In this paper, an Energy Management System (EMS) that manages a Battery Energy Storage System (BESS) is implemented. It performs peak shaving of a local load and provides frequency regulation services using Frequency Containment Reserve (FCR-N) in the Swedish reserve market. The EMS optimizes the approach of BESS resource dispatch distribution between two ancillary services, such that it maximizes profits and resource efficiency while enhancing overall system reliability of the electricity grid. The EMS consists of; a Prognosis Module running a day ahead to allow for identification of intervals for peak shaving and frequency regulation, and a Real-time Operation Module running on the day of operation creating BESS control commands. Implementing the Prognosis module on Öckerö ice-rink results in 12% cost saving on the grid tariff with 21% power peak reduction and three hours of daily frequency reserve. Multiple such systems can be aggregated to improve flexibility of the system.