A system and method provide emergency back-up power for communications, security and other systems of an electric power consumer, and for peak-shifting of the electrical load so that electricity is generated and stored when demand is low, and the stored power is used when demand is high. Embodiments include providing an electric power management device having a battery and a communication system at the premises of a consumer of electricity, and connecting the power management device to an electric power provider. The battery is charged at an off-peak time when a demand for electricity is low, as determined by the electric power provider; and discharged to provide electricity to the consumer at a time when the demand for electricity is high, as determined by the electric power provider. The charging and discharging is controlled by the electric power provider.