Summary form only given. One of the foundations of the Smart Grid is the real-time information and data exchange between all of its components, facilitated by the extended application of smart metering and information technologies. Advanced control functions integrated with the complicated and slow-dynamic electricity grid, will necessitate the use of an electricity buffer in order to maintain balance and stability at all times. Owing to their relatively low footprint and flexible geographical placement, Battery Energy Storage Systems (BESS) will play the key role of providing the electricity buffer of the future smart grid. The challenge of BESS and their different technologies will be discussed in various scenarios of grid-related functionalities and roles. The development of BESS in Australia will be reviewed, identifying market potential and opportunities.