Wind turbine replacement and redesign, which boost output and have the potential to reduce the number of birds killed in the blades, look like a promising way to help meet the state's renewables targets. However, the California Public Utilities Commission's recent approval of a 38 MW wind replacement for Buena Vista LLC marks the only repower progressing on Altamont Pass, the western edge of California's Central Valley and an area known for avian fatalities. With the commission's June 8 approval in hand, Buena Vista can now seek local government permitting approval for its upgrade. Repowering is the "easiest, quickest way to increase rewewables production, because new turbines are so much more efficient than the old ones" and infrastructure is in place, according to George Hardie, president of G3 Energy, a Buena Vista partner. Replacing old turbines and associated towers with fewer, newer turbines and towers will increase output more than five times, Hardie predicted. Buena Vista's owners appear to be moving ahead. Meanwhile, the first repower at Altamont Pass?a 36 MW plant owned by FPL Group?is not proceeding in spite of the potential upgrade benefits. That repower was permitted by Alameda County in September. Additionally, as a huge owner of wind generation in the state, FPL says that the renewables portfolio standard?mandating an ever-increasing amount of renewables?is not prodding the company to invest in repowering. FPL spokesperson Steve Stengel said the key issue is whether it makes economic sense to upgrade equipment when the company's current fleet is still in good operating order. He conceded that some turbines date back to the 1980s but pointed to FPL's solid track record as the largest owner and operator of wind turbines in the country. Meanwhile, a batch of wind turbine permit renewals have stalled as Alameda County works to resolve challenges by the Center for Biological Diversity to extending operating permits for FPL's Altamont wind farms. The center brought a suit against FPL and its partner, NEG Micon, last January charging that wind towers have killed eagles, hawks, and owls for 20 years, in violation of federal and state laws. The repowering on hold for FPL is only a small fraction of its 2,000 turbines in the area owned with NEG Micon. FPL and its partner own roughly half of the 400 MW of wind farms in the region. FPL's spokesperson would not comment on pending litigation but said that some old turbines have been removed and the company is working with the other wind developers to address the bird-kill problem. Last November, the California Energy Commission urged Alameda County to address the bird deaths before repermitting turbines. The commission noted that more than 1,000 birds are killed from collisions with wind turbines at Altamont each year. According to Linda Speigel, wildlife biologist for the energy commission, more birds?especially raptors?are killed at Altamont wind farms than at other sites because of their abundance there. The region is near one of the highest concentrations of eagles in North America. A CEC report noted by Hardie, but yet unavailable to the public, is expected to claim that repowering has potential to substantially reduce bird fatalities. Initial studies indicate that replacing older, smaller towers with newer, taller structures can reduce bird collisions by as much as 50 percent, because most bird flights occur below blade heights of the new towers, according to Speigel. Reducing bird deaths is the "number-one concern" for Buena Vista, said Hardie. Unlike repowering a fossil plant, wind upgrades can be shaped to the geography of the site and don't have to be done exactly in the same spot as the structures to be decommissioned. For instance, Buena Vista is considering several avian protections, including locating towers at the edge of canyons where birds tend not to congregate. These repowering plans have not been finalized, according to Hardie.