Flat battery? Urine luck

A group of researchers at the University of Bath, in Great Britain have developed a urine-powered miniature fuel cell that's already capable of recharging a smartphone.

The device is just 25 square millimeters and uses a carbon catalyst created from the protein commonly found in an egg white -- in other words, biomass. The urine passes through it and thanks to the ‘electric' bacteria present in the substance, electricity is generated that can be sent to a battery for storage or used to directly power an electrical device.

A single fuel cell can generate 2 watts per cubic meter, that's sufficient for topping up a smartphone, but the cells can be stacked for boosting electrical output.

Lecturer in the University of Bath's Department of Chemical Engineering and corresponding author, Dr Mirella Di Lorenzo, said: "If we can harness the potential power of this human waste, we could revolutionize how electricity is generated."

There are already numerous renewable sources of energy available to those wanting to reduce their carbon footprint. However, what makes the pee-powered fuel cells so exciting is first and foremost their cost. Rather than precious metal such as platinum, the catalyst is created from biomass, decomposing waste that would be recycled or sent to landfill anyway, while the cost of producing urine is essentially non-existent. What's more, as long as there are people, there will always be urine, it's an energy source that is never going to wane.

"Microbial fuel cells can play an important role in addressing the triple challenge of finding solutions that support secure, affordable, and environmentally sensitive energy, known as the ‘energy trilemma'," explained Dr Di Lorenzo. "There is no single solution to this ‘energy trilemma' apart from taking full advantage of available indigenous resources, which include urine."

The research team, which includes members of Queen Mary University of London and the Bristol Bioenergy Centre, are particularly excited about the technology's potential in rural areas or in emerging countries.

Lead author Jon Chouler said: "To have created technology that can potentially transform the lives of poor people who don't have access to, or cannot afford electricity, is an exciting prospect. I hope this will enable those in need to enjoy a better quality of life as a result of our research."