National Interconnected System: Isolated Systems

The isolated systems are located mainly in the States in the Northern region of Brazil (the region with the lowest population density), and are distributed across the interior of these States. These systems are characterized by a large number of small diesel generating units and by great difficulties in supply logistics.

The existence of isolated systems is explained by the continental dimensions of Brazil and the remote location of some towns, cities and regions in relation to major consumption centers, mainly in the Northern region. Their existence is also due to the goal of preserving the Amazon region. 

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• The National Interconnected System requires systemic coordination to ensure that the energy generated in the country will provide the consumer with a secure supply

The operation of isolated systems is coordinated by the Northern Region Technical Operations Group (GTON, acronym in Portuguese), who are responsible for planning and operational monitoring of Isolated Systems in the Northern region. The GTON is coordinated by Eletrobras and is composed of representatives from public and private companies who accompany monitoring, planning, expansion and operation to ensure the supply of electricity to consumers with adequate security and quality.

The principal isolated consumption centers are currently in the process of being integrated into the SIN, particularly those systems supplying the State capitals in the North. The integration of these systems is being undertaken over time.

In October 2009, the States of Acre and Rondônia were interconnected. This interconnection allows transmission of up to 210 MW, ensuring a reliable electricity service and greater security of supply for the two States. In addition, it provides a significant reduction in consumption of petroleum products used in the thermal power plants that used to supply regional demand.

It is planned to interconnect the Amazonas and Amapá systems by 2013, with the completion of the transmission line between Tucuruí-Macapá-Manaus, which is currently under construction. In 2014 it will be the turn of the State of Roraima, with the completion of the Manaus-Boa Vista transmission line, tendered in September of this year. This will signify that 99.6% of the Brazilian electricity market will be connected via a single system. The Ten-Year Expansion Plan (PDE 2011-2020) prepared by EPE shows a significant drop in isolated systems. However, some of the generating units on these systems will remain in place for operation in emergencies.

Sources:
National Electric Energy Agency (Aneel)
National System Operator (ONS)
Energy Research Company (EPE)