I guess you could call it the "poop"cycle. Definitely a limitless energy source.
Link is to the GM-volt website.
http://gm-volt.com/2012/03/29/hybrid-rickshaw-runs-on-human-trash-animal-poo-and-electrons/
Link is to the GM-volt website.
http://gm-volt.com/2012/03/29/hybrid-rickshaw-runs-on-human-trash-animal-poo-and-electrons/