Will Material Shortages Threaten Thin-Film Solar Cells?
What is the future of thin film cells? Photo Credit: Solar Power Notes
Do you remember just over a year ago when the solar industry was reeling because it couldn’t get the polysilicon needed to manufacture solar panels fast enough to meet demand? Half the industry was in a panic, prices were actually rising and polysilicon producers were scrambling to ramp up production volume.
Then, the stock market crashed and demand fell, but madcap production of solar-grade silicon did not. That leaves us with solar panels incredibly cheaper today and barely a word is uttered about supply. A similar worry plagued First Solar and the tellurium they need to make their cadmium-telluride (CdTe) solar cells.
Now, a new sector of the thin-film market, CIGS solar cells, is showing a sudden increase in panel production. In just a few months, Solyndra received federal funding to increase manufacturing by 500 MW annually and Nanosolar announced the opening of a 640-MW CIGS plant in Germany. And these are just the bigger examples.
Should CIGS manufacturers be concerned about supply shortages?
According to PV-Tech.org, no, they should not. PV-Tech’s Mark Osborne’s interest piqued at Intersolar North America, when Greentech Media predicted that CIGS production would rise from just 32 MW in 2007 to 1.3 GW by 2012. So, Osborne contacted Indium Corporation and received their review of supply side stats for CIGS solar cells.
The key ingredients in question are gallium and indium. Gallium is extremely abundant in the earth’s crust and spread out across the globe. Indium requires a more technical answer, but it boils down to this: given a mining rate of 500 megatons (MT) of virgin indium recovered each year, plus 500 MT of residue (indium as a byproduct of other processes) recovered each year, plus improved technology and further exploration make for an unending supply of indium as far as the eye can see.
Within this positive supply outlook for CIGS solar cells is a key advantage inherent to thin-film technologies. They require a relatively small amount of material to produce. It’s part of what helps keep thin-film solar cells cheaper (if less efficient) than conventional, silicon wafer cells. Silicon is also abundant. The problem causing the recent silicon shortage was production capacity, not the availability of the element on earth.
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