What are the energy-balance ratios for alternative fuels?
The ratio for various biodiesel grades ranges from 2.0 to 3.0. The ratio for corn-derived ethanol is 1.3 to 1.8. In fact, it has been estimated that the ratio at the beginning of the American corn program was negative, ie., less than 1. The process of producing the corn-ethanol consumed more energy that the ethanol could give back. For beet ethanol (such as that produced in Germany) or wheat ethanol (in some European countries), the ratio is approximately 2.0; sweet sorghum, used in African production, achieves a ratio of 4.0. The main reason for the strongly positive ratio provided by the Brazilian ethanol is because the sugarcane industry does not use any fossil energy in the ethanol production process – only the sugar-cane bagasse, the plant material remaining after sugarcane stalks are crushed, is used. As a result, the production process (as well as the product) in Brazil features much greater sustainability than those of other countries.
