Hidden Solar Cells Could be an Option for Homeowners

The bigger problem with solar is the need for energy storage, or an energy substitute when the sun isn't shining. Energy can be stored in batteries or more elaborate systems. For most homeowners, the best substitute is the electricity grid - sell excess solar energy to the grid during the day and buy cheap electricity from it at night.

Once you've made these decisions, then aesthetics of the solar array can be considered and the article below may have a solution for some folks.

Our home faces south, so photovoltaic cells would need to be mounted on the street facing surface of our roof, or we would have the increased expense of building frames to hold them at the correct angle on the back side of the roof. Our neighbors might not mind a bunch of solar panels, but they would also need to be approved by the dreaded HOA.

Hidden Solar Cells: 3-D System Based On Optical Fiber Could Provide New Options For Photovoltaics:
"Converting sunlight to electricity might no longer mean large panels of photovoltaic cells atop flat surfaces like roofs.

Using zinc oxide nanostructures grown on optical fibers and coated with dye-sensitized solar cell materials, researchers at the Georgia Institute of Technology have developed a new type of three-dimensional photovoltaic system. The approach could allow PV systems to be hidden from view and located away from traditional locations such as rooftops.

"Using this technology, we can make photovoltaic generators that are foldable, concealed and mobile," said Zhong Lin Wang, a Regents professor in the Georgia Tech School of Materials Science and Engineering. "Optical fiber could conduct sunlight into a building's walls where the nanostructures would convert it to electricity. This is truly a three dimensional solar cell."

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Dye-sensitized solar cells use a photochemical system to generate electricity. They are inexpensive to manufacture, flexible and mechanically robust, but their tradeoff for lower cost is conversion efficiency lower than that of silicon-based cells. But using nanostructure arrays to increase the surface area available to convert light could help reduce the efficiency disadvantage, while giving architects and designers new options for incorporating PV into buildings, vehicles and even military equipment.

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Wang and his research team, which includes Benjamin Weintraub and Yaguang Wei, have produced generators on optical fiber up to 20 centimeters in length. "The longer the better," said Wang, "because longer the light can travel along the fiber, the more bounces it will make and more it will be absorbed."

Traditional quartz optical fiber has been used so far, but Wang would like to use less expensive polymer fiber to reduce the cost. He is also considering other improvements, such as a better method for collecting the charges and a titanium oxide surface coating that could further boost efficiency.

Though it could be used for large PV systems, Wang doesn't expect his solar cells to replace silicon devices any time soon. But he does believe they will broaden the potential applications for photovoltaic energy."