The Megawatts behind Your Megabytes: Going from Data-Center to Desktop
David Costenaro, Anthony Duer · 2012
Businesses and individuals are migrating in droves to cloud-based software, offsite data warehouses, and streaming media services; clamoring to shed the responsibilities of owning and maintaining IT equipment and infrastructure. But should energy issues drive us to be MORE conscious of this world – of what goes on behind our flatscreens when we surf 23 websites in a tabbed browser or stream a whole season of “The Sopranos” in the background while we cook? Research on computational energy use has occurred in many segregated clusters, from end use devices to data centers to servers, but what happens at a system level? What happens between the server rooms and our screens? Has there been disproportionate focus on “datasupply” efficiency; and should demand-side management techniques be applied to promote “data-use-efficiency”? This paper is a thought-piece on the how’s and why’s of end-to-end, IT energy use. It will pursue questions like: What type of equipment is used to get a MB from the data-center to your desktop? Is multi-tabbed browsing the IT equivalent of leaving the refrigerator door open? How much energy does it use? How much does it cost; and who pays for it? Our major finding is that the Internet uses an average of about 5 kWh to support the utilization of every GB of data, which equates to about $0.51 of energy costs. Only 38% of those costs are borne by the end-user, while the remaining costs are thinly spread over the global Internet through which the data travels; in switches, routers, signal repeaters, servers, and data centers (See Figure 1 below). This creates a societal “tragedy of the commons,” where end users have little incentive to consider the other 62% of costs and associated resources.