Multi-tier energy buffering management for IDCs with heterogeneous energy storage devices

Energy buffering, has been proposed to store renewable energy and low cost electricity in Energy Storage Devices (ESDs) and use it judiciously to reduce electricity bill in Internet data centers. Recent research have considered long term variation in electricity price, renewable power and workload and have shown the efficiency of energy buffering in reducing electricity bill. However, these aspects of data centers exhibit both long and short term variation. Further, there is inherent heterogeneity in ESD physical characteristics (e.g., charging and discharging rates). We hypothesize that a multi-tier energy buffering management can leverage the heterogeneity in ESD characteristics and better optimize utilization of renewable energy and low-cost power in presence of both short and long term variabilities in a data center. This paper proposes an analytical study of multi-tier workload and energy buffering management technique that frames each tier as an optimization problem and solves them in an online and proactive way using Receding Horizon Control (RHC). Our study shows that multi-tier energy buffering management increases the utilization of the renewables by upto two times compared to one-tier management.