This article was taken from the April 2012 issue of Wired magazine. Be the first to read Wired's articles in print before they're posted online, and get your hands on loads of additional content by subscribing online.

Machines traditionally rely on humans to provide access to

­electricity. But what if they could generate their own fuel?


Devised by a team at Bristol University, EcoBot III is claimed to be the world's first self-sustaining robot. It collects water and acetate; microbes in its "stomach" break this down and pass it to 48 fuel cells that turn the fluid into ­electricity, powering the 63-cm-tall EcoBot to forage again -- for up to eight days before it needs cleaning. "One possible application would be to have a fleet of machines living in the sewers, cleaning while ­gathering their own food," explains Ioannis Ieropoulos, a senior research fellow at the Bristol Robotics Laboratory. The team has been working on some new applications: "The next EcoBot will work like a conventional flytrap, whereby the robot attracts its own food. Flies will be the source of energy." EcoBot can also turn urine into electricity.

What happens to all the products EcoBot doesn't use? It passes semi-solid pellets into a litter tray. Like a cat. Ew.