Going black is the new going green — at least that is according to a selection of Web sites that claim to use Google in way that saves energy.
Blackgoogle is a customized take on the search engine with a black background instead of a white one.
Its creators say: "It's a fact that computer monitors displaying predominantly white backgrounds consume more energy than those that display simple screens with a black background.
"A typical white screen uses around 74 watts of electricity. A black version of the same screen uses around 59 watts — so saving around 15 watts per hour.
"A saving of 15 watts isn't huge on its own — you couldn't even run a household lightbulb with it.
"However, Google gets around 200 million hits a day. Multiply our modest 15-watt saving by 200 million and things start to get interesting."
Blackgoogle asks people to add a link to their blog or Web site and forward a link asking friends and colleagues to do the same.
The idea was suggested in a blog entry in January that estimated that a "black Google" could save 750 megawatt-hours a year.
A Google spokesperson stressed that the sites are not affiliated with Google.
Users of the Sky News message boards are debating whether the black background really will save energy or whether it's just hype.