Peak Power Demand Analysis by Using Battery Buffers for Monotonic Controllers

Demand of electricity varies on hourly basis whereas the production is quite inelastic. This results in heavy fluctuation in the price of the electrical energy. Consequently many power companies have started offering time based tariffs. Data centers and industrial consumers of electricity are penalized for the peak power demand of their loads. To shave the peak power demand, a battery buffer can be adopted. The battery is charged during low load and is discharged during peak loads. One essential question is to analyze the reduction of the peak power demand by adopting battery buffers. The power loads are modeled in this paper by adopting the concept of arrival curves in Network Calculus. We analyze monotonic controllers, which have these two properties: (1) comparing one given trace of power loads and two initial battery statuses, if we start from higher battery status, the resulting battery status in the future will not become lower; (2) to increase the power demand at time slot t, the power loads released before t should be as close as possible to t. We present a simple and effective monotonic controller and also provide analyses for the peak power demand to the power grid. Our analysis mechanism can help determine the appropriate battery size for a given load arrival curve to reduce the peak.