Bacteria-powered solar panels could work in cloudy skies

Canadian researchers have created a bacteria-powered solar cell that works as efficiently in dim light as in bright light.

It could lead to wider adoption of solar technology in areas of the world where overcast skies are common, such as northern Europe, or British Columbia where the research team are based. With further development, these so-called ‘biogenic’ cells could become as efficient as current synthetic technology.

Previous efforts at building ‘biogenic’ solar cells have focussed on extracting the natural dye that plants use to turn light into energy during photosynthesis. But it’s an expensive and time-consuming process involving toxic solvents.

Instead, the researchers from the University of British Columbia decided to leave the dye in the bacteria. They genetically engineered E. coli to produce large quantities of lycopene – an orange-red dye found in tomatoes that is particularly effective at harvesting light for conversion to energy.

They then coated the bacteria with a mineral to act as a semiconductor, and applied the mixture to a glass surface. Their simple cell was able to generate a current density of 0.686 milliamps per square centimetre, an improvement on the 0.362 achieved by others in the field.

"We recorded the highest current density for a biogenic solar cell," said Vikramaditya Yadav, a professor of chemical and biological engineering who led the project. "These hybrid materials that we are developing can be manufactured economically and sustainably, and, with sufficient optimisation, could perform at comparable efficiencies as conventional solar cells."

Yadav believes the process could reduce the cost of producing biogenic solar cells to one-tenth of current levels, and that there could be other potential applications in mining, deep-sea exploration and other low-light environments.