It's kinda been really invented.
(I know this might be LBN but I thought it'd get lost in there; sorry)
Scientists develop portable generator that turns trash into electricity
WEST LAFAYETTE, Ind. - A group of scientists have created a portable refinery that efficiently converts food, paper and plastic trash into electricity. The machine, designed for the U.S. military, would allow soldiers in the field to convert waste into power and could have widespread civilian applications in the future.
"This is a very promising technology," said Michael Ladisch, the professor of agricultural and biological engineering at Purdue University who leads the project. "In a very short time it should be ready for use in the military, and I think it could be used outside the military shortly thereafter."
The "tactical biorefinery" processes several kinds of waste at once, which it converts into fuel via two parallel processes. The system then burns the different fuels in a diesel engine to power a generator. Ladisch said the machine's ability to burn multiple fuels at once, along with its mobility, make it unique.
..more at link..
http://news.uns.purdue.edu/x/2007a/070201LadischBio.html