Note that over 10% of data center power use is for Facebook, with all of those updates and photos … as noted in the article:
The company’s data centers range from from 10,000 square feet to more than 35,000 square feet, and their energy use is enormous. The average leased data center uses between 2.25 megawatts of power and 6 megawatts of power. This could provide electricity for one month to somewhere between 1,730 and 4,615 homes.
With their new data center, however, Facebook aims to lift a little of its guilt, saving approximately 2.5 million kilowatt hours per year with efficiency measures. They’ll save the company $230,000 and reduce carbon emissions by more than 1,000 tons.
This gives you some sense of the electricity required to power our use of Internet applications, electricity use that is largely taken for granted by end-users, but is a substantial cost for firms. I recommend clicking through to the full post, which includes a detailed analysis of power use from Facebook, Google, Yahoo, and WordPress (all applications near and dear to our hearts at KP!).
The extended graphic discusses an important metric of data center power use — power usage effectiveness (PUE). According to Wikipedia,
Power usage effectiveness (PUE) is a measure of how efficiently a computer data center uses its power; specifically, how much of the power is actually used by the computing equipment (in contrast to cooling and other overhead). … PUE was developed by a consortium called The Green Grid. PUE is the inverse of Data Center Infrastructure Efficiency (DCiE). An ideal PUE is 1.0.
Realistically, PUE=1.0 is unattainable as long as computing technologies give off heat while working and thus require cooling. It’s a metric that provides Internet firms, data center operators, and chip manufacturers clear incentives to reduce the heat that chips produce while working. And it’s also a good illustration of an alignment of economic and environmental incentives — reducing the need for cooling reduces electricity use, reducing both electricity expenditure and the environmental consequences of electricity generation and use.
Google’s discussion of their data center PUE performance is thorough and informative, and explains the issues in a clear way to non-specialists. Note that they consider “state of the art” PUE to be 1.2, based on some industry benchmarking reported in an EPA analysis in 2006. At that time, they estimated the industry PUE to be 1.9, which means that for every watt used in computing, 0.9 watt is used in an ancillary way in the data center (largely for cooling). In the ensuing 5 years, Google reports that 10 of their large data centers have PUEs in the 1.1-1.35 range (Figure 1). They have invested substantial resources in reducing their data center power use, as this discussion and the visualization above indicate.