No Batteries Needed! Future Robots May Run on Urine
 

Okay, let the jokes begin, but keep in mind there is serious scientific research being done in restrooms all over Bristol. Two universities have collaborated on what can only be called "pee power" to fuel autonomous robots in the near future. In the past 10 years, researchers have built four generations of EcoBots, each able to use microorganisms to digest the waste material and generate electricity from it, the university said.

http://www.hardocp.com/news/2013/11/..._run_on_urine/