“Just-For-Peak” Buffer Inventory for Peak Electricity Demand Reduction of Manufacturing Systems

The reduction of the electricity demand during peak periods is considered as an effective tool for load management to relieve the financial pressure of the investment on the capability expansion for the grid in the U.S. Compared to a great deal of research in the commercial and residential sectors, little work on the electricity demand reduction during peak periods for industrial manufacturing systems has been conducted due to the concern of the system throughput variation and the complexity of modern manufacturing systems. This thesis presents a novel “Just-for-Peak” buffer inventory methodology to reduce the power demand during peak periods for typical manufacturing systems with multiple machines and buffers. The basic idea is to build up the “Just-for-Peak” buffer inventory during off-peak periods and thus the corresponding machines can be turned off during peak periods by using the accumulated “Just-for-Peak” buffer inventory. Firstly, the model under the constraint of system throughput is developed using Nonlinear Integer Programming (NIP) for the mathematical formulation. The optimal building policy and control action are identified to minimize the holding cost of the “Just-for-Peak” buffer inventory and energy consumption cost under the system throughput constraint. Next, the system throughput constraint relaxed model is formulated with the objective function to minimize the holding cost of the “Just-for-Peak” buffer inventory, the energy consumption cost and the production shortage cost throughout the production horizon. The numerical case study based on the same section of an auto assembly line is developed for both models to illustrate the effectiveness of the methods