Sustainable Energy Blog

Interesting article in the Oil Drum today:

“Silicon is the 2nd most abundant element in Earth’s crust (27.7% by weight). By all rights we should be able to make as many silicon PV cells as we want; we should be able to cover the planet with them.

The reality is different and more strange. Silicon PV production began as an offshoot of the semiconductor industry. The chip industry started with circular wafers made into single crystals by dipping a slowly turning crystal into a molten bath of silicon and drawing it out incrementally; the continuous turning created a rough cylinder consisting of a single crystal, which was sliced into wafers. Single crystals create the most efficient cells, but this is a slow and expensive process. Far from covering a planet, it remains far outside the typical household budget to completely cover even the house’s roof.

New processes are changing this. Polycrystalline and amorphous silicon films are much cheaper than large single crystals, in both money and energy. But until recently the PV industry has been too small to be worth its own supply of silicon, so it has survived on the surplus from the semiconductor industry. This surplus had a way of disappearing when electronics were hot, squeezing out the PV industry. But this may be about to change in a very big way, and the consequences may be earth-shaking.”

http://www.theoildrum.com/node/3047#more