This paper presents a series of operating schedules for Battery Energy Storage Companies (BESC)to provide peak shaving and spinning reserve services inthe electricity markets under increasing wind penetration.As individual market participants, BESC can bid in ancillary services markets in an Independent System Operator(ISO) and contribute towards frequency and voltage supportin the grid. Recent development in batteries technologiesand availability of the day-ahead spot market prices would make BESC economically feasible. Profit maximization of BESC is achieved by determining the optimumcapacity of Energy Storage Systems (ESS) required formeeting spinning reserve requirements as well as peak shaving. Historic spot market prices and frequency deviationsfrom Australia Energy Market Operator (AEMO) areused for numerical simulations and the economic benefitsof BESC is considered reflecting various aspects in Australia's National Electricity Markets (NEM).