Freethought & Rationalism Archive

elwoodblues · 03-30-2002, 03:27 PM

"We don't need huge centralized power generation... it really only provides two things... (three if you count convenience, which in my opinion any small scale power generator would also have to provide in order to be feasible...) it puts money in the pockets of those who own the current energy production/distribution system, and provides a target to people with malicious intent."

Centralized power generation provides exactly the same thing that all large-scale production provides: economy of scale. The bigger the manufacturing facility is, generally, the cheaper the product will be per unit. It's a huge effect.

turtonm- Maybe I just know too many caricature-like activists. I'm sitting here in the heart of a pretty liberal university. If you're right, that's a great thing.

"Also, I've understood that the problem with solar power isn't that we can't catch it efficiently enough, but the storing of it."

Storage is certainly a problem, a huge problem. Batteries and other power storage methods just haven't progressed much in the last fifty years. If the AA battery had mapped onto the progress of computer power in the last 50 years, each one would today contain the power of a tactical nuclear weapon. No joke. Instead, they contain roughly the same energy today as 50 years ago. For roughly the same cost.

Production and durability is also a problem. Current generation solar cells are just too bloody expensive to make, in energy AND in dollars. And they're relatively fragile. They break fairly easily.

A lot of progress is being made in those areas. Energy storage could be the breakthrough that's really needed. However, sufficient progress in production efficiency and durability (and possibly transmission) could make up for a lack of progress elsewhere.

alek0 · 03-30-2002, 04:55 PM

Can we go back from sensationalistic and inaccurate news reports back to science here?

Organic solar cells are nothing new. However, every now and then there is an uproar over some paper published in Science and Nature which gives
novel structure and supposedly improved performance.

Last year news where full of enthusiastic reports about paper published in Science by Schmidt-Mende. Which was nothing but crap, I mean novel structure (liquid crystals) but lousy efficiency. He used monochromatic low power excitation, which is an old trick. Organic solar cells have decent efficiencies for small power, but efficiency goes down significantly when you go to AM1 radiation.
There have been much better works, like the one reported by Peumans et al. in Applied Physics Letters with 3.5% AM1 efficiency which is what truly counts. However, journalists who report "great progress" typically read Science and Nature instead of more physics oriented journals which publish the real stuff.

I've seen demonstrations of organic solar cells used in calculators (prototype, of course, ny Heeger's group). I can make you one which is good enough for that if you want. I can make you one good enough for that. However, I don't see that in near future these devices will be used for power generation.

I would also like to dispell the myth that you just "spray" or "paint" "plastic" on the surface and voila! a solar cell. Doesn't work that way. You have 3 types of organic solar cells:
1) small molecule cells which are typically fabricated by thermal evaporation in vacuum
2) polymer solar cells which are typically fabricated by spincoating
3) dye sensitized solar cells which consist of inorganic and organic materials, and frequently are notll solid state but contain electrolyte also.

Inkjet printing is another possible fabrication method for organic devices though it is very rarely used. However, just by depositing organics job is by no means done. You have to fabricate a top electrode, too, which is not done by "spraying" or "painting". The cells which contain selforganized nanostructures frequently have to be annealed too in order to acheieve this selforganization.

JohnR · 03-30-2002, 11:01 PM

Quote:

Originally posted by Corwin:
<strong>
Ideally I'd love to see some sort of inexpensive small scale power generation that was simple and convenient. (Say, you have to check it once a month or so being the main inconvienience.) Can solar provide this? Possibly. We'll see what they come up with.</strong>

As a powerplant operator I object! I love sitting here feeding the grid up to 900 megawatts of clean hydroelectric power.
As for other clean power sources what ever happened to fuel cells?
<a href="http://www.internationalfuelcells.com/fuelcell/how_fl.shtml" target="_blank">http://www.internationalfuelcells.com/fuelcell/how_fl.shtml</a>
Seems they would be a nice de-centralized power supplier.

tronvillain · 03-31-2002, 12:01 AM

Well, you still need power to produce the hydrogen, so that wouldn't really work.

Corwin · 04-01-2002, 09:01 AM

That's the main problem with most new power sources. They're hydrogen based, which would be great if we had a ready source of free hydrogen. Problem is, we have virtually no free hydrogen. It's all bound up in other compounds, and requires energy to crack it loose.

I'm not sure if this is related stuff here, but there was a posting on another site I visit a few months back about self-assembling solar cells. Basically just paint something with the chemicals and watch them assemble into a solar panel. Again, get the efficiency up and we might have something workable here.

tronvillain · 04-01-2002, 09:17 AM

Most new power sources are hydrogen based? The only thing I can think of is fusion.

elwoodblues · 04-01-2002, 09:55 AM

I think he was referring to fuel cells that are coming to market now.

tronvillain · 04-01-2002, 10:08 AM

Ah. I just don't think of them as a power source.

Corwin · 04-01-2002, 10:16 AM

Yes, fuel cells, hybrid cars, fusion of various sorts, etc.

A lot of them can use hydrogen compounds, like methane and alcohol, but those aren't as clean or efficient.

Solar would have the benefit of not actually burining anything, and also not requiring pure hydrogen as a fuel. However, we'll have to see if they can get the efficiency up high enough to make it feasible.

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03-30-2002, 03:27 PM	#11
elwoodblues Veteran Member Join Date: Mar 2001 Location: Dunmanifestin, Discworld Posts: 4,836	"We don't need huge centralized power generation... it really only provides two things... (three if you count convenience, which in my opinion any small scale power generator would also have to provide in order to be feasible...) it puts money in the pockets of those who own the current energy production/distribution system, and provides a target to people with malicious intent." Centralized power generation provides exactly the same thing that all large-scale production provides: economy of scale. The bigger the manufacturing facility is, generally, the cheaper the product will be per unit. It's a huge effect. turtonm- Maybe I just know too many caricature-like activists. I'm sitting here in the heart of a pretty liberal university. If you're right, that's a great thing. "Also, I've understood that the problem with solar power isn't that we can't catch it efficiently enough, but the storing of it." Storage is certainly a problem, a huge problem. Batteries and other power storage methods just haven't progressed much in the last fifty years. If the AA battery had mapped onto the progress of computer power in the last 50 years, each one would today contain the power of a tactical nuclear weapon. No joke. Instead, they contain roughly the same energy today as 50 years ago. For roughly the same cost. Production and durability is also a problem. Current generation solar cells are just too bloody expensive to make, in energy AND in dollars. And they're relatively fragile. They break fairly easily. A lot of progress is being made in those areas. Energy storage could be the breakthrough that's really needed. However, sufficient progress in production efficiency and durability (and possibly transmission) could make up for a lack of progress elsewhere.

03-30-2002, 04:55 PM	#12
alek0 Senior Member Join Date: Feb 2002 Location: Hong Kong Posts: 640	Can we go back from sensationalistic and inaccurate news reports back to science here? Organic solar cells are nothing new. However, every now and then there is an uproar over some paper published in Science and Nature which gives novel structure and supposedly improved performance. Last year news where full of enthusiastic reports about paper published in Science by Schmidt-Mende. Which was nothing but crap, I mean novel structure (liquid crystals) but lousy efficiency. He used monochromatic low power excitation, which is an old trick. Organic solar cells have decent efficiencies for small power, but efficiency goes down significantly when you go to AM1 radiation. There have been much better works, like the one reported by Peumans et al. in Applied Physics Letters with 3.5% AM1 efficiency which is what truly counts. However, journalists who report "great progress" typically read Science and Nature instead of more physics oriented journals which publish the real stuff. I've seen demonstrations of organic solar cells used in calculators (prototype, of course, ny Heeger's group). I can make you one which is good enough for that if you want. I can make you one good enough for that. However, I don't see that in near future these devices will be used for power generation. I would also like to dispell the myth that you just "spray" or "paint" "plastic" on the surface and voila! a solar cell. Doesn't work that way. You have 3 types of organic solar cells: 1) small molecule cells which are typically fabricated by thermal evaporation in vacuum 2) polymer solar cells which are typically fabricated by spincoating 3) dye sensitized solar cells which consist of inorganic and organic materials, and frequently are notll solid state but contain electrolyte also. Inkjet printing is another possible fabrication method for organic devices though it is very rarely used. However, just by depositing organics job is by no means done. You have to fabricate a top electrode, too, which is not done by "spraying" or "painting". The cells which contain selforganized nanostructures frequently have to be annealed too in order to acheieve this selforganization.

03-31-2002, 12:01 AM	#14
tronvillain Veteran Member Join Date: Oct 2000 Location: Alberta, Canada Posts: 5,658	Well, you still need power to produce the hydrogen, so that wouldn't really work.

04-01-2002, 09:01 AM	#15
Corwin Veteran Member Join Date: Jan 2002 Posts: 4,369	That's the main problem with most new power sources. They're hydrogen based, which would be great if we had a ready source of free hydrogen. Problem is, we have virtually no free hydrogen. It's all bound up in other compounds, and requires energy to crack it loose. I'm not sure if this is related stuff here, but there was a posting on another site I visit a few months back about self-assembling solar cells. Basically just paint something with the chemicals and watch them assemble into a solar panel. Again, get the efficiency up and we might have something workable here.

04-01-2002, 09:17 AM	#16
tronvillain Veteran Member Join Date: Oct 2000 Location: Alberta, Canada Posts: 5,658	Most new power sources are hydrogen based? The only thing I can think of is fusion.

04-01-2002, 09:55 AM	#17
elwoodblues Veteran Member Join Date: Mar 2001 Location: Dunmanifestin, Discworld Posts: 4,836	I think he was referring to fuel cells that are coming to market now.

04-01-2002, 10:08 AM	#18
tronvillain Veteran Member Join Date: Oct 2000 Location: Alberta, Canada Posts: 5,658	Ah. I just don't think of them as a power source.

04-01-2002, 10:16 AM	#19
Corwin Veteran Member Join Date: Jan 2002 Posts: 4,369	Yes, fuel cells, hybrid cars, fusion of various sorts, etc. A lot of them can use hydrogen compounds, like methane and alcohol, but those aren't as clean or efficient. Solar would have the benefit of not actually burining anything, and also not requiring pure hydrogen as a fuel. However, we'll have to see if they can get the efficiency up high enough to make it feasible.

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