These days almost everyone has a computer. While the trend is towards more energy efficient desktop models and laptops, people are increasingly confused about how and when to use the most efficient power modes.
The bottom line is that you should set your computer to “sleep” or turn it off when you are not using it, especially overnight.
Collectively, it could cut costs in half.
On average, computers and laptops use the following amount of energy:
Let’s assume each student has a laptop and leaves it on continuously during the school year:
250 days x 24 hrs on x 25 watts x 1660 students / 1000 = ~250,000 kWhs/yr x $0.14/kWh = $35,000 per yr
Now, let’s assume every student sets their computer to sleep mode when not in use:
250 days x 10 hrs on x 25 watts x 1660 students / 1000 = ~100,000 kWhs/yr x $0.14/kWh = $14,500 per yr
250 days x 14 hrs sleep x 3 watts x 1660 students / 1000 = ~17,000 kWhs/yr x $0.14/kWh = $2,000 per yr
Faculty and staff have 381 desktops and 342 laptops. You can apply the same equation to estimate the impact leaving these computers on continuously.
*Includes only personal computers. Labs, workstations and kiosks excluded.
Each kWh of electricity produces just under a pound of carbon dioxide (CO2).
That means we could cut our campus’ carbon emissions by more than 130,000 lbs – 60 metric tons – of CO2 per year just by powering down student computers.
So how do we make this easy in practice? Let’s dispel the myths:
#1 Screen savers DO NOT save energy. A moving screen saver consumes just as much power as the monitor would use in active mode.
#2 Turning your computer off does not harm the equipment. The life of electronic equipment depends on operating hours and heat, both of which are reduced by turning your computer off when not in use, and modern hard drives are designed to operate reliably for thousands of off/on cycles.
#3 Turning your computer off and on according to your use patterns is LESS energy intensive than leaving your computer on in sleep mode continuously.
Power Management Settings
The best thing to do when you are not using your computer is to turn it off. For intermittent periods of inactivity make sure your computer is powered down. Most computers are equipped with EnergyStar power management features to automatically enter into a low power state or “sleep mode” when they are not being used.
You can access your laptop’s power management settings by following these simple steps:
MACINTOSH
From any application select the Apple Menu
Select “System Preferences…” (OS X) or “Control Panels” (OS9) and click on “Energy Saver”
Choose the “Better Energy Savings” default option or create your own
WINDOWS
Right click on your desktop background
Choose “Properties” from the menu and click on the “Screen Saver” tab
In the lower right-hand corner click “Settings”
This will bring up a dialogue box where you can choose your power management settings
On laptops, be sure to activate these settings in the AC power profile — not just the DC (battery power) profile
Did you know? Bates formed an Energy Task Force in June 2009.
This ad hoc committee is charged with reducing energy consumption on campus. It is comprised of faculty members and staff who work directly with the campus’ mechanical, plumbing, lighting, and heating infrastructure.
ASSUMPTIONS:
# of Computers On Campus:
1 laptop per student (1660 students): 1,660 laptops
Faculty/Staff: 381 desktops 342 laptops
Labs, workstations and kiosks: 721 desktops 83 laptops
Energy Use by Mode:
Average watts taken from the following report:
“Energy Use and Power Levels in New Monitors and Personal Computers” by Judy A. Roberson et. Al. July 2002
Berkeley National Lab LBNL-48581
http://enduse.lbl.gov/Info/LBNL-48581.pdf
# Days in academic year:
365 – 90 (summer) – 25 (breaks) = 250 days in academic year