This paper looking the peculiarities of the Brazilian Electrical System, like the country's continental extension and the strong dependence on renewable energy (hydroelectric), discusses growth options according to the country's demands. It is done making reference to the world trends in diversified sources of power generation, priority of using native resources and environmental sustainability. Electrical energy demand in Brazil is increasing more than 4% a year. This number represents the necessity of an expansion higher than four thousand Megawatts of new energy per year in the system. The Brazilian Electrical System is peculiar because of the country's continental extension and also its strong dependence on renewable energy (hydroelectric). Another reason for its peculiarity is the potential of inserting other forms of renewable and 'green' energy in the system. Despite of the environmental advantages of the 'renewable sources', these kinds of energies are variable and depend of the weather conditions. In order to the electrical system be more reliable, its operation must be combined with a larger addition of thermal energy. Thus, this paper analyzes the options for thermal power generation in Brazil. From this perspective, issues like the required modulation with thermal use are addressed. The need for implementing modern technologies to attend the environmental legislation, and the required updating in the legislation, are also discussed.