As New Scientist (via Green Car Reports) points out, such a process now exists, at least on an experimental scale. Developed by British firm Air Fuel Synthesis (AFS), the process is complex and costly, at least in the short term.
We’re not chemical engineers, so our knowledge of the process is rudimentary, at best. Step one involves blending air with sodium hydroxide, which forms sodium carbonate when it binds with carbon dioxide. Adding energy splits off the carbon dioxide for later use.
The next step involves dehumidifying the air to remove water vapor before splitting this into hydrogen and oxygen molecules. Take the hydrogen and blend it with the carbon dioxide from step one, and you have a synthetic gaseous hydrocarbon, which can be processed into methanol.
The methanol can be further refined to create a synthetic fuel that behaves much like gasoline, and can be run in internal combustion engines. Engines can be tuned to run on this fuel, or it can be blended with traditionally refined and petroleum-derived gasoline.
The methanol precursor to this compound has already been used to power a Lotus Exige 270E Tri-Fuel, so a limited proof of concept (of sorts, anyways) already exists.
Since this “designer gasoline” will be very pure and very expensive, at least in the beginning, AFS sees motorsports as a likely early adopter of the fuel. Even at the highest levels, motorsports has been tasked with getting “greener,” and what better way to demonstrate this than with (potentially) carbon-neutral fuel.
We say “potentially” carbon neutral because there’s a caveat: liberating hydrogen and oxygen molecules from water is a very energy-intensive process, and that energy has to come from somewhere. If that’s a coal-fired generation plant, then net result wouldn’t be carbon-neutral. If it’s derived from wind power, it could be very clean indeed.
While AFS’ process shows promise, air-derived synthetic gasoline won’t be coming to a filling station near you any time soon. The next step for AFS is to test for feasibility on a larger scale, which will likely give a better idea of the costs associated with commercial production.