Brazil took a decisive step toward modernizing its electricity sector by approving the regulatory framework that enables the first battery energy storage (BESS) auctions. The new regulation, built over 18 months of public consultations, defines technical criteria for storage systems' participation in capacity auctions. International investors are already mobilizing, drawn by the size of the Brazilian market and the complementarity with solar and wind sources. Storage solves one of the main bottlenecks of the renewable mix: the lack of dispatchability. With batteries, daytime energy can be shifted to the evening peak. However, sector sources warn of regulatory risks still to be addressed. The main one is the absence of a long-term contracting mechanism specific to storage. Chile's experience, which already held auctions with 15-year contracts, serves as a reference.