New solar cells achieve 40% conversion efficiency
Scientists at a Boeing subsidiary have developed a new type of photovoltaic cell that has surpassed an energy conversion efficiency of more than forty percent for the first time. Instead of the usual single-junction silicon cells, Spectrolab scientists have fabricated multi-junction cells. The advantage is that multi-junction cells can absorb many more of the frequencies that are available in sunlight. This has allowed them to achieve a conversion efficiency of 40.7 percent. The theoretical limit of single junction cells is only 37 percent and actual measured values are much lower than that. The three junction cells that the team are building right now have a theoretical limit of 58 percent efficiency and they predict that 45-50 percent measured efficiency can be achieved.
[Source: PhysOrg, thanks to Ray and TX CHL Instructor for the tip]
Reader Comments (Page 1 of 1)
DB 9:55AM (6/04/2007)
If these can be produced at an economical price point, in the words of many wise men, "forgedaboudit."
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kert 11:00AM (6/04/2007)
some guys over at RC Groups forums have gotten their hands on previous gen Spectrolab sample batches and built amazing solar flying RC micro airplanes.
the sad fact is, that the most efficient ones commercially available in quantities are about 18%.
Spectrolab ought to be licencing this tech out like crazy.
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Tony Belding 1:09PM (6/04/2007)
According to the original article, these are concentrator cells. So, you need mirrors or lenses to concentrate the sunlight, and some kind of sun-tracking system.
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small-wee-wee 2:21PM (6/04/2007)
They use multiple layers of cells all focused at different light spectrum. Using multiple layers increases the costs by the factor of layers. three layers uses 3x as much resources and costs about 3x as much.
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PeakVT 11:13PM (6/04/2007)
Higher efficiency is good for space-limited applications like the roof of a car, but the bottom line is $/W. A 10% efficient system that costs $4/W is better than a 40% efficient system that costs $8/W with respect overall energy use.
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mikeinBuilding7 4:36PM (6/05/2007)
- Isn't unit cost based upon the size of the run?
- Mass Produce these and the unit cost should drop substantially.
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kert 5:31AM (6/05/2007)
"but the bottom line is $/W"
not for every application. for solar-powered flight there is a efficiency treshold to be crossed to make it even workable. you can get very slow gliders to fly with current thin-film cells, but barely so. for practical UAV platforms you would need more speed ( read: weather tolerance )
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Dave 9:13AM (6/05/2007)
small wee-wee
The installed cost will not triple because acreage, labor, and other installation costs will not triple.
That is why this is important.
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bill 1:16PM (6/05/2007)
40% conversion? Most NBA basketball teams can't convert 40% of anything, so maybe we need to dump NBA basketball and spend our leisure time watching solar cells converting whatever it is they convert.
Will there be technical fouls, or just technical obstacles to overcome?
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Manu Sharma 4:38PM (6/06/2007)
These are prohibitively expensive cells not meant for flat panels (except when you're sending satellites in space or rovers on Mars).
They cost around $10-$20/sq.cm (that's correct) so a 1 sqm panel should set you back by only $100,000 to $200,000.
Multi junction cells are already in mass production (all those satellites need power to keep those instruments running) for a while but the industry could do with some competition. Right now there are only two companies producing these cells - Boeing's Spectrolab and Emcore.
The high cost doesn't mean you'll never see them on rooftops...a bunch of companies are planning to launch concentrators that have these cells at their core.
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