Fuel from water? A form of Alchemy? Researchers have been trying for years to find a limitless, environmentally benign source of fuel.

Now a University of Colorado Boulder team has developed a radically new technique that uses the power of sunlight to efficiently split water into its components of hydrogen and oxygen, paving the way for the broad use of hydrogen as a clean, green fuel.

The CU-Boulder team has devised a solar-thermal system in which sunlight could be concentrated by a vast array of mirrors onto a single point atop a central tower up to several hundred feet tall. The tower would gather heat generated by the mirror system to roughly 2,500 degrees Fahrenheit (1,350 Celsius), then deliver it into a reactor containing chemical compounds known as metal oxides, said CU-Boulder Professor Alan Weimer, research group leader.