AskPablo: Black Google

blackle.jpgThis week’s question comes from Julia. She asks “is it really true that a black Google page would save energy?” She is, of course, referring to a very popular article written by Mark Ontkush back in January. He claims that turning the Google page black would save 3000 MWh per year! As a result, Blackle was created. While it may be true that a CRT monitor uses 15 watts less with the black screen Mark does admit that only 25% of the world’s monitors are CRT. What about the rest of us, with shiny new LCD monitors?

According to Nielsen/NetRatings (“Researchers take time out to measure online audience,” Financial Times, July 16, 2007, p. 15) Google users spent 2,557,000,000 minutes on Google websites in May of 2007 (746M for Yahoo, 7,535M for MySpace, and 2,117 for Youtube). That’s 426,616,666 hours, or roughly 4,865 years! Over the course of one year that would amount to 511,400,000 hours of Google website use.
For the 25% of CRT users there is a savings of 15 watts. This does amount to 1,917,750 kWh saved (511,400,000 hours x 25% x .015 kW). For LCD screens it’s a different story. While CRT monitors function like a light bulb, getting dimmer and brighter, and therefore using more and less electricity depending on screen brightness, LCD screens are a back-lit display where a liquid crystal display selectively blocks out certain wavelengths of light. What this means is that, when I hook up my Kill-A-Watt meter to my screen I get a reading of 16 watts when it is on the regular page. Surprisingly, I actually get a reading of 17 watts when I switch over to the page! So, with a black screen a LCD monitor actually uses 1 watt more. If 75% of monitors are LCD this amounts to 383,550 kWh (511,400,000 x 75% x 0.001).
So, while the net savings are 1 534,200 kWh (1,917,750 – 383,550) it probably does not make sense for LCD monitor users to switch to the black screened Google. This also means that screen-savers don’t actually save you any energy either. In fact, running the video card that powers the screensaver may use even more electricity. The best setting, therefore, is for your monitor to turn off or your computer to hibernate.
I would also like to point out that the black Google does not save any energy in the server hardware that runs the website, or in the desktop/laptop computer that you view it with, which is where most of the energy gets consumed.
So, there’s your answer Julia…
Pablo Päster, MBA
Sustainability Engineer

18 responses

  1. i used a kill-a-watt on my laptop and saw no difference. if you look at the scientific paper on blackle’s site, it shows that lcds also require more energy for an all white screen vs black. Perhaps their equipment is more accurate than a killawat I looked at the paper and using an average of the 17” CRTs( one i presume is the most common nowadays) the savings is 24 watts, but it doesn’t matter because all of the LCDs required more energy for white except one which there was no observed change. unless LCD technology has changed since the study(2002) It seems to make sense that using blackle would save energy.

  2. I am loving this green movements. Its really good that people are worried about our future.
    I recommend using and following its 10 easy ways to save energy. Plus its nicer to watch (since userfriendly colorcoded search results) than Blackgrey-blackle and its copycats.

  3. Although there is debate about whether or not using black backgrounds saves energy. I think its a very innovative idea on helping the environment any little way we can. Since Blackle was launched there have been other search sites as well that introduced this concept. My favorite is Greenback Search at
    It uses eco-friendly colors but more importantly it purchases carbon offsets for users of the site plus it has some tips and information on the environment that are informative. Check it out for yourselves.

  4. I was totally unaware of the debate going on about black web sites until after I pointed to my astore. There is no doubt that black will win out not because it is more energy efficent but because it is more elegant. (if you know what you are doing.)
    I have been designing in black since my very first web site in 1997. And have won four Golden Web Awards from the International Association of Web Masters and Designers.
    The future belongs to the bold. Eventually every site will be mandated to have a black background unless something drastically changes in physics. My goal is for to be the black Amazon.
    Let’s do some real math. There are over 2 billion I.P. addresses in the world today. Assuminbg 1 hour of use per I.P. address per day and a saving of 1 watt per hour that equals a saving of two billion watt hours per day. that is equal to 2 mega watt hours per day. Very conservative figures to say the least.
    These are just basic figures but history will bear me out. Again I just came into the debate, separate and apart from the nay sayers,
    I suggest that all of you grab a piece of the Rock. This is the Beginning of the creation of God. P.S. visit to see my first site.

  5. It’s true that energy is only saved with a black screen on CRT monitors. However, LCD monitors consume less energy than CRT monitors in general.

    I’ve seen people say that a black screen is harder on the eyes. I can’t believe people would say that! I look at my LCD monitor all day long, and I find that reading off of a white screen is MUCH harder on my eyes. Long before the first post regarding Black Google ever surfaced (sometime in 2006), I went searching for a black google (by googling “black google,” of course).

    Back then, there was only one black google search page that actually showed search results with a black background (believe me, I tunneled down over 20 pages in the google results, and that was the only one). I’ve been using ever since and I’ve found that it’s greatly reduced the strain on my eyes.

    So many people say that it’s just the opposite, that a black screen is harsher. Anyway, there’s been all this hype about black google and whether it actually saves energy, and I think people are missing out on the true advantage of a black background. If anyone is still reading this post, I’d like to challenge them to try the black google page at for a day and then report back here whether or not you found it reduced eye strain compared to the regular google page. Also, please note whether you’re using a CRT or LCD monitor (maybe that makes a difference).

    Jabago was originally branded as “Black Google, a Search for Sore Eyes” before Google made them re-brand. I think their new look is much nicer anyway (I don’t know if their screenshot will show up in this post):

    Thanks to anyone who participates in this little experiment and submits feedback here.

  6. I am not sure whether the black background on computer screens do much on saving energy, but I am sure that the web masters who created those web sites have the same purpose in raising people’s awareness about global warming issues.
    I have found many versions of black Google. The one I like best is, its home page has facts & tips on global warming and energy saving. Labundi also has links to Nasa reports and other sites on global warming issues.

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