Optimizing Wind Farms – lessons learned at Altamont Pass
Altamont Pass is perhaps a classic example of how unexpected consequences can make a “green” project quickly turn brown. East of San Francisco on I-580, Altamont pass is home to very strong winds – ideal for wind turbines that use this wind to generate electricity. Also along this pass is an established migration route for many birds, including several types of raptors. In 2004, the California Energy Commission found that up to 1,300 raptors are killed each year in Altamont.
While I could spend this blog post on criticizing the engineers behind the Altamont Pass wind farm that results in the death of more than 4,000 birds, including 70 golden eagles each year, the truth is that this farm has taught us a lot about optimum wind farm designs.
For instance, we now know that large wind turbines are optimally spaced when they are 15 rotor-diameters apart, more than double today’s commonly used 7 rotor-diameter spacing. According to Dr. Charles Meneveau at Johns Hopkins, who has developed an algorithm for optimizing wind turbine spacing, the greater spacing allows for optimum wind flow along the wind farm (closer spacing “muddies” the flow of the wind). This spacing might also dramatically decrease the number of bird kills in the area. It might also lower the cost of electricity generated in these wind farms.
Dr. Meneveau’s work, combined with other research being done throughout the world, are taking the mistakes we have made in the past, to help us optimize our future wind farm designs. The results – lower cost renewables and reduced environmental impacts.