Researchers have developed a prototype device that directly converts sun rays into fuels that can be stored. The BBC reports that the devices uses a quartz window and cavity to focus sunlight into a cylinder lined with cerium oxide.

According to Gizmag, ceria is hygroscopic and will also absorb carbon dioxide. As the sunlight heats the ceria, it thermochemically breaks down the water and carbon dioxide pumped into the cylinder to produce carbon monoxide and hydrogen that can be converted to a liquid fuel.

The device was developed by researchers from the California Institute of Technology and the Swiss Federal Institute of Technology. They believe the technology could be applied in large scale applications since cerium is the most abundant rare earth element.

Several obstacles must be overcome, however, before large scale application is feasible. The largest obstacle being inefficiency. Currently, the fuel created in the prototype harnesses just 0.7-0.8 percent of the solar energy put into the device. Researchers attribute this to heat loss through the reactor’s wall or aperture.

“The chemistry of the material is really well suited to this process,” says Sossina Haile of Caltech. “This is the first demonstration of doing the full shebang, running it under (light) photons in a reactor.”

The paper was published in the last issue of the journal Science.