Holographic Solar: At Least 25% More Efficient!
by Justin Thomas, Virginia on 07.12.06
In a demonstration in Japan, Holographic Solar was shown to increase the efficiency of solar cells by at least 25%. Prism Solar Technologies provided a "Gen-1" module for testing in Japan earlier this month. The module incorporates less than 12 cents (US) per watt of Prism’s proprietary holographic optical material (not including glass) and achieved a 25% increase in power output over the cells themselves. The module was tested by a Japanese solar cell/module manufacturer and was conducted by engineers at the Japanese company’s facility. The “Gen-1” module incorporates mono-facial cells and uses PST’s Holographic Planar Concentrator (HPC) technology.
Prism’s core technology is based on holographic optics, which can use a variety of PV cells and can spectrally select the desired portion of sunlight allowing for “cooler” solar cell operation while maintaining an increased power output by concentrating specific solar wavelengths unto the cells. Through passive tracking, Prism’s Holographic Planar Concentrator (HPC) technology can achieve higher output in the morning and late afternoon while reducing the amount of expensive silicon necessary in a module. Prism PV modules minimize the use of expensive solar cells in our modules but still maintain above average output.
:: See also this previous post on Holographic Solar.
I'm not entirely certain if it's what they mean, based on the news item on their website, but I think the 25% power output increase means that using the holographic material, they got 25% more power out of a given amount of solar cells than they would have otherwise. So, solar cells that would yield 100 Watts (W) of power before would yield 125 W of power afterwards. Solar panels cost in the neighborhood of $5/W right now, so a 100 W panel costs about $500.
If you count the $0.12/W cost for the holographic material before you count the power it adds, then you have a $512 panel [100*($5+$0.12)] that gives 125 W, for a cost of about $4.10/W which is a very nice 18% savings in $/W. Looking at Prism Solar Technologies' website, it seems that their panels use a lot more glass for a given amount of PV material than conventional panels do, however. Though the glass used in solar panels is a substantially smaller fraction of the $/W cost of a panel than the solar cells (not that I have numbers about, unfortunately), this still means that the actual $/W savings with this generation of Prism Solar Technologies' technology is going to be less than 18%. Any $/W savings for solar whatsoever is good news to me, though.
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I have thought of doing a similar experiment to this. Since solar power depends on the compton effect, the wavelength of the light has direct affect on the electricity generated. Therefore, filtering certain wavelengths, using a prism, would certainly generate different amounts of power.