Developing nations' next alternative power source: Urine

Can tech that tries to generate power from urine help produce sustainable energy in developing countries? A new study says yes.

The research from University of Bath, Queen Mary University of London and the Bristol Robotics Laboratory describes a new design of microbial fuel cell that's smaller, cheaper and more powerful than traditional ones.

The world's supply of fossil fuels is being depleted and there is increasing pressure to develop new renewable sources of energy. Bioenergy is one such source and microbial fuel cells can produce it.

The new design overcomes two limitations of standard microbial fuel cells: their cost and low power production.

"Microbial fuel cells have real potential to produce renewable bioenergy out of waste matter like urine," said Dr. Mirella Di Lorenzo, corresponding author. "The world produces huge volumes of urine and if we can harness the potential power of that waste using microbial fuel cells, we could revolutionize the way we make electricity."

The new miniature microbial fuel cell uses no expensive materials for the cathode; instead it's made of carbon cloth and titanium wire. To speed up the reaction and create more power, it uses a catalyst that's made of glucose and ovalbumin, a protein found in egg white. These are typical constituents of food waste.

"We aim to test and prove the use of carbon catalysts derived from various food wastes as a renewable and low-cost alternative to platinum at the cathode," said corresponding author Dr. Mirella Di Lorenzo.

They then tweaked the design to see what would produce more power. Doubling the length of the electrodes from 4mm to 8mm increased the power output tenfold. By stacking up three of the miniature microbial fuel cells, the researchers were able to increase the power tenfold compared to the output of individual cells.

Lead author Jon Chouler said that microbial fuel cells could be a great source of energy in developing countries, particularly in impoverished and rural areas, adding "Our new design is cheaper and more powerful than traditional models. Devices like this that can produce electricity from urine could make a real difference by producing sustainable energy from waste."

The study is published in Electrochimica Acta.