[ncmncm]

Ultra-pure silicon is not a pollutant. It is a resource.

You could say the same about nuke waste. But the pollutant threatening us with global collapse is CO2.

Placed elsewhere than desert, lifetime can be rather longer. But prices are still falling. In 20 years, how cheap will replacement be?

The point of renewables is renewal. Lately, this means opex near zero. It will come to be impossible to compete with generation and storage that have near zero opex, and capex less than a few years of your opex. No one will buy your power for the price you have to quote just to stay open, never mind pay down your construction loan.