Energy efficient scheduling problems under Time-Of-Use tariffs with different energy consumption of the jobs

This paper deals with single machine scheduling problems, where the machine may be in processing, idle or off state. The machine consumes a different amount of energy in function of its state. Moreover, during processing (ON state), the energy consumption depends on the job. The complexity of these problems, when the jobs' sequence is fix, for the uniform-speed problem and the speed-scalable problem are analyzed. For this purpose, a dynamic programming approach is proposed to solve these problems by using a finite graph. The results demonstrate that the uniform-speed problem is polynomial of degree 3, and its speed-scalable case is pseudo polynomial. (C) 2018, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.