>She said it takes too much energy to make ethanol from corn for it to become a popular fuel choice.
Such is a person who supports using cloth diapers over plastic, but the energy cost involved to clean the diapers is a lot more. <G>
Ethanol can be made from sources besides corn.
Biomass for Energy
In order to expand the available resource base for sugars and to identify lower cost sources, we have focused on the use of non-starch, non-food-related biomass such as trees, grasses, and waste materials. The three largest components of these biomass sources are cellulose, hemicellulose, and lignin. Lignin is a biopolymer rich in phenolic components, which provides structural integrity to plants. Ranges of cellulose, hemicellulose, and lignin contents in biomass are presented in Table 1. Ranges for five-and six-carbon sugar content in hardwoods, softwoods, and agricultural residues are provided in Table 2. The combination of hemicellulose and lignin provide a protective sheath around the cellulose, which must be modified or removed before efficient hydrolysis of cellulose can occur. Lignin is often referred to as "clean" (i.e., sulfur-free) coal because it is the lignin portion of plants that is the ancestor of coal (which is, after all, fossilized biomass). Lignin remains as residual material after the sugars in biomass have been fermented to ethanol. Economic use of this byproduct is critical to the financial feasibility of biomass-to-ethanol technology. |
