Joint Workload Scheduling in Geo-Distributed Data Centers Considering UPS Power Losses

Abstract

Recent years have witnessed the rapid growth in the electricity consumption of internet data centers (IDC) and consequently their high operational cost. Fortunately, geo-distributed multiple data centers could be jointly optimized to reduce the total operational cost using the flexible computational workload scheduling in terms of local electricity price and power consumption level of data center facilities, where in particular the power losses of uninterruptible power supply (UPS) contribute to around 5%. However, the nonlinear characteristics of UPS depending on load ratio have not been fully considered in the joint operation of multiple data centers. In view of this, this paper proposed a new joint workload scheduling method by carefully regulating the UPS power losses within multiple geo-distributed data centers. To precisely formulate the optimization problem, a comprehensive model of multiple geo-distributed data centers is built by considering local electricity price, renewable generation, conventional generator units, energy storage system (ESS), scheduling flexibility of different types of computational workload and especially the characteristics of UPSs. Furthermore, to guarantee the feasibility of the joint workload scheduling method when the renewable power and electricity varies, a day-ahead and intraday scheduling method is proposed for the first time. In consequence, six cases are simulated and solved by the Gurobi software, whose results have illustrated that the proposed method can reduce the operational cost by up to 4.69% under different scenarios.