Energy-aware scheduling for improving manufacturing process sustainability: a mathematical model for flexible flow shops

Energy-aware scheduling (EAS) of manufacturing processes demands a mathematical model to optimally plan energy saving for a given schedule. The proposed approach starts from a reference schedule generated by an Advanced Planning & Scheduling (APS) system which does not consider energy saving. The new approach relies on a Mixed Integer Programming (MIP) model where the reference schedule is modified to account for energy consumption without changing the jobs' assignment and sequencing provided by the reference schedule. The applicability of the approach has been validated through a test case; the results obtained using one commercial MIP solver and an original MIP-heuristic are discussed.