Wind could provide 10 percent of the world's electricity needs by 2017. Already, nearly 30 million Europeans use wind power and the U.S. has the potential to generate up to 40 percent of its electrical needs through wind within 20 years. Already large wind turbines producing megawatts of power are common, as the cost per kilowatt-hour continues to drop, falling 90 percent since the 1970s, and countries such as Denmark are replacing outdated wind turbines with new ones.
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