Partitioning a memory into multiple banks that can be independently accessed is an approach mainly used for the reduction of the dynamic energy consumption. When leakage energy comes into play as well, the idle memory banks must be put in a low-leakage `dormant' state to save static energy when not accessed. The energy savings must be large enough to compensate the energy overhead spent by changing the bank status from active to dormant, then back to active again. This paper addresses the problem of energy-aware on-chip memory banking, taking into account - during the exploration of the search space - the idleness time intervals of the data mapped into the memory banks. As on-chip storage, we target scratch-pad memories (SPMs) since they are commonly used in embedded systems as an alternative to caches. The proposed approach proved to be computationally fast and very efficient when tested for several data-intensive applications, whose behavioral specifications contain multidimensional arrays as main data structures.