Environmental: October 2009 Archives

Assuming 3.4 billion Barrels (average 9.3 million Barrels per day) of gasoline consumed in 2006 the 5.7 billion gallons (372,000 Barrels per day) of maximum ethanol production represents 4 percent of the gasoline pool. The percentage of gasoline that can be replaced by ethanol drops to a modest 2.9 percent (266,000bbl per day) because it takes 1.4 unit volume of ethanol to replace 1 unit volume of gasoline to account for equivalent heat contents in these fuels.

The Energy Policy Act of 2005 mandated a steady growth in annual ethanol production from renewable sources reaching 7.5 billion gallons of output in 2012. Renewable sources include dedicated energy crops, trees, wood, plants, grasses, fibers, agricultural residues, and waste materials. Assuming 10 percent increase in gasoline consumption in 2012 compared to present levels, the 7.5 billion gallons of ethanol targeted by the Energy Policy Act from any renewable sources would still replace only 3.4 percent of the gasoline pool adjusted for equivalent heating values. To achieve this goal from corn alone would require 32 percent increase in the quantity of corn dedicated to ethanol production compared to the present level. This scenario would likely upset the balance with other important uses of corn such as food for humans and feed for livestock.

In More Hype Than Hope, environmental expert Zoltan Mester, Ph.D., explains how conservation evaporates ethanol's benefits for cars:

The sharp increase in crude oil prices during the past year created an urgent need to search for alternative sources of transportation fuels. Ethanol emerged as the primary candidate to replace a part of the gasoline pool used for transportation. Ethanol can be produced from carbohydrates which are abundantly present in nature as key structural and functional constituents of plants. Carbohydrates come in a great variety including simple sugars, most prominently glucose, and in more complex forms such as starch and cellulose, which consist of several thousand interconnected glucose units. Ethanol production from complex carbohydrates is a two-step process: first the carbohydrate structure has to be broken down to its simple sugar units which in turn need to be converted to ethanol by fermentation. Starch can be converted to ethanol with relative ease while other carbohydrates such as cellulose are more resistant to ethanol conversion. Factors influencing commercial scale ethanol production include availability of the renewable source material in sufficient quantities, efficient means of conversions to ethanol, attractive pricing conditions, government subsidies and tax incentives.

In the USA more than 95 percent of the ethanol is produced from corn, while other sources include cheese whey, barley and shorgum. The United States Department of Agriculture (USDA) forecasted 10,550 million bushels of corn crop from 71 million acres of land for 2006. Approximately 20 percent (2,100 million bushels) of the corn crop is slated for ethanol production.