[Crusher138]

Yeah, but we are talking about most of the "energy" coming from fairly useless stuff. When you look at the entire process of drilling and refining oil in the traditional sense, I'm sure its efficiency, when viewed as an entire process, isn't too great.

[boris]

"Yeah, but we are talking about most of the "energy" coming from fairly useless stuff. When you look at the entire process of drilling and refining oil in the traditional sense, I'm sure its efficiency, when viewed as an entire process, isn't too great."

If it were not then nobody would drill and refine oil. The reason oil drilling pays off is that the 'battery' was charged over millions of years by photosynthesis from the Sun. Oil is condensed solar energy, which is 'free' because we are obtaining it for far less energy than one can release by burning it.