With regard to electrical energy sector, budgetary factors, power must be utilized as soon as possible once it is generated. Since storing large amounts of electrical energy is prohibitively expensive. Consequently, as energy storage substance have become mostly accessible, evenly distributed production is becoming more workable, especially with the Smart Grid concept. Distributed ESS (Energy Storage Systems) are gaining popularity. There is a diverse category of ESS namely, battery, thermal, mechanical, hydrogen and so on. But this paper investigates about the techniques used in Battery energy systems by several researchers to stabilize energy output and usage, these systems supplement variable renewable sources such as wind, tidal, and solar power.