A Sticker Makes Solar Panels Work Better

[greencat]

A startup's polymer sticker increases power output by 10 percent, and can be applied to panels that are already installed.



The power output of solar panels can be boosted by 10 percent just by applying a big transparent sticker to the front. Developed by a small startup called Genie Lens Technologies, the sticker is a polymer film embossed with microstructures that bend incoming sunlight. The result: the active materials in the panels absorb more light, and convert more of it into electricity.


The technology is cheap and could lower the cost per watt of solar power. Also, unlike other technologies developed to improve solar panel performance, this one can be added to panels that have already been installed.

The polymer film does three main things, says Seth Weiss, CEO and cofounder of Genie Lens, based in Englewood, CO. It prevents light from reflecting off the surface of solar panels. It traps light inside the semiconductor materials that absorb light and convert it to electricity. And it redirects incoming light so that rather than passing through the thin semiconductor material, it travels along its surface, increasing the chances it will be absorbed.

Researchers designed the microstructures that accomplish this by using algorithms that model how rays of light behave as they enter the film and encounter various surfaces within the solar panel--the protective glass cover, the semiconductor material, and the back surface of the panel--throughout the day. The key was bending the light the optimal amount, enough that it enters the solar panel at an angle, but not so much of an angle that the light reflects off and is lost. If light does reflect off either the glass or semiconductor surfaces, the film redirects much of it back into the solar panel.

Tests at the National Renewable Energy Laboratory showed that the film increases power output on average between 4 percent and 12.5 percent, with the best improvement under cloudy conditions, when incoming light is diffuse. Adding the film--either in the factory, which is optimal, or on solar panels already in use--increases the overall cost of solar panels by between 1 percent and 10 percent. But the panels would then produce enough additional electricity to justify the price. What's more, increasing the power output of a solar panel decreases other costs--such as shipping and installation--because fewer solar panels are required at each installation, says Travis Bradford, a solar industry analyst and president of the Prometheus Institute

Read more Technology Review: A Sticker Makes Solar Panels Work Better