2015 Energy Balance for the Corn-Ethanol Industry
The ratio of energy in a gallon of ethanol relative to the external fossil energy required to produce the corn and process and ship the ethanol is an important measure of sustainability of the corn ethanol industry (Pimentel). Some revisions of initial energy balance calculations have already verified enhanced industry performance and identified methods that could yield further improvement (Shapouri, et al., 2002: Gallagher and Shapouri). A post-expansion survey of ethanol processors thermal and electrical energy use showed further improvement in energy balance (Shapouri, et al., 2010). Ethanol made the transition from an energy sink, to a moderate net energy gain in the 1990s, and to a substantial net energy gain by 2008. This study investigates whether ethanol energy balance still improves and reviews some potential sources of future improvement.
Estimates of the current energy balance situation are presented in this report. We update effects of current corn production practices, using current fertilizer and chemical application rates from the most recent data collected by the USDA. Updates also include the energy embodied in modern farm machinery. Energy use by the transportation system for corn procurement and ethanol distribution is also revised to reflect current marketing practices. Current thermal and electrical energy use by ethanol processors is also included. Furthermore, we discuss the range of energy balance outcomes in the industry, according to byproduct marketing practices and process energy sources. Lastly, we examine the potential for further energy balance improvements through improved economic management of byproduct marketing and power choices. We find that profitable practices followed by some firms also tend to improve the energy balance above the industry average.