Scientist Michael Hoffmann at the California Institute of Technology, who has been experimenting with solar-powered water treatment on a small scale, is now planning to incorporate the technology into a portable toilet. Michael found that sunlight powers an electrochemical reaction with human waste in water that generates microbe-killing oxidants and releases hydrogen gas. He plans to collect the hydrogen in a fuel cell to power a light or possibly even a self-cleaning mechanism. Hoffmann received grant from the Bill and Melinda Gates Foundation to build a prototype.