The expansion of the Brazilian energy supply from fossil sources prompted environmental concerns about the emission of Green House Gases (GHG). Furthermore, the Brazilian government was committed to the United Nations Framework Convention on Climate Change (UNFCCC) to reduce GHG emissions by 43% by 2030, compared to 2005. The aim of this study was to design the Brazilian electricity mix for 2030, while taking into account economic, technical and environmental criteria. In order to get this, Linear Programming optimization has been applied to obtain an electricity matrix with minimum cost of the Brazilian electricity generation system, considering GHG emission constraints – defined via the Life Cycle Assessment (LCA) technique –, as well as capacity generation and supply needs. In addition, LCA was also applied to obtain the environmental performance of the projected scenario and results were compared with those of 2005 and 2015. The analysis depicted that renewable sources represent 88% of the projected Brazilian electricity production in 2030, mainly hydropower, which accounts for 66%. In terms of Climate Change there is an impact reduction of 12% compared to 2005, while other categories such as Ionized Radiation and Terrestrial Ecotoxicity doubled and upped more than forty times. These findings led to conclude that environmental management should not be limited to GHG analysis, and must encompass other adverse effects. Moreover, this reinforces the importance of conducting analyses such as those provided by the LCA approach and include these results in the planning and decision-making processes of the energy sector.