Finding new angles on solar energy
If you鈥檝e ever looked at a flat-screen TV or computer monitor from an odd angle, you鈥檒l get an idea of the challenge facing manufacturers of solar panels. Just as you can鈥檛 properly see the image on a flat screen from the wrong angle, a solar panel can鈥檛 capture solar radiation properly unless the angle is dead on.
Not any more, according to Glint Photonics, a new company whose technology is so intriguing that it has received funding from the US Department of Energy鈥檚 Advanced Research Projects Agency for Energy (ARPA-E).
骋濒颈苍迟听听that it has developed a protean material that adapts its reflectivity depending on the heat from concentrated sunlight. This passive, 鈥渟elf-tracking鈥� technology enables the panel to capture sunlight shining on the panel at different angles at different times of the day.
Some solar panels now use complex mechanisms, which enable manufacturers to produce smaller, less costly solar cells. But the current method involves mirrors or lenses whose angles must be changed precisely as the Sun moves across the sky. This requires an expensive structure of steel and concrete to ensure stability.
Glint says its light concentrator technology is less complex and much less expensive. It starts with a set of thin, inexpensive lenses that concentrate sunlight. It also has a sheet of glass that gathers light over its surface and can concentrate light up to 500 times more than conventional solar panel surfaces.
Here鈥檚 how it works: The glass sheet is coated on both sides with reflective materials that trap sunlight inside the glass itself. The light energy bounces back and forth between these reflective coatings within the glass sheet until it reaches the edge of the glass, where it becomes concentrated. At this edge is mounted a small solar cell that absorbs the energy and generates electricity.
Meanwhile, as the Sun moves across the sky, the material on the glass adapts to get the optimal angle for absorbing solar radiation. This cuts the need to keep the focusing mechanism pointed directly at the Sun.
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Peter Kozodoy, Glint鈥檚 CEO,听听that once Glint鈥檚 solar panels hit the market, the power they generate could cost as little as 4 cents per kilowatt-hour, exactly half the cost of today鈥檚 best conventional solar panels. So far, though, the startup has been limited to testing only tiny prototypes measuring just about an inch wide.
Thanks to a $2.2 million grant from ARPA-E, though, Glint will be able to begin testing panels measuring almost a foot wide, nearly large enough for a commercial application.
Yet there鈥檚 one more hurdle, according to Howard Branz, a program director at ARPA-E. He says Glint should find a way to increase the amount of sunlight that the lenses and the glass panel deliver to the solar cells. So far, he explains, some of that light is diverted, and therefore wasted, before it reaches its goal.
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