Technology Review Article: Making Gasoline from Carbon Dioxide
This is the most significant article I’ve seen in all of the research I’ve done on biofuels. I’ve stated in a few other blog postings that my personal bet in an end-game type solution is something that utilizes an abundant material within its natural energy flows. Solar-derived Hydrogen has been one solution that’s been floating around. The notion of converting solar-derived electricity into chemical energy is compelling. Hydrogen, however, has many limitations.
The research noted in this article, performed by researchers at UC San Diego, is significant because it implicates converting solar electricity into chemical energy using CO2 as the transfer agent. It’s consuming something we have in excess (CO2) and utilizing it to make a versatile fuel source from it.
It’s a rarity that any process actually consumes CO2. In fact the article notes this:
At least at first, such a process will not make a significant impact on reducing greenhouse gases in the atmosphere–that would take quite large-scale operations, Kubiak says. But “any chemical process that you can develop that uses CO2 as a feedstock, rather than having it be an end product, is probably worth doing.” He adds that “if chemical manufacturers are going to make millions of pounds of plastics anyway, why not make them from greenhouse gases rather than making tons of greenhouse gases in the process?”
But the real notion here is that we can finally utilize any carbon-based fuel as part of a whole system. As it stands, we dig up carbon under the ground and convert it, via our cars, into carbon dioxide. This is a one directional system. We have no other way of getting it back into the ground. The only other naturally occurring process that metabolizes CO2 are plants and trees. However, we’ve been steadily destroying those over the years – we probably should have been growing 100X more of them to keep up with our oil consumption (we probably still should regardless).
The research notes the process would work as such:
In the prototype device, sunlight passes through carbon dioxide dissolved in a solution before being absorbed by a semiconductor cathode, which converts photons into electrons. Aided by a catalyst, the electrons react with carbon dioxide to form carbon monoxide at the electrode.
It’s not known how scalable this process is or how stable it can be made.
The carbon monoxide that can be generated can be combined with hydrogen (also made from solar?) and pyrolyzes into syngas. Syngas can be converted via Fisher-Tropsch process into a variety of hydrocarbons (ethanol and butanol included). There are a few companies utilizing this thermoprocessing technology including RangeFuels in Lakewood, Colorado. It’s a costly, but effective process that is gaining in attention. This type of process could be a great first step towards creating powerful solutions to this problem.
