Harvest logistics and economics of Sweet Sorghum crop for fuel ethanol, grain feed, and bioproducts under Midwest conditions

Isaac P Serbin, Purdue University

Abstract

Of the 136 billion liters (36 billion gallons) of biofuels required to be produced under the United States Energy Independence and Security Act of 2007 (EISA), the act specifically states that 79.5 billion liters (21 billion gallons) of the ethanol must be produced from non-food or cellulose resources, such as switchgrass or wood chips. Sweet Sorghum is one possible crop that could help meet the EISA 2007 demand. Sweet Sorghum is a multiproduct crop that produces juice which contains high levels of easily fermentable sugars making it ideal for ethanol production; it also produces valuable co-products such as sorghum grain and lignocellulosic plant material known as bagasse. However, the logistics of harvesting and handling sweet sorghum in the large volumes required for biofuels production is yet to be developed. This study investigated logistical pathways using event simulation in EXTEND Sim7.0.5 © (Imagine That, Inc., San Jose, CA) and analyzed the cost of several harvest and post-harvest processing systems for sweet sorghum. The objective of the study was to determine the best logistical pathways based on cost for the production of sweet sorghum grown for biofuels, feed and bio-products. The effect of harvest window on cost using 21 and 60 days was investigated. Of the six harvest pathways investigated, the use of specialized combines for harvesting juice on the field, bagasse and grain was the least cost pathway ($1381 USD per ha) when the harvest window was at 60 days. In this pathway, the juice was used for the Sorganol Process to produce neat ethanol, the bagasse was used for silage and the crop was harvested before grain was produced. The most costly harvest pathways were harvesting Whole Cane Harvest and Windrow Whole Cane Harvest systems. In general, harvest within the 21 days window was more expensive than the 60 days window. There was a tradeoff between growing sweet sorghum varieties which produce juice and bagasse only and varieties which produce juice, bagasse and grain. A further reduction in cost is expected as the industry grows and experimental equipment under development move into commercial production.

Degree

M.S.

Advisors

Ileleji, Purdue University.

Subject Area

Alternative Energy|Plant sciences|Agricultural economics|Agricultural engineering|Energy

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