New continuous-time scheduling formulation for continuous plants under variable electricity cost

Research output: Contribution to journalArticleScientificpeer-review


Research units

  • ABB Group
  • Carnegie Mellon University


This work addresses the scheduling of continuous plants subject to energy constraints related to time-dependent electricity pricing and availability. Discrete-and continuous-time formulations are presented that can address these issues together with multiple intermediate due dates. Both formulations rely on the resource-task network process representation. Their computational performance is compared for the objective of total electricity minimization with the results favoring the discrete-time model due to the more natural way of handling such a wide variety of discrete events. In particular, it can successfully handle problems of industrial size. Nevertheless, the new continuous-time model is a major breakthrough since it is the first model of its type that is able to effectively incorporate time-variable utility profiles. When compared to a simple manual scheduling procedure, the proposed scheduling approaches can lead to potential electricity savings around 20% by switching production from periods of high to low electricity cost.


Original languageEnglish
Pages (from-to)6701-6714
Number of pages14
JournalIndustrial and Engineering Chemistry Research
Issue number14
Publication statusPublished - 15 Jul 2009
MoE publication typeA1 Journal article-refereed

    Research areas

  • continuous time models, discrete-time model, energy constraint, Resource-task network, scheduling

ID: 6321908