Developed in the 1970’s on 50,000 acres in Altamont Pass, California, the nation’s oldest wind farm is being “repowered” by NextEra Energy Resources. More than 4,000 aging wind turbines are being dismantled or shut down and replaced with newer, quieter, and more efficient units. The first phase of the repowering project has been completed, with the company replacing 400 of its turbines with 34 Siemens-built 2.3 megawatt turbines, each standing taller than some redwood trees at 430-feet-tall. The new turbines each generate enough power for 650 average-sized homes.

An agreement (PDF) between NextEra Energy, environmental groups, and state officials to replace the outdated turbines in an effort to protect migrating gold eagles, hawks, and bats was the impetus for the project. The Altamont Pass is a main migratory route and the outdated turbines have been implicated in the deaths of over 4,300 birds each year. The reduced number of turbine installations combined with their slower-spinning blades is expected to significantly reduce the amount of bird deaths.

Much of the land used for the wind farm was initially, and still is, leased from cattle ranchers in the area. Rancher John Jackson owns 480 of the acres and has turbines on his land. He likes the new turbines quite a bit, telling the Mercury News “I like them. The old ones would shut down if the winds got too strong, and then they’d fall down and hit the wires and start grass fires. These spin slower than the old ones, and they are very quiet.”

By the completion of the repowering project in 2015, just 100 wind turbines will be in operation on the property, capable of generating the same amount of energy as the original 4,000 did for the last 30 to 40 years. All combined they will provide enough electricity for over 19,500 homes each year.

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