Researchers Find New CO2 to Fuel Method

Carbon capture schemes almost always require sequestration — compressing CO2 gas and pumping it underground for permanent storage. But those plans will be discarded as excessively complex if a simpler method to store CO2 can be found. The best idea so far is turning it into a liquid fuel that can be used, like gasoline, for transportation.

Enter archaea, a primeval microorganism family of which some types can break down CO2 to produce methane, also known as natural gas. A set of researchers at Pennsylvania State University have uncovered a strain of archaea that’s particularly effective at separating the gas.

Like the biofuel from duckweed announcement I covered a few weeks back, this isn’t a new discovery, despite the apparent willingness of the scientists to spin it as one. Methane-producing archaea are abundant (one strain that lives on rice plants produces much of the atmosphere’s methane), and others have worked on getting the tiny organisms to split CO2 molecules. However, the Penn State research may still break new ground.

The archaea they discovered are particularly efficient as using direct pulses of electricity to power the reaction, and it’s reported that they’re 80 percent efficient in their use of the energy. Provided the archaea can be made to multiply and maintain colonies, they would provide a significantly cheaper way of getting rid of CO2 than those being worked on now.

Exactly what the costs are today is uncertain, but they’re high. I looked into the issue for an article in the Economist about carbon capture. Most of the scientists I talked to were estimating that they could make a liquid fuel profitably if gasoline were around $5 per gallon, but a particularly effective way of splitting CO2 might bring those costs down to a more manageable level.

Luckily, more startups are making the attempt of late. A recent USA Today story (reprinted at NewsFactor) took a look at several methods, including one using solar energy in development by Sandia National Laboratory and, in secret, by a company called Sundrop Fuels. Another startup they cover, Carbon Sciences, recently claimed in Newsweek that it will reach $4 per gallon with its own method, although it’s doubtless in that company’s interest to be wildly optimistic, as it’s publicly traded over-the-counter.

It takes energy both to capture and split CO2, so there are some limits to how cheap making a fuel. But with luck, one of these methods will turn out to be cheaper than the others soon, removing the need for complicated sequestration methods.

Update: Also check out the New Scientist on a CO2 conversion method found by Singaporean researchers and first reported in a prestigious scientific journal. While they use a manufactured catalyst, the reaction takes place at room temperature, which could help keep energy costs low.