1. A process comprising: tracking U i (t) for each of N virtual-machine guests VMG i , where U i (t) corresponds to utilization over time of a pre-migration host by an ith virtual-machine guest prior to migration to a target host, where i is an index ranging from 1 to N, and t is time; projecting U i ′(t) for each VMG i based at least in part on U i (t), where U i ′(t) is a projected utilization over time by VMG i of the respective pre-migration host; projecting U i ″(t) for each VMG i , based at least in part on U i (t), where U i ″(t) is a projected utilization over time by VMG i of the target host, each U i ″(t) having a respective peak value V i ; calculating U T ″(t) at least in part by combining U i ″(t) over i, where U T ″(t) is a projected utilization over time of the target host, U T ″(t) having a peak value V T , the calculating being such that the sum of the peak values V i is greater than the peak value V T of the sum; and projecting P″(t) based at least in part on U T ″(t), where P″(t) is a projected power consumption for the target host for a scenario in which all VMG i are hosted by the target host.