Windmills dot the landscape as Interstate 580 passes through the Altamont Pass Wind Farm
Older wind turbines
The Altamont Pass Wind Farm is located in the Altamont Pass of the Diablo Range in Central California. It is one of the earliest wind farms in the United States. The wind farm is composed of 49301 relatively small wind turbines of various types, making it at one time the largest farm in the world in terms of capacity. Altamont Pass is still the largest concentration of wind turbines in the world, with a capacity of 576 megawatts (MW), producing about 125 MW on average and 1.1 terawatt-hours (TWh) yearly.2 They were installed after the 1970s energy crisis in response to favorable tax policies for investors.
The small turbines used at Altamont are dangerous to various raptors that hunt California Ground Squirrels in the area. 1300 raptors are killed annually, among them 70 golden eagles, which are federally protected; in total, 4700 birds are killed annually.3 Overall there has been an 80% decline in golden eagles in Northern California, with no golden eagles nesting near the facility, although it is a prime habitat.4 Considered largely obsolete, these numerous small turbines are being gradually replaced with much larger and more cost-effective units. The larger units turn more slowly and, being elevated higher, are claimed to be less hazardous to the local wildlife. This claim is supported by a report done for the Bonneville Power Administration.5
As of 2010, a settlement has been reached between the Audubon Society, Californians for Renewable Energy and NextEra Energy Resources (who operate some 5,000 turbines in the area). Nearly half of the smaller turbines will be replaced by newer, more bird-friendly models. The project is expected to be complete by 2015 and includes $2.5 million for raptor habitat restoration.6
A turbine with blades 40 metres long (40 m.) might turn at twice the rpm of one with 80 m. blades, but the tips of the blades travel at the same speed. You also have fewer turbines, but the area of sky being swept by 80 m. blades is four times that of 40 m.
^Paul Driessen (22 December 2012). "DRIESSEN: Big Wind tax credit exterminates endangered species". Washington Times. Retrieved 29 December 2012. "In an 86-square-mile area blanketed by the Altamont wind facility, no eagles have nested for more than 20 years even though the area is prime habitat, Mr. Wiegand says. Overall, there has been an 80 percent population decline for the golden eagle in Southern California, he notes."