  Data center operators are typically faced with three significant problems
when running their data centers, i.e., rising electricity bills, growing carbon
footprints and unexpected power outages. To mitigate these issues, running data
centers in microgrids is a good choice since microgrids can enhance the energy
efficiency, sustainability and reliability of electrical services. Thus, in
this paper, we investigate the problem of energy management for multiple data
center microgrids. Specifically, we intend to minimize the long-term
operational cost of data center microgrids by taking into account the
uncertainties in electricity prices, renewable outputs and data center
workloads. We first formulate a stochastic programming problem with the
considerations of many factors, e.g., providing heterogeneous service delay
guarantees for batch workloads, interactive workload allocation, batch workload
shedding, electricity buying/selling, battery charging/discharging efficiency,
and the ramping constraints of backup generators. Then, we design a realtime
and distributed algorithm for the formulated problem based on Lyapunov
optimization technique and a variant of alternating direction method of
multipliers (ADMM). Moreover, the performance guarantees provided by the
proposed algorithm are analyzed. Extensive simulation results indicate the
effectiveness of the proposed algorithm in operational cost reduction for data
center microgrids.
