Afaik(!) there are now saws down to 100µm and Recycling not only for SiC dust but also for Si dust.
I have some numbers on energy usage but they are not published.
What has been published is the numbers for the Solarwold concern in 2015. They used (including everything) 0,52kWh/Wp.
That's not the entire production process (and also does not include inverter, glass, aluminium rails, transport and installation), but Solarworld makes/made a lot from wafer to module inhouse.
Wacker Chemie is one of the largest producers of polysilizium worldwide and they produce around 60,000t/a in Germany (who would have thought with our -oh so high- energy prices)
In Burghausen they use around 3,000GWh/a (https://www.wacker.com/cms/de/wacker_gr ... igures.jsp
This is only one of two facilities, but they also produce other stuff than just Polysilicium
So to make it very easy lets say the electricity consumption for making 1kg of Polysilizium (solar grade and semiconductur grade!) is not more than 3,000GWh/a / 60,000,000kg = 50kWh/kg. Propably less.
You Need 6m² of PV cells for 1kWp and if you say 0.5kg to 1.6kg Si/m² this translates to 3kg to 10kg of Si for 1kWp solar power.
That would be only 150kWh tp 500kWh for 1kWp or 0.15Wh to 0.5Wh for 1Wp.
Using the numbers above with 15kWh/1kg this would only be 0.045Wh to 0.15Wh for 1Wp
Add to that the Solarworld numbers for wafer and module production and you are under 1Wh for 1Wp.
Add to this everyting else you are most likely less than 2Wh for 1Wp installed.
Btw, Wacker has ist own Chart for eneryg payback time for solar power plants and how that developed over the years
https://www.wacker.com/cms/media/public ... 416_DE.pdf
(see Chart on page 12)
Wacker says it takes 0.4 to 1.5 years for a solar power plant tp produce all the energy that has been used to make them.
(This is similar to my very rough estimation from above. During 1.5 years 1Wp PV produces 1,5Wh in Germany, which would be equivalent to the energy needed for 1Wp installed (all incl.))
Let's assume a solar power plant works for 30-40 years this would be an EROEI from 20 to 100.
Easily good enough.
Wacker is maybe not "neutral" on that topic either, but I guess they now it much better than someone wanting to promote nuclear power and guessing from some old published data!
Don't believe the liars!
It's always the same with disruptive technologies. People from the old industry will tell you how bad the new stuff is as long as they are able to do.
Driving more than 20kph on a train will kill you because it is against the "human nature". Better ride on horses.
Solar EROEI is so low. Better build more nukes.