A web page totally white uses about 74 W in order to be viewed on a computer monitor. A black page uses 59 W. Starting from this assumption, Mark Ontkush has calculated how much will be saved if Google would put a black background on the home page.

Assuming that the results of each query will be shown by a browser for a period of about 10 seconds and knowing that Google serves about 200 milion queries daily, we found that Google is viewed daily for about 500.000 hours all around the world.

The savings would be about 3000 MegaWatt-hours yearly.

If we use the average UK cost of energy in terms of CO2 footprint, then the white Google background is responsible for 1410 tons of CO2 of emissions yearly.

If you prefer to calculate the emissions with different colors, you can check here on the consumption of using a pixel of different colors.

Thanks to Tagliablog for the signalation.