Posted on 03/01/2005 7:56:56 AM PST by grundle
http://www.hindu.com/seta/2005/02/03/stories/2005020300431600.htm
Breakthrough in solar photovoltaics
THE HOLY Grail of researchers in the field of solar photovoltaic (SPV) electricity is to generate it at a lower cost than that of grid electricity. The goal now seems to be within reach.
A Palo Alto (California ) start-up, named Nanosolar Inc., founded in 2002, claims that it has developed a commercial scale technology that can deliver solar electricity at 5 cents per kilowatt-hour.
Molecular self-assembly
The breakthrough has come through the application of nanotechnology to create components via molecular self-assembly, including quantum dots (10nm large nanoparticles) as well as nanotemplates with structural order extending through all three dimensions.
In addition, Nanosolar has demonstrated that the three dimensionally engineered nanotemplates can be conformally coated or solidly filled with semiconductor paint to create ultra-thin solar cells with layers that are yet another factor 100x thinner than conventional thin-film amorphous silicon solar cells.
This allows a 10x larger surface area of these structures to be used to achieve a 10x increase in efficiency for such thin layers, thus making it possible to use even less material for similarly efficient cells. Conventional inorganic semiconductors tend to require intricate processing to ensure large grains of crystallinity (in the extreme case: mono-crystallinity) so that charges can travel hundreds of nanometres without getting trapped and lost (at internal crystal boundaries).
The 3D nanocomposite architecture of the ultra-thin-absorber cells makes possible absorption of a substantial fraction of the incoming sunlight despite the ultra-thin layers since the charges need to be transported only several nanometres without much opportunity for a loss.
This means the requirements on the semiconductor material can be relaxed and low cost materials such as inorganic semiconductors of the IIb/VIa and Ib/IIIa/VIa families as well as solution-coatable organic semiconductors can be used.
Lower cost
According to the CEO, Martin Roscheisen, the conversion efficiency (percentage of incident light energy converted to electrical energy) of the Nanosolar SPV cell is above 12 per cent for its first product prototypes. He claims that the Nanosolar SPV cell costs only $ 0.36 per peak watt.
The semiconductor paint can be applied to a flexible substrate , such as a polymer sheet , through a simple web printing process, to create an array of ultra-thin solar cells.
Nanosolar has developed proprietary substrate technology that keeps the substrate cost within a smaller fraction of the overall product cost than any other state-of-the-art thin-film solar cell technology. The company has also developed a powerful new way of interconnecting individual solar cells into larger modules and large-area sheets and allows high-throughput module assembly at high yield.
The flagship product, Nanosolar SolarPly, is a 14 feet x 10 feet solar electricity module delivering 120 watts per square inch at 110V. The company is now offering solar panels at below $1 per peak watt.
The Nanosolar team, headed by CEO Martin Roscheisen (listed by Fortune in 2003 among the top ten U.S. entrepreneurs below 40 years of age), has some top-notch Indian technologists assisting it.
Among them are Dr. Siva Sivaram (ex-Intel) and Dr. Arati Prabhakar , former Director of the U.S. National Institute of Standards and Technology.
N.N. Sachitanand
Sign me up for the extension cord contract.
Microwaves are our friends.
Looks like these things cost ~$360/kW panel and only last ~2yrs.($0.05/kW*Hr)
Ping.
Two of these in direct sunlight could handle the load of most houses.
I was thinking more low-volume storage. Small house-level energy storage methods. Hadn't thought about compressed gas: it would be a bit lossy, but what isn't. . .
The idea I see for photvoltaics of this sort is to get individual homes off the grid. . .
Isn't solid state physics fun!
Photovoltaics along with in-home natural gas fuel cells. I worked for the electric utility for eight years and nothing would do my soul more good than to see them lose some customers.
"120 watts per square inch at 110V" LOL on what planet
I'm not aware of any technology that can move large amounts of power through large distances using microwaves. Pity the airplane that flies through them>
Solar power will be relevant when Home Depot or Lowes has a do-it-yourself solar power roof tiles so you can power your whole house.
This is good news.
(s)Of course the environwackos will then pass a law outlawing night and taxing sunlight usage.(/s)
Then you're not familiar with the technology. An SPS would have a receiving antenna in a roughly 8 x 10 km oval (measurements would vary by latitute), and the land underneath could still be used for raising crops or cattle.
Yes, there will be losses. But even at the center, with peak beam density, it's nowhere near harmful levels, it's calculated that if a bird flew through the longest axis of the rectenna, directly through the peak area of the beam, the net effect would be a rise of about .1 degrees C, or a tad over a fifth of a degree temperature rise Fahrenheit. . .
hmm.....a 140 sq ft module produces 120 watts/in*2:
140 ft*2 x 144 in*2/ft*2 x 120 watt/in*2 = 2.4192 mega watts.
Absolutely f***ing amazing!!.
Sounds like a theoretical dream to me. A microwave has short wavelengths (that's why they call them microwaves). Since an efficient antenna has to be 1/4 wavelength to capture the power, the grid spacing would have to be very tight. Supporting a 100 square Km antenna grid at 1/4 wavelength spacing and still passing light and cows would be quite a feat, in my view. The power requirements at the transmitter would also be unique. To be comparable with a single land based powerplant would require hundreds of megawatts of power. How would this be serviced at geo-synchronous orbits since the shuttle won't go up that high? It's hard to imagine a hundred megawatt powerplant that needs no service.
I suggest that you talk to Raytheon and the Japanese. They have been developing and testing such technology for decades.
Pity the airplane that flies through them.
Simply don't fly through the no fly zone. The aluminum skin would protect the passengers and crew (as they would pass through the beam quickly), but the skin might heat up significantly and if there was any minor fuel leak, it might be an engine fire hazard.
Clearly you wouldn't want to sunbathe in the rectenna zone for extended periods, but the Japanese are doing tests on plants and animals living under a typical rectenna continuously bathed in microwaves at the power it would see from a space-based solar power satellite.
Don't fear what you don't understand. Understand what you fear.
I don't think so.
My first thought, too. Solar flux is more like one Watt/square inch. However, it is possible to focus sunlight using mirrors. But at anything approaching 120 Watts per square inch, you'd have one helluva cooling problem.
I suggest you inform yourself using a primer.
No, the shuttle can't go to Geosynch. But the vehicles proposed for the President's Space Exploration Initiative CAN. . .
Please see post 35
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