Ethanol is consolidated as fuel to drive light vehicles in Brazil, but for the past 40 years, only the cultivation of sugarcane has been commercially exploited for the production of this fuel. On the other hand, agricultural development has provided high yields of grain in recent decades. Corn production is distinguished by increased productivity, and can be sown as main crop or as a winter crop in rotation with soybeans. Sorghum, in turn, has a higher roughness and tolerance to drought and can act as a substitute for corn. Given this situation, ethanol plants in Mato Grosso were associated with corn and sorghum producers to include new raw materials in the fuel production process, sharing the same plant, called Integrated Plant or Plant Flex. However, the development of new technology and production sectors requires consideration of its potential energy and environmental implications. The Life Cycle Assessment (LCA) is management tool used to evaluate potential environmental impacts associated with products, processes and services. Its main feature is to provide such an assessment in a systematic way, taking into account all stages of their life cycle. The objective of this study was to evaluate and compare the environmental and energy performance of ethanol production from sugarcane, corn and sorghum in the context of integrated autonomous plant, according to the life cycle approach. For that, LCA studies were conducted for each of the three products, following the guidelines of the standards ISO 14040: 2009 and ISO 14044: 2009. For environmental analysis the method of Life Cycle Impact Assessment (LCIA) Recipe midpoint was applied and for energy analysis Cumulative Energy Demand method was used, followed by the estimate of the Energy Return On Investment (EROI) for each fuel. The functional unit of the studies was 1 m³ of hydrous ethanol and the product system includes the production inputs, production of agricultural raw material, production of ethanol, cogeneration and transport stages. The results of the environmental analysis showed that the ethanol sugarcane performs better than the ethanol maize and sorghum in a greater number of impact categories. Energy analyzes have shown that the use of wood chips in cogeneration stage of corn ethanol production processes and sorghum has resulted in energy savings, but the ethanol sugarcane still performs better by using bagasse for cogeneration. In terms of EROI, the sugarcane ethanol provided 9.77 units of energy for every unit consumed, corn ethanol provided 2.68 and sorghum ethanol provided 3.10.