhile, lure countless more to glassy ends.) The U.S. has enormous wind energy potential, and it makes sense to go forward and harness it. But, as at Altamont, let's make sure the best available studies on birds (and bats!) help lead the charge.