The Green Data Center Blog just found a report-out by the Microsoft Research community on "Auto-Shift", essentially energy-aware server provisioning. Hmm... this sounds familiar.
To me, the report further validates the "server power management" space I've been speaking about -- i.e. turning-off temporarily idled servers, and re-starting them when needed (or per policy, schedule, etc.).
Most sources agree that an idled server chews-up between 60%-80% of its fully-loaded power; a massive waste of energy & cooling during off-peak hours. And, most authorities (DOE, EPA, Uptime Institute) also agree that intelligent power management has to come to the data center.
Stay tuned for some numbers & statistics proving-out the actual performance and savings of this technology.