Fuel made from yellow snow...
 

Minus the snow.

Short version, four teenage girls from Africa created an electric generator that works off the yellow stuff.

Thing is, us guys might suffer. Public restrooms already have seperate waste receptacles for the liquid stuff. If there was an attempt to harvest potty, it'd likely start there, but that might involve urinals that don't water the stuff down anymore.

Which could lead smelly bathrooms. Then again, they might find a way around this, that could cut down on the stink.

Edit: This article paints a picture that the process is necessarily the answer to energy needs.

Well... that's the most vile, gross fuel source I've seen yet.

... This knowledge will prove most useful.

Beats making a meat from shit by a significant margin!

By a mile even!

Still can believe that's a thing people do.

Its no different than electrolysis of water into hydrogen. You can't get more energy out of making a chemical bond than you got from breaking. I mean maybe the bond energy of the hydrogen in the urea is slightly higher in energy (bonds having negative energy meaning higher energy bonds take less energy to break) than the bond energy of hydrogen in water. Unfortunately with the inefficiencies of the electrolysis and the unavoidable inefficiencies of any engine (like 20% efficiency is actually really really good for an engine) you'd need a very large difference in bond energy. Much larger than I think there is between urea and water. The very fact that urea doesn't oxidize (read burn) probably means that it takes more energy to break bond between the Hydrogen and the Nitrogen than you'll get from forming water and whatever other products.

Of course its quite obvious that since urea is an end product of metabolism (read burning things very slowly in cells to give you energy) it probably has very little to no available energy. Otherwise we'd metabolize it into something else and use that energy.

still doesn't beat the article I read once about a prototype train that runs off of corpses.

In all seriousness though, that is very disturbing
 

Best job Kratos ever had.

The British had those a century ago. They just shoveled Egyptian mummies into steam locomotives. At least according to Mark Twain.

Ahahahahahaha, "used to". Twenty-seconds-ago me is so adorably naive.
 

Mummies used to be used for a lot of shit, including kindling and medicines. I may be misremembering from my many, many "Hey Kids! It's Ancient Egypt!" -type books, but some high-society types in England even held "unwrapping parties" where they'd just start sawing into a nice-lookin' mummy and dig around in it to see what they'd find. ("Wow, I got a lapis lazuli amulet!" "...I got a toe.")

People used to treat their history like shit, is what I'm saying.

Guys, I have invented an engine that runs on the blood of the innocent! (A 60-40 ratio mix of innocent to stained with knowledge is also possible.) The wheels make a weird whining noise but that's probably just a lubrication issue.