The aim of this research has been to identify the most sustainable options forelectricity production in Mexico with an outlook to 2050. An integrated methodologyfor sustainability assessment of different electricity technologies and scenarios has beendeveloped, taking into account environmental, economic and social aspects. Theenvironmental impacts have been estimated using life cycle assessment; the economiccosts considered include total capital and annualised costs while social aspects includesecurity and diversity of energy supply, public acceptability, health and safety impactsand intergenerational issues. To help identify the most sustainable options, multi-criteriadecision analysis has been used.The methodology has been applied to Mexican conditions for the assessment ofboth current and future electricity production. The results for the current situation showthat on a life cycle basis 129 million tonnes of CO2 eq. are emitted annually from 225TWh of electricity generated in Mexico. Heavy fuel oil, gas and coal power plantscontribute together to 87% of CO2 eq. emissions. Total annualised costs are estimated atUS$ 22.4 billion/yr with the fuel costs contributing 54%, mainly due to the operation ofgas and heavy fuel oil power plants.A range of future scenarios up to 2050 has been developed in an attempt toidentify the most sustainable options. The development of the scenarios has been drivenand informed by the national greenhouse gas emission reduction target of 50% by 2050on the 2000 levels, translating to an 85% reduction from the power sector. The resultsshow that the business as usual (BAU) scenario (with the highest contribution fromfossil fuels) is the least sustainable option with the CO2 eq. emissions increasing byalmost 300% for a projected electricity demand of 813 TWh in 2050.Overall, the most sustainable scenarios are those with higher penetration ofrenewable energies (wind, solar and hydro) and nuclear power, as in Green, A-3 and C-3. For example, compared to the BAU scenarios, the CO2 eq. emissions reduce by 84%,89% and 89%, respectively. Although renewable energy based scenarios require highcapital costs, the total annualised costs even out over time due to lower fuel costs. Thelowest annualised costs are for C-3 and A-3 scenarios, representing a 40% reduction onBAU which is by far the most expensive option.With respect to social issues, the BAU scenario is also the least preferred optionwith the highest risks related to security and diversity of supply, health and safety andclimate change. The most sustainable options are scenarios A-3 and Green, with socialbarriers related to public acceptability, reliability of supply and availability of energyresource. Most critical aspects for scenario C-3 are health and safety risks, andintergenerational issues related to nuclear power. In the case of the energy policy driverfocusing on climate change mitigation and annualised costs, scenarios A-3 and C-3 arethe most sustainable options.. Therefore, the Mexican Government should aim tostrengthen the current low carbon energy policies as well as put measures in place toencourage reducing the electricity demand.