Life Cycle Assessments (LCAs) of thermoelectric plants frequently focus on impacts related to fuel and water consumption. The purpose of this research was to determine the environmental impact of the chemicals used for water conditioning in a Combined-Cycle Gas Turbine (CCGT) plant in Mexico. An LCA of the electricity generation process was carried out using the SimaPro software with the ReCiPe method, which includes 18 midpoint environmental impact categories. The process was broken down into stages, which were analyzed separately. To complete the study, an analysis of the fuel cycle and the materials used for maintenance works were included. Results showed that the most affected impact categories were water depletion (9.77 × 10⁻¹ m³/MWh), due mainly to the high volume of water consumption in the cooling systems and the reverse osmosis process; freshwater, marine, and terrestrial ecotoxicity (1.59 × 10⁻² kg 1,4 -DB eq/MWh), and human toxicity (1.1 × 10⁻¹ kg 1,4-DB eq/MWh)—due to the production and consumption of the chemicals used. One such chemical is hydrazine, which is a highly toxic compound to humans and other living organisms. It is worth mentioning that traces of some chemicals in wastewater discharges could be considered as emerging pollutants because of their potential health hazards, which have not been reported yet.

A comparative assessment of alternative expansion plans for the Mexican electricity generation system was made by applying the Position Vector of Minimum Regret Analysis as a decision tool. The expansion plans were ranked according to seven decision criteria which consider: internal cost, risk, diversity, external cost, foreign capital fraction, carbon-free fraction, and severe accidents. Electricity expansions were optimized by using the WASP-IV model; internal costs and externalities over a long-term planning horizon were simultaneously minimized when the external cost was added into the variable component of the operation and maintenance cost. Special attention was paid to studying the convenience of including nuclear power in the electricity expansion. The new decision analysis tool ranked the plans in terms of the minimum global regret, and results showed that the plans which added nuclear power plants were in general relatively more attractive than the plans that did not.