This book constitutes the thoroughly refereed post-conference proceedings of the Second International Workshop on Energy Efficient Data Centers, E²DC 2013, held in Berkeley, CA, USA, in May 2013; co-located with SIGCOMM e-Energy 2013. The 8 revised full papers presented were carefully reviewed and selected from numerous submissions. The papers are organized in topical sections on energy and workload measurement; energy management; simulators and control.