1. C.P Pabón Pereira 1, J.B. van Lier 1, M.A. Slingerland 2, W. Sanders 1, R. Rabbinge 2 1 Wageningen University. Department of Agrotechnology and Food Sciences. Sub-department of Environmental Technology. 2 Wageningen University. Sustainable Development and Systems Innovation Group. 1 Claudia Patricia Pabón Pereira Environmental Technology Dpt. PO Box 8129. 6700 EV Wageningen. The Netherlands Tel +31 317 485762 Fax +31 317 482108 Claudia.Pabon@wur.nl Anaerobic Digestion in Bioenergy Chains The potential of the sugarcane industry in Colombia Figure 1. Different possible cascade configurations for sugarcane benefiiting from AD Anaerobic Digestion plays a potential central role in different biomass conversion chains. Methane, nutrients, and digestate add to environmental and economical sustainability of the entire chain. Building materials Paper High value chemicals Bioethanol Sugar cane Other industries Sugar BiogasFertilizer/ Soil conditioner Anaerobic Digestion Sugar industryBioethanol Vinasses Animal ind. Manure Fiber Electricity / Biogas Back into the system FeedBagasse Scums& Molasses Trash Building materials Paper High value chemicals Bioethanol Sugar cane Other industries Sugar BiogasFertilizer/ Soil conditioner Anaerobic Digestion Sugar industryBioethanol Vinasses Animal ind. Manure Fiber Back into the system FeedBagasse Scums& Molasses Trash AD potential of sugarcane by-products in Colombia Table 1 Estimation of the amount on residues produced by sugarcane transformation industries in Colombia a.Observatorio Agrocadenas de Colombia 2004 (Data for 2002); b. Estimations based on the area required to fulfill the demand considering the incentive given by Law (Cardenas Gutierrez 2004); c. Estimations based on De Carvalho Macedo et al. (2001);d. Estimations based on Van Haandel (2004) and Baudel et al. (2004); e. Estimations based on El Bassam (1998);f. Estimations based on Van Haandel (2004).N.D. Not determined Final Product Total Area CultivatedTrashBagasseVinasses Cachaza - Molasses (has)(Ton DM/yr) (Ton/yr) Panela243.700 a 3.411.800 c 3.289.950 d N.D0 Sugar168.900 a 3.688.776 c 3.557.034 d 01.053.936 e Ethanol103.000 b 1.442.000 c 1.802.500 d 9.000.000 f 0 TOTAL516.6008.542.5768.649.4849.000.0001.053.936 Table 2 Estimation of the potential of anaerobic digestion to transform Colombian sugarcane residues into bioenergy Estimations for bagasse and vinasses yields based on Van Haandel (2004): Bagasse 125 kgCH 4 / ton DM at 50% COD conversion and vinasses 100 Kg CH 4 /m 3 ethanol; Estimation for molasses based on assumptions based on figures compiled by Wilkie et al (2000): Average conversion of molasses 70 gCOD /l molasses and 65% COD conversion efficiency (60% methane content in biogas). N.D. Not determined Final product BagasseVinassesMolasses Methane (KTon CH 4 /yr) Energy yield (MW) Methane (KTon CH 4 /yr) Energy yield (MW) Methane (KTon CH 4 /yr) Energy yield (MW) Panela41123500N.D Sugar 44525400 2916 Ethanol22512990051400 TOTAL1.0816179005142916 Importance of Sugarcane for Colombia Sugarcane currently occupies 9% of the total area cultivated in Colombia (412.600 ha), its destination being the production of sugar and panela (traditional unrefined whole sugar). Bioethanol is a new product gaining importance.  Sugar: Annual production of 2 million tons of raw sugar on 169,000 has which corresponds to a share of 5.3 % in the value of agricultural production.  Panela: Responsible for 4.1 % in the value of agricultural production is more important in terms of area cultivated (244.000 has in 2002) and employment (Second largest provider of rural employment in Colombia after coffee).  Bioethanol: From 2005 onwards about 46% of the gasoline sold in Colombia should be oxygenated. About 750 million liters of bioethanol per year are required meaning 103.000 has sugarcane cultivated additionally (Cardenas Gutierrez 2004) and 9 to 12 ethanol distillation plants with capacities in the range of 150-300 tons per day (Gonzalez 2004). Conclusions and recommendations AD of sugarcane residues in Colombia could generate approx 1140 MW. This without considering further reclamation of energy from the combustion of the dried digestate and the potential energy generation from trash and molasses from panela. Bagasse residues are currently employed in combustion, therefore the benefits of AD have to be analyzed against this technology. Implementation of AD for the case of bioethanol refineries shows to be an interesting alternative. Expected vinasses alone can produce approximately the same amount of energy as the bagasse of the three industries together plus a major environmental problem is avoided. If the whole plant was to be digested, 1900 MW could be theoretically produced plus the energy generated by CHP of digested dry material. References Baudel, H., Zaror, C., and Abreu, C. (2004). Industrial Crops and Products, Article in Press. Cardenas Gutierrez, J. (2004)."I Seminario Internacional de alcoholes carburantes, Medellin, Colombia. De Carvalho Macedo, I., Lima Verde Leal, M., and Hassuani, S. J. (2001). 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