Abstract Shortage of fossil fuels and global oil crisis are leading many national energy authorities to switch from traditional fuels to other renewable ones. On the other hand, in several western countries – due to an increasing environmental awareness – public acceptance of traditional power plants (e.g., coal or fired oil) is steadily decreasing, mostly because of their significant environmental pressures. Decision makers’ activities need to be supported by objective tools, which must be designed to be able to select the best alternative in order to achieve some prefixed goals. Therefore, in the present study, a tool is proposed to support decision makers: it is based on Life Cycle Assessment data from seven different power plants (coal, fired oil, fired gas, nuclear, wind, solar and hydroelectric), to understand what is taken into in terms of material fluxes, and how much it costs in a specific context. Consequently, an Analytic Hierarchy Process has been proposed to select which one might be the best alternative in function of the considered scale and ten environmental criteria. The proposed procedure aims to evaluate different power plants and identify the most environmentally sustainable one in function of plant construction and operation phases.