Is the urea – also called carbamide – found in urine a waste that may be too precious to waste? NewScientist hints that it might be a new source of fuel for producing renewable energy. “An adult produces enough urine each year to drive a car 1678 miles (2700 km) on energy from the urea it contains, according to calculations by Shanwen Tao, who develops urea-powered fuel cells at Heriot-Watt University in Edinburgh, UK.”  Dr Shanwen Tao and his research partner Dr Rong Lan have developed a prototype (diagram below) that does just that. Dr. Tao explains how he came upon the idea:

“Growing up in rural eastern China I was aware of the use of urea as an agricultural fertiliser. When I became a chemist and was looking at fuel cell development I thought of using it in the process. We are only at prototype stage at present, but if this renewable material can be used as a commercially viable and environmentally friendly energy source then we will be absolutely delighted, and many people around the world will benefit.”

Though still quite far from any practical application, the idea might not be as preposterous as it seems. The fuel cell system created by the research team can breakdown urea or urine from humans or animals into water, nitrogen and CO2, and also produce electricity at the same time. It does this without using any of the precious metals needed for current batteries, all while using cheaper membranes and less expensive catalysts. The team was supported by $200,000 in grant money from the Engineering and Physical Sciences Research Council to build the fuel system, which they think could be ideal for islands, deserts, and even on submarines. With a lot of energy and money spent to remove urea and other impurities from waste water, perhaps a system using urea would also bring down waste water treatment costs. A demonstration fuel cell is scheduled to be ready by next year.

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