A Generalized Approach for Commercial and Industrial Load Shifting Control

Load shifting is one means whereby buildings may reduce their peak demand and provide other services to the electric grid. Current rate tariffs penalize facility peak demand, and large commercial and industrial buildings may realize cost savings by reducing this facility peak demand. The successful shifting of electric load requires some knowledge or prediction of the peak demand. This prediction is generally imperfect, and the resulting load shifting control is sub-optimal. This paper develops the optimal load shifting operations using a battery energy storage system under certain assumptions. This optimal solution is then used to develop a generalized strategy for load shifting battery control with the purpose of reducing peak 15-minute demand. This generalized strategy involves a prediction of the target demand level and a prediction of the current 15 minute period. The method whereby these predictions are made is critical to the success of load shifting. The general control logic may be used to analyze the sensitivity of load shifting to prediction error and sampling rate..