For decades, Brazil and the United States were the major countries producing biofuels. In Brazil, sugarcane was the raw material and ethanol producers simply fermented the extracted sugars. The spent cane (bagasse) was fed into solid fuel boilers to produce steam and power, and the excess was sold as bedding or became waste. In the United States, corn was the raw material; the starch was converted to sugar and fermented. Dried distillers grain was a by-product and was sold as animal feed. The cornhusks and stover were usually left in the fields to maintain soil fertility and structure. Most U.S. corn ethanol producers used natural gas to supply process heat. Sugarcane and corn for both processesis renewable. More important, the feedstock continues to be replanted and harvested—a key ingredient to sustainability. However, both processes have been criticized for using land or product that displaced food-growing capacity (the food versus fuel issue).1
In addition, corn ethanol has been criticized for inefficiency and for not being sustainable. The industry is improving land use by increasing yield, gaining 30 to 50 percent yield through using spent crops. Energy required per gallon has decreased from 37,000 BTU per gallon in 1994 to 23,862 BTU per gallon in 2012. Similar gains have been made in reducing water consumption. As industries mature, they typically become more efficient. In the United States, corn ethanol may not have been the best gasoline replacement, but it has brought significant benefits. In particular, it became a profitable, commercial business segment with steady employment that provided financial benefit to farmers, helped lower the price of gasoline by about a dollar per gallon, deferred the importation of about 450 million barrels of oil in 2013, and helped the U.S. balance of trade by about $45 billion annually.
Republished by courtesy of the authors and Paper360º, where the article originally appeared.