Electric Ethanol
Biomass could heat and power ethanol plants

By Becky Beyers

Making energy takes energy.

That’s particularly true in the corn ethanol industry, where the heat and electricity needed to fuel production plants can be major costs, both financially and in terms of the plant’s carbon footprint.

Most plants currently are powered by natural gas and electricity purchased from the grid. But a study by three CFANS scientists shows that corn biomass—cornstalks and the co-products of ethanol production—in various forms could be used to fuel entire plants, thus improving the plants’ energy balance as much as three-fold and potentially making them more profitable.

The study by Vance Morey, a professor in the Department of Bioproducts and Biosystems Engineering; Doug Tiffany, a research fellow in the Department of Applied Economics; and Matt De Kam, a graduate student in Bioproducts and Biosystems Engineering shows how biomass can be an accessible, renewable source of fuel. Most ethanol plants are located in corn-growing areas, which reduces the cost of hauling corn stover; the plants also produce energy-containing co-products on site that can be used for heating and electricity.

Extra power produced by the system could be sold to utility companies for redistribution. Even better, existing ethanol plants could easily be retrofitted to accommodate the biomass technology.

Morey and Tiffany’s study involved using engineering and economic models to evaluate numerous combinations of biomass fuels and conversion technologies that provide energy on three levels: process heat; process heat and electricity for the plant; and process heat and electricity for the plant plus sale of surplus power. The researchers tested their theories by working with five corn ethanol plants in Minnesota and Wisconsin that were built using contrasting designs in the study funded by the Xcel Renewable Development Fund.