Not to be outdone in the "green" category, Google says that the white background on its home page doesn't waste more energy than a black background would.
Blackle, a site created by a company called Heap Media, points to research published in 2002 as well as a blog post by Mark Ontkush, an IT administrator and founder of the consulting company New View Data Solutions, as evidence of the energy saving potential of black Web pages.
Discussions have followed online about the legitimacy of the calculations. Ontkush, who calls himself a green computing evangelist, posted a longer explanation on Monday that includes differences in energy savings based on the type of monitor a computer user has.
The research he has found suggests that LCDs, which are the most common type of monitor, typically consume only slightly less or in some cases slightly more energy when displaying black screens. The biggest energy savings from black screens appears to come from CRT (cathode ray tube) displays, which are common in some places of the world but overall make up about a quarter of computer screens, he said.
Google points to an informal test that an Australian conducted, posting the results on a blog. His findings largely corroborate Ontkush's.
Google interprets that research to show that switching from white won't help improve energy waste, since LCDs are the most commonly used monitors. "Our own analysis as well as that of others shows that making the Google homepage black will not reduce energy consumption," Google wrote in the blog.
Blackle argues that even scant energy savings are worth the effort. "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," the site reads.
Google provides search results for Blackle, which presumably earns revenue from ads that are displayed in search results.