University of Capetown's Disposable Solar Panel
by John Laumer, Philadelphia on 11.22.05
Researchers at the University of Cape Town SA have developed a protoytpe method for printing solar panels on paper. We wish we had a photograph of their working prototype SPV panel on display, but none yet seem to exist. However, our 'concept bait' picture does fairly represent the designers' intent of producing electricity affordable by the poorest of rural families. The method seems to involve printing with modified color printers, using three or four separate print runs with black, blue, yellow and magenta inks containing tiny silicon particles. They print the metal contacts, then the semiconductor structure, then more contacts. The voltage and power output of the solar cell is determined by the size of the poster. An "A2-sized poster" will deliver up to 100W of power, enough to charge a cellphone, power a radio or provide five hours of lighting, according Prof David Britton. News coverage from SA outlets mentions that 'Shops could stock rolls of solar panel posters, and cut it to meet a customer's needs. The poster could be mounted behind a window or attached to a cabinet'.
Apparently the research team is seeking to commercialise the project. Coupling nanotech with AutoCad fast prototyping is about as advanced as TreeHugging gets. Let's hope they're as good at business as they are at inventing because this could help drive down the price much faster than anyone imagined possible. Recalling that paper can be made of various non-woven polymer strands that are entirely water resistant, this seems like it has great potential. Might even be room to recycle the paper at end of life. Guess we're getting ahead of the prototype idea though. Congrads to Professor Britton and his Capetown associates.
this is an interesting progression, let's not forget though that DISPOSABLE is not eco friendly even though business loves it because it means "sell more"
=== author's response follows ====
Categorically, your's is a legitimate and typical response. However, every product is in fact a a throwaway at some point. The range of experience is minutes, like a paper cup, to 30 years, like a crystialline silica SPV panel. The inventor's point is that rural families in SA can simply not afford the 30 year design life, whereas an 18 month design life (on paper) is imminently affordable and results in the desposal of far less mass and far less loss of embodied energy per year of useful life than the traditional panel system. Argueably, once they get beyond prototype the makers can work out the optimal materials of construction vs cost to extend design life.
A2 size is (in mm): 420 x 594 = 0.25 m^2. At the rate of the most common panels around, one can expect about 200W/m^2, or 50W from that area. They say they're getting 100W from it. That seems unlikely. In fact, the sun only puts out about 1KW/m^2. If they're getting 400W/M^w, that's 40% efficiency, which is perhaps attainable with the most expensive possible space age materials.
I suspect either a typo, or maybe they meant 100KWh, meaning in a day (nominally 5 hours of light in Africa) it gets 20W per hour. Recall that a rigid panel will reliably generated 50W. 20W would seem feasible for amorphous media.
If they can print these cheaply, that's impressive!
I suspect considering the likely efficiency of the panels the output of the the panel is probably 100mw or one thousandth of the 100w that the article says. The 100mw figure also is in line with the function of charging small electronics.
It is still very interesting, especially if they are waterproof. If you need to print new ones every time it rains on one it could get expensive;)
Thanks for being such great fact checkers. I suspect your comments are on point and attribute the mistake to the original press release which was essentially copied by at least three separate publications. THe same mistake would not have occurred thrice of course. If the researchers had posted more precise and detailed information on their university website I certainly would have linked back to it and had the corrected figure to offer. But they did not. Maybe if we are lucky they will comment here!
Step 1: Horizontal printing.
Step 2: Solar powered grafitti.
Wow, quite impressive. It would help us in the Renewable Energy market, since in developing countries (Latin America for example) the prices are so high due to the demand in the developed countries.