Yes, it's come to the stage in human evolution that someone has found use in the contents of our toilet flushes. Meet the poo-powered Beetle by Geneco, UK.

Volkswagen Beetle-Bio Bug

The team at Geneco specialise in recycling solutions you see, so they gave eco-friendly car building a crack. Called the Bio-Bug, the car essentially runs on the gas produced by human waste. You can't simply 'do your business' in the car's 'petrol tank' though. The gas is first extracted, in this case, from Bristol sewage treatment works in Avonmouth. Then the gas is refined and pressurised so it can be dispensed into the Bio-Bug's gas tank.

Geneco general manager, Mohammed Saddiq, sees the technology as a potential power alternative for future company cars. Geneco says waste from around 70 humans is able to power the car, which they say drives like a normal Volkswagen Beetle, for about 16,000km.

Not bad for a relatively eco-friendly, efficient and completely organic source of power. It may not be the cleanest technology but it is very clean to the Earth when compared to current fuels. And besides, how cheap can you get.