Industrial energy costs are $1 per million BTU (MMBTU) or 300kWh, or $3*10^-6 per watt hour (Wh).
Solar has 1 kg of 9n silicon per 100W, at $20/kg. Since raw material prices are mainly energy costs, this is:
($20/kg)/($3e-6/Wh) = 6MWh/kg
Kg per watt solar is:
1kg/100W = 0.01kg/W
That means energy use to build a watt of capacity is:
0.01kg/W * 6MWh/kg = 0.06 mwh = 60kWh
Let's say a 1 watt cell operates for 20 years:
At 20% capacity this is:
0.2 * 180kWh = 36kWh
Is this correct?
This is a specific new question and not a dupe of the above.