Black Google Would Save 750 Megawatt-hours a Year

Terrific article from Rising Phoenix Design that points out a rather obvious-when-you-think-about-it fact; black pixels take less energy than white pixels. Background to background, black comes in at about 59 watts, white is at 74, a full 15 watts higher. I'm convinced; the look you see at ecoIron is now permanent. More colors here, and here's a link to Varlath's blog that explains why we changed from black to white in the first place.

As noted, an all white web page uses about 74 watts to display, while an all black page uses only 59 watts. I thought I would do a little math and see what could be saved by moving a high volume site to the black format.

Take at look at Google, who gets about 200 million queries a day. Let's assume each query is displayed for about 10 seconds; that means Google is running for about 550,000 hours every day on some desktop. Assuming that users run Google in full screen mode, the shift to a black background [on a CRT monitor! mjo] will save a total of 15 (74-59) watts. That turns into a global savings of 8.3 Megawatt-hours per day, or about 3000 Megawatt-hours a year. Now take into account that about 25 percent of the monitors in the world are CRTs, and at 10 cents a kilowatt-hour, that's $75,000, a goodly amount of energy and dollars for changing a few color
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Blackle was created by Heap Media to remind us all of the need to take small steps in our everyday lives to save energy. Blackle searches are powered by Google Custom Search.

Blackle saves energy because the screen is predominantly black. "Image displayed is primarily a function of the user's color settings and desktop graphics, as well as the color and size of open application windows; a given monitor requires more power to display a white (or light) screen than a black (or dark) screen." Roberson et al, 2002

In January 2007 a blog post titled Black Google Would Save 750 Megawatt-hours a Year proposed the theory that a black version of the Google search engine would save a fair bit of energy due to the popularity of the search engine. Since then there has been skepticism about the significance of the energy savings that can be achieved and the cost in terms of readability of black web pages.

We believe that there is value in the concept because even if the energy savings are small, they all add up. Secondly we feel that seeing Blackle every time we load our web browser reminds us that we need to keep taking small steps to save energy.

How can you help?

We encourage you to set Blackle as your home page. This way every time you load your Internet browser you will save a little bit of energy. Remember every bit counts! You will also be reminded about the need to save energy each time you see the Blackle page load.

Help us spread the word about Blackle by telling your friends and family to set it as their home page. If you have a blog then give us a mention. Or put the following text in your email signature: "Blackle.com - Saving energy one search at a time".

Have a look at our energy saving tips page for ideas on steps you can take to save energy or you can follow Blackle on Twitter and we will keep you updated with simple energy saving tips.

There are a lot of great web sites about saving energy and being more environmentally friendly. They are full of great tips covering the little things that we can all do to make a difference today. Try Blackling "energy saving tips" or visit one of the many great blogs dedicated to environmental awareness.

How do I set or unset Blackle as my home page?

It depends which browser you are using. Here are some instructions for changing your home page setting.

What is the aim of Blackle?

The aim of Blackle is to remind people of the need to take small steps every day to save energy. We do not expect the energy savings from Blackle to change the world on their own, but the point of Blackle is that every little bit counts. We hope that the flow on effect from people using Blackle and thinking more about other things they can do to save energy will make a significant difference. To further this flow on effect we have added a section to Blackle packed with energy saving tips.

Does Blackle save energy on LCD and CRT monitors?

There is a significant difference in energy consumption between black and white screens for CRT monitors. CCFL backlit LCD screens are less affected by color because of their constant backlight. However, new monitor technologies such as LED backlit LCDs screens, Plasma screens and OLED screens do not have a constant backlight so we will see larger energy savings with Blackle as these new monitors replace the old CCFL LCDs. While technology is constantly changing the need to take steps to save energy (even small amounts of energy) is constant.

Will Blackle be adding other features such as image search or a search toolbar?

We are investigating the best ways to improve Blackle. We will continue to focus on providing the best and most environmentally aware search that we can with Blackle.