Scientific America: On the outskirts of Seville, Spain, 600 rotating mirrors send shafts of light to a collector atop a soaring 380-foot- (115-meter-) tall tower. Its scalding 480-degree-Fahrenheit (250-degree-Celsius) steam drives a turbine generating a peak capacity of 11 megawatts (MW) of electricity for the national grid. This “power tower” is the first of nine to be built by Spanish engineering giant Abengoa Solar, which all told will produce enough electricity for 153,000 homes by 2013. From power …