In this chapter, the role of decentralized energy storage in residential feeders with Photovoltaic (PV) is addressed. The increasing penetration of PV power generation is more and more contributing on relieving the overall loading of (low voltage) LV distribution grids by increasing the rate of local generation and consumption of houses and larger buildings. However, LV grids have been originally designed to accommodate unidirectional power flow from the distribution grid to the consumers. With high PV generation, the power flow may invert its direction going from downstream towards the medium voltage grid. Under such conditions, events of overvoltage may occur, posing new challenges to distribution system operators. Decentralized battery based energy storage can prevent such events by storing the surplus of energy which is locally generated.