Nowadays, there is a tremendous global interest in the biofuels production. However, first generation biofuels have been debated about that energy-crop compete with food crops and thus cause food deficiency and price increases. In this sense, researchers have started looking for potential feedstock for ethanol such as lignocellulosic biomass (e.g., sugarcane bagasse), which does not affect food security. In this paper, the integrated use of sugarcane bagasse is analyzed as raw material for second generation of biofuels production. This case study implements a design and process integration to compare several biorefinery topologies using the typical mass flow rate of residual biomass produced by the sugar industry (1200 ton per day). Based on evaluation of chemical composition of bagasse (cellulose, hemicellulose, and lignin) several process schemes for integral utilization of biomass were proposed. This paper is the first part of the study on the exergy, life cycle analysis (LCA) and economic analysis of sugarcane bagasse for sustainable biofuels production using Aspen Plus (TM) software. Part 1 presents the exergy and life cycle analysis developed while part 2 describes economic analysis and selection of an optimal configuration with minimal environmental impact, by means of the combined use of raw material and energy integration.