For the past century, millions of tons of a particular waste product have been piling up all over the earth. This waste product contains no useful energy or rare elements, so its potential has taken longer to be widely recognized. It might just become something far more important to the future: a cheap and abundant energy-maker.
Engineer-Poet: "We've been ignoring a major supply of silicon-containing material. This material can be made into elemental silicon very cheaply. The silicon product is ready for direct fabrication into raw wafers for PV cells. These PV cells may be extremely cheap: about 3 peak watts per dollar. If we used all the annual supply of this silicon source, we could create peak capacity of about 10% of US average electric consumption every year."
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.
