Saint Louis University engineers have developed a fuel cell battery that can run on flat soda, maple syrup, or any other sugar source. Enzymes in the device convert sugar into electricity with water as the byproduct.
Guess what, that carbon doesn't just disappear in the process. (The original article claims that water is the "main" by-product. Because as we all know, anything you release into the atmosphere is no longer your problem. Though it admittedly takes less time to grow more sugar than it does to grow more oil.)