he hydrogen economy is not a futuristic concept. The U.S. Department of Energy's 2006 Advance Energy Initiative calls for competitive ethanol from plant sources by 2012 and a good selection of hydrogen-powered fuel cell vehicles by 2020.
Researchers at Virginia Tech, Oak Ridge National Laboratory (ORNL), and the University of Georgia propose using polysaccharides, or sugary carbohydrates, from biomass to directly produce low-cost hydrogen for the new hydrogen economy.
According to the DOE, advances are needed in four areas to make hydrogen fuel an economical reality for transportation – production, storage, distribution, and fuel cells. Most industrial hydrogen currently comes from natural gas, which has become expensive. Storing and moving the gas, whatever its source, is costly and cumbersome, and even dangerous. And there is little infrastructure for refueling a vehicle.
"We need a simple way to store and carry hydrogen energy and a simple process to produce hydrogen, said Y.-H. Percival Zhang, assistant professor of biological systems engineering at Virginia Tech.
Using synthetic biology approaches, Zhang and colleagues Barbara R. Evans and Jonathan R. Mielenz of ORNL and Robert C. Hopkins and Michael W.W. Adams of the University of Georgia are using a combination of 13 enzymes never found together in nature to completely convert polysaccharides (C6H10O5) and water into hydrogen when and where that form of energy is needed. This "synthetic enzymatic pathway"research appears in the May 23 issue of PLoS ONE, the online, open-access journal from the Public Library of Science (www.plosone.org).
Polysaccharides like starch and cellulose are used by plants for energy storage and building blocks and are very stable until exposed to enzymes. Just add enzymes to a mixture of starch and water and "the enzymes use the energy in the starch to break up water into only carbon dioxide and hydrogen,"Zhang said.
A membrane bleeds off the carbon dioxide and the hydrogen is used by the fuel cell to create electricity. Water, a product of that fuel cell process, will be recycled for the starch-water reactor. Laboratory tests confirm that it all takes place at low temperature -- about 86 degrees F -- and atmospheric pressure.
The vision is for the ingredients to be mixed in the fuel tank of your car, for instance. A car with an approximately 12-gallon tank could hold 27 kilograms (kg) of starch, which is the equivalent of 4 kg of hydrogen. The range would be more than 300 miles, Zhang estimates. One kg of starch will produce the same energy output as 1.12 kg (0.38 gallons) of gasoline.
Okay. Seriousness time and political advocacy aside, this tech has a long ways to go. However, the idea that we drive over to a station and fill up with, oh, corn starch or potato starch is just plain amusing. I am sure that we can make the enzymes cheaper through one of the biotech companies going fullbore with a recombinant bacteria or yeast.
Hey, Carlos, what do you know/think on this one?