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New Solar Cell Sets World Efficiency Record
asoduk writes to tell us that a new world record has been set for the most efficient photovoltaic device. Topping the scale at 40.8% efficiency, the new solar cell differs significantly from the previous record holder. "Instead of using a germanium wafer as the bottom junction of the device, the new design uses compositions of gallium indium phosphide and gallium indium arsenide to split the solar spectrum into three equal parts that are absorbed by each of the cell's three junctions for higher potential efficiencies. This is accomplished by growing the solar cell on a gallium arsenide wafer, flipping it over, then removing the wafer. The resulting device is extremely thin and light and represents a new class of solar cells with advantages in performance, design, operation and cost."
At 40%, you're talking about 400W when in direct sunlight. With eight hours of sunlight per day the average house needs less than four square metres. Now, of course, you aren't going to be using the most power at the times when these are generating, but it can definitely put a significant dent in your electricity bills.
I am TheRaven on Soylent News
Was taking forever to load, so here's the article:
Scientists at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) have set a world record in solar cell efficiency with a photovoltaic device that converts 40.8 percent of the light that hits it into electricity. This is the highest confirmed efficiency of any photovoltaic device to date.
The inverted metamorphic triple-junction solar cell was designed, fabricated and independently measured at NREL. The 40.8 percent efficiency was measured under concentrated light of 326 suns. One sun is about the amount of light that typically hits Earth on a sunny day. The new cell is a natural candidate for the space satellite market and for terrestrial concentrated photovoltaic arrays, which use lenses or mirrors to focus sunlight onto the solar cells.
The new solar cell differs significantly from the previous record holder - also based on a NREL design. Instead of using a germanium wafer as the bottom junction of the device, the new design uses compositions of gallium indium phosphide and gallium indium arsenide to split the solar spectrum into three equal parts that are absorbed by each of the cell's three junctions for higher potential efficiencies. This is accomplished by growing the solar cell on a gallium arsenide wafer, flipping it over, then removing the wafer. The resulting device is extremely thin and light and represents a new class of solar cells with advantages in performance, design, operation and cost.
NREL's Mark Wanlass invented the original inverted cell, which recently won a R&D 100 award. His design was modified by a team led by John Geisz that further optimized the junction energies by making the middle junction metamorphic as well as the bottom junction. Metamorphic junctions are lattice mismatched - their atoms don't line up. The material properties of the mismatched semiconductors allows for greater potential conversion of sunlight.
NREL is the U.S. Department of Energy's primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for DOE by Midwest Research Institute and Battelle.
http://www.treehugger.com/files/2006/12/new_world_recor.php
TFA is slashdotted, but a little googling shows this happened two years ago.
How can I believe you when you tell me what I don't want to hear?
Your smile says that you also know this; but fission was supposed to be "too cheap to meter". Wonderful how it worked out.
I think it depends on what you mean by "the market". There are plenty of places where, due to low average solar energy/square meter and cheap grid power, solar will be unexciting until the day when you can get spray-on 95% efficient solar cells in a can. On the other hand, if you are paying 5 or 10 thousand dollars/kg to launch satellites, cutting edge solar cells might well be cost effective even if they cost as much, per square centimeter, as top edge microprocessors. All other markets fall somewhere between those two.
The previous record holder was 40.7%
I'm not sure why this is here, this was a press release in Mid august.
Indium is a very rare material
Gallium is even rarer and is needed in equal quantities for this application.
I'm not so sure. I use gas for hot water only right now; my gas bills are $15-20 a month. A fair chunk of that is the line fee, so if I install a gas stovetop, as my wife insists we will, I'll be paying that anyway. Even if I could disconnect it entirely, it's barely feasible to put in solar hot water & have it pay for itself in 20 years. I was all fired up to do it last year, but when I ran the numbers it just wasn't worth it.
"Complete" solar's ROI is 20 years, but solar hot water heaters here in Hawaii - where we get a lot of sun - with the federal solar tax credit - I'll make my money back in O N E year!
Horns are really just a broken halo.
Nit-picking begin! The dark side of the moon is, like all points on the moon, in direct sunlight approximately half the time. All the "dark side of the moon" means is the side facing away from Earth, not facing away from the sun. So you'd get tons of power during a new moon. It'd just have to be enough to last you about two weeks during the long night.
40.8% of solar power captured. That is, 40.8% of ~1000W/m^2 solar output, which means roughly 408W per square meter, which is exactly why this is so important.
These kinds of cells are typically multi-layer junction devices so that the longer wavelengths that are transparent to higher silicon layers are captured at lower layers. The whole spectrum still isn't captured, but we're right at the cutting edge with what's capable with current technology.
Not entirely correct. First Solar uses CdTe, not CIGS (CuInGaSe2). Nanosolar uses an ink like printing process for the absorber layer in the cell. However, they have yet to produce more than samples.
The CIGS companies who are making money (or nearly) today are Global Solar, Wuerth Solar, Showa-shell, and soon to be joined by Ascent Solar. Avancis Solar is scaling up as well. There is literally a metric ton of financing for thin film PV right now. I could probably add a dozen names (Miasole, heliovolt, Solibro, etc.)
The attraction to the thin film PV is due to the fact that the world output of metalurgical grade of silicon is throttling the growth of traditional PV. Last year, Si hit $500/kg. FWIW, in 2001, it was
Yes, I have been doing a lot of esearch on this lately...
Suppose you were an idiot and suppose you were a member of Congress
Fission very well could be, but half-vast fission we've been saddled with as a result of the Carter administration's (the one president who should've known better, btw, what with his degree in nuclear engineering) machinations.
Except the nuclear power industry had about 20 years to reduce cost before Carter came along. Lewis L. Strauss, chairman of the Atomic Energy Commission, said the "energy too cheap to meter" quote in 1955 not 1975.
Falcon
Should there be a Law?
Call me when the ROI on home solar breaks the 20 year mark in my area. Right now it's almost 100 years.
You don't get much sun where you're at do you? Here's a spread sheet you can play with to calculate ROI, now I haven't looked at it so I don't know how good it it. This is the webpage that links to it. Of course you'd get a better return by increasing energy efficiency.
Falcon
Should there be a Law?
Very valid point. The ROI is directly dependent on the expense it's replacing. California and Florida have the shortest ROI on home solar due to their combination of high electricity prices, large governmental subsidies, and sunlight density. If oil went up to $500 a barrel tomorrow, the ROI on solar becomes VERY interesting even in sunlight poor areas. As an interesting perspective, the proposed $700 billion bailout currently under consideration by the government would fund 100% of home solar power needs for 35 million US homes.
actually, the dark side of the moon is more dark.
In the moons night sky, the earth is more than 4 times larger than the moon is in our sky. The earths albedo is also about 3 times higher than the moon. So "Earthshine" on the moon is about 12 times brighter than moonshine is on earth.
Effectively, the night time on the far side of the moon is about 12 moonshines darker than the near side.
He's obviously talking about the home market. Your squishy "it depends" answer doesn't cut it either. I live in Arizona where we have clear skys 300 days of the year. Nobody here is pushing solar because they all know it's an exotic technology that costs too much. I wish it weren't true, but it is.
In the early years ('99) I found a complete construction plan for a nuclear bomb on the net. Including contacts. First I thought this was a joke, but nowadays I know better, because I know quite a bit about that stuff.
The point is, that it's very easy to build a nuclear bomb... in theory!
In reality, it's very very hard, because first, you have to have uranium 235 (or plutonium 239, if you can get it), which must be extremely purified. And because of this, it is horribly expensive. If you buy the cheap crap, you get a dirty bomb, witch has exponentially less power, and is not very useful except for explosions that are so small that regular explosives would be more easy and more cheap.
And then comes the hard part! If you build the classic hollow sphere design, you have to place the compressing explosives around the uranium in an extremely regular way. It has to ignite even more regular. One tiny timing difference, and you get no real compression, but the uranium blows out at the place where the explosion was delayed the most. Therefore you most probably do not even get a critical mass, and fission does not start. So you end up with a small explosion and some uranium pollution. Yeah. Great. All the hassle, for nothing.
Don't even dream of going bigger and create a fusion bomb by putting (super)heavy water around it. You will never get it to work, because you have to make so many tests that the whole world would notice, before you would even get it to work right.
That's why "terrorists" do not care for nuclear bombs. It's not economic and not worth the hassle. And if you're so crazy that you want to nuke something anyway, you either try to build it yourself and fail, or steal a real warhead. (Easy in the ex-CCCP countries, if they're not eaten by the rust by now.)
And: No, I'm no spy, Russian, terrorist, American, or anyone special. I only was fascinated with Albert Einstein and the technology and physics behind fission/fusion as a kid. :)
Any sufficiently advanced intelligence is indistinguishable from stupidity.