At Tuesday's Green:Net 09 conference, Jonathan Koomey of Lawrence Berkeley National Laboratory and Stanford University shared his research on the amount of electricity used by data centers. Koomey's 2007 research on the topic has been widely cited by the EPA and many other sources. In this talk, Jonathan makes a key point that often gets lost in discussions of IT energy efficiency. "The biggest environmental story is not the actual electricity use," Koomey says. "The main story is how IT affects efficiency in the broader society." Here's a 21-minute video of Jonathan's presentation, along with his slide deck.