As the wireless industry evolves towards heterogeneous networks, mobile terminals have been given the ability to handover from one network to another. The network selection process starts by a network discovery operation which involves scanning the candidate networks in order to collect the required information for handover decision. Such operation consumes a considerable amount of energy at the terminal-end and yet the mobile terminal battery is limited. In this paper we propose a battery-aware scanning mechanism in which the number of scanned networks is dependent on the battery level at the terminal-end. Simulation results show an improvement of the terminal performance in terms of energy consumption and energy efficiency compared to the conventional approach where all the networks are scanned periodically.