Millions of years have evolution has resulted in plants being the most efficient harvesters of solar energy on the planet. Much research is underway into ways to artificially mimic photosynthesis in devices like artificial leaves, but researchers at the University of Georgia (UGA) are working on a different approach that gives new meaning to the term “power plant.” Their technology harvests energy generated through photosynthesis before the plants can make use of it, allowing the energy to instead be used to run low-powered electrical devices.

Photosynthesis turns light energy into chemical energy by splitting water atoms into hydrogen and oxygen. This process produces electrons that help create sugars that the plant uses to fuel growth and reproduction. A team led by Ramaraja Ramasamy, assistant professor in the UGA College of Engineering, is developing technology that would interrupt the photosynthesis process and capture the electrons before the plant puts them to use creating sugars.

The technology involves interrupting the pathways along which the electrons flow by manipulating the proteins contained in thylakoids. Thylakoids are membrane-bound compartments at the site of the light reactions of photosynthesis that are responsible for capturing and storing energy from sunlight.

The modified thylakoids are immobilized on a specially designed backing of carbon nanotubes that acts as an electrical conductor to capture the electrons and send them along a wire. The researchers say that small-scale experiments of this system have yielded a maximum current density that is two orders of magnitude larger than previously reported for similar systems.

While you won’t be running your HDTV off the nearest tree anytime soon, Ramasamy says the technology has the potential to find its way into less power-intensive applications in the not too distant future.

"In the near term, this technology might best be used for remote sensors or other portable electronic equipment that requires less power to run," he said. "If we are able to leverage technologies like genetic engineering to enhance stability of the plant photosynthetic machineries, I'm very hopeful that this technology will be competitive to traditional solar panels in the future."

Ramasamy and his team are already working to improve the stability and output of the technology to get it to a stage suitable for commercialization.

"We have discovered something very promising here, and it is certainly worth exploring further," he said. "The electrical output we see now is modest, but only about 30 years ago, hydrogen fuel cells were in their infancy, and now they can power cars, buses and even buildings."

The team’s study appears in the journal Energy & Environmental Science.

Source: University of Georgia

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