Revision as of 02:17, 9 December 2024

Working Doc

Metallurgical grade silicon is 98% (one nine?) [1]
Solar grade silicon is 6-8N [2]
Microchip silicon (Electronic Grade Silicon) is nine nines pure, whereas power transistor silicon is 6 nines. [3]. Solar grade silicon is same purity as transistor grade - 6 nines. [4].
3 nines pure by acid leaching [5]
Czochralski silicon is 11 nines pure [6]

Siemens process involves chemical vapor deposition of silanes, with metallurgical grade silicon as the feedstock. [7]
Fluidized bed reactor - similar feedstocks as Siemens, but is continuous, thus capable of lower energy use
3 possible processes: upgraded metallurgical, Siemens, Fluidized Bed - [8]

Microchip silicon is nine nines pure, whereas power transistor silicon is 6 nines. [9]

See this reference for more detail [10]
And this discusses poly si vs mono si [11]
embodied energy of 165-375 kWhr/kg [12]
- Good news - 65% of all energy goes into the wafers, as opposed to everything else (glass + All + EVA) according to same link
- Similar for amorphous silicon [13]
Compare to steel at 20 MJ/kg [14], and 200MJ/kg more than this for aluminum [15]
How many grams of silicon are needed for 1kW of PV panels? 2 kg [16], based on 2g/W.
5% of weight of PV is silicon [17]. 76% is glass, 10% is aluminum, and 10% is EVA.
Embodied energy of EVA is about 80 mega joules per kilogram [18]

600 kWhr for 2 kg of silicon
3kWhr per kg for glass, or 90 kWhr for 30 kg glass. [19]
About 40 kWhr per my of EVA/aluminum x 8 kg = 320 kwhr
Total 1010 kWhr
- if the low estimate of 165 kilowatt hours above is true and this is 65% of the energy required then we have around 300 kilowatt hours of energy for wafers, and total around 500 kWhr for 1 kW of new PV panels - meaning energy payback of around 1/4 year!
The case here would be easy for open sector PV production
365*6kWhr~2100 kWhr/yr
Payback is thus 1/2 yr with only the above.
This matches results from Fraunhofer 2021, close enough - .7-1.4 year payback time. [20]

@@ Line 13: / Line 13: @@
 =Production Processes=
 *Siemens process involves chemical vapor deposition of silanes, with metallurgical grade silicon as the feedstock. [https://www.google.com/search?sxsrf=ALeKk026QG9BbsZl0rNsBS9KmerMgczY_w%3A1602863734253&source=hp&ei=dsKJX6q8DJDYsAXHkpG4Cw&q=what+purity+is+polysilicon&btnK=Google+Search&oq=how+to+configure+nvidia+geforce+gtx+1650+super+on+linux+mint&gs_lcp=CgZwc3ktYWIQAzIFCCEQoAEyBQghEKsCMgUIIRCrAjoOCAAQ6gIQtAIQmgEQ5QI6DgguELEDEMcBEKMCEJMCOggILhDHARCvAToLCC4QsQMQxwEQowI6CAgAELEDEIMBOggILhCxAxCDAToFCAAQsQM6AggAOgQIABAKOgYIABAWEB46CAghEBYQHRAeOgcIIRAKEKABUMsQWOmzAWD8tAFoBnAAeACAAeQGiAGhS5IBDTExLjQ3LjMuMi42LTGYAQCgAQGqAQdnd3Mtd2l6sAEG&sclient=psy-ab&ved=0ahUKEwiqz4DcvLnsAhUQLKwKHUdJBLcQ4dUDCAk&uact=5]
+*Fluidized bed reactor - similar feedstocks as Siemens, but is continuous, thus capable of lower energy use
+*3 possible processes: upgraded metallurgical, Siemens, Fluidized Bed - [https://ratedpower.com/glossary/polysilicon/#:~:text=to%20automotive%20electronics.-,How%20is%20polysilicon%20made%3F,use%20for%20a%20short%20time.]
 =Purity Levels=