3-D Solar Cells Could Work Underground, Improve PV’s Aesthetic Value
Solar Cells underground? Photo Credit: ABC Science
The Georgia Institute of Technology developed solar cells that don’t look like solar cells at all. The fiber optic cables (2-3 times the width of human hair) collect light and send it to a unit buried in the wall or beneath the floor of the structure. The process of production requires less heat, and so damage to the system is less likely. The drawback? They are brand-new and not even close to market efficiency (compare their 3.3% efficiency with silicon PV panels’ 15-30%).
The low efficiency is certainly a drawback. But Dr. Zhong Wang of Georgia Tech thinks he can raise the efficiency to 8% with a little more work. That number is still low, but the optical cables, which are a lot like the stuff telephone companies use, have a more pleasing aesthetic. Only the tips of the cables need to be exposed to the environment, so it won’t look like your house grew a head full of hair.
“No one wants to buy a big, nice, fancy car with a huge solar panel on the roof,” Wang told ABC. He’s probably right. I might buy a solar car, given the money was there, but I would certainly lean toward little silver dots as a first choice if there was an option over bulky panels.
How Do the Fiber Optic Cables Work?
The cells use optical fibers with the ends coated in a zinc oxide nanostructure, a substance that Treehugger said was “much like the white stuff on a lifeguard’s nose.” The oxide is then coated with dye-sensitized material, which converts the sunlight to electricity using the photovoltaic effect - the process of converting light to electricity. The charge is captured in electrolyte that surrounds the nanostructures. Add a couple of wires and you can turn the lights on. Just amazing.
Each 10 centimeter-length (4 inches) of the optical line produces 0.5 V of power, so a 10-watt light bulb would need about 10,000 fibers. Sounds like a lot, but those fibers actually amount to a small handful of human hair.
Another advantage of this development is the energy it takes to make the optical cables. Zinc oxide is used at 70 degrees Centigrade, about the temperature of a cup of coffee. Silicon panels require hundreds of degrees and large equipment, which take up more energy. Also, silicon panels are exposed to the elements and that makes them susceptible to breakage. The sensitive parts of the whole operation for the optical cables are buried or within the walls, where such damage is unlikely.
New Jersey-based EarthSure recently announced their plans to use this type of technology inside a structure. In a hospital or other industrial building where the lights never go off, the optical cable system can recapture that energy into the building’s electric grid. The CEO of EarthSure also said that these panels the optical cables connect to could be constructed from cheaper material due to their protected location within or under the structure. The thing is that EarthSure needs a prototype or Wang needs a company behind him, so nothing is even close to a marketing stage yet.
Still, with the ability to use this technology indoors and out because of its unobtrusive nature, it’s an absolute win-win. Re-harvesting energy from light bulbs would become one of the highest forms of recycling ever invented, and is just a plain wise move. Building owners no longer have the same issues of aesthetics (there will, however, always be aesthetic issues because we’re all human). Solar cars would also benefit from something like this. Pretty darn spiffy, huh?
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