About Energy Balance of Producing Ethanol: Ethanol Is Energy Efficient

About Energy Balance of Producing Ethanol: Ethanol is Energy Efficient

People interested in ethanol production often ask about the net energy balance of ethanol production. Energy is measured in BTUs or British Thermal Units. In 2004, the United Department of Agriculture (USDA) determined the net energy balance of corn ethanol to be 1.67 to 1. This means that for every BTU of energy used to make ethanol, 1.67 BTUs are produced. These measurements have been confirmed by additional studies conducted by the University of Nebraska and Argonne National Laboratory.

According to the National Corn Growers Association, nine independent studies conducted since 1995 found ethanol to have a positive energy balance. In 2001, the USDA and Argonne Labs found that "only 17% of the energy used to produce ethanol comes from liquid fuels, such as gasoline and diesel fuel. For every 1 BTU of liquid fuel used to produce ethanol, there is a 6.34 BTU gain."

Other studies have been even more positive. A publication by BBI International, Fuel Ethanol: A Technical Evolution, estimated energy measures using record corn crop yields from 2000 to 2002 to result in a net energy balance for a dry mill ethanol plant to be as high as 1.89 to 1.

Recent studies have debunked old studies that questioned ethanol's energy balance. Some of these older studies, including much-publicized work of David Pimentel of Cornell University used outdated figures, such as corn yields from 1992 and ethanol plant energy use measures from 1979.

Energy balance studies take into account the energy required to plant, grow and harvest corn, as well as the energy required to manufacture and distribute ethanol. The net energy balance of ethanol production continues to improve. Modern farming practices, better corn varieties, and conservation measures increase the yield of corn per acre. The National Corn Growers Association reported record yields averaging 160 bushels of corn per acre, and predicts average yields of 173 bushels per acre by the year 2015. With higher corn yields, the positive energy balance will be increasingly significant.

Adding to increased efficiencies is modern ethanol production technology, which continues to evolve through scientific innovations. According to an Issue Brief prepared in 2004 by the American Coalition for Ethanol, "modern