US ethanol yields

Last year, US fuel ethanol production hit 14.3 billion gal. of ethanol fuel, the highest ever. The growth in US fuel ethanol production has outpaced growth in corn consumed as feedstock, as the industry has grown, it has become more efficient using fewer bushels of corn to produce a gallon of ethanol.

If ethanol plant yields per bushel of corn in 2014 had remained at 1997 levels, the ethanol industry would have needed to grind an additional 343 million bushels, or 7% more corn, to produce the same volume of fuel. To supply this incremental quantity of corn without withdrawing bushels from other uses would have required 2.2 million additional acres of corn to be cultivated, an area roughly equivalent to half the land area of New Jersey.

Yield increases

There are several factors that contribute to yield increases from a bushel of corn. Increased scale has allowed producers to incorporate better process technology, such as finer grinding of corn to increase starch conversion and improved temperature control of fermentation to optimise yeast productivity. The growth of the corn ethanol industry also enabled the development of better enzymes and yeast strains for improved output per bushel of corn.

The growth in ethanol production has been made possible by a rise in demand for ethanol to increase octane levels as methyl tert butyl ether, a gasoline additive, has been phased out of gasoline, and to meet Renewable Fuel Standard targets enacted in 2005 and expanded by subsequent legislation in 2007. RFS requirements effectively placed a floor under ethanol demand. Recently, ethanol’s volumetric share of total US motor gasoline supply has been just below 10%, reaching 9.8% in 2014.

Edited from press release by Claira Lloyd

Read the article online at: https://www.hydrocarbonengineering.com/the-environment/14052015/us-ethanol-yields/