Apple's 2012 Facilities Report provided detail on on the sustainability features, ranging from 'free air' cooling to real-time power monitoring, in Apple's Maiden (NC-USA) data center. A more recent report commits to 100% renewable energy.

A Pike Research report says that the trend to greener data centers will yield a significant GHG slowdown as well as drive a substantial market opportunity. Here are some of the top-line numbers from Pike.

The Green Grid released a survey of data centers' use of economizers, cooling technologies that take advantage of favorable outdoor conditions (air and/or water) to provide partial or full cooling without using a refrigeration cycle. Fifty percent reported that they were already using economizers, but it is not clear that economizer use translates into overall data center energy efficiency.

We've always taken a broad view of the definition of an ICT facility. More than just data centers, ICT facilities include everything from broadcast studios to telecom network operating centers. Hospitals' network closets, an instance of decentralized ICT, are the focus of an informative white paper from Emerson Power Networks.

The Green Grid paper on data center power efficiency metrics covers two key measures of data center infrastructure efficiency: PUE and DCiE (formerly DCE). The basic notion is that the most efficient facility is one in which most of the power goes directly to power the IT equipment, rather than to cooling, etc. But there are complexities.

A lot has changed since we wrote three years ago: "Yahoo plans to go carbon neutral by the end of 2007. Part of this will be achieved through carbon offsets, including hydroelectric and sustainable agriculture projects in Brazil." Co-founder and Chief Yahoo David Filo now says, "Reducing our carbon footprint has always been a priority and we’ve decided to focus all our energy and investment on that philosophy. We will no longer purchase carbon offsets as announced in 2007. Instead, we’ll focus our resources on reducing our carbon impact while helping the rest of the industry do the same. We believe creating highly-efficient data centers will have a greater long-term, direct impact on the environment and gives us the best opportunity to play a leadership role in addressing climate change."

Another focus appears to be reducing the amount of water typically consumed by a data center. Here is Yahoo's report about its newest data center, the Lockport, NY "Chicken Coop":

Repurposing military facilities into green data centers appears to be a growing trend in Europe. We recently noted a Swiss data center built in an old military bunker and an Icelandic facility in a decommissioned NATO base. Now Sweden offers another variation on this theme: an underground data center with a Cold War pedigree.

Broadcast Engineering reports that WPEC-TV achieved a considerable reduction in energy consumption by lighting its two HD news sets with LEDs.

Our recent post containing information about Green ICT issues at universities generated a lot of interest. Here is another insight: it is laboratory facilities are the big energy consumers on campuses.

Here are some public data centers and ISPs offering various shades of green computing