TheNextBigThing

Despite being only 13, me and a friend were thinking of new ways to advance automotive travel. We came up with the idea of a hydrogen-powered engine powered by water, but after further research found that our idea was already a reality. I then thought of a new option: why not use a human by-product like urine? I'd seen it done before with vegetable oil, so why not use a similar reaction involving electrolysis to extract hydrogen from the urine? Responses to my theory please.