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A Step Closer To The Optimum Solar Cell
An anonymous reader writes "Besides cost, solar cell efficiency is the second most critical criteria. Scientists from Berkeley Lab and other institutions, have announced a new solar cell material that may be able to achieve an extraordinary efficiency of about 50 percent -- twice the amount of the current record holder."
Ah, an efficient solar cell. This is the last you will hear of this! Halliburton and Big Oil will immediately buy the patent and sit on it, just like they did the antigravity saucer, the 300 mph carburetor, cold fusion, and Skynet microchips from the future. Save your cache while you can!
Don't blame Durga. I voted for Centauri.
In 1999, Walukiewicz and others at Berkeley Lab were working with solar-cell designers at DOE's National Renewable Energy Laboratory, who were trying to build a three-junction cell. The NREL researchers inadvertently created the first photovoltaic semiconductor with a split band gap. But at first they didn't realize it.
...
"They needed a new material with a 1-eV band gap and a crystal lattice structure that matched the other layers of the cell," Walukiewicz explains. "They used gallium indium arsenide nitride alloys in which just a little nitrogen could achieve the desired band gap, and an almost perfect lattice match."
Since the band-gap reduction was unexpected, Walukiewicz set out to find out how it worked. The answer, it developed, was that the few atoms of nitrogen, which are much more electronegative than the host atoms (much more strongly attractive to electrons) produced a narrow energy band of their own, splitting the GaInAs conduction band into two parts. The gap to the lower of the two conduction bands was the desired 1 eV.
In the case of GaInAs, other characteristics of the split bands made for a poor solar cell material. Nevertheless, Walukiewicz and his colleagues continued to investigate the phenomenon and developed a model of the split-band phenomenon known as "band anticrossing."
Yu admits that forming highly mismatched alloys is "challenging from a crystal-growth point of view," but there is hope that crystals can be grown epitaxially (the growth on a crystalline substrate of a crystalline substance that mimics the orientation of the substrate). One good sign, he says, is that Japanese researchers have already grown thick oxygen-doped crystals of a related material, zinc selenium.
http://tinyurl.com/4ny52
I used to jump for joy whenever I saw things like this.
But experience generally showed that Breakthrough X which would produce cheap power/double battery life/allow 5 terabytes in my computer never actually arrived at the market.
I'm still waiting for holographic storage from 10 years ago!
My Journal
The calculated efficiency of a single-junction solar cell made with this material would be a remarkable 57 percent. But while the single-junction architecture is elegantly simple, many questions have to be answered before ZnMnOTe or any of its highly mismatched cousins prove they can do the job.
So not only does it not work yet, but any article that starts off with the words "besides cost..." is obviously talking about an economic impossibility.
We're stuck with cheap oil until it runs out in a few decades. And then we're stuck trying to rebuild civilization with coal.
One things that I've never seen is the lifetime and disposal costs of solar cells . . . that never seems to be factored into the so called "solar renewable energy" equation.
When it comes to adoption of solar power, there's only one calculation that really matters:
C = Cost of installing solar panel
R = Revenue generated (or money saved) per year
M = Maintainence costs per year
(R - M) >= C * 20%
In plain english, when you can get (somewhere around) a 20% return on investment from installing a solar panel, you'll start to see them on top of office building, parking garages, and just out in the middle of open fields, soaking up money.
Until then, solar power will be a technical curiosity for use in special situations (outer space) and for those with a political agenda.
If I am not mistaking, nuclear power is the cheapest.
A bucket of fission waste under your bed, or a bucket of coal.
Don't compare these things. The first is a waste product, the second is the raw material.
The choice should be between a bucket of fission waste and a room filled the ashes and gasses that resulted from burning coal. I am not sure what would kill you first.
I don't want either of them. But the fission waste can be stored and handeld. I a century or so, we might find a solution for it. The gas on the other hand goes in the atmosphere. You try getting it out. It too might be possible in a century. At least with fission waste the poles don't melt and the climate doesn't change. Although I do have to say that the sun is also partially responsible for a temp-rise.
I don't understand the problem people have with fission. Sure it aint pretty, but it's the best we have so far.
Now we can run 5 100-watt light bulbs per square meter in death valley in full sunlight.
You can tell a great deal about the character of a man by observing those who hate him.
Under Socialism, R is also 0, but M might not be. You pay for it alright, just not directly.
So under Socialism there is *no* incentive to use them other than political adgendas.
=Smidge=
- the peak total of plants are pretty much maxed out and will require building of new plants
- Alternative energy is sporadic and can not be counted on (except for tidal).
Right now, we have money going into generation, but really need to spend it on storage as nothing really works well. I would love to money put into Beoings use of salt and a stirling engine for doing this. But I doubt it will happen.I prefer the "u" in honour as it seems to be missing these days.
Anyway, this is a discussion on solar cells, which lend themselves to distributed power generation of some form or another - they don't have to be big. More efficiency there makes the solar powered laptop easier to acheive.
In plain english, there are other design criteria other than a very simple equation even an economist could understand. Economies of scale mean that in most cases it is cheaper for a business to get power from a grid, no matter what powers it.
The bad news is that shortly thereafter, everything will turn an odious dull black.
Is it fascism yet?
You can get around this by using a non-polar solvent instead of water. Liquid carbon dioxide is good for this, with two further benefits:
- CO2 is a byproduct of combustion, so is plentiful, and
- Putting CO2 into the earth is a good way of sequestering it, so using recovered CO2 to dissolve and lift oil can simultaneously help meet CO2-reduction targets.
The real interesting times will come when (I'm sure it's when, not if) energy from solar becomes so cheap that we wind up using it to perform environmental remediation. We might wind up making crude-like oil and pumping it back into the earth just to put excess carbon away. We are already able to make "light sweet" oil from organic goo using thermal depolymerization, so taking it to that conclusion it is only a matter of purpose and scale.Time is Nature's way of keeping everything from happening at once... the bitch.
And if you wait a century, you don't have much beyond cold metallic waste. At one point the anti nuclear folk thought they'd stop the plants by refusing any movement of the waste. They thought the plants would choke on it. However, they let the plants double the size of the waste ponds. Since the stuff cools and can be compacted reasonably quickly, doubling the space gave something like 3-5 times more space (I no longer remember the real number, but it's exponential), and when you do pull stuff out, it's much less radioactive than before.
I'm not a nuclear engineer, but I met a bunch there, and found them all worth respect. The only liars and fools in the argument were the anti-nuke-power folk.
- Cu, In, Ga, Se and S are deposited via a vacuum & diffusion process
- Can be deposited on plain glass (same stuff used for window panes)
- 1 micron of this stuff absorbs more sunlight than 350 microns of Si (about 99% of light - don't know how this translates to efficiency, though - article not too technical).
- Panels like these would cost roughly a tenth of the price of those currently available.
- Pilot plant for manufacturing was expected to begin manufacturing somewhere in April (this month), manufacturing panels 400mm x 500mm @ 20W
- Pilot plant (100 sq m) to cost about US$ 2.3 - probably within reach for many developing countries.
Unfortunalty there's not much more detail or Web references....Free, as in your money being freed from the confines of your account.
You were aware that coal ash is highly toxic as well as radioactive, weren't you? With direct exposure to nuclear waste, you could die from radiation sickness (needing something like >10,000 rems to do that) or get cancer somewhere down the road. With direct exposure to coal ash, you could get poisoned by toxins, die from cancer somewhere down the road from that exposure, or die from cancer from the outputs of that power plant in the groundwater or air. Did you know that radioactivity in and around coal plants is higher by two orders of magnitude than those found outside a nuclear power plant? Did you know that the NRC rules for radioactivity outside a power plant are lower than the ambient radioactivity found in nature? Did you know that Grand Central Station in NYC would be automatically disqualified as a site for a nuclear power plant simply because the amount of radioactivity in its granite construction exceeds NRC maximum levels?
... the American taxpayer also pays $1 billion, not total, but year after year, to Black Lung victims -- not to cure or eliminate it, but just to compensate its victims."
... has very few enterprises that make money. But one of the them is uranium enrichment, for which the fuel manufacturers pay through their noses, and another is Price-Anderson insurance, the premia for which are paid by utilities, partly to private insurance pools, partly to the US government. The private insurances pay first, and they have so far paid $400,000 for 26 minor claims; Uncle Sam hasn't paid anything yet (and probably never will), but sits on a fund of $8 million of as yet unused premia. And, of course, the utilities pay taxes -- local, state, and federal -- with the stockholders paying a second round of taxes from their dividends. You call that a subsidy?"
"Yes, the American taxpayer has paid $1 billion [as of 1980] to research nuclear safety
"... the US government
- The Health Hazards of Not Going Nuclear by Dr. Petr Beckman. © 1980
The only reason nuclear could be more expensive (though still cheaper per kilowatt than solar) is because of the much expanded regulations on the nuclear industry that do not exist in the other industries.
A hairline crack was found in the plumbing of stand-by equipment in a nuclear power plant some years back. This was found by visual inspection. There was no leakage -- even taking into account that this was not radioactive water in the pipes. So what was the NRC's decision? Take down this plant and every nuclear plant in the country with the same design -- I believe something like 22 of them at the time. And what did they find? The one hairline crack: the one originally found by regular visual inspection. If ANY industry were held to the same safety standards as nuclear, they would be bankrupt. As it stands, nuclear is still competitive. If such ornerous (ridiculous) safety checks were not in place, it would be substantially more reliable and cost effective than any alternative.
Well, that and the fact that rabid Greens have lobbied successfully against breeder reactors in the U.S. which could make nuclear power generation even more profitable than it is today. IFR reactors could process the "waste" waiting to be stuck into Yucca Mountain AND repurpose nuclear warheads for power generation -- a proper end in my opinion to a large portion of our current nuclear stockpile.
But no. Nuclear is BAD.
Or did you have delusions that solar power would save the day or that coal is better than nuclear?
Please do not misunderstand. I welcome increased usage of solar, wind, and to some extend tidal, but these are not enough to supply 3,720 billion kilowatt hours of po
- I don't need to go outside, my CRT tan'll do me just fine.
In many Mediterranian countries, water is heated using solar panels which utilize the greenhouse effect. The idea is that blackened water pipes are running through a glass panel installed on the roof, facing south. Hot water is stored in a tank. In summer, and in many winter months, this removes the need for heating water electrically. Coming to a sunny part of the US, I was pretty astonished not to find that. Well, at least not in Cali. Makes you wonder why how much this new development will be implemented.