Yeah, if you read about it more, it's the bad gap on silicon pv that sets the limit at 29%. You simply can't do better with simple silicon cells, because they don't have a way to capture some of the range of photons.
The carnot limit is easier to understand (and is definitely well established science fact), here are a couple of places you can read if interested:
People use different conditions when they calculate the carnot limit, but the most generous but vaguely reasonable ones put it at 95%, which is only about double the current state of the art at ~45%.
Unfortunately, that's not the actual result. Solar panels, if they were in fact built using this technology, would be 80% more efficient. But nobody is building solar panels using this technology (or at least, not that i'm aware of). And while this technology makes a jump from 1.8 to 3.2 percent overall efficiency, the current technology actually used in solar panels delivers 22%. This technology might be used in much cheaper panels in the future. If they could make a few more small gains in efficiency, a 5% panel based on their technology might be so cheap to produce that you could buy 5 for the price of one 22% panel. Then you just need to have enough space.
Honest people are nice and all, but in reality, does anyone ever not get reimbursed for this reason? I mean, who blurts out 'well, I left my car unlocked, and it got stolen', rather than just 'my car got stolen'.
PV has a theoretical maximum of 29%, so it isn't going to have any huge jumps from the current 22% efficiency. It will have to be a different fundamental design that goes higher than that (and perfect carnot conversion is only ~85% with solar, so we'll be lucky to triple today's efficiencies, ever.
1-4 years to pay off the energy required to manufacture them. After which they are a net benefit to our economies.
You can buy the cells anywhere. 15 years ago you could buy 14% efficient cells. Today you can buy 22% cells. Lab cells are approaching the theoretical limit of 29% for simple PV. That's a 50% improvement already, with another 30% on the table, whjch we will see gradually creep into commercialization over the next 15 years as we have over the last 15 years.
Solar cells are actually significantly ahead of where they were 15 years ago. There's no huge jump, but there really can't be, as we're nearing the theoretical limit of simple pv cells. More complicated cells can do better, but again the maximum amount better is less than 3x, and that is all the improvement we can ever get.
Actually, it does matter, because if you start from a less efficient process and go up, you may not exceed the efficiency of a more efficient process. So the amount you can 'get from a solar panel' may not change at all.
Which is, if you read the article, actually the case here.
Slashdot Mirror
You are not supposed to trust the police. That's the propaganda getting to you.
They came for the egregious bandwidth hogs, and I said nothing.
They came for the pedophiles, and I said nothing.
That was where it ended, and the world was a better place. Whew!
Unfortunately, if you live in a comcast owned area, the business plans start at 179, not 69. :-(
Poor sad little drug companies. Sniffle. Profits reduced from potentially twenties of billions, to merely tens.
http://en.wikipedia.org/wiki/List_of_pharmaceutical_companies
The left hand doesn't know what the right is doing. Because the right has built years of expertise in maintaining secrecy.
No one at Caltech has to use Bose, they can build their own that are better. It's really just MIT that gets an improvement from upgrading to Bose.
Since I was talking about what is for sale at an affordable price, it seemed like real-world to me.
But it puts a proper upper bound on the possible efficiency. If it didn't you could build a machine to violate the 2nd law.
Yeah, if you read about it more, it's the bad gap on silicon pv that sets the limit at 29%. You simply can't do better with simple silicon cells, because they don't have a way to capture some of the range of photons.
The carnot limit is easier to understand (and is definitely well established science fact), here are a couple of places you can read if interested:
http://trappist.elis.ugent.be/ELISgroups/solar/projects/springer.html
http://en.wikipedia.org/wiki/Solar_cell_efficiency#Thermodynamic_efficiency_limit
http://forums.xkcd.com/viewtopic.php?f=18&t=44807
People use different conditions when they calculate the carnot limit, but the most generous but vaguely reasonable ones put it at 95%, which is only about double the current state of the art at ~45%.
Unfortunately, that's not the actual result. Solar panels, if they were in fact built using this technology, would be 80% more efficient. But nobody is building solar panels using this technology (or at least, not that i'm aware of). And while this technology makes a jump from 1.8 to 3.2 percent overall efficiency, the current technology actually used in solar panels delivers 22%. This technology might be used in much cheaper panels in the future. If they could make a few more small gains in efficiency, a 5% panel based on their technology might be so cheap to produce that you could buy 5 for the price of one 22% panel. Then you just need to have enough space.
Sorry, I should have clarified I was referring to standard crystalline silicon pv. PV was too general a term.
http://en.wikipedia.org/wiki/Solar_cell#Efficiency
In terms of the fundamental limit, carnot comes into play:
http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4915369%2F5021489%2F05021557.pdf%3Farnumber%3D5021557&authDecision=-203
There are different estimates out there for exactly where we'll hit it with solar, but it is well short of 100%.
Yes, I should have clarified.
No, a gas car engine converts sunlight to motive power at something like 1% efficiency.
It probably was. Almost nothing bad actually happens in the world, it's only slow news days that cause crime.
Honest people are nice and all, but in reality, does anyone ever not get reimbursed for this reason? I mean, who blurts out 'well, I left my car unlocked, and it got stolen', rather than just 'my car got stolen'.
Genius. I feel like we could be witnessing the return of Meept here.
How is this too early for me to decide what grad school to attend for research in nanomaterials?
On the shelves. Commercial efficiencies 15 years ago were about 14-15%. Today, about 22%.
PV has a theoretical maximum of 29%, so it isn't going to have any huge jumps from the current 22% efficiency. It will have to be a different fundamental design that goes higher than that (and perfect carnot conversion is only ~85% with solar, so we'll be lucky to triple today's efficiencies, ever.
1-4 years to pay off the energy required to manufacture them. After which they are a net benefit to our economies.
You can buy the cells anywhere. 15 years ago you could buy 14% efficient cells. Today you can buy 22% cells. Lab cells are approaching the theoretical limit of 29% for simple PV. That's a 50% improvement already, with another 30% on the table, whjch we will see gradually creep into commercialization over the next 15 years as we have over the last 15 years.
The dollars per watt has dropped to 1/3rd, WITHOUT even accounting for inflation, which is favorable to this example.
Yes, lots. The steady pace of innovation is slowly but surely raising the efficiency of cells toward a limit set by fundamental physics.
Solar cells are actually significantly ahead of where they were 15 years ago. There's no huge jump, but there really can't be, as we're nearing the theoretical limit of simple pv cells. More complicated cells can do better, but again the maximum amount better is less than 3x, and that is all the improvement we can ever get.
Have a look at
http://en.wikipedia.org/wiki/Solar_cell_efficiency
and you'll see the slow but steady march of progress. That march is reflected in the commercial cells you can buy as well.
Actually, it does matter, because if you start from a less efficient process and go up, you may not exceed the efficiency of a more efficient process. So the amount you can 'get from a solar panel' may not change at all.
Which is, if you read the article, actually the case here.
But innovations like this are exactly why solar efficiency has, in fact, slowly but steadily improved over the last couple of decades.