eldavojohn writes "A new reactor developed by CalTech shows promise for producing renewable fuel from sunlight. The reactor hinges on a metal oxide named Ceria that has very interesting properties at very high temperatures. It exhales oxygen at very high temperatures and inhales oxygen at very low temperatures. From the article, 'Specifically, the inhaled oxygen is stripped off of carbon dioxide (CO2) and/or water (H2O) gas molecules that are pumped into the reactor, producing carbon monoxide (CO) and/or hydrogen gas (H2). H2 can be used to fuel hydrogen fuel cells; CO, combined with H2, can be used to create synthetic gas, or "syngas," which is the precursor to liquid hydrocarbon fuels. Adding other catalysts to the gas mixture, meanwhile, produces methane. And once the ceria is oxygenated to full capacity, it can be heated back up again, and the cycle can begin anew.' The only other piece of the puzzle is a large sunlight concentrator to raise the temperature to the necessary 3,000 degrees Fahrenheit. The team is working on modifying and refining the reactor to require a lower temperature to achieve the two-step thermochemical cycle. Another issue is the heat loss which the team claims could be reduced to improve efficiency to 15% or higher. Since CO2 is an input, the possibility exists for coal and power plants to collect CO2 emissions to be used in this process which would effectively allow us to "use the carbon twice." Another idea listed is that a "zero CO2 emissions" is developed along these lines: 'H2O and CO2 would be converted to methane, would fuel electricity-producing power plants that generate more CO2 and H2O, to keep the process going.' The team's work was published last month in Science."