Optimizing hybrid systems and energy storage: Self-sufficiency and economic viability under metering policy changes

This study optimizes the economic viability and energy autonomy of hybrid systems (photovoltaic and wind energy) with battery storage considering regulatory provisions. A multi-objective optimization model is proposed using two objective functions, Net Present Value and Self-Sufficiency, modeled using the Response Surface Methodology (RSM). The Normal Boundary Intersection (NBI) method is used for multi-objective optimization. The methodology is applied to the Brazilian context, incorporating Law 14,300/2022 and current tariff structures, and tested across cities in all geographic regions, offering a tangible and broadly relevant case. The main contribution lies in combining RSM and NBI to analyze residential hybrid systems with batteries from a regulatory perspective. Key results indicate that changes in net metering rules do not make investments unfeasible, especially for photovoltaic energy. However, part of the energy distribution costs paid by prosumers - related to the so-called "B Wire" component (grid infrastructure usage fees), cannot be offset and can only be avoided by reducing power injection into the grid, achievable with batteries. Furthermore, the savings from this reduction are insufficient to make the battery use economically feasible under current conditions. The results highlight the need for region-specific policies to harness distributed generation potential, particularly in areas with wind resources, which can increase the Self-Sufficiency level and address reverse power flow issues. Finally, the best residential tariff model is assessed, with most cities favoring the conventional tariff from an economic standpoint. This suggests the need for a tariff model review to achieve positive technical, financial, and environmental impacts.