A group at the Bristol Robotics Laboratory have developed a novel way of charging mobile phones - using urine as the power source to generate electricity.

Lead author Dr. Ioannis Ieropoulos from the University of the West of England is an expert at harnessing power from unusual sources using microbial fuel cells and says, “We are very excited as this is a world first, no-one has harnessed power from urine to do this so it's an exciting discovery. Using the ultimate waste product as a source of power to produce electricity is about as eco as it gets.”

Basically, the microbial fuel cells contain bacteria that produce electricity from pee. Bet you never thought of that, Muad'Dib.

“One product that we can be sure of an unending supply is our own urine. By harnessing this power as urine passes through a cascade of microbial fuel cells (MFCs), we have managed to charge a Samsung mobile phone," Ieropoulos says. "The beauty of this fuel source is that we are not relying on the erratic nature of the wind or the sun; we are actually re-using waste to create energy.

“So far the microbial fuel power stack that we have developed generates enough power to enable SMS messaging, web browsing and to make a brief phone call. Making a call on a mobile phone takes up the most energy but we will get to the place where we can charge a battery for longer periods. The concept has been tested and it works – it's now for us to develop and refine the process so that we can develop MFCs to fully charge a battery.”

The Microbial Fuel Cell is an energy converter, which turns organic matter directly into electricity, via the metabolism of live microorganisms. Essentially, the electricity is a by-product of the microbes' natural life cycle, so the more they eat things like urine, the more energy they generate and for longer periods of time; so it's beneficial to keep doing it! The electricity output from MFCs is relatively small and so far we have only been able to store and accumulate these low levels of energy into capacitors or super-capacitors, for short charge/discharge cycles. This is the first time we have been able to directly charge the battery of a device such as a mobile phone and it is indeed a breakthrough.

The researchers believe that the technology has the future potential to be installed into domestic bathrooms to harness the urine and produce sufficient electricity to power showers, lighting or razors as well as mobile phones.

Ieropoulos concludes, “We are currently bidding for funding to work alongside partners in the US and S. Africa to develop a smart toilet. Watch this space.”

Bristol Robotics Laboratory is a collaboration between the University of the West of England (UWE Bristol) and the University of Bristol.  The project has been funded by the Engineering and Physical Sciences Research Council (EPSRC), the Gates Foundation and the Technology Strategy Board.

Citation: Ioannis Ieropoulos, Pablo Ledezma, Andrew Stinchcombe, George Papaharalabos, Chris Melhuish and John Greenman, 'Waste to Real Energy: the first MFC powered mobile phone',  Phys. Chem. Chem. Phys., 2013 DOI: 10.1039/C3CP52889H