Can you save the planet by switching to a "black" Google?

Can you save the planet by switching to a "black" Google?

Summary: Over the past few weeks I've come across dozens of websites promoting the idea that switching over to using a version of Google that had a black background as opposed to a standard white one would save me money/electricity/the planet* (delete as appropriate). Well, does it?

TOPICS: Google, Hardware

Over the past few weeks I've come across dozens of websites promoting the idea that switching over to using a version of Google that had a black background as opposed to a white one would save me money/electricity/the planet* (delete as appropriate). 

The alternative search site most often linked to is one called Blackle, a website that offers visitors the ability to use Google via an interface consisting of a black background and grey font.  I've had dozens of emails from people suggesting that I switch to this search site, dozens from people wanting my opinion on it and dozens more from people wanting to know if switching to it can help them save the planet.

I decided to find out for myself what the energy savings, if any, are likely to be and if switching all my searches to Blackle really would help me save the planet.

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The Test

Over at the PC Doc HQ we came up with two very different approaches to testing this energy savings. 

  • Go large scale The first way was to go large scale.  Hook up half a dozen monitors together, have them display mostly black for a fixed period of time (a week say) and then switch them over to white and see which use the most power.
  • Go small scale The alternative method was to go small scale.  Take one LCD panel and one CRT panel and do some testing over a few hours and see what the results suggested. 

In the end we decided to go for small scale testing.  Not only would we get quicker results but it really didn't feel like chucking kilowatts of power at trying to find out what was the best method for saving electricity. And anyway, if there's any substance to this black background hypothesis, it should be easy to spot.

So here's what we decided to use for the test:

  • One generic 19 inch LCD panel.  This was purchased within the last 12 months.
  • One generic 15 inch CRT unit.  This has been hanging around the PC Doc HQ for some time now.
  • One power meter capable of measuring, amongst other things, power usage in Watts.

For the test we would measure the power consumption of both the flat panel and the CRT when displaying a variety of different images.

The first thing that we needed was a baseline figure for power usage for both the LCD and the CRT.  The LCD panel was fitted to a PC running Windows Vista with the default desktop while the CRT was on a system running Ubuntu, again with the default desktop. 

Baseline power usage:

  • LCD - 28 Watts
  • CRT - 57 Watts

So, right off the bat we find that the small 15 inch CRT is consuming twice as much power as the much larger LCD panel.  But what variation does changing the background color have on these baseline figures.

First off, we tested the LCD panel.  We set it up to display first a completely white screen and then a completely black screen (by doing nothing more sophisticated than changing the background desktop color and hiding the icons).  Here are the results:

  • LCD displaying black screen - 28 Watts
  • LCD displaying white screen - 28 Watts

As you can see there's no detectable change in power consumption.

Next we repeated the test on the CRT.  This time we saw a pretty dramatic variation:

  • CRT displaying black screen - 49 Watts
  • CRT displaying white screen - 60 Watts

So running a CRT with the screen totally black uses 14% less power than the baseline measurement, while a completely white screen uses 5% more power. 

Since no one in their right mind is going to run a screen 100% black or white, we decided that some more real world testing was required.

Since both systems were running at 1024x768 screen resolution we fired up a web browser (Internet Explorer on the Windows Vista system and Firefox on Ubuntu, both systems switched back to default themes) and set it to be an 800x600 pixel window and into each loaded in turn Google and Blackle.  Here are the results:

LCD Panel

  • Google - 28 Watts
  • Blackle- 28 Watts

CRT Monitor (Ubuntu)

  • Standard desktop - 56 Watts
  • Google - 56 Watts
  • Blackle- 53 Watts

Does the operating make any difference?  I switched the CRT to Windows XP system running at 1024x768 and duplicated the test.  Here are the results from that test:

CRT Monitor (Windows XP)

  • Standard desktop - 57 Watts
  • Google - 60 Watts
  • Blackle- 58 Watts

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OK, so what's the bottom line here?  Well, first off, if you're running an LCD panel then none of this means anything to you.  LCD panels seem to draw the same power no matter what (dimming the display did cause a drop in power consumption but only when dimmed beyond the point of being readable).

If you're running a CRT and are interested in doing your bit to save the planet then one of the best things that you could do is bin the CRT and replace it with an LCD panel.  Not only will you get a better screen, it'll consume half the power.  However, if you don't want to change your monitor, then darkening your screen does have an effect.  Running a CRT with the screen totally black uses 14% less power than the baseline measurement, while a completely white screen uses 5% more power but these numbers are nowhere near as dramatic when you consider a standard user desktop.  Here the difference between using Blackle compared to the baseline is small and we certainly couldn't get power consumption anywhere near as low as 49 Watts (which was the power consumption of the CRT displaying a black image).

We also tested to see whether dimming the CRT had any significant effect.  We found that the difference between running the CRT at full brightness and being barely readable was only 1 Watt.  Measurable but hardly significant.

The bottom line is that if you want to save the planet, there are far better ways to do it that shifting your searches to Blackle. 

Personal Note:  Going through this experiment has made me glad of the fact that over the past few years that we've eliminated almost all CRTs from the PC Doc HQ and shifted over to LCD panels.  We've also taken other steps such as:

  • Changed all light bulbs for energy saving ones
  • Implemented power saving features on most systems
  • Made it easier to switch off the power to devices on standby by hooking them up to a single isolation point


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Topics: Google, Hardware

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  • Backlight

    You'll probably find that most of the LCD power draw was to support the backlight used to make things visible.

    Something like Blackle seems just like a tricky way to capture traffic and monitor people's queries. You could probably just gin up a custom CSS for the google page and get the same result without having to go through someone else's web site. (Of course the energy consumed to run that server and the network connection and what not will cancel out at least some of the savings for individual monitors.)
    Robert Crocker
  • Ironically

    Ironically, as soon as you find your site, you leave Blackle's energy saving site for a bright white site (typically). SO I guess you have to stay with them to save money....

    Or script GreaseMonkey to change the web backgrounds to black.
    • Or come to ZDNet

      Whose background is the brightest, snow white they can find. You might go blind going from a black screen to ZDNet's all white screen! :)
      • Yeah ...

        ... the contrast can be quite jarring!
        Adrian Kingsley-Hughes
  • The second I seen this, I balked the idea

    LCDs always light up the crystals in the display no matter the
    colour. This is different than CRTs. because they don't have
    to bounce a colour in other to create black, so they save
    energy. Still you are right in switching to LCDs. No only are
    more energy efficient, but they also are quicker to respond
    coming out of sleep mode.
  • Thanks for the info...but want more!

    Thanks for the energy info. But I wish you'd gone a little deeper into the subject
    (maybe someone else already has)? I've got a eight-year-old, 19-inch Viewsonic
    monitor that's on at least 12 hours a day. I'm reluctant to change the monitor since
    it's still working fine. But I wonder what the payback in energy costs would be if I
    switched to a new LCD monitor. Assuming I spent $300 for an 20-inch LCD monitor,
    would the energy savings pay for itself in one year? Three years? 30 years???

    Very curious!
    • A 20+ inch LCD and you would still see savings

      I don't see any reason why you wouldn't save. The problem is
      that the 60 Watt CRT was only 15"s. Your 19" monitor is
      probably around 60% bigger and probably has 60% or more power
      draw. You are considering around 70 watts an hour more times
      12 hours a day times 21 days a month and 12 months a year and
      say that your electric bill is around 4 cents a kilowatt hour.
      I don't know on this, so you would have to check your local
      rate. But for me, you would save 8 dollars a year which is
      negligible. However, consider the amount of time 1 to 5
      minutes for that mighty CRT to warm up just so your workers can
      use it. Combine that with the amount that you save and you
      might make some more damage on justifying the cost.
      • warm up time

        few CRT monitors take over 30 seconds to come up to 90% brightness. (older ones sometimes do take a while to get that last 10%) Most Computers take longer than that to be ready to work.

        Even an average CRT has a better picture than all but a top 75% LCD display. particularly if you are concerned with colour values.
      • Add in the extra heat...

        Factor in the additional heat generated by the CRT and how much it costs in Air Conditioning to eliminate it and you would find some additional savings. I don't presume to be able to do the math but it is low, like the original $8.00 in energy cost.
        Richard H
        • Or heating costs

          In winter, that $8 (or more like $50 in my case -- much higher marginal electric rate) goes to offset heating costs. In many locations, I would think these would approximately balance out.

          Still, you also have to consider the electric consumption in manufacturing what you replace. I think it makes sense to discard incandescent bulbs, but often it's not clear.

          There are other issues, though -- like mercury in fluorescent bulbs, proper disposal of CRT's, etc. I think it makes no sense to buy a CRT these days.
  • We did the same test and filmed it

    We went ahead and tested with an LCD monitor and found that it actually uses more energy than Please see the video at:
    • Interesting

      Thanks for posting that!
      Adrian Kingsley-Hughes
  • Don't forget to turn off the lights when you leave!

    What effect would just shutting down PCs when not needed have on power consumption??

    To me, it follows the same premise as turning lights off when I leave a room.

    I don't know if we can save the planet but I would think we can reduce our energy bill measurably.

    Clearly, there is plenty of room for discussion on ways that power consumption can be reduced.

    Interesting and surprising that a CRT draws less current when the screen is predominantly black!

    Thanks Adrian
    D T Schmitz
  • Screensaver..

    It would be interesting to hook a watt meter to the whole system and see what effect a screensaver has- try a fancy 3D screensaver, then a plain 2D (like scrolling text) and finally blank screen.
    Rumor has it that 3D screensavers use quite a bit of CPU power...
    • Good idea!

      I'm already in the middle of more testing ... it just takes time ... but it's a lot of fun!
      Adrian Kingsley-Hughes
  • Saving the planet

    I'm not so sure adding another (operable) CRT monitor to the trash pile will help save the planet. In fact, various heavy metals, flame retardants, and other substances toxic to many living things leach from those CRT monitors when they are tossed out into the very environment you are proposing to protect by getting rid of them! Are you sure the benefits of power reduction would offset this other type of environmental toll?
    • You make a good point

      You know, you make a good point. I try my best to throw away as little gear as possible - I still have functional 286 and 386 systems at the PC Doc HQ. Most gear that we have "upgraded" ends up in other duties for years. I also make sure that things are sent off for recycling rather than just trashed.
      Adrian Kingsley-Hughes
    • I take most of my tech junk to

      The electronics recycling place about 10 miles away. I don't know about other states, but here in California there are such places. Originally they accepted only PCs, parts and monitors, but now I know for sure they at least take TVs too. What they actually do with them to sequester toxins I have no idea, but since they're specifically commissioned to deal specifically with that stuff, hopefully they're environmentally responsible. As far as operable stuff goes, you can always post it in the freebie section of Craig's List if you'd rather have it be useful to someone. I've donated stuff to the Boys & Girls Clubs and other non-profits too, but even they might not want CRTs these days as I'm sure they're as concerned about conserving energy as anyone.
  • Blackle's owner

    They list 6 sites as being owned by the folks who run Blackle (including Blackle) and 5 of them are blindingly white.
  • Save the planet

    I think it's funny that people are changing light bulbs to the more un-ecofriendly, toxic-in-a-landfill florescent bulbs.

    An electrician will tell you to put dimmer switches on any incandescent bulb. When used at even 90 percent of full power, a dimmer will save power more power than a florescent AND extend the life of the bulb substantially.

    Save your money on