From the “I had no idea Google was not green” department comes this story from our friends down under. Early this year members of a fledgling search engine company in Australia read a blog by environmentalist Mark Ontkush. In that posting, Ontkush speculated that, collectively, Google users with CRT screens could save the world 3,000 megawatt-hours of electricity per year if the search engine’s background was black instead of white.

Here is his logic:

“Take a 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.”

That is a lot of electricity.

“Blackle,” as they say, was born. The site essentially does what Google does but instead of that megawatt-sucking white screen there is a black one. The idea is catching on. The Blackle search engine is growing in popularity as people choose to save the environment while they do their searches.

Critics of the black background idea say that with modern LCD screens the energy savings derived from a black screen are negligible. That’s probably true. Still, this story is important because it illustrates how many people are willing to change their ingrained habits – like using Google – if they are given a green alternative.

Green entrepreneurs everywhere rejoice. If Blackle can take on a mammoth company like Google then no entrenched market is safe. Opportunities for success are everywhere. Now if we could only vote for green government with our PowerBooks . . .