Posted on 08/28/2008 9:01:18 AM PDT by Clint Williams
Scientists at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) have set a world record in solar cell efficiency...
(Excerpt) Read more at nrel.gov ...
At what cost?
I will believe it when I see it in action.
Not that bright today? You need more suns.
The 40.8 percent efficiency was measured under concentrated light of 326 suns.
326 suns eh, that shouldn’t be to hard to arrange in the real world. /s
Jimmy Carter comes through again.
So they’re down to 20 cents a kilowatt-hour now?
Serious rays, man!
Let me try explaining if I can. Solar cell captures light (photon) and converts them to electricity. They basically have sandwiched layer of semiconductor (like silicon), one almost positive, the other almost negative. When the light hit, the electron jumps out from one side to to the other (junction) therefore producing electricity, like battery. More light, more electritity.Common solar cells sold for calculator etc, in practice only convert about 10% of light to electricity. The rest just lost as heat. This is like car with low, 10 MPG. In theory, they can be like 20-30%. This newest one on the news is the latest generation triple junctions In-Ga-As-P. It has 40.8% efficiency, like 40MPG car, giving more electricity from sun.
‘This newest one on the news is the latest generation triple junctions In-Ga-As-P. It has 40.8% efficiency, like 40MPG car, giving more electricity from sun.”
Whats the efficiency with one sun as a source and not 326?
It's realistic ... there have been some serious advances in production-quality arrays. IIRC, there are currently satellite solar arrays operating above 30%.
You can have more than one sun. Just get yourself a magnifying glass. Then you can concentrate our one sun into the equivalent of dozens.
If you put 326 mirrors around to reflect light onto the solar panel, you have in effect given it 326 suns.
BTW, the more suns you put on the solar panel, the harder it is to get efficiency, because of the magnitude of the heat.
Back in the 1970s, I read a book by a Czech electrical engineer named Petr Beckmann titled “The Health Hazards of NOT Going Nuclear.” I remember him writing that even if a solar cell were 100% efficient at converting sunlight into electricity, it would still only produce 1 kilowatt per square meter under ideal conditions (i.e., clean cell, cloudless sky, sun’s rays perpendicular to the surface of the cell). The upshot is that one would need to cover many square miles with these cells to generate the same power as a nuclear plant does on a few acres.
He also wrote that even if used on a small-scale basis (e.g., the roofs of peoples homes), the number of injuries and deaths from accidental falls, as owners clean the cells from dust, debris, snow, etc., would no doubt increase.
Though pro-nuclear, Beckmann wasn’t anti-solar. He was, of course, against subsidizing solar-cell technology.
That may seem expensive now, but whey the environazis and NIMBY's get through with coal, nuclear, and hydro power, it will appear cheap. The 'rats know that this renewable energy can't compete straight on with fossil fuel, so they do their best to raise the price of fossil.
Great point. 326 suns is like adding “supercharged” fuel for cars. It can be used in space though, where sunlight is much more intense.
LOL!
You’re probably right.
First is the high efficiency. Yes, this is higher than previously reported, but only marginally so, as compared to a similar structure by Spectrolab (40.7% I recall) a few months ago. It's like a 0.5 in improvement in the pole vault record. A new record, yes, but no earth-shattering breakthrough. Nonetheless, it is a good result.
The second issue is one of concentration. Think magnifying glasses and ants on a sidewalk. The accompanying article alludes to this. Typically, one places a cheap plastic Fresnel lens over the cell (ok, it's marginally more complicated than that) and focuses the sunlight onto a small area. The “one-sun’ efficiencies for these cells are typically in the 30+% range but the structure is, in fact, optimized for concentration. Concentrating the sunlight onto a small cell is - overall - much better than using more solar cell material to get similar power out under ‘one-sun conditions.
And these cells are more expensive than their silicon counterparts so high efficiency under concentration (more or less replace more expensive solar cell material with a cheap plastic lens) makes them more economically viable. Earlier generations of this type of cell are indeed used in most satellites, not because of the concentration (sunlight is not that much greater in space) but becuase of the higher efficiencies at low weight. One still needs large areas, etc, however, to produce decent power...
Of course, they are closer to the sun. :-)
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