Friday, May 10, 2013

Electricity Production From Plant Photosynthesis

Ramaraja Ramasamy, right, and Yogeswaran Umasankar
work together to capture energy created during photosynthesis.
Ramasamy is an assistant professor in the UGA College of Engineering
 and Umasankar is postdoctoral research associate working i
n his lab. (Credit: Image courtesy of University of Georgia)
Ramaraja Ramasamy, assistant professor in the UGA College of Engineering, is the author of a paper describing the process of how to get electrical power from sunlight using plant-based systems.  The process was published in the Journal of Energy and Environmental Science. Plants are the undisputed champions of solar power. Most of them operate at nearly 100 percent quantum efficiency, meaning that for every photon of sunlight a plant captures, it produces an equal number of electrons. onverting even a fraction of this into electricity would improve upon the efficiency seen with solar panels, which generally operate at efficiency levels between 12 and 17 percent.

During photosynthesis, plants use sunlight to split water atoms into hydrogen and oxygen, which produces electrons. These newly freed electrons go on to help create sugars that plants use much like food to support growth and reproduction.  The researchers have developed a way to interrupt photosynthesis so that they can capture the electrons before the plant uses them to make these sugars.

According to Ramasamy, who is also a member of UGA's Nanoscale Science and Engineering Center, the technology involves separating out structures in the plant cell called thylakoids, which are responsible for capturing and storing energy from sunlight. Researchers manipulate the proteins contained in the thylakoids, interrupting the pathway along which electrons flow.  These modified thylakoids are then immobilized on a specially designed backing of carbon nanotubes, cylindrical structures that are nearly 50,000 times finer than a human hair. The nanotubes act as an electrical conductor, capturing the electrons from the plant material and sending them along a wire.
In small-scale experiments, this approach resulted in electrical current levels that are two orders of magnitude larger than those previously reported in similar systems.

Ramasamy cautions that much more work must be done before this technology reaches commercialization, but he and his collaborators are already working to improve the stability and output of their device. In the near term, this technology might best be used for remote sensors or other portable electronic equipment that requires less power to run. The researcher believe that if they we are able to leverage technologies like genetic engineering to enhance stability of the plant photosynthetic machineries, they are very hopeful that this technology will be competitive to traditional solar panels in the future. (Science Daily, 5/9/2013)

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