(115a) Comparison of Environmental Releases in Ethanol and Gasoline Production

As the use of biofuels for transportation grows, it is important to scientifically assess the impacts associated with their production.  Currently corn ethanol provides the largest volume of transportation biofuel in the United States with more than 13 billion gallons produced in 2010 and 15 billion gallons projected by 2015.

Most prior studies of fuel ethanol plants include greenhouse gas emissions and in some cases criteria air pollutants. In this contribution the focus is on assessing all reported pollutants released from ethanol plants and petroleum refineries. Ethanol is viewed as an alternative to gasoline, and a model is provided to describe the environmental releases at a facility level for ethanol and gasoline production.

Data is collected from the National Emissions Inventory (NEI) database and compiled for emissions for the species in the database. This includes criteria air pollutants and hazardous air pollutants. This research also shows a relative comparison of toxic releases in the United States with data compiled from the Toxics Release Inventory (TRI). Water and land releases are available from the TRI database.

In this work, the focus is on the dry grind ethanol production process rather than the wet grind alternative because the dry grind process is more directly associated with ethanol as the main product, is responsible for over 85% of US ethanol production, and is the primary technology anticipated for future ethanol production. This study addresses suitable methods and criteria for allocating the co-products of ethanol and gasoline production.

The present work attempts to capture these results and present them for further evaluation.