UK scientists are claiming a world first in developing a way to charge mobile phones using human urine.
The Bristol-based boffins have been able to charge a Samsung phone by putting urine through a cascade of microbial fuel cells.
They have generated enough electricity to send text messages, browse the internet and make a brief phone call.
The scientists now plan to develop the technology to be able to fully charge the handheld device.
The discovery has been made by a team of experts working at the Bristol Robotics Laboratory, which is a collaboration between the University of the West of England and the University of Bristol.
Dr Ioannis Ieropoulos, from the University of the West of England, is an expert at harnessing power from unusual sources using microbial fuel cells.
"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," he said.
"Using the ultimate waste product as a source of power to produce electricity is about as eco as it gets.
"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, we have managed to charge a Samsung mobile phone.
"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 microbial fuel cells to fully charge a battery."
The microbial fuel cells 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.
The electricity output from microbial fuel cells is relatively small and so far the Bristol scientists have only been able to store and accumulate these low levels of energy into capacitors or super-capacitors, for short charge or discharge cycles.
It is the first time they have been able to directly charge a mobile phone battery.
The project has been funded by the Engineering and Physical Sciences Research Council, the Gates Foundation and the Technology Strategy Board.
Dr Ieropoulos believes 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.