Since sugarcane bagasse and trash are used as fuels in conventional bioethanol production, the amount of surplus lignocellulosic material used as feedstock for bioethanol production depends on the energy consumption of the production processes. Residues from the second generation process (e.g., unreacted lignocellulosic material) may be used as fuels and increase the amount of surplus bagasse, along with improved technologies. Pentose fermentation to ethanol instead of biodigestion to produce biogas will lead to higher ethanol production, increasing energy consumption of the process and consequently, decreasing the amount of surplus lignocellulosic material available. In this study different configurations of the second generation ethanol production process (e.g. pretreatment with steam explosion coupled or not with delignification, pentose biodigestion or fermentation to ethanol, solids loading on hydrolysis), are evaluated in the integrated first and second generation ethanol production from sugarcane through simulation using Aspen Plus. The results show which process alternatives, potentially, may lead to higher ethanol production, pointing towards where research should be directed in order to provide important gains on ethanol production in the integrated process. (C) 2012 Elsevier B.V. All rights reserved.