Biorefining is a fancy term for something people have done for centuries: break down crops into simple sugars, ferment them into alcohol and distill them. Basically, ethanol is moonshine. Pure, concentrated and very combustible. “Distilling” moonshine is a marvelously simple process. But on an industrial scale, each step now benefits from astonishing breakthroughs in technology.
Some of that innovation comes in the form of biotechnology. Enzymes, for example, have largely replaced the “cooking” process once used to break complex carbohydrates into simple monomeric sugars that can be fermented by yeast. That eliminates a major environmental and financial input: heat from natural gas. Enzymes work at relatively low temperature and are themselves a renewable resource.
Yeast technology has led to more complete fermentation and considerable, consistent improvements in ethanol yield. More output with less input.
Other innovations are in process technology or engineering. One ethanol producer (an ACE member) has perfected a system that turns corn fiber, a previously underutilized or wasted product in biorefining, into a cellulosic feedstock for extra biofuel production and corn oil production.
Other system improvements have drained water use in the overall biorefining process. Today one gallon of ethanol only takes 2.7 gallons of water to produce. By contrast, a single gallon of gasoline consumes 97 gallons of water
And the combination of biotechnologies and engineering have delivered a remarkable leap in yield: today, many biorefineries can squeeze 3.0 gallons of ethanol out of a single bushel of corn, compared to only 2.64 gallons per bushel in 2001. That’s a gain of an astonishing 1.6 billion extra gallons of fuel from the same amount of corn.