The energetic transition of the electric generation to the low carbon emission sources is a primary objective to the attenuation of the damages caused to the environment. Variable Renewable Energy (VRE) sources such as wind and solar come out as the main targets of investments around the globe. The electricity market also goes through transformations in the characterization of consumption, as the insertion of the Distributed Energy Resources (DER), namely, Distributed Generation (DG), Load Response (LR) and Battery Energy Storage Systems (BESS). Aiming to reduce insufficiency risks of VRE generation and take advantage of arbitrary pricing, there is vast interest in the insertion of BESS on many voltage levels. In transmission, it could help on the improvement of reliability indexes and reduce the waste of non-dispatched energy by big VRE centers. In medium and low voltage (distribution companies), it could reduce the necessity of contracting the amount of transmission system usage and for arbitrary pricing. It is proposed, in this Undergraduate Final Project, to do a technological state of art survey of BESS, its main applications and prospective, the regulatory scenario in Brazil and the general challenges for its wide short-medium term implementation on the electric sector.