Dispatching Rules in a Job Shop: The Case of Dynamic Scheduling under Time-of-use Electricity Costs

In many regions of the world, energy providers attempt to smooth energy demand during the day by employing time-of-use tariffs. This study considers dispatching rules for scheduling operations in a multi-machine job shop that operates under time-of-use tariffs, with dual performance objectives of minimizing the mean tardiness of completed jobs, as well as total energy cost. A number of new dispatching rules designed for the energy objectives are tested alongside other traditional dispatching rules on test problem instances. Results show that the new energy-oriented rules tend to perform better in balancing satisfaction of the two conflicting objectives, in comparison to rules such as the shortest processing time (SPT) and cost-over-time (COVERT), which generally exhibit good performance for mean tardiness in job shop environments.