Planejamento hidrotérmico de médio prazo com base em programação quadrática e trajetórias de referência: uma nova abordagem

Abstract

Since the beginning of the 21st century, the Brazilian electricity matrix has undergone significant transformations driven by increasing energy demand, the reduction in the regulation capacity of the Energy Equivalent Reservoirs (EERs), and the growing participation of intermittent renewable sources. In this context, reservoirs have become a strategic element, acting as a compensation mechanism against the variability of renewable generation. The storage capacity assumes a crucial role in ensuring energy security and preventing the sharp depletion of reservoirs, which would compromise the system’s resilience during critical periods. Given this scenario, the computational tools used in energy planning must continuously evolve to incorporate new operational strategies that ensure efficient operations and guarantee energy security. Thus, this work proposes a new approach for medium-term hydrothermal planning, focused on the operational and water security of plants with reservoirs. The developed methodology is presented as an upgrade to the NEWAVE model, which is based on Quadratic Programming with the introduction of seasonally adjusted Reference Trajectories to keep reservoir levels within operational ranges. Two types of Reference Trajectories were considered: Energy and Socio-environmental. The simulation results were compared to those of the NEWAVE model. Different penalties associated with the quadratic term of the Objective Function were also analysed to observe their effects on the solution. Additionally, simulations with multiple hydrological scenarios were conducted using all historical flow series from the NEWAVE model’s January 2024 deck. The study also explored the methodology’s application in the DECOMP model through two distinct approaches to incorporate the Reference Trajectories’ Lower Limits: generating linear cuts in the Future Cost Function and using Hydraulic Energy Constraints (HEC). To achieve the proposed objectives, the study considered the complete modelling of the National Interconnected System (SIN), encompassing all four subsystems with all their respective EERs, thermal plants, and interconnections. The results obtained were satisfactory and achieved the primary goal previously established: maintaining the EER storage levels above the Lower Limits of the Reference Trajectories. Moreover, the methodology demonstrated flexibility when applying different penalty values and considering various inflow scenarios. Finally, the approach was effective in coupling with the DECOMP model, guiding the EERs to levels close to or above those defined by the Reference Trajectories.