Google's Bill Weihl gave an update on ICT sustainability at Green:Net 2010 iin April. Livestream has posted the video; here the items I found useful. (Time location in video for each item is in parentheses in mm:ss format.)

Edge gear (clients, etc.) already represent about half of ICT GHG emissions and will approach three-fifths by 2020. (01:20). This is not new data, but reminds us that Green ICT has to focus on the edge, as well as the facilities/telecom infrastructure, to have maximum impact. See Vertatique's inventory of 12 billion edge devices.

He repeats the 2007 statistic that typical PUE is 2.0 (04:50), but there is evidence suggesting average PUE is significantly worse. Nonetheless, Weihl argues that "A PUE of 1.5 or less should be achievable in most facilities" without a "purpose designed" facility or "without using any exotic technology." (11:00) Weihl urges us to "spec high efficiency components, from power distribution infrastructure all the way through your computing systems (including client systems" (12:00). Ironically, this could increase a facilities' PUE, so it is important to remember that minimizing total in energy consumption, not just achieving good consumption efficiency ratios, is the bottom line.

Cooling accounts for more than 70% of non-IT data center power consumption. His solutions: keep hold and cold separate, turn up the thermostat, and give chillers a rest. More on innovative cooling. (05:25)

Google's practice: "typically run our data centers at around 80 degrees Fahrenheit." (07:35) But "make sure you've eliminated hot spots." (09:25)

Google is experimenting with simple aisle end caps and meat-locker curtains to separate hot and cold air at one of its corporate data centers. "There are very cheap solutions...you can apply in virtually any data center" for hot/cold-aisle containment. The vinyl curtains appear to be both cheaper and more flexible than hard-wall containment systems. (picture at 08:20)

Google uses economizers (evaporative cooling, cooling towers, free air) to minimize chiller use (10:00)

One of the most interesting topics came up in the Q&A, when an audience member asked about the authority granted Google by the Federal Energy Regulatory Commission (FERC) in February to buy and sell power. Weihl explained it in terms of being able to quickly stimulate greater investment in renewable power generation. The idea is that Google can commit to large, long-term contracts for its facilities early on, knowing it can resell the excess power until it is fully needed. "We don't want to be an energy trader…the next Enron." (18:45)

Google Fiber Goes Green video