The wind turbines on the gusty Altamont Pass were installed after the energy crisis in the 1970s. Today, the world's oldest wind farm powers an average of 100,000 homes with clean green energy. But environmentalists say it comes at a steep price.
"Over the last 25 years there have probably been 17,000 raptor mortalities -- about a thousand golden eagles," said Dr. Michael Fry of the American Bird Conservancy in Washington, D.C.
Dr. Fry is concerned about the Altamont wind farm's dubious distinction of being the nation's deadliest for birds of prey. Frequently, those raptors are an endangered or threatened species.
"Unfortunately, Altamont Pass was built in an area that has very high raptor use," he said.
In 2007, the Alameda County Board of Supervisors agreed to settle a lawsuit brought by environmentalists to reduce the risk to wildlife.
Under the settlement, energy companies agreed to shut down wind turbines during the winter and remove and relocate some of the older more dangerous turbines. The goal is to reduce the number of raptor deaths by 50 percent within three years. That time is nearly up. Alameda County expects to release their report on the number of bird deaths since the agreement, any day now.
Environmentalists and the industry alike are eagerly anticipating the report's outcome.
"The industry has been working for several years now to try to reduce mortality," said Dr. Fry. "But it's proven to be very difficult."
The report comes at a crucial time for the wind industry. California has set high standards for energy savings; 33 percent of our total power must come from renewable sources by 2020.
"If we are going to scale up renewables to become the major part of our electric system, we're going to have to build bigger projects and that means we're going to have to manage wildlife impacts," said John White with the Center for Energy Efficiency and Renewable Technologies (CEERT), a partnership of major environmental groups and clean energy companies. He was referred to us by the American Wind Energy Association. "We've spent some time on wind and wildlife because of the controversy in Altamont."
He says Altamont has provided a wealth of information about what works and what doesn't.
"I think generally we've come to the conclusion that you don't put them in the canyons, you don't put as many of them up," said White. "The newer machines are bigger and turn more slowly."
He points to the new generation of wind turbines in southern Solano County as an example of what has been learned. There, bigger, slow moving turbines turn with a much smaller impact on wildlife.
"All renewable energy resources, no matter whether it's solar, wind or geo-thermal, have some impact on the environment. All these resources have strengths, they all have weaknesses, they all have impacts," he said.
But that doesn't solve the problems at Altamont. Despite industry attempts to slow the bird deaths, some scientists are still worried about the number of birds that continue to be killed.
"Fatality rate estimates for the Altamont are conservative," said biologist Shawn Smallwood who has been studying bird deaths at the Altamont for nearly a decade. "They should probably be higher than what we are coming up with."
Smallwood just released a study in August for the East Bay Regional Park District and California Energy Commission.
"In total, we're killing maybe about 1,500 to 2,000 raptors per year; killing I'd say anywhere from 10,000 to 15,000 thousand birds per year," he said.
Smallwood says there are just too many wind turbines in places birds of prey like to hunt.
"All indications are that the birds are aware of the wind turbines when they're operating. They do try to avoid them, but when you have so many turbines out there, it's hard to avoid them all the time," said Smallwood. "Almost every ridge is covered by wind turbines in the Altamont Pass."
Wind advocates agree mistakes were made 20 years ago. However, they say we can learn from them.
"We learned a lot from that experience and there are a lot of things that were done in Altamont that we would never do again," said White. "We would never put that many machines up all in one place."
The upcoming report may shed light on what to do next. That may include a conservation and mitigation plan and possibly the replacement of all the old wind turbines with newer, safer models.
Written and produced by Ken Miguel