The increasing of Renewable Energy Source (RES) generation requires power systems to become more flexible, in order to manage injections variability and uncertainty at various timeframes. Energy storage systems, such as electrochemical technologies, represent a broadly deployable asset, which could support effectively RES deployment. The present paper describes a Mixed Integer Linear-constrained Programming (MILP) model to simulate battery energy storage systems behavior within the Italian ancillary services market. The main purpose of the tool is to investigate the economic viability of storage technologies in the provision of network services.