Optimal Sizing of Battery Energy Storage Systems in Grid-Connected Power Systems

This paper presents a novel methodology for optimal sizing of multiple Battery Energy Storage Systems (BESS) in grid-connected Hybrid Generation Systems (HGS), focusing on centralized dispatch of wind and photovoltaic sources. Using Particle Swarm Optimization (PSO), the study evaluates key reliability indicators, such as dispatch expectations, curtailment reduction, and grid impact, to determine the optimal BESS size. Climatological data from Brazil and load profiles from the Brazilian Northeast system are utilized to assess the BESS impact on the grid. Applied to two configurations on the IEEE 14-bus test grid, the methodology identifies optimal BESS capacities of ${3 3 . 3 3}$ MWh for Site A and 19.47 MWh for Site B, achieving reductions of $8.15 \%$ in system inflexibility, ${9 . 0 9 \%}$ in curtailment potential, and ${8 . 3 4 \%}$ in slack-bus import fluctuations.