http://www.ncga.com/ethanol/main/energy.htm
National Corn Growers Association
Last reviewed June 10, 2005
Ethanol Production: A Net Energy Winner
There is clearly no doubt that fuel ethanol contains more energy than it takes to produce.
In June 2004, the U.S. Department of Agriculture updated its 2002 analysis of the issue and determined that the net energy balance of ethanol production is 1.67 to 1. (For every 100 BTUs of energy used to make ethanol, 167 BTUs of ethanol is produced.) In 2002, USDA had concluded that the ratio was 1.35 to 1.
The USDA findings have been confirmed by additional studies conducted by the University of Nebraska and Argonne National Laboratory. In fact, since 1995, nine independent studies found ethanol has a positive net energy balance, while only one study – which used outdated data – found the energy balance to be negative.
A Michigan State University study (2002) found that ethanol produced from corn provided 56 percent more energy than is consumed during production (1.56 to 1). This study looked at producing ethanol from both dry and wet milling of corn—and included corn grain production, soybean products from soybean milling and urea production.
These studies take into account the entire life cycle of ethanol production—from the energy used to produce and transport corn to the energy used to produce ethanol to the energy used in the distribution of ethanol in gasoline.
What’s behind this continual increase in net energy balance?
Production efficiency is one factor. Compared to just five years ago, today’s ethanol plants produce 15 percent more ethanol from a bushel of corn—and using 20 percent less energy in the process.
The energy efficiency of American farmers is another reason. According to USDA statistics, U.S. agriculture uses about half the energy to produce a unit of output today than was needed to produce the same output in 1950.
Better corn varieties, improved production practices and conservation measures also figure into the equation. A 1 percent increase in corn yield raises the net energy value by 0.37 percent.
It’s also important to note that energy from ethanol is not the only result of ethanol production. Coproducts such as distillers grains, gluten feed, carbon dioxide, and corn sweeteners are also created in ethanol production. That means that not all the energy used by an ethanol plant is directed at manufacturing ethanol, thus further improving the net energy balance of ethanol production.
Ethanol opponents frequently cite a study by Cornell University’s Dr. David Pimentel, who concluded that it takes 70 percent more energy to produce ethanol than it yields. Pimentel’s findings have been consistently refuted by USDA and other scientists who say his methodology uses obsolete data and is fundamentally unsound.
America's Dependence on Oil Imports
Analysis by the U.S. Department of Energy and USDA shows that, for every 100 BTUs of energy used to make ethanol, 135 BTUs of ethanol is produced. That is a positive net energy balance of 1:1.35.
A more recent Michigan State University study (2002) underscores these findings. In the MSU study, ethanol produced from corn was found to provide 56% more energy than is consumed during production. This study looked at producing ethanol from both corn wet and dry milling—and included corn grain production, soybean products from soybean milling and urea production.
These studies take into account the entire life cycle of ethanol production—from the energy used to produce and transport corn, to the energy used to produce ethanol, to the energy used in the distribution of ethanol in gasoline.
Additionally, U.S. agriculture has become more energy efficient. According to USDA statistics, U.S. agriculture uses about half the energy to produce a unit of output today than was need to produce the same output in 1950.
Ethanol opponents frequently cite a study by Cornell Professor David Pimentel, who concluded that it takes 70% more energy to produce ethanol than it saves. Pimentel’s findings have been consistently refuted by USDA and other scientists who say it uses obsolete data and is fundamentally unsound.
Future Role of Ethanol
Ethanol is uniquely positioned to grow in importance as the nation continues its quest for renewable energy and new engine technologies.
E85: This blend of 85 percent ethanol and 15 percent ordinary unleaded gasoline has become a rapidly growing alternative fuel since the dramatic increase in gas prices. Millions of vehicles on American highways can operate on E85. These flexible fuel vehicles (FFVs) can actually operate on E85, E-10 Unleaded, ordinary unleaded or any combination of these fuels. A computer in the fuel system automatically adjusts for the amount of ethanol in the blend.
The number of E85 fueling stations across the United States is growing at an accelerated rate—and U.S. automakers are manufacturing a larger number of FFVs.
Obviously, replacing 85 percent of the petroleum in a gallon of gasoline will help America wean itself from imported oil even faster—and create a greater demand for ethanol in the nation’s fuel supply.
Ethanol-Based Aviation Fuel: Extensive research has shown that an aviation fuel blend containing 85 percent ethanol offers superior performance in prop-driven aircraft. The Federal Aviation Administration and several universities are conducting research on ethanol-based aviation fuel to determine the feasibility of the fuel as an alternative to the leaded aviation fuel currently being used.
E diesel: Off-road equipment, city buses and other vehicles that run on diesel fuel are major contributors to air pollution. Research is under way to discover the optimum blend of ethanol and diesel fuels to replace straight diesel fuel in these engines. The cities of Lincoln, Neb.,, and Springfield, Ill., as well as Johnson County, Kan., have converted their city bus fleets to an E diesel blend on a test basis—and other cities in the Midwest are considering similar tests.
Fuel Cells: This is the next evolution in engine technology—and ethanol is poised to become an integral part of this new wave of automotive innovation. Fuels cells work by combining hydrogen and oxygen in a chemical reaction to create electricity, without the noise and pollution of conventional engines. Ethanol is a hydrogen-rich liquid with a simple molecular structure—offering a practical, economical and efficient solution as a hydrogen source for onboard fuel cells in vehicles or stationary applications.
Biomass Sources: While starch from the corn kernel is the feedstock of choice for ethanol production, the industry may soon have the capability to efficiently convert crop residues such as corn stalks and cobs into ethanol. Other raw materials such as trees, grasses, and other agricultural crops can also be used to derive ethanol. These biomass sources may eventually be used in ethanol production facilities that are located where corn production is not prevalent.