Ethanol plants continue to increase in efficiency. A new University of Illinois at Chicago study of facilities that produce most of the nation’s ethanol found that the energy needed to make a gallon of the corn-based fuel decreased on average by about 30 percent within the past decade.

The study, conducted by Dr. Steffen Mueller at the Energy Resources Center at the university and funded by the Illinois Corn Marketing Board, surveyed 90 of the 150 dry mill ethanol plants operating during 2008. Results were compared to a 2001 survey conducted by BBI International on behalf of the U.S. Department of Agriculture.

In 2001, ethanol plants used an average of 36,000 Btu of thermal energy and 1.09 kWh of electrical energy, per gallon of ethanol. They also produced 2.64 gallons of ethanol per bushel. Ethanol plants in 2008 used an average of 25,859 Btu of thermal energy and 0.74 kWh of electricity per gallon of ethanol produced – that’s 28 and 32 percent less than 2001, respectively. Ethanol per bushel of corn, meanwhile, increased 5.3 percent to 2.78 gallons per bushel.

The findings may prove useful to state and federal energy policy makers studying the pros and cons of fuels based on their “full life-cycle” — the total energy needed to create a fuel compared to its energy output, the greenhouse gases emitted during production, the water used in production, and other factors.

“Policy makers rightfully pay attention to life cycle greenhouse gas emissions of fuels,” said Mueller. “Biofuel refineries, including corn ethanol plants, are in a rapid innovation phase.”

He said his survey shows that adoption of new technologies reduces energy production needs since many older dry mill ethanol plants installed energy efficiency retrofits during that time period.