Bioenergy production in Central America: Integration of sweet sorghum into sugar mills

Abstract

This paper aims to evaluate the potential for electricity and ethanol production in Central America using sweet sorghum as an energy crop. Three scenarios were built to analyse sweet sorghum production in terms of the land where it can be cultivated: cropland, sugarcane land in fallow and land in continuous production (intercropping system). The land under permanent crops was not considered for this evaluation. We propose the integration of sweet sorghum into Central American sugar mills, by using the existing machinery to process it. The short growing period of sweet sorghum would allow the Combined Heat and Power (CHP) plants and distilleries to operate outside the sugarcane crushing season using sorghum bagasse and molasses as raw materials. This production could be performed 1month before, and 1month after the sugarcane season.Results indicate that by growing sweet sorghum on 5% of Central America's cropland, sorghum could supply around 10% of region's electricity demand. Thus, Central America could increase its CHP share of electricity supply from 4.4% to 5.6%. The increase in renewable electricity production would allow countries such as Guatemala, Honduras and Nicaragua to reduce fossil fuel bills by USD$ 13, 10 and 20 million, respectively.The ethanol produced from sweet sorghum during off-season can help to implement and maintain a sustainable ethanol program in the region that does not only depend on sugarcane. Sweet sorghum would allow distilleries to easily supply the ethanol required to implement an E5 or ED3 program. Central America could produce about 387 million liters of ethanol by growing sweet sorghum on 5% of its cropland. This ethanol production would help the region to reduce fossil fuel bills by USD$ 517 million by using ethanol–gasoline blends or USD$ 463 million by using ethanol–diesel blends.