Thursday, July 3, 2008

Solar: Peak Gallium? Indium?

Sometimes I feel as if we're doing a 'Groundhog Day' (or maybe it's just me, Rip Van Climateer).
Paul Erlich has a book out, forty years after 'The Population Bomb', folks are mentioning The Club of Rome, forty years after its founding and 36 years after 'The Limits to Growth'. Any moment I expect Julian Simon to arise from the grave with prop bets. Anywho, here's a year-old story that might be relevant today. From New Scientist via Nova (Australia):

"I get excited every time I see a street cleaner," says Hazel Prichard....

Armin Reller, a materials chemist at the University of Augsburg in Germany, and his colleagues are among the few groups who have been investigating the problem. He estimates that we have, at best, 10 years before we run out of indium. Its impending scarcity could already be reflected in its price: in January 2003 the metal sold for around $60 per kilogram; by August 2006 the price had shot up to over $1000 per kilogram.

Take the metal gallium, which along with indium is used to make indium gallium arsenide. This is the semiconducting material at the heart of a new generation of solar cells that promise to be up to twice as efficient as conventional designs. Reserves of both metals are disputed, but in a recent report René Kleijn, a chemist at Leiden University in the Netherlands, concludes that current reserves "would not allow a substantial contribution of these cells" to the future supply of solar electricity. He 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....MORE

This excursion was prompted by a brief essay at Asimov', "Reflections: The Death of Gallium"

Sacre bleu! Quel catastrophe! No more airplanes, no more trains or buses, no bridges, no weapons, no scissors, no shovels, no can-openers, no high-rise buildings. Subtract one vital element and in short order society collapses into Neolithic anarchy, and then into a nomadic post-technological society founded on mysticism and magic. This forgotten book has an exciting tale to tell, and tells it very well.

It’s just a fantasy, of course. In the real world iron is in no danger of extinction from strange diseases, nor is our supply of it running low. And, though I said a couple of paragraphs ago that the ninety-two natural elements are essential building blocks of the universe, the truth is that we’ve been getting along without two of them—numbers 85 and 87 in the periodic table—for quite some time. The periodic table indicates that they ought to be there, but they’re nowhere to be found in nature. Element 85, astatine, finally was synthesized at the University of California in 1940. It’s a radioactive element with the very short half-life of 8.3 hours, and whatever supply of it was present at the creation of the world vanished billions of years ago. The other blank place in the periodic table, the one that should have been occupied by element 87, was filled in 1939 by a French scientist, who named it, naturally, francium. It is created by the radioactive decay of actinium, which itself is a decay product of uranium-235, and has a half-life of just 21 minutes. So for all intents and purposes the world must do without element 87, and we are none the worse for that.

Gallium, though—

Gallium’s atomic number is 31. It’s a blue-white metal first discovered in 1831, and has certain unusual properties, like a very low melting point and an unwillingness to oxidize, that make it useful as a coating for optical mirrors, a liquid seal in strongly heated apparatus, and a substitute for mercury in ultraviolet lamps. It’s also quite important in making the liquid-crystal displays used in flat-screen television sets and computer monitors.

As it happens, we are building a lot of flat-screen TV sets and computer monitors these days. Gallium is thought to make up 0.0015 percent of the Earth’s crust and there are no concentrated supplies of it. We get it by extracting it from zinc or aluminum ore or by smelting the dust of furnace flues. Dr. Reller says that by 2017 or so there’ll be none left to use. Indium, another endangered element—number 49 in the periodic table—is similar to gallium in many ways, has many of the same uses (plus some others—it’s a gasoline additive, for example, and a component of the control rods used in nuclear reactors) and is being consumed much faster than we are finding it. Dr. Reller gives it about another decade. Hafnium, element 72, is in only slightly better shape. There aren’t any hafnium mines around; it lurks hidden in minute quantities in minerals that contain zirconium, from which it is extracted by a complicated process that would take me three or four pages to explain. We use a lot of it in computer chips and, like indium, in the control rods of nuclear reactors, but the problem is that we don’t have a lot of it. Dr. Reller thinks it’ll be gone somewhere around 2017. Even zinc, commonplace old zinc that is alloyed with copper to make brass, and which the United States used for ordinary one-cent coins when copper was in short supply in World War II, has a Reller extinction date of 2037....MORE

HT: Futurismic

Among the solar companies with approaches using Copper-Indium-Gallium-Selenide are:

Global Solar

And probably another half-dozen whose names escape me.

You know how this ends up?
We'll figure something out. That is really the only claim to fame of Homo Sapiens, singular and collectively.

But, it's a pretty good one.