Energy and economic study of the increased energy production of cascaded hydroelectric plants due to the heightening of the upstream reservoir: A case study in Cipó-Rio das Antas dam

Abstract

Increased hydroelectric reserve capacity through cascade heightening is one option for increasing its overall output. Such increases are relevant to the circumstances faced by the Brazilian energy matrix, which is heavily dependent on hydroelectric dams and where many environmental restrictions may slow the construction of new dams. Thus, this article studies the increase in storage volume in a Brazilian dam and evaluates the gains in terms of electricity generation and water flow on downstream dams. A dam located on the Antas River, in Brazil, was chosen as the study area. Flow regulation capacity from the increased height was determined through multiple hydrological methods which enabled the estimation of energy gains on downstream dams. The results obtained demonstrate that, by increasing the dam height by 1 m to the upstream structure, there would be a regularized flow of 2.47 m3/s along with an increase in energy production of 3.34 GWh/y throughout the entire downstream cascade. Investments of 500,000 USD would be necessary to add an additional meter to the dam construction height, which would be paid off over a period of five years with the increase in energy production. The methodology herein presented can be replicated in other regions, thus aiding in greater efficiency and operation of hydroelectric power plants.