The Altamont Pass Wind Farm located in the Altamont Pass of the Diablo Range in Central California. It is one of the earliest wind power plant in the United States. The wind farm is composed of over 4900 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. They were installed after the 1970s energy crisis in response to favorable tax policies for investors.

Considered largely obsolete, these numerous small turbines are being gradually replaced with much larger and more cost-effective units. The small turbines 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. According to the most recent data, wind operations in the Altamont Pass kill approximately 7,300 to 9,600 birds each year, including as many as 94 golden eagles, 477 American kestrels, 433 red-tailed hawks, and 718 burrowing owls. Species such as the golden eagle, red-tailed hawk, and the burrowing owl are protected by the Migratory Bird Treaty Act, which makes any killing of the birds a violation of federal law. The larger units turn more slowly and, being elevated higher, are claimed by the manufacturers and wind farm proponents to be less hazardous to the local wildlife. This claim is supported by a report done for the Bonneville Power Administration. Currently the Altamont wind farm is shut down by government order for several months of the year to attempt to mitigate bird mortality.

An advantage of this particular site is that under hot inland (California Central Valley) conditions a thermal low is developed that brings in cool coastal marine air through this pass, driving the turbines at a time of maximum need. Unfortunately this is not always reliable and with an inland high pressure condition the entire region can be both hot and windless. At this time additional power is provided by natural gas powered gas turbine peaker plants. Future development of solar power stations may provide a complementary source of renewable energy, because summertime heat events often feature abundant sunshine to compensate for the low winds.

Altamont Pass Wind Farm
Turbines near Livermore, California
Location	Altamont Pass
Coordinates	37°43′57″N 121°39′09″W / 37.732389°N 121.652416°W / 37.732389; -121.652416Coordinates: 37°43′57″N 121°39′09″W / 37.732389°N 121.652416°W / 37.732389; -121.652416
Fuel	Wind
Turbines	4900
Maximum capacity	576 MW
Annual generation	1.1 TWh
Commissioned	1981