>Kill The Screensaver, Save The World

>A screensaver wastes power when it shows you the pretty graphics. It keeps the screen out of power-save mode and keeps the CPU and GPU active.

This is my attempt to quantify just how much power the screensaver wastes for just one average Ubuntu user. Using the default Ubuntu setup the screensaver starts after 10 minutes as a blank screen and it asks the monitor to sleep after 40 minutes. *Diff = difference between device in normal operation and power save mode in watts.
Variables

  • % CRT Use: 50%
  • Diff CRT: 60
  • Diff LCD: 25
  • Time screensaver is active a day: 2 hour

.50 * 60 + .50 * 25 = Diff Avg Monitor 42.5 Watts (also Watt hours)
Total for one user per day is 85 Watt hours.
That is 31 KwH for a year. Or at $ .15 a KwH, $5.

Variables

  • User Base Of Ubuntu Desktop: 10 Million
  • Diff Screensaver: 85 Watt-hours (a day)

That is 850 MWH (Million Watts) a day for all Ubuntu users.
That is 31 GWH a year. Or somewhere in the range of $46,537,500 a year.

Please if you can get more accurate variables please tell me about them, also send corrections. Kill the screensaver, Save the World.

6 thoughts on “>Kill The Screensaver, Save The World”

  1. >Even when the screen just goes black, plasma type monitors consume way more because of the way they function (and lots of laptops use a plasma monitor).

  2. >@sup : no, one Watt is *not* 3600 times less than one Watt hour.

    It would be like saying that one km/h is 3600 times less than one km.

    Just like speed and distance, power and energy are two different physical quantities that are represented by two different units : one Watt hour is the energy used by a 1 Watt component powered during an hour, just like 1 km is the distance covered by a vehicle driving at 1km/h during an hour.

    @gQuigs : You could also consider that GPU & CPU both have to work to display the screensaver, which uses some more power as well.

    By the way, its kWh, like kilo Watt hour, not KwH. It's easy to remember, because Watt is the only family name of the three.

    Then come MWh (Mega Watt hour) & GWh (Giga Watt hour). M is uppercase in order to be distinct from m (milli). G is uppercase because it's huge (one billion).

    Thanks for the post!

  3. >I am for a long time worried because of the fact that in Gnome you can’t enable just the monitor sleep mode or the other power saving settings without enabling the screen saver too.

    Are there any way to do just the power saving in Gnome/Ubuntu?

    The Gnome project should take care of this issue. That’s something the PowerTOP project is about, too.

  4. >I also wish Ubuntu/Gnome would default to more sane times for this. 40 minutes before the screen goes off? Never suspend? Our company which previously pretty much had the defaults from Ubuntu implemented a policy where desktops should turn off the monitors after 10 minutes (screensaver disabled) and suspend after 20 minutes… this saved over $60/year/computer. You’re not even taking into account how much less work the AC will have to do as well as many other things.

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