Correlation Between Precipitation Index and Energy Generation in Hydroelectric Plants

A recent water crisis that befell over several states in Brazil negatively affected hydroelectric plants energy production once rainfall regime exerts a major influence in predominantly hydraulic power systems. This paper analyses the correlation between power generation and data collected from tributary flow, reservoir level, standardized precipitation index (SPI) on hydroelectric plants located in the Sao Francisco river basin. The analysis is performed by Pearsons Coefficient of Correlation, for a period of 28 years that includes the dry season, and for the dry season separately. The results showed weak and moderate correlation coefficients between SPI and generation for both analyzed periods with slightly higher correlations in the last years when a decrease in power generation is observed. The correlations found between the affluent flow, reservoir level, and the generation were influenced by the reservoir characteristics, and were slightly higher than those of the dry periods.