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At the Top of Their Game • 197

Annual Savings Per Server

Electricity
500 kWh saved
$30 saved
Carbon Dioxide per server
300 kg saved per year!

:ater
1000 gal saved

Figure 11.2
Annual savings per server (courtesy of Google).

According to Google’s Web site, “Up to a third of total energy consumed
by a typical server is wasted before reaching the computing components.
The majority of these losses occur when converting electricity from one
kind to another. The power supply, which converts the AC voltage com-
ing from a standard outlet to a set of low DC voltages, is where most of
the energy is lost.” Therefore, scrutiny of the efficiencies of their servers
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is paramount. The goal is to either increase the efficiency of their present
servers or replace them with more-efficient ones (see Figure 11.2). For the
project manager, if servers are part of the project, or even the process, effi-
ciency may be a key part of saving scarce resources.
“Reducing the environmental footprint of our data centers starts with
reducing their electricity consumption.” Power and cooling are the major
13
factors in energy use of data centers. In a 2007 report, the U.S. EPA confirmed
this sad state and estimated the average energy overhead of current data cen-
ters at 96%. Google’s data centers are now using the evaporation process,
14
similar to nuclear power plant cooling towers, to provide additional cooling.
By using cooling towers, Google’s goal is to reduce the time the chillers have
to run, thereby reducing the energy consumption of the chillers. Figure 11.3
shows a simple representation of how a cooling tower works.
The third step in their initiative is to look at water usage in their facili-
ties. “On average, two gallons of water is consumed for every kilowatt-
hour of electricity produced in the U.S.” When you think about how
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many data centers there are and how much energy they produce, that is a
lot of water. To reduce water usage, Google is instituting water-recycling
efforts. Their goal is to provide recycled water in 80% of their facilities by
this year (2010).