Brazil outlines methodology to steer contracted battery storage toward grid-weak regions ahead of capacity-reserve auction
Source：ess-news
Brazil’s Energy Research Office (EPE) has introduced a methodology to guide where battery energy storage systems should be installed in the capacity-reserve auction. The aim is to direct contracted projects toward weaker points of the National Interconnected System, where storage can improve robustness, support voltage stability, and provide dependable capacity.
The technical note, now under public consultation until December 1, proposes a locational criterion focused on nodes with lower electrical strength. EPE argues that targeting these areas should reduce inefficient investments and avoid future regret as the grid evolves. A final list of priority locations will be published with the completed auction design, and projects connecting at those points will receive a bonus.
Early emphasis on the Northeast and northern Minas
Preliminary testing shows strong overlap between the nodes identified by the method and areas already known for voltage-control challenges. These include regions where the system operator (ONS) is considering equipment such as synchronous condensers. EPE says this alignment supports the technical validity of the approach and indicates that batteries — particularly grid-forming systems — could help stabilise voltage, improve dynamic performance, and reduce the need for additional hardware.
Locational screening based on electrical robustness
Instead of a simple capacity threshold, the methodology evaluates how robust each grid node is when interacting with inverter-based resources such as solar and wind. Nodes are ranked statistically, allowing EPE to flag the least robust 10, 20, or 30 percent as Level 1 priority areas.
A second screening step tests these shortlisted nodes against dynamic stability criteria under multiple operating scenarios and contingencies. The analysis highlights locations with deeper voltage dips and slower recovery, which become the highest-value sites for storage.
The final output will be a map of regions where battery storage delivers the strongest system-level benefits. EPE expects that using this method in the auction process will produce storage projects that add flexibility, strengthen voltage support, and prepare the grid for higher shares of renewable generation.