Wow... My immediate idea is exactly the oposite from the one proposed in the article:
Have robots that can "live" by eating "food"! Imagine a robot, say a "spider" or a "mouse", that roams around a city, collecting food (and has a form of a "stomach", similar to say the one that cows have, where there are bacteria, dissolving food and producing glucose), and it can use that glucose to generate electricity, indefinitely... An interesting idea!
Have robots that can "live" by eating "food"! Imagine a robot, say a "spider" or a "mouse", that roams around a city, collecting food (and has a form of a "stomach", similar to say the one that cows have, where there are bacteria, dissolving food and producing glucose), and it can use that glucose to generate electricity, indefinitely... An interesting idea!