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46 46 P P a r t I I : a r t I I : C o n s u m p t i o n I s s u e so n s u m p t i o n I s s u e s

Energy-Saving Action Savings (kW) Savings (%)
Lower-power processors 111 10
High-efficiency power supplies 141 12
Power management features 125 11
Blade servers 8 1
Server virtualizations 156 14
Cooling best practices 24 2
Variable-speed fan drives 79 7
Supplemental cooling 200 18

TABLE 3-1 The Various Ways You Can Cut Power and Costs

Power isn’t cheap. As if rising prices aren’t enough, datacenters use a lot of juice. U.S.
datacenter power consumption totaled 45 billion kilowatt (kW) hours in 2005. That’s more
than Mississippi and 19 other states. The entire world used 123 billion kW hours in 2005.
U.S. businesses spent between 4 and 10 percent of their IT budgets on energy. Gartner
predicts that this will rise fourfold in the next 5 years.
It gets even more alarming. Power supply vendor Liebert Corp. announced that 33 percent
of respondents to a datacenter survey expected to be out of power and cooling capacity by the
end of 2007. That number jumped to 96 percent by 2011—Lisbert, 2006.
According to a study by Gartner, 50 percent of datacenters said they will have insufficient
power and cooling capacity by 2008—Gartner, November 2006.
So what’s the upshot of all this? It’s a business imperative to reduce power use wherever
you can. It’s not just for the planet. It’s not just to save some money. It’s for the sake of
your business.
There are sundry changes you can make in your organization to save power. Some
changes are big (such as installing new servers) whereas others are small (such as changing
the desktop color of your monitors).
Table 3-1 shows how making corrections throughout your organization can help you
save money.
Another way to look at the figures in Table 3-1 is like this: A US$10 billion company
spends about 4 percent of its revenue on IT costs. So if we take a couple figures from Table 3-1
(variable-speed fan drives, for instance, at 7 percent), then the company stands to save
US$2.8 million a year. That’s because 10 billion × 0.07 × 0.04 = 2.8 million.
For your own organization, you can compute savings by plugging in how much your IT
department spends and then doing a rough estimate with the numbers in Table 3-1.

Monitoring Power Usage
Obviously, the server room isn’t the only place where power gets used. Your whole organization
uses power, all the time. The place to start is with an overall assessment of the power you use.
As you are an IT professional, you’re likely only interested in the computers and network
infrastructure, but you can take this task to whatever level of granularity you choose.