Try this Google in Black Firefox search extension and save 750 Megawatts-Hours of energy a Year.

I have created this search plug-in using Google's Custom search. The specialty of this plug-in is , the search result will be on a black background with white and green text. To display black color on screen monitors requires a very small amount of power comparing other colors.

Install Google in Black.

Related: You can save 750 Megawatt-hours of energy while browsing