I recently read an article on green computing, and it got me thinking about how linux compares to osx and windows in terms of power usage and carbon emissions. Obviously it depends quite a bit on the hardware involved, but I would imagine that, on similar hardware, linux and osx would beat windows by far. Unfortunately I haven't managed to find any real data to back this up, except for whats given on Apple's website. Its interesting to see that Microsoft's website asks you to install silverlight first (great energy saving right there!) and doesn't give anything other than marketing retoric, not that I really expected anything else from them. Linux is even more difficult to find out about, probably because linux marketing is pretty much non-existant.
So if anyone has seen any concrete info on linux, osx or windows energy usage please could you post it.