Sandia researcher Rich Diver checks out the solar furnace which will be the initial source of concentrated solar heat for the CR5 prototype. Eventually, parabolic dishes will provide the thermal energy.

Using concentrated solar energy to reverse combustion, a research team from Albuquerque, N.M.-based Sandia National Laboratories is building a prototype device intended to chemically “reenergize” carbon dioxide into carbon monoxide using concentrated solar power. The carbon monoxide then could be used to make hydrogen or serve as a building block to synthesize a liquid combustible fuel such as methanol or potentially gasoline, diesel and jet fuel.

The prototype device, called the counter-rotating ring receiver reactor recuperator (CR5 for short), will break the carbon-oxygen bond in the carbon dioxide to form carbon monoxide and oxygen in two distinct steps. CR5 inventor Rich Diver says the original idea for the device was to break down water into hydrogen and oxygen. The hydrogen could then fuel a potential hydrogen economy.

Then the Sandia researchers came up with the idea to use the CR5 to break down carbon dioxide, just as it would water. Over the past year, they have shown proof of concept and are completing a prototype device that will use concentrated solar energy to reenergize carbon dioxide or water, the products of combustion. This will form carbon monoxide, hydrogen and oxygen, which ultimately could be used to synthesize liquid fuels in an integrated system.

The Sandia research team calls this approach “sunshine to petrol,” and the resulting “liquid solar fuel” -- the methanol, gasoline or other liquid fuel made from water and the carbon monoxide produced using solar energy -- would be the end product.

Team researchers say scientists have known for a long time that theoretically it might be possible to recycle carbon dioxide, but many thought it would not be technically or economically practical. “This invention, though probably a good 15 to 20 years away from being on the market, holds a real promise of being able to reduce carbon dioxide emissions while preserving options to keep using fuels we know and love,” says Ellen B. Stechel, manager of Sandia’s Fuels and Energy Transitions Department. “Recycling carbon dioxide into fuels provides an attractive alternative to burying it.”