Customer-side electricity load management for sustainable manufacturing systems utilizing combined heat and power generation system

Customer-side electricity load management can effectively improve the reliability of electricity grid and reduce the cost of electricity for customers. Combined heat and power (CHP) generation systems have been considered a promising method to implement electricity load management and have been widely applied in commercial and residential building sectors. Recently, the benefit of CHP application in electricity load management in industrial sector has also been gradually recognized. On-site generated electricity by a CHP system can be utilized to support the operation of industrial equipment and thus the cost of electricity purchased from the grid can be reduced. In this paper, we focus on the utilization of CHP in electricity load management for industrial manufacturing systems to examine the benefits regarding cost savings for the manufacturers. The optimal schedule for both the manufacturing and the CHP systems under a Time-of-Use (TOU) electricity tariff can be identified by minimizing the electricity billing cost and CHP operation cost under the constraint of production throughput. Mixed-Integer Nonlinear Programming (MINLP) formulation is developed to model this scheduling problem mathematically. Particle Swarm Optimization (PSO) is used to find a near optimal solution for the problem with a reasonable computational cost. A numerical case study is used to illustrate the effectiveness of the proposed method.