Making urine an energy source for the future

The search is on for new sources of renewable energy and a promising field for these sources is bioenergy, the energy derived from living or recently deceased organisms. One means of sourcing bioenergy is to use microbial fuel cells that can produce electricity from waste matter such as urine. Researchers at the University of Bath, Queen Mary University of London and the Bristol Robotics Laboratory have worked on methods to make these microbial fuel cells a more viable large-scale source of renewable energy.

“The world produces huge volumes of urine and if we can harness the potential power of that waste… we could revolutionise the way we make electricity” claims Dr Mirella Di Lorenzo and indeed the accessibility of urine makes it an attractive source of bioenergy, particularly in developing countries. However, microbial fuel cells are typically flawed by their high cost due to the materials needed to catalyse the reaction and their low power production.

Where initially platinum was needed to catalyse the reaction, the researchers have found that certain types of food waste may be used as an alternative and that the platinum cathode can be replaced with carbon cloth and titanium wire. Furthermore, it was found that power output could be increased tenfold by increasing the length of the electrodes and then increased by tenfold again by stacking fuel cells.

The fact that the cell design has such an impact on the performance of the fuel cell is encouraging and the scientists want to further this research by working on optimising the surface area to volume ratio of the cells. Dr Di Lorenzo hopes this research can be used to miniaturise the fuel cells to make “compact batteries of multiple miniature units” which would “scale-up power production”.

The original paper can be found here.

Image credit: © felipecaparros / Fotolia