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Researchers Improve Solar Cell Performance
Vegematic writes "Researchers at MIT have improved solar collectors using dyes. They just increased their performance results by a factor of 4. These paint-on materials can increase the power obtained from existing solar cells by a factor of over 40 without needing to track the sun. 'By collecting light over their full surface and concentrating it at their edges, these devices reduce the required area of solar cells and consequently, the cost of solar power. Stacking multiple concentrators allows the optimization of solar cells at each wavelength, increasing the overall power output.' There is also a shorter FAQ available."
Imagine that Window come crashing down... *cough*
You know, when they post another story about the incredible discoveries in solar power that seem to never actually make it to those of us who would be interested if it was cheaper and more efficient..... Show me a company that is already selling this stuff and then I'll be interested.
RTFG - Read The F#$%ing Google!
They should use this with the new 40% efficient solar cells. Then they'll have 160% efficiency!
Why did LSCs fail in the 1970's? Two reasons: the collected light was absorbed before it reached the edges of the glass or plastic plates, and the dyes were unstable.
What about stability? We tested one of our devices and found that it was stable (to 92 percent of initial performance) for three months. This isn't good enough yet for products but we are confident that the technology developed for organic light emitting devices (OLEDs) in televisions will be portable to this application.
once we reach peak solar in 2015.
http://twitter.com/OLDTELEGRAM
I have heard about a ton of solar technologies in the last 24 months that are supposed to revolutionize the way we get energy.
However, I don't see a product.
This is an uber product. The ability to generate electricity up to 40 times the amount of existing solar while allowing as low as 10% of the light to enter?
Commercial Buildings? This technology is off the hook. It not only generates electricity, it SAVES electricity being used to cool the building.
I am sure this would be used on new and existing residential buildings as well. The ability to create skylights while providing power?
I hope this one actually makes it to the market within 5 years.
If solar cell efficiency actually increased a mere 1% for each story slashdot has posted regarding solar cell improvement, then panels would be generating electricity in complete darkness by now.
Better known as 318230.
For those that didn't RTFA (aka, almost everyone)
The focus of the article is on how this could work in place of a regular window// not just as something to amplify solar cells. Since it can push the light to the edges, only the rim has to be fitted with collectors.
Pretty cool
FYi, its 40 time better than standard solar cells and 4 times better than their previous results.
The reference from the FAQ
1. Currie, M. J., Mapel, J. K., Heidel, T. D., Goffri, S. & Baldo, M. A. High-efficiency Organic Solar Concentrators for Photovoltaics. Science. In Press.
Shop smart, Shop S-Mart.
The quoted factor of 40 improvement is a comparison against unconcentrated solar cells, which nobody uses. At present, all the solar generating plants in the world use mirrors to concentrate the sunlight on the solar cells, thereby greatly increasing performance.
The "factor of 4" improvement refers to how much they've improved over their previous results; it does not refer to an improvement over currently-deployed technology.
But the question is, how much does this technology improve performance relative to currently-deployed mirror concentration? And, what is the cost relative to currently-deployed mirror concentration?
uhh... you just need to make their life time long enough to do that.
Here is a link to the actual paper published by the MIT team:
http://www.sciencemag.org/cgi/content/short/321/5886/226
This article says the window treatment for the dye alone would run around $300-$400 per square meter of glass. The solar cells would cost extra. The process requires vapor deposition which adds to the cost and it alters the light color passing through the window which may or may not be acceptable to the end user. And then there's this:
Oddly enough, a number of reports appearing today (for example, in the Associated Press) suggested that Covalent's concentrators would be of use in actual windows, but cofounder John Mapel made no mention of that possibility when we talked last week. That's no great surprise -- it would be difficult to get high-intensity light into vertically-positioned windows, much less windows placed on the wrong side of a building.
As a number of other posters have pointed out - wait for an actual product to see what it actually is and what it's capable of.
At present, all the solar generating plants in the world use mirrors to concentrate the sunlight on the solar cells, thereby greatly increasing performance.
Only the ones in areas with few clouds. Of course those places are best for solar anyway, but for the rest there's this new technology.
Finally! A year of moderation! Ready for 2019?
Go to science.com and read the actual research paper from the MIT team before blasting their work.
The method collects sunlight from a larger area and concentrates it on solar cells in a smaller area, meaning you can get more power with fewer solar cells. So the way to get "500% efficient" solar panels would be to extract, say, 20% of the sun's energy hitting an area, with only 4% of that area covered by actual solar cells, with concentrators to collect the sunlight from a larger area and directing it to the cells.
Not quite there bud. It produces 40 times the amount of power for the amount of solar cells but the collection area is MUCH larger. The concentration of light is what makes it produce 40 times more power.
This won't work for the same reason that interior paint won't last on the outside of your house. Interior paints use organic dyes, just like this MIT concentrator. To the great frustration of the paint industry, organic dyes just do not last in sunlight: the molecules breakdown.
Similar solar concentrator concepts have been looked for three decades (look up, for example, Prof. Reisfeld's work at Hebrew University) and have not yet made it out of the lab.
Where, and at what time of year? 50w/square meter (this is what you are quoting) is about 5% efficiency in a sunny spot during the summer, and something you could expect from current commercial cells.
Nerd rage is the funniest rage.
With all the solar cell breakthroughs since 2005, we should be up to 10,000% efficiency by now.
I've been watching those folks over at M.I.T. for a while now, of all the projects out there this looks to be the more promising in the near term.
"So long and thanks for all the fish."
Every time there is a discussion about solar, someone comes on and begins to spout the usual nonsense that the panels never produce as much power as they use during production, a claim that has been disproven repeatedly. Given that this time it was an AC shows that the message might be getting through. Avg payback in energy for crystalline-silicon PV systems is 1-4 years. On a product that is warrantied for 25 years and expected to last well beyond 50 years. http://www.nrel.gov/docs/fy99osti/24619.pdf
While it's great that we have an improved solar cell film, the reality is that, for the most part, the most efficient method used on a practical worldwide scale involves passive solar heating, especially for providing heating and hot water.
Part of the problem is that the manufacturing process - such as that used by Sony in cranking out OLEDs (which they build at the same plant as their photovoltaic solar cells) - causes a fair bit of pollution, both thru film extrusion, bonding, and the doping process.
By 2020 we may see some useful scaled implementation of photovoltaics, but it's still projected that the vast and overwhelming majority of growth in solar will be it's use in passive solar heating (and cooling, using heat exchangers) and in passive solar water heaters, as both such uses have little in the way of pollution in the manufacturing process and have an easier permitting process for factories, installation, and residential and commercial use, and easier to develop tax incentives for on the local and national scales worldwide.
-- Tigger warning: This post may contain tiggers! --
Solar cells undergo degradation with light exposure. The degradation is usually proportional to the number of photons incident on the cell. Does this method *shorten* the effective lifetimes of existing solar cells by a factor of 40? Are there cells that exist that this solution is practical for? Do the gains outweigh the costs if I use this system to "upgrade" my solar cell array and end up slashing the array's lifetime by a factor of 40?
Right, most of the trucks driving around in a Solar Farm aren't replacing hydraulic pistons (which operate at one cycle per day).
The trucks are cleaning the surfaces. This technology won't require cleaning because why?
They have achieved 40x concentration; but there is no cell currently manufactured which is cost competitive at 40 suns. If you find one - there are hundreds of ways to concentrate light to 40x.
The reason concentrators are 1000x is because that is precisely where III-V cells are most economic.
Also no discussion of module efficiency. This puts the tech in a class with nanotech, which are equally quiet about their efficiency.
Indeed the disturbingly inaccurate use of the term effeciency by the author suggests a weak grasp of the subject.
BP sells 200 watt panels that are 14.85 sq ft each. 1000/15 = 66.67 x 200watt = 13.3kw
Of course, that is under ideal generating circumstances.
http://www.bp.com/sectiongenericarticle.do?categoryId=9019633&contentId=7036926
The 1970's called, and said that it was time for you to move on. Solar technology certainly has.
Oh, you're not stuck, you're just unable to let go of the onion rings.
Well no, the angle doesn't change the amount of energy hitting the panel. What it changes is how well the semiconductor solar cells can convert that energy. You don't have to track with these panels because the organic film absorbs, then re-emits the light, and due to the nature of the molecules, it always re-emits the light in the same direction, regardless of the incoming angle. The classic semiconductor solar cells themselves, attached all the way around the edges, are the devices that are sensitive about angle. They receive light at their optimal angle always, emitted from the organic film on the plates, rather than directly from the sunlight.
You lose efficiency in the absorption and re-emission process, but that loss is apparently worth the cost of admission, if these guys have done their math right. Being from MIT, we can hope they can do math.
This technique has a whole host of advantages over classic off-the-shelf panels you can buy today, which the article didn't go into.
The panels you can buy today are very sensitive to shadows. Each cell produces only so much voltage. To get a useful voltage out of them, you have to wire them up in series. If some percentage (50%) of a row is shadowed, the panel will actually effectively shut itself down, and produce no power at all, because of the non-participating cells. (The shutdown is accomplished with passive circuitry, not some sort of machine or processor.) This means that in a typical residential situation, you can't have so much as a chimney on your roof, or your panels could become very expensive powerless decorations. You certainly can't have any trees that could even partially shade your roof. This concept eliminates that problem. The organic molecules in question are very egalitarian about how they re-emit what they absorb. It gets spread out evenly, all the way around. This means that if any portion of the panel is shaded, all of the semiconductor cells still get a lot of (concentrated) light, and it takes a lot more shadow to shut them down.
Another issue with modern panels is the fact that a classic semiconductor solar cell is useful only through a very narrow band of wavelengths. Sunlight is very broad band light. (No jokes about bitrates, thank you.) It shows up at your roof in all kinds of frequencies. The panels you can buy today ignore a large fraction of those frequencies, since they only work at what they're tuned for. However, in the process of ignoring the other frequencies, your standard cell also blocks them entirely. So even though you can manufacture semiconductor cells with different bandgaps that will absorb different sunlight frequencies, you can't stack them directly on top of each other and gain anything. The uppermost in the stack shadows all those beneath, so they're pointless. An older slashdot story about how to manufacture a multi-bandgap semiconductor cell was posted a while ago, but that's still in early research stages too, and it apparently involves fairly difficult semiconductor manufacturing techniques. These panels do an end-run around that problem. Different dye coatings absorb different frequencies of sunlight and DON'T block the remaining frequencies. They pass through. So you can stack concentrator panels, up to some limit, and each one has semiconductor solar cells around the edges specially tuned to utilize the light frequency the dye emits. This is the big win, and the cause for the whopping efficiency claims. The transmissiveness of these concentrators for frequencies they're not tuned for means you can make a sandwich out of them and the resulting panel can use many more frequencies out of the same square meter. There's probably still some limit to how many layers you can stack before you're wasting your efforts, but it's enough to be worth the trouble.
Lastly, classic semiconductor cells can be manufactured specifically to operate efficiently in concentrated light vs standard out-of-the-sky sunlight. That's the reason for the Fresnel lens panels that have
Concentrated Solar
In their defense, I don't think that they are claiming that this will replace the big solar farms. I think that they are envisioning this tech being used where windows currently are installed, or where solar was only worth installing with tracking collectors - so basically you get feasible solar installations where it wasn't feasible before.
They did nothing to improve solar cells themselves, and thus the efficiency is not touched upon - these guys are just getting light to the edge of a piece of glass.
W..w..W - Willy Waterloo washes Warren Wiggins who is washing Waldo Woo.
A. Goetzberger et al., "Solar Energy Conversion with Fluorescent Collectors", Applied Physics 14, 1977, pp. 123-139.
Yes 1977!!!
I was also playing with this using plastic from TAP plastics (in the SF Bay Area) http://www.tapplastics.com/ in the late 80's.
Works ok.
See:
Patent 4149902
Patent 5227773
Patent 5816238
Patent 7316497
Mobay Chemical Corporation make a fluorescent called LISA. "fluorescent dye-doped edge-illuminating emitter panels" Technically.
There were some articles.
"A Little Light Goes a Long Way with Lisa", Mobay Corp. Marketing Document.
"Light-Collecting Plastics-A Brilliant Idea", Provisional Information Sheet, Mobay Corp.
Steven Ashley, "Razzle-Dazzle Plastic", Popular Science, pp. 100-101. Sorry can't find the year, (any one can you help here)
I am always doing that which I can not do, in order that I may learn how to do it. - Pablo Picasso
There is a glut of new and exciting ways to bounce light. We have lenses and fresnel mirrors in conical or linear; funnel mirrors, holograms, diffraction grates, and concentric funnel mirrors. (I am the very picture of a modern...)
I think we've safely reached the point where novel can no longer be consider a useful parameter.
What is the cost - and what is the efficiency? longevity etc ...
At some level, we find ourselves on a Titanic, and in need of a solution to a problem with significant time and resource constraints.
I submit that this proposal, like so many in the same camp, does more to run out the clock, than it does to advance the ball.
EPRI has reported that Heliostats with salt storage and steam power is the least expensive means to a post-oil world. Unless this technology can demonstrate some advantage relative to the gold standard; I think its noise.
To your point, there is no real market for neighborhood solar; and there is no social benefit for wasting tax dollars on roof-toys - or anything other than the best-of-breed solutions.
AIK
California has struggled with an unregulated power supply industry.
CA didn't really deregulate electricity, power, they shifted the regulations. Before, the same company could own both power generation and power transmission. but when the so called deregulation came it split generation and transmission, a company wasn't allowed to do both. Then transmitters were barred from raising rates but generators weren't.
Falcon
Should there be a Law?
A massive country wide nuclear power plant building spree would need to take place. Right now we have over 100 nuke plants that supply 20% of our electricity
Nuclear power isn't needed. By 2050 solar power could provide 69% of the US's electrical needs. Wind can also supply a lot, I read where the Rocky Mountains alone contain enough potential wind power to supply the lower 48 states but I didn't find a reference. Then a lot of waste heat goes up smokestacks daily. Here's a quote from TFA: "Here's a Maxwell House coffee roaster in Duval County. They're roasting beans, so all that heat has to go somewhere. About twelve megawatts' worth of potential electricity is going up the stack." In Hawaii about 30% of the big Island's, Puna, is from geothermal power. Geothermal sources produced about 13,000 gigawatt hours in California in 2007, with more available.
Add all these together and every coal fired plant should be able to be closed without any more nuclear power plants being built and still have plenty of electricity.
Falcon
Should there be a Law?
I know we will all nit pick this to death so here is mine...
From the FAQ:
"The sun is an inexhaustible source of clean power."
Well, not quite. I know that we cannot exhaust it just by using it's normal emissions as we would place no additional drain on the sun's resources by using solar power than if we didn't exist, however, the suns normal processes will eventual exhaust even it's vast resources of Hydrogen and then start "burning" (there you go, nit pick me now) hydrogen which will drastically change its characteristics. I do however agree that we (everyone alive today and probably the human race in general) won't really care by that time because, hopefully, everyone alive today will be long dead by then and, again hopefully, the human race will have moved on to the rest of the galaxy (galaxies?) by then and look back at "the birth place of mankind" with fond memories but the loss of the Earth due to the sun running out of Hydrogen will be a fairly minor news item.
"Computer Scientists can count to 1024 on their fingers" (non-mutant, non-mutilatated, human computer scientists)