Posted: Thu Jul 03, 2008 4:48 pm Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
isgota wrote:
"Bye, bye photovoltaics" LOL! Let's talk about exaggerating here:
- Almost 90% of current production is the "old" technology of silicon doped with phosporous and boron, and all of them are not rare in earth's crust.
Sure, but the goal of the photovoltaics industry is either to make the cells three to four times more efficient, which means you have to take the CIGS route. And that route is closed off because of resource scarcity.
Or you have to make silicon based solar cells four to five times less expensive (in fact, in order to be really competitive, you have to make them 10 to 20 times less expensive). Now, as it happens, high-grade silicon has become extremely expensive, and long-term trends don't look good.
So I think we can safely conclude that it's indeed "bye bye" classic photovoltaics.
We will have to come up with new materials, which either are not very scarce or which are very cheap.
We are also not talking about concentrated solar power, which probably has a much bigger potential than PV. _________________ The Beginning is Near!
Joined: Aug 03, 2007 Posts: 3771 Location: Boston Suburbs
Posted: Thu Jul 03, 2008 5:24 pm Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
isgota wrote:
"Bye, bye photovoltaics" LOL! Let's talk about exaggerating here:
- Almost 90% of current production is the "old" technology of silicon doped with phosporous and boron, and all of them are not rare in earth's crust.
- And what about Dye-sensitized solar cells? They have the same advantages that thin-films but using titanium dioxide (pretty common, is used in paints and toothpaste). Their industrial development is starting right now.
And regarding the platinum/fuel cells issue, 2 possibles technofixes:
Dye-sensitized solar cells are currently using ruthenium, a very rare element. They should be shifting to organic compounds, though. _________________ Paranoia is demonstrated to be an infectious disease, and stupidity plus the internet its major vector.
Joined: Aug 03, 2007 Posts: 3771 Location: Boston Suburbs
Posted: Thu Jul 03, 2008 5:27 pm Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
lorenzo wrote:
Or you have to make silicon based solar cells four to five times less expensive (in fact, in order to be really competitive, you have to make them 10 to 20 times less expensive). Now, as it happens, high-grade silicon has become extremely expensive, and long-term trends don't look good.
So I think we can safely conclude that it's indeed "bye bye" classic photovoltaics.
You're just being pessimistic for the sake of being pessimistic.
Right now the trend with classic PV is to team up with computer chip fabrication which is way ahead of PV in scalability. For instance, you can take bad batches of computer chips, shave off the circuitry, and convert them to solar cells. So don't count them out yet. _________________ Paranoia is demonstrated to be an infectious disease, and stupidity plus the internet its major vector.
Joined: Aug 03, 2007 Posts: 3771 Location: Boston Suburbs
Posted: Thu Jul 03, 2008 5:47 pm Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
anagami wrote:
LCDs are much more energy efficient than CRTs... going back to CRTs will make even more demand for the electric grid.
LCDs on laptops that use LED backlights are very efficient.
Desktop LCDs have been getting bigger and bigger and use more powerful flourescent backlights. The difference in power draw between these large LCDs and their CRT antecedents isn't as great as you'd think.
There are new technologies, though. OLED and laser projection. Laser rear projection is coming out this fall from Mitsubishi. For the screen size, they should be very efficient.
Quote:
LaserVue draws under 200 watts, about half that of LCD and a third of plasma.
Posted: Thu Jul 03, 2008 6:54 pm Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
mos6507 wrote:
lorenzo wrote:
Or you have to make silicon based solar cells four to five times less expensive (in fact, in order to be really competitive, you have to make them 10 to 20 times less expensive). Now, as it happens, high-grade silicon has become extremely expensive, and long-term trends don't look good.
So I think we can safely conclude that it's indeed "bye bye" classic photovoltaics.
You're just being pessimistic for the sake of being pessimistic.
Right now the trend with classic PV is to team up with computer chip fabrication which is way ahead of PV in scalability. For instance, you can take bad batches of computer chips, shave off the circuitry, and convert them to solar cells. So don't count them out yet.
You should know better. If there's one optimist on this forum, then it must be me. Only, my optimism is always based on pure reason.
The PV industry has had an intensive R&D cycle of more than 6 decades now. Progress has just not gone fast enough. Efficiency increases and cost-effectiveness remain extremely low and weak. If you have a look at the PV cost curve, prices per KWheq have decline merely by percentages over the decades. Other breakthrough technologies slash prices on logarithmic scales.
The technology can surely benefit from scale-advantages once production is boosted and panels (or sheets) flow of the roll by the millions. But there are no indications that this is going to happen. And if it does, there's the stark reality of the resource base which is unsustainable. That's the problem.
There is nothing pessimistic about dismissing one of the many ways to harvest solar energy, is there. There simply are better technologies available not in the least concentrated solar power, which is very friendly on raw materials (basically steel and glass). _________________ The Beginning is Near!
Posted: Thu Jul 03, 2008 7:01 pm Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
mos6507 wrote:
anagami wrote:
LCDs are much more energy efficient than CRTs... going back to CRTs will make even more demand for the electric grid.
LCDs on laptops that use LED backlights are very efficient.
Desktop LCDs have been getting bigger and bigger and use more powerful flourescent backlights. The difference in power draw between these large LCDs and their CRT antecedents isn't as great as you'd think.
There are new technologies, though. OLED and laser projection. Laser rear projection is coming out this fall from Mitsubishi. For the screen size, they should be very efficient.
(...)
Well sure, if you use 1/3 of the energy of a CRT but one a display 3 times bigger the efficiency is lost. But I'm using a 17" desktop LCD, with should be enough for most desktop uses. Also, CRTs are dangerous; you can die if opening it... I think about 20000 volts. They're uglier, bigger and tire more the eyes.
LED could scale too as background light, and later as colored light. Adding a 4th white pixel may help too. _________________ anagami.net
Joined: Aug 03, 2007 Posts: 3771 Location: Boston Suburbs
Posted: Thu Jul 03, 2008 11:55 pm Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
lorenzo wrote:
And if it does, there's the stark reality of the resource base which is unsustainable. That's the problem.
CIGS and gallium arsenide panels are not sustainable. Silicon effectively is. At any rate, why don't you let this play out a while before calling the endgame?
lorenzo wrote:
concentrated solar power, which is very friendly on raw materials (basically steel and glass).
Concentrated solar power is a non-starter for residential solar unless you have a large rural property in order to host a large enough trough or parabola to boil water and drive a turbine. As such, silicon PV will remain a critical technology. The unobtrusive nature of roof-mounted panels is hard to beat. In the end, expensive renewables are better than nonexistent renewables or renewables that are too awkward to fit into your property. _________________ Paranoia is demonstrated to be an infectious disease, and stupidity plus the internet its major vector.
Joined: Sep 03, 2005 Posts: 75 Location: Germany, State M-V
Posted: Fri Jul 04, 2008 4:18 am Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
About OLED i read an article in a technology magazine four weeks ago.
There is an article in Wikipedia about OLED:
Quote:
"Indium tin oxide is commonly used as the anode material. It is transparent to visible light and has a high work function which promotes injection of holes into the polymer layer. Metals such as aluminium and calcium are often used for the cathode as they have low work functions which promote injection of electrons into the polymer layer."
So this OLED also uses Indium. But perhaps the words "commonly used" is offering hope?
In the german version there is no hint to a substitute for Indium, but beside aluminium and calcium there are also Barium, Ruthenium, or a alloy of magnesium and silver as material for a cathode mentioned.
lorenzo wrote:
The PV industry has had an intensive R&D cycle of more than 6 decades now. Progress has just not gone fast enough.
I think that the price for silicon cells went down a lot in the last 6 decades. If the budget for PV would have been as big as for nuclear research then we wouldn't have problems - for sure.
E.g. six or seven years ago researchers discovered that the efficiency of a sandwich cells (gallium, indium, arsenid?) is a lot better than thought. There was a fault in the measurement of this compound in all the literature about PV.
About one year ago two PV silicon factory in Germany or Europe were built. They are not producing high grade silicon for chips but low grade silicon for PV. This is a lot less expensive.
Also silicon can be cast and you get amorphous (?) silicon with a lower efficiency but it's relatively cheap.
Nevertheless saving energy is still the most effective and cheapes solution today.
Posted: Fri Jul 04, 2008 5:34 am Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
mos6507 wrote:
lorenzo wrote:
And if it does, there's the stark reality of the resource base which is unsustainable. That's the problem.
CIGS and gallium arsenide panels are not sustainable. Silicon effectively is. At any rate, why don't you let this play out a while before calling the endgame?
lorenzo wrote:
concentrated solar power, which is very friendly on raw materials (basically steel and glass).
Concentrated solar power is a non-starter for residential solar unless you have a large rural property in order to host a large enough trough or parabola to boil water and drive a turbine. As such, silicon PV will remain a critical technology. The unobtrusive nature of roof-mounted panels is hard to beat. In the end, expensive renewables are better than nonexistent renewables or renewables that are too awkward to fit into your property.
But why would spreading "personal" or "residential" solar be so praiseworthy a goal to achieve? If it's ultra-costly, not sustainable and not very efficient?
It's about energy, don't you think, and not so much about personal possession or the fetish of decentralisation.
A medium-scale CSP plant can be put near nearly every town and city suitable for "residential" solar. (Decentralised and localised enough for me.)
Look at Sevilla in Spain, where the first commercial CSP plant works. It's located in a barren field a few kilometers outside of town. No biggie. It's ten times more cost-effective and an order of magnitude more efficient than PV.
So yes, with CSP plants you will have to deal with companies who own the stuff. You can own shares in that company.
Much better model than having your own extremely inefficient and costly panel on your roof. _________________ The Beginning is Near!
Posted: Fri Jul 04, 2008 5:11 pm Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
lorenzo wrote:
But why would spreading "personal" or "residential" solar be so praiseworthy a goal to achieve? If it's ultra-costly, not sustainable and not very efficient?
Just like most everything we make, it isn't sustainable until it is. Solar thermal isn't sustainable right now, but will it be in the future? Maybe, and it eventually has to be if we want to keep using it for a really long time. The advantage of solar power in locations where infrastructure hasn't already been payed for tends to be cost. Stringing up even a quarter mile of power lines to someone's house these days costs enough to drop in a solar PV system.
lorenzo wrote:
It's about energy, don't you think, and not so much about personal possession or the fetish of decentralisation.
It is, as well as cost, and transmission infrastructure takes energy as well. It really depends on what the specific situation is. _________________
Joined: Sep 25, 2005 Posts: 1989 Location: Waiuku, New Zealand
Posted: Sat Jul 05, 2008 6:03 am Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
lorenzo wrote:
But to answer your question: I've never been a cornucopian. I do think however that we can stretch resources far enough into time, to the moment when world population stabilizes at 9 billion (2050)
The problem with that is that population growth has not been slowing for the last 5 years, and actually accelerated slightly in the last two. If it doesn't resume its decline, 2050 will see 11 billion with more on the way.
Joined: Sep 25, 2005 Posts: 1989 Location: Waiuku, New Zealand
Posted: Sat Jul 05, 2008 6:11 am Post subject: Re: Bye bye photovoltaics: rare earth elements depleted by 2
mos6507 wrote:
The difference in power draw between these large LCDs and their CRT antecedents isn't as great as you'd think.
I second that, having recently looked for an LCD TV to replace our ailing CRT. I automatically assumed that LCD would have a much lower power rating than CRT, but I actually couldn't find an LCD TV that had even as low a power rating as my CRT (90W). It was a real surprise.
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