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Myth #2: The business case for PC power management isn’t very compelling.
x
=
x
Total assets
Hours of operation
Energy draw per hour (W)
No power mgt.
With power mgt.
x
=
x
Annual savings
(-)
=
1
24
89
1
8
89
x
x
1
16
5
2.13
.79
kWh/day (1,000 W = 1kW)
$0.19
$0.07
$/day ($.09/kWh)
2.85
1.06
CO2/day  (1.34 Lbs./kWh)
=
=
=
489 kWh/yr
$43.80/yr
653 Lbs. CO2/yr
+60% savings!
•Let’s walk through the math assuming 1 desktop that draws 89w in active mode and 5w in sleep.
•With no power management we come up with the following.
•Now let’s assume we put the desktop into sleep in non-business hours. So during the workday, there is no power management – but note this is only for 8 hours; during the remaining 16 hours of the day, the PC is in “Sleep” drawing only 5w/hr not 89w/hr.
•And this just assumes this cycle is repeated 365 days per year – which is conservative because its safe to assume no work is being performed weekends, or roughly 104 days out of the year.