What is the current spot price for solar grade polysilicon?

The numbers you've been viewing are for common "metallurgical grade" silicon, which must be highly refined - from native "two nines" - 99% pure - of purity to somewhere north of "six nines" - 99.9999% pure - of purity for use in photovoltaic - or "PV" - (solar) applications. For electronics applications, it's nine to eleven nines. PV benefits from trickle-down of advances in refinement of electronics-grade production, with the result that the best - and best-performing - PV grades are pushing 8 nines. Even at 6 nines, spot price has been hovering at $400 to $500/kg for well over a year.

If you're interested, metallurgical grade ("MG Silicon") is produced in reducing furnaces from common quartz sand - the stuff dirt's made of. At very high temperature and in the absence of oxygen, the silicon dioxide sand (silica sand, one of the most abundant minerals on earth) gives up its oxygen and leaves behind 99+% pure silicon - a gray metal which is granulated by crushers in preparation for sale.

For electronic applications, including those for PV, the MG Silicon is reduced (usually) with hydrogen and chlorine so as to yield gases which may be chemically refined to varying levels of purity. The resultant compounds are further processed to yield various forms of solid pure silicon, including Solar and Electronics grades.

The multi-tiered refining processes are extremely expensive to operate, so that the cost of refined silicon is several times that of MG Silicon. Long-term, large-quantity contract prices are frequently in the range of 50% of spot price level.

(JPiConsult 10/12/2009)