Energy consumption vs % utilization?

["Gregory (Grisha) Trubetskoy" <grisha () ispol com>]

Sorry, this is somewhat OT.

I'm looking for information on energy consumption vs percent utilization. 
In other words if your datacenter consumes 720 MWh per month, yet on 
average your servers are 98% underutilized, you are wasting a lot of 
energy (a hot topic these days). Does anyone here have any real data on 
this?

Grisha