Grid-connected battery energy storage systems (BESS) are essential for improving the transient dynamics of the power grid. There is ongoing research about how BESS integration with renewable energy sources can improve renewable energy deployment in the grid. However, the economic feasibility of BESS is a practical limitation of their integration into power systems. BESS costs include both the start-up costs of building the system and the operating costs. Optimizing the operation of the BESS to maximize operating profit would make the BESS more economically feasible to power system operators, and lead to smoother integration of BESS. This manuscript overviews a program tool that analyses grid connected BESS in real world situations and optimizes the operation of the battery system. Through the use of this tool, a better understanding of the economic feasibility of BESS is achieved.