Wind is one of the major and fast growing source of green energy in the world. However, it’s naturally variable and this reduces its percentage penetration in a power system because of costs associated with balancing reserves. One of the solution being proposed in the recent times is the use of battery energy storage systems (BESS). This is coupled by the fact that there has been continuous reduction in the cost of BESS which has been experienced recently. The objective of this research study is to find optimal BESS location for minimum total cost of power generation in a power system with wind power generation and branch flow power limits. The study used the IEEE 30 bus system. Simulations were done using MATPOWER. Particle swam optimization technique was used to determine optimal BESS location. Results show that bus number 24 was BESS optimal location for several wind location buses.