Optimal integration of alternative energy sources in production systems with customer demand forecast

The objective of this paper is to develop an optimal planning framework for a production system utilizing multisource distributed energy supplies, in order to improve its energy efficiency and to reduce the dependency on grid energy and outage risk. The energy consumption of an automotive seat assembly plant is modeled using a discrete-event simulation, which consumes energy supplied by wind and solar, as well as traditional power grids. Machines can be halted for designed time period to avoid high peak load and operate efficiently in terms of power consumption. On the other hand, the inventory level can be planned by adjusting production goal to better utilize alternative energy and accommodate demand uncertainty using stochastic programming method. The results from case studies show that optimizing waiting time for each process can effectively reduce outage risk while meeting customer demands. Having the optimal production goal to over-produce when alternative energy supply is high can reduce the dependency on grid energy. Also, the benefit of considering predicted future customer demands would have the effect of safety inventory, which can prevent shortages during extremely high customer demand periods.