There Are Alternatives to Ethanol
More Efficient Alternative Fuels Are Being Developed
Ethanol, with all of its problems, is a costly, stop-gap replacement for gasoline. The alternatives to ethanol are being developed in biotechnology laboratories.
Ethanol has become the green replacement fuel of choice for gasoline in the United States, but many people are looking for more efficient alternative fuels to replace gasoline. The current use of ethanol is understandable; the technology to produce it is well understood, and the United States has a well prepared infrastructure to produce corn, the raw material of choice in this country. Finally, most cars on the road can already use at least some ethanol in their fuel tanks.
Problems with Ethanol Production
Ethanol is not without problems of its own. First, and perhaps foremost, is the high cost of ethanol production. Depending on who is doing the calculations, the energy cost to produce ethanol is higher than the fuel value of the end product (Patzek, Critical Reviews in Plant Sciences, 2004), or very close to the cost of that fuel value (Shapouri, The Energy Balance of Corn Ethanol, 2002).
Another problem is the low energy density of ethanol; there is less energy in a gallon of ethanol than in a gallon of gasoline. This reduces the miles per gallon a vehicle makes when burning ethanol blends. In addition, the extreme solubility of water in ethanol, and the fire fighting issues make ethanol a much less desirable option as a fuel replacement. More efficient alternatives need to be found.
Butanol Produced from Biomass
Butanol is a longer carbon-chain alcohol than ethanol (C4 vs. C2). This means that the energy density is higher, about the same as gasoline, and it is much less flammable. While it still requires significant energy input to dry butanol, it requires much less energy than it takes to dry ethanol.
The main draw back to butanol is the difficulty in producing the material by fermentation. Active research is being done (Bullis, Technology Review, 2007) on developing a fermentation process that can use waste biomass and cellulose as the feed stock to produce biobutanol. Fermentation will make butanol cost competitive with Ethanol.
Gasoline Produced from Biomass
A remarkable new idea being investigated by a biotech company in California, LS9, is using bioengineered bacteria to produce gasoline (Savage, Technology Review, 2007). While still in the early development stages, the idea appears to be feasible. Gasoline is nothing more than a complex blend of hydrocarbons extracted from oil. These hydrocarbons are closely related, chemically, to the fatty acids that are produced by bacteria. Remove the acid group from the fatty acids and you have the associated hydrocarbon.
Biogasoline, gasoline from biomass, would be a direct drop-in replacement for the fossil fuel gasoline used today. Another major advantage that biogasoline would have is that it would be cleaner, having almost none of the sulfur or heavy metals that contaminate today's fuels. This would help to reduce air pollution.
The biotechnology revolution that has had such a dramatic effect on the discovery and production of new medicines is now being harnessed to address the issues of biofuel replacements for gasoline. While ethanol is now produced by a readily available technology, the fuels that will provide a cleaner, cheaper and safer alternative to today's gasoline are now being developed in those biotechnology laboratories. Biobutanol and biogasoline are just two of the potentially new fuels currently under development.
