Techno-economic analysis of integrating sweet sorghum into sugar mills: The Central American case

• Published in: Biomass & bioenergy Vol. 68; pp. 195 - 214
• Main Authors: Cutz, L., Santana, D.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-09-2014; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Alcohols: methanol, ethanol, etc; Alternative fuels. Production and utilization; Applied sciences; Biological and medical sciences; Biomass; Central America; Electricity; Energy; Ethanol; Exact sciences and technology; Fuels; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Natural energy; Sorghum; Sweet sorghum; Use of agricultural and forest wastes. Biomass use, bioconversion; Central America; America; Central America; Biomass; Electricity; Ethanol; Sweet sorghum; Monocotyledones; Alcohol; Cereal crop; Sugar plant; Case study; Sorghum bicolor; Gramineae; Angiospermae; Technicoeconomic study; Spermatophyta; Sugar; Grinder
• ISSN: 0961-9534; 1873-2909
• DOI: 10.1016/j.biombioe.2014.06.011

This paper aims to evaluate the potential for electricity and ethanol production in Central America using sweet sorghum, performing a techno-economic analysis. The study proposes the integration of sweet sorghum into Central American sugar mills, by using the existing machinery to process this crop during off-season. A process simulation and a cost model were developed to estimate the technical and economical feasibility of sweet sorghum integration. The data on various parameters used for techno-economic assessment were collected from an existing sugar mill and distillery in Central America. The results show that a sugar mill operating 2 months during off-season could obtain an average revenue of US$ 3 M for a crushing rate of 6500 t/d. Ethanol production costs are estimated to be 24.76 ¢US$/L. In case a new CHP plant is built, a sugar mill operating under the integrated scenario would have a payback period of 4.49 years, as compared to 7.47 years for a sugar mill using sugarcane bagasse as the only fuel. Although several studies highlight the potential of sweet sorghum for ethanol production, the results from this work prove that sweet sorghum must also be seen as a viable feedstock for electricity production. A sensitivity analysis was also performed to determine the variation of the average cost of electricity and ethanol with the variables used in the economic analysis. For all analysed scenarios the effects of installed capacity and crop yield prevailed over the increasing costs of land and transportation.
•This study is based on data from existing sugar mills in Central America.•Sweet sorghum would allow sugar mills to extend their operation season.•Sweet sorghum must also be seen as a viable feedstock for electricity production.•A sugar mill firing sweet sorghum bagasse could produce electricity for 3.56 ¢US$/kWh.•A sugar mill operating 2 months during off-season could obtain average revenue of US$ 3 M.