There's an energy-saving version of google available on the web.

www.blackle.com is the google search engine, but it's all in black as opposed to white.

It saves power because black screens use less energy than white ones.

One estimate says black screens could save up 750 megawatt hours a year over the totally white screen.

As noted, an all white web page uses about 74 watts to display, while an all black page uses only 59 watts.

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 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 codes.

The site's only differing function from Google is the fact that its background is black and the results are white - making it a hard-to-read, but allegedly power-saving, adaptation of the world's favorite search site.

Apparently, the idea for the site was born from a 2007 blog post, Black Google Would Save 750 Megawatt-hours a Year, which proposed that a black version of the Google search engine would save a fair bit of energy and the fact that "a given monitor requires more power to display a white (or light) screen than a black (or dark) screen." None of this has been proven, but the creator's of Blackle say they believe that there is value in the concept because even if the energy savings are small, they all add up.