A Stochastic Optimization Approach to Reschedule Productions Steps According to Volatile Energy Price

Manufacturing systems are one of the main consumers of electrical energy worldwide. Meeting this demand, an increasing percentage is generated by fluctuating renewable resources. Time-dependent renewable power generation and inaccurate prediction can cause volatile energy prices. Managing of energy demand affects not only the profitability but has also a positive effect on the CO2-emissions. Taking into account the degrees of freedom coming from the adaptation of electrical energy demand to volatile prices, various operations in production lines can become more profitable. This requires rescheduling of production operation based on order situation, volatile energy prices and electrical energy demand. A stochastic optimization approach for rescheduling of production systems with variable processing times has been developed and implemented as a software prototype. The optimization approach is validated for milling, drilling and turning machines as a part of a production line to shift load to off-peak hours when electricity prices have been reduced.