That is a good question, but I do not have the answer.

Did you know that production of hydrogen from silicon can also be used for medical treatments.

Read here

"Si and its oxide are nonpoisonous materials, and thus, it can be taken for medical effects. We have developed a method of generation of hydrogen by use of reactions of Si nanopowder with water in the neutral pH region.........

...........The present study shows a possibility to use Si nanopowder for hydrogen generation in the body in order to eliminate hydroxyl radicals which cause various diseases."

Although I'm guessing that the silicon for medical purposes would need to be of higher purity than for electricity production, I find that very interesting and exciting.