The electric power sector is key to the country's social and economic development. As it is a sector of high importance and complexity, it is up to the government to regulate and plan the system, in order to ensure the feasibility and security of supply at the lowest social costs possible. In 2014, Brazil consumed 45.710 6 toe (ton of oil equivalent) of electricity, representing 18.3% of the total energy consumed in that year (Empresa de Pesquisa Energética, 2015). The electric power sector has monopoly characteristics in the transmission and distribution, and it also has a peculiar need of automatic control grid systems that allow one to obtain the balance between load and generation, that is, a constant and instantaneous balance between supply and demand, due to the fact that the cost of electric power storage is economically unfeasible. It is up to the Brazilian Electricity Regulatory Agency (ANEEL) to act as the regulator and it is up to the Brazilian Power System Operator (ONS) to control the operation (Law 9,648/98). The energy load forecast is a vital part for the operation, expansion and electric power system's reinforcement planning process. Described as the total energy generated by the Brazilian Interconnected Power Grid (SIN in the Portuguese acronym) power plants, the energy load considers all the energy required for supply, by the SIN, in the process of generating, transmitting and distributing electric power energy. The SIN is composed of the