Harvesting electricity directly from the best solar power plants in the world (photosynthetic plants)? Sound too good to be true? Well it may be a possibility in the near future, thanks to new research from the University of Georgia.
Researchers there have developed a way to “interrupt” photosynthesis and redirect the electrons before they are used to make sugars. If you’re wondering why this is a potentially importent discovery, it’s because photosynthetic plants function at nearly 100% quantum efficiency. What that means is that almost every photon of sunlight that is captured by the plant is converted into an electron. For comparison, most of the solar cells of today operate at about 12-17%. That’s a huge difference, and potentially a huge improvement in efficiency for solar energy generation. Though, of course, that’s only if the technology and economics can be worked out….
“Clean energy is the need of the century,” said Ramaraja Ramasamy, assistant professor in the UGA College of Engineering and the author of the paper published in the Journal of Energy and Environmental Science. “This approach may one day transform our ability to generate cleaner power from sunlight using plant-based systems.”
For a bit of background, during photosynthesis, the photons that are captured by the plant are used to split water molecules into the component parts of oxygen and hydrogen. By doing so, they produce electrons. The electrons are then utilized by the plant to create sugars that are then used by the plant (and the animals that eat it) for growth and reproduction.
The press release from the University of Georgia gets into the specifics:
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.
As a result of the first, small-scale experiments of this technology, electrical current levels that are two orders of magnitude larger than any previously reported in similar systems have already been produced.
There is obviously a great deal that would still need to be done before such a technology could be commercialized, but it’s definitely an interesting one….
The researchers are currently working on improving the output and stability of the technology.
“In the near term, this technology might best be used for remote sensors or other portable electronic equipment that requires less power to run,” Ramasamy 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.”
“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.”