4 ms·

It also has to be enriched from the .72% natural concentration of U-235 and U-234. The SWU (energy) that goes into that is negligible, but the concentration pr

It also has to be enriched from the .72% natural concentration of U-235 and U-234. The SWU (energy) that goes into that is negligible, but the concentration process isn't perfect and you still need several times more natural uranium to produce something that can be used in a reactor (3-4%). I used a 33-40 year lifetime weighted by measured degradation rate[1]. Interestingly, NREL blames a lot of the capacity loss on the degradation of solder interconnections. I also used real insolation values in four regions of the US and 15%-23% (median to high efficiency) efficient cells, but assumed perfect MPPT tracking. I did guesstimate the amount of silicon though, by assuming 60-200 micron panels, which according to your link is off by a factor of 4-10x. So in the end real world solar loses to fusion (obviously) but beats light water reactors handily. It's initially a tossup when compared to breeder reactors, but only if you neglect silicon recycling (should that happen). At that point fission obviously loses. [1]: https://www.nrel.gov/pv/lifetime.html https://www.nrel.gov/pv/lifetime.html

philipkglass 9y ago
The World Nuclear numbers use mined natural uranium on the input side, so enrichment losses are implicitly included for nuclear. There are a lot of different PV degradation mechanisms. Most of them have known engineering solutions. I personally think that some modules installed today will have an operational lifetime in excess of 50 years, but I'm conservative when it comes to picking defensible numbers for extrapolation. Did you account for cell-to-module energy losses and inverter loading ratios > 1 when you made your estimates? I chose 20% capacity factor, despite published national (US) EIA numbers in excess of 25% for utility scale projects, because EIA reports AC (post-inverter) numbers. With typical utility scale inverter loading ratios now at 1.3 or so, the module-level capacity factor is more like 20%. None of these issues change your major conclusions. I'm just going into details because I rarely find anyone else interested in the subject matter.

philipkglass 9y ago

The World Nuclear numbers use mined natural uranium on the input side, so enrichment losses are implicitly included for nuclear. There are a lot of different PV degradation mechanisms. Most of them have known engineering solutions. I personally think that some modules installed today will have an operational lifetime in excess of 50 years, but I'm conservative when it comes to picking defensible numbers for extrapolation. Did you account for cell-to-module energy losses and inverter loading ratios > 1 when you made your estimates? I chose 20% capacity factor, despite published national (US) EIA numbers in excess of 25% for utility scale projects, because EIA reports AC (post-inverter) numbers. With typical utility scale inverter loading ratios now at 1.3 or so, the module-level capacity factor is more like 20%. None of these issues change your major conclusions. I'm just going into details because I rarely find anyone else interested in the subject matter.