Ethanol 101

20 March 2008

Henry Ford started it all in 1896 when he fueled his first auto with pure ethanol. That made sense. Ethanol is ethyl alcohol derived from corn and other high-starch crops, which abound throughout the Midwest.

In the 111 years since that first fill-up, ethanol has moved in and out of favor as freely as pop music and skirt lengths. Sometimes, it jumped in popularity. Once, it disappeared.

Ethanol drew little attention during World War I, then became an important motor-fuel additive in the 1920s and 1930s. When the US entered World War II, restricted fuel supplies kept civilians off the road. Ethanol fell from favor again.

The World War II armistice sent military petroleum needs plummeting. Cars roared across the American highway again, but without ethanol in their tanks. Leaded gas was cheap and abundant, apparently finishing ethanol as a motor-fuel additive. Commercial ethanol production halted.

But not today. Ethanol is back, stronger than ever. Maybe this time for good. Middle East instability, which sustains a constant supply threat in the world's most oil-rich region, accelerates ethanol production. So does demand for cleaner-burning engines.

Combusting this colorless, slightly toxic liquid turns it into water (H2O) and carbon dioxide (CO2). Gasoline with now-standard 10% alcohol content means a 30% reduction in emissions. Carbon monoxide (CO) is a major contributor to smog. The higher the ethanol content in gas, the lower the CO emission. Combusting pure ethanol yields no CO. In Brazil, half the cars can operate well on pure ethanol.

The US produced only 10 million gallons of ethanol in 1970. Oil supply disruptions sent production soaring to 175 million gallons in 1980. Production leaped to 4 billion gallons in 2005, a total soon to double.

Demand for corn and less popular ethanol feedstocks – including sugar, grasses and even cattle waste – keep rising. Farmers in the US produced 10.5 billion bushels of corn in 2006 and will increase harvests to 12.2 billion this year. About a quarter of US corn yields go to ethanol plants.


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