Solar panel efficiency vs extraction cost? Don't solar panels deplete?
>>8104095
This interests me. However, please be more specific.
Yes, solar cells degrade over time. It's an unavoidable problem IIRC because when solar rays that hit electrons to cause a current, that same process also slowly degrades the solar cell.
What do you mean by extraction cost? And what do you want to know about it and solar panel efficiencies?
>>8105474
Yeah, no chemical process is completely reversible. Everything degrades. It's unavoidable. That being said, I think the issue right now is the total carbon cost of extracting semiconductor materials from the ground. Is it actually carbon neutral, or are we using a fuckton of fossil fuels in the mining and manufacturing process that won't be recouped during the operational lifetime of the PV cells.
>>8105524
"True believers" in renewables will tell you that it will eventually be powered with renewables entirely.
When you do a systems analysis, e.g. an end to end analysis, one finds that solar alone cannot support the production of more solar, and also sustain our modern standard of living. For further reading, I suggest starting here:
https://bravenewclimate.com/2014/08/22/catch-22-of-energy-storage/
>>8105524
>Yeah, no chemical process is completely reversible. Everything degrades. It's unavoidable. That being said, I think the issue right now is the total carbon cost of extracting semiconductor materials from the ground. Is it actually carbon neutral, or are we using a fuckton of fossil fuels in the mining and manufacturing process that won't be recouped during the operational lifetime of the PV cells.
Solar panel production requires significant amounts of energy, whci his currently mostly derived from fossil fuels. The exact amount of time it takes for a solar panel to "pay for itself" is difficult to calculate, but it's probably in the realm of 4-10 years.
>>8105540
>one finds that solar alone cannot support the production of more solar, and also sustain our modern standard of living.
>https://bravenewclimate.com/2014/08/22/catch-22-of-energy-storage/
This is an extremely minority view, and I wouldn't consider "brave new climate" a terribly impressive source - especially when they're citing a paper published in "Energy and Environment" of all places.
>>8105683
>This is an extremely minority view
How do you know that? I don't think so.
As for the reliability of the source, I've seen it supported elsewhere from other sources as well. I haven't seen a convincing rebuttal to it, and I've looked.
>>8105474
>>8105540
Hey newfag, trips suck.
>>8105685
>How do you know that?
Because I've read other studies. His numbers are way below everyone else's.
There's a reasonably good discussion of the Weißbach paper here. It IS just a blog post, but it still covers the important points.
http://rameznaam.com/2015/06/04/whats-the-eroi-of-solar/
It references a pretty good meta-study, which puts the EROI of solar at around about 8.7:
http://astro1.panet.utoledo.edu/~relling2/PDF/pubs/life_cycle_assesment_ellingson_apul_%282015%29_ren_and_sustain._energy_revs.pdf
And here's some other papers. They make different assumptions.
http://www.clca.columbia.edu/241_Raugei_EROI_EP_revised_II_2012-03_VMF.pdf
https://www.researchgate.net/publication/260112297_Strengthening_the_case_for_recycling_photovoltaics_An_energy_payback_analysis
>>8105742
I'm actually probably the longest posting tripfag, going back over a decade IIRC.
>>8105752
>http://rameznaam.com/2015/06/04/whats-the-eroi-of-solar/
Yea, I've read this page and the other pages already. 4 something vs 8 something for EROEI doesn't matter for the argument. It's still insufficient when you throw in reliability requirements / energy storage requirements.
>>8105752
Also, regarding this paper, which is linked by your source:
http://astro1.panet.utoledo.edu/~relling2/PDF/pubs/life_cycle_assesment_ellingson_apul_%282015%29_ren_and_sustain._energy_revs.pdf
I'm a little confused on how they got some of these numbers. Could you help me out here?
For polycrystal silicon solar cells, it says the embedded energy is 3.914e9 J / sq meter of solar cell (plus supporting equipment, like mounting, inverters, etc.).
Let's be generous and use numbers for the Sahara desert, yearly average, which IIRC is close to 230 W / sq meter. Let's be generous and say 30 year lifetime and 13.3% average lifetime conversion efficiency (the number from the paper). That comes out to:
total energy produced over lifetime
= (30 years) (230 W / sq meter) (.133)
= 2.90e10 J / sq meter
That should give an EROEI of
2.90e10 J / 3.914e9 J
= 7.41
How are they getting an EROEI number of 11.6 for polycrystal silicon solar cells? I am confused.
>>8105764
Well, longest posting tripfag on /sci/ at any rate.
>>8105752
Note: His numbers are for Germany, which does greatly influence the yearly average solar radiation values, which greatly influences the EROEI value. I've been meaning to start compiling sources to see how and where they disagree on the EROEI calculations, but offhand, if you change the solar radiation values from Germany to the Sahara desert, that sounds about right for the 2x observed difference in some quoted EROEI values.
But as I said, 4 or 8, it's still way too low when we have to also account for overbuilding, storage, and/or massive grid interconnects to obtain reliable power generation.
>>8105752
I haven't yet read the last two papers. I'm doing that now.
http://www.clca.columbia.edu/241_Raugei_EROI_EP_revised_II_2012-03_VMF.pdf
Lists EROI of polycrystal silicon solar cells as 5.9. (I really need to sit down and this source and other sources again to understand what games they're playing with eqn 4. Right now, I don't understand.)
Still reading this last paper.
