Human poo is now about to become one of the world's most valuable bio-fuels, if it can be harvested and extracted properly.

Researchers at the United Nations University Institute for Water, Environment and Health have priced the current amount of poo produced by humans at $9.5 billion or €8.75 billion.

"We recycle the nutrients in human waste effectively via agriculture in many places, yet the potential energy value of human waste has been given much less attention to date," explained Chris Metcalfe of Trent University, one of the authors of the report.

"Challenges are many but clearly there is a compelling, multi-dimensional financial case to be made for deriving energy from waste."

The human poo is harvested and turned into methane-rich biogas that's generated by the bacterial breakdown of poo in an oxygen-free environment. Researchers believe that the residue could then be dried and charred into sludge, an energy source that's similar to fossil fuels like coal or charcoal.

What's not so simple, however, is the actual cost of initial production, something researchers believe will make the process unfeasible - not to mention people's own disgust about the whole thing. "Clearly there is a financial incentive in generating energy by-products from waste, but this may not be sufficient in all cultures to overcome the 'ick' factor of using our own waste."

No sh**.