Evaluating the possible impact on power system of a large number of electric vehicles (EVs) is becoming of great interest. With the development of V2G technology, electric vehicles constitute a significant power reserve. In addition, batteries in electric vehicles may be used to provide storage capability for energy produced by renewable sources and to supply auxiliary services to the grid. The paper presents the preliminary results of an on-going project aimed at evaluating the impact of electric vehicles on power system. The simulation results shows significant benefits of V2G on the daily load profiles and network planning. Hypotheses such as battery size, number of users, load profiles without and with different EV penetration are presented for successive scenarios set-up and simulations.