The Brazilian National Interconnected System (SIN) is a large scale hydrothermal system with a strong predominance of hydro generation, characterized by large reservoirs with multi-annual regularization capabilities. However, with the prospect of entry in operation in the Amazon region of new large plants with high generation capacity but low inflows regularization capacity, methodological changes in the energy planning operations are expected due to Amazon’s region strong seasonal cycle and low complementarity with other regions of Brazil. This way, the current methodology, which minimizes the expected value of the total operations cost, tends to raise the risk of the drawdown of the Southeast subsystem reservoirs reaching low levels at the end of the dry season, with the assumption that the reservoirs, on average, will be recovered by the energy imported from Amazon during the wet season. The low drawdown of Southeast subsystem reservoirs can pose a risk for dry scenarios, which may not be able to meet the energy demand. In this context, this work proposes the development of a model using multicriteria decision support methods, which allows consideration of multiple objectives, to define the minimum level of storage of the Southeast subsystem at the end of the dry season to minimize the expected value of cost, provided that it guarantees the energy security of the SIN during the next year. The performance of the proposed methodology has been evaluated by means of case studies applied to SIN, for both the current conditions and the expected future conditions. The results obtained, as well as the advantages observed when using the multicriteria methodology, are discussed throughout the text.