New algae fuel cell packs a punch

algae fuel cell
© Kadi Liis Saar

A new algae-based fuel cell developed by the University of Cambridge is five times more efficient than existing devices. Researchers have long looked to algae as a power source because of its efficiency in turning sunlight into energy. This new technology, called a biophotovoltaic, is able to harvest the energy in sunlight to produce electricity like a synthetic solar cell, but using organic materials.

The basis of the new technology is a genetically-modified algae that carries mutations that lower the amount of electric charge released nonproductively during photosynthesis, so less was going to waste. The other major change was building a two chamber system for the device. The two chambers separate the two processes of generation of electrons through photosynthesis and the conversion of those electrons to electricity, which in previous devices has be done in a single unit.

“Separating out charging and power delivery meant we were able to enhance the performance of the power delivery unit through miniaturisation,” said Professor Tuomas Knowles from the Department of Chemistry and the Cavendish Laboratory. “At miniature scales, fluids behave very differently, enabling us to design cells that are more efficient, with lower internal resistance and decreased electrical losses.”

The biophotovoltaic cell is five times more efficient than their last design, but is still not only about one-tenth as efficient as a silicon solar cells. The researchers are not discourage by this though because the algae-based cell has many advantages over synthetic version.

Since algae grows and divides naturally, the devices based on it can be made cheaply and could be literally homegrown. The other advantage to this system is its dual chamber system which would automatically allow for electricity to be generated during the day and stored for later use at night.

The researchers see this technology being particularly well-suited to regions where there isn't a centralized electrical grid, but there is an abundance of sunlight, like rural Africa.

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