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Photovoltaics: (some more) depressing news

Photovoltaics do take energy to make and use toxic elements that can cause nasty pollution unless they’re contained. We knew that. But what I didn’t really bother to think about is that those same rare elements that are toxic are also, well, rare. We’re using them like they’re not rare. So . . . doh! . . . they’ll run out soon. Meaning soon. Times like “five years” and “2017″ come out of the number-crunchers.

From New Scientist, reporting on Gordon, Bertram, and Graedel’s recent paper (abstract, pdf).

It’s not just the world’s platinum that is being used up at an alarming rate. The same goes for many other rare metals such as indium, which is being consumed in unprecedented quantities for making LCDs for flat-screen TVs, and the tantalum needed to make compact electronic devices like cellphones. . . . Even reserves of such commonplace elements as zinc, copper, nickel . . . will run out in the not-too-distant future. . . . [T]he metal gallium, which along with indium is used to make indium gallium arsenide . . . is the semiconducting material at the heart of a new generation of solar cells . . . . Reserves of both metals are disputed, but . . . RenĂ© Kleijn, a chemist at Leiden University in the Netherlands, . . . estimates gallium and indium will probably contribute to less than 1 per cent of all future solar cells – a limitation imposed purely by a lack of raw material.

Iridium is the material that blankets the planet in a thin layer, left over from the asteroid strike that bothered the dinosaurs. Some of the other elements are found in sand in nano-quantities. However, grinding up the whole planet to make solar panels doesn’t seem like a much better idea than turning it inside out to burn it.

Time to get extremely serious about organic (in the sense of carbon-based) photovoltaics. It’s complicated, though. To begin with, organic molecules break down easily. And then, as Terry Pratchett might say, it’s quantum. However, plants do it. Bacteria do it. You’re not going to tell me we’re stupider than plants, are you? (Don’t answer that.)

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