Indicadores ambientais e socioeconômicos como critério para análise de vazões mínimas residuais de centrais hidrelétricas de derivação de fluxo: estudo de caso da PCH Inhapim - MG

Abstract

The establishment of the residual flow of flux derivation hydroelectric plants in operation constitutes an analysis to obtain the grant of the right to use water resources, and the operational relationship with the National System Operator (NSO) must be considered, according to procedures established by Joint Resolution SEMAD/IGAM n. 1,768, of November 30, 2012. However, in Minas Gerais, more than 80% of the hydroelectric power plants in operation do not have an operational relationship with the NSO, among these, those that fit the modality of adduction of flow by flux derivation. The objective of this study is to propose a methodology to evaluate, in the context of the administrative procedure for granting the right to use water resources, the minimum residual flow in the reduced flow stretch (RFS) of hydroelectric plants, in the form of abstraction in derivation, which does not have the operational conditions approved by the National Electric Energy Agency (NEEA) or by the NSO, in order to meet the requirements of Joint Resolution SEMAD/IGAM n. 1,768/2012. The methodology of the work contemplates the survey of the energy availability of the Small Hydroelectric Plant (SHP) Inhapim, when selected percentages of 30 and 50% of the reference flows (F7,10) in the RFS of this one, and in the elaboration and use of indicators environmental and socioeconomic that have correlation the Sustainable Development Goal (SDG) 7 of the 2030 Agenda to compare the scenarios of variable flows in the RFS of SHP Inhapim front of the hydraulic generator park of Minas Gerais and Brazil. The calculation of the energy availability of the SHP Inhapim also included the comparison between the flow adopted in the Study of Regionalization of Flow of the Rio Doce Basin (ANA/IGAM, 2022), as determined by Ordinance IGAM n. 32, of September 6, 2022, and the flow achieved by the method of regionalization of flows through the selection of the linear regression model of the reference flows of the fluviometric stations of the Caratinga river basin. The research results indicate that the increase in energy availability, due of the selection of percentages lower than 100% of the minimum reference flow in the RFS, allows potentializing expressively the positive impacts caused by the implantation of hydroelectric power plants of flux derivation for the reservoirs in the run-of-river mode of operation when compared to the mode of operation through flow regularization. This analysis also allowed the adoption of a comparative model to assist the decision-making process for the selection of technological arrangements that provide the fulfillment of the goals of SDG 7 of the 2030 Agenda, when not involving restrictions of ecological flows for the RFS.