A multi-area approach to evaluate the Brazilian power system capacity to supply the peak load demand using detailed simulation model of power plants operation

In hydro dominated systems, such is the Brazilian system, the evaluation of the adequacy of the generating system to supply the maximum power demand (peak load) should consider the variation of the output capacity of the hydropower plants with respect to the inflows to the reservoirs, which are also random. This parameter, referred as "available power" depends on the volume of water stored in the hydro plant reservoir and the inflow scenarios. Currently, the available power of each hydro plant in the Brazilian system is calculated by an approximated approach which extrapolates the percentage of water volume stored in the equivalent reservoirs to the reservoir of each hydro plant. This paper analyses the impact of using a methodology based on an individualized model, which represents the detailed operation of hydro plants considering the optimum policy calculated for the aggregated system, to calculate the available power of hydropower plants; thus, parameters such as the water head and the stored volume of the reservoirs are considered individually for each hydro plant. This methodology to estimate the available power is then used in a multi-area approach to evaluate the capacity of the generation system to supply the peak load. The system interconnected operation was performed by an optimization model that minimizes the total power deficit of the whole system (risk sharing approach). In order to assess the impact of the optimized interconnected operation, two other criteria were analyzed: minimization of the power deficit of the subsystem with the highest power deficit in absolute terms, and minimization of the power deficit of the subsystem with the highest power deficit in terms of percentage of its maximum power demand. The proposed methodology is applied to the configuration of the Brazilian Ten-Year Energy Expansion Plan 2020.