ASSESSMENT OF THE LOSS OF USEFUL VOLUME AND THE PHYSICAL GUARANTEE OF HYDROELECTRIC DEVELOPMENTS LOCATED ON THE PARAÍBA DO SUL RIVER

Abstract

This study evaluated the reduction in usable volume due to sedimentation and its implications for the physical guarantee of hydropower plants' reservoirs located in the Paraíba do Sul River. The analysis was based on a comparison between the design elevation, area, and volume curves and the updated curves from the plants of Paraibuna, Santa Branca, Funil, Simplício/Anta, and Ilha dos Pombos. Data were obtained from the National Water and Basic Sanitation Agency, the National System Operator, the concessionaires, and the National Electric Energy Agency. The results indicated reductions in usable volume ranging from 0.18% (Paraibuna) to 10% (Ilha dos Pombos). As the decrease in reservoir storage capacity is reflected in the reduction of regulated flow and indirect benefits, it was assumed that the losses in the physical guarantees of the projects correspond to the percentage reduction in usable volume. The results for physical guarantee were 44.39 MW average (Paraibuna), 28.61 MW average (Santa Branca), and 108.5 MW average (Funil). It is concluded that the periodic updating of the Elevation x Area x Volume curves is essential for the operation of the reservoirs and for guaranteeing the production of hydroelectric power in the National Interconnected System.