The EPA is involved and has announced Energy Star Data Center numbers. It will require a severe level of analysis to get your data center Energy Star-compliant.
Following a discussion with DOE, EPA is adjusting its timeline with the intention of finalizing the Draft 2 Version 1.0 ENERGY STARĀ® Specification for Uninterruptible Power Supplies (UPS) before the end of 2011.
I strongly disagree EUE is a better metric than PUE. There are many variables outside a data center’s control that make EUE impractical. First, power generation efficiency is dependent on weather conditions, type of fuel, maintenance and operation styles, site environmental controls, to mention a few factors.