One of the primary fuels that can be produced from biomass is ethanol. It is hoped that increased use of ethanol as a motor fuel will result in fewer greenhouse emissions and less reliance on fossil fuels in the form of petroleum. However, current technology limits the amount of biomass and ethanol production, thus limiting its use in the transportation system.
The highest concentrations of ethanol are produced by fermentation of starchy grains such as corn. However, this is also a food source for animals and humans. Scientists are working on methods of deriving ethanol from plant cellulose so that it can be distilled from plant waste as well as the grains.
At the present time, plant cellulose is very difficult to break down into the sugar molecules that are needed for fermentation to work. Certain enzymes have been detected that are capable of performing this action, however, their production requires a great deal of energy in itself.
One possibility that shows promise is the creation of "biorefineries" that operate much like petroleum refineries. In addition to the production of ethanol, biomass based polymers and other products could be captured. Lignin could be used as a fuel to power the refinery process and other materials could be used as fertilizer for future crops.
Once a system is put into place that could refine all the usable products from the cellulosic biomass, production of ethanol and other materials could prove to be the answer to the problems associated with use of fossil fuels in many ways.
It would be essential to calculate the environmental impact of producing enough high energy feedstocks to supply such a refinery or fuel plant and how it would affect the production of food and animal feeds. There is little doubt that a balance would need to be struck between crops and lands used for food production and land devoted to growing energy crops.
In addition to crops grown specifically for conversion to ethanol fuel, plant waste matter could be used as feedstock which would help to offset a portion of this conflict between the food demands of the world and its energy demands.
The first key to making ethanol production from biomass a feasible replacement for fossil fuels may lie in genetically engineering enzymes and microbes that are more efficient at breaking down the complex molecules of cellulose into simple sugars that will ferment and form ethanol. However, extreme care would have to be exercised to ensure that the bio-engineered enzymes and microbes did not escape into the environment.
There are many problems ahead for the biomass and ethanol industry in the transportation sector. Some of them go beyond the production of ethanol alone and encompass proper use of arable land and a balance between food production and energy production. More research is needed to determine the exact best course of action, but it is a certainty that with fossil fuels being a finite resource that will be exhausted some day, expansion of biomass production and conversion to ethanol is one of the keys to keeping the world moving.