The report, "2015 Energy Balance For The Corn-Ethanol Industry," said ethanol, on average, has a 2:1 energy ratio (ie: it makes twice the amount of energy needed to produce it), putting to rest contrary claims that continues to being propageted by the oil industry. 

While an energy ratio of 2:1 is the national average, it increases to 4:0 in states like Minnesota and Iowa in cases where some ethanol producers use the lowest corn energy, produce wet distillers grains instead of dried distrillers grains and sell ethanol locally along the I-35 and I-29 interstates. 

In both cases ethanol is produced in plants that use conventional fossil fuels for thermal energy and electricity. Other energy requirements factored in include the energy required to produce corn such as nitrogen and direct energy use for fuel and electricity, farm machinery, the transportation of corn to ethanol plants and the shipment of ethanol to refineries, marketers and traders, the energy used to process distillers grains (a high-protein animal feed). 

"Overall then, ethanol has made the transition from an energy sink, to a moderate net energy gain in the 1990s, to a substantial net energy gain in the present. And there are still prospects for improvement," the report said. 

The report, which was from the USDA's Office of the Chief Economist, said ethanol plants that derive 50 percent of their energy use from biomass power would have an energy ratio of 4.2:1 even with dried distillers grains produced.

"If processors would master the logistics of handling bulky biomass, the energy balance ratio could eventually reach 60 BTUs of ethanol per 1 BTU of inputs used," the report added.

In a separate statement, Agriculture Secretary, Tom Vilsack said : "Between 1991 and 2010, direct energy use in corn production has dropped by 46 percent per bushel of corn produced and total energy use per bushel of corn by 35 percent. Moreover, between 2005 and 2010, direct energy use fell by 25 percent and the total energy use by 8.2 percent per bushel - meaning that between 2005 and 2010, the energy required per bushel of corn produced dropped by about 5 percent."

To read the full report, go to 2015 Energy Balance For The Corn-Ethanol Industry.