Peak Solar power

[The Grim Squeaker]

No, it's not about the Sun going out.

German researchers claim breakthrough that may salvage the solar industry from the brink of disaster

It sounds like the death knell of the solar power industry -- shrinking Earth supplies of indium, which experts estimate will only last for another decade. Facing its darkest hour, a new breakthrough by researchers at Germany's Max Planck Institute for Polymer Research holds the promise of saving the solar industry from an untimely demise.

Solar cells have always relied on the metal indium, due to its transparency, which is essential to light emission or absorption in electronics. Engineers also regard indium valuable in LCDs and other transparent electrical devices. However, indium is a relatively rare metal on Earth and existing supplies are rapidly dwindling. Researchers have frantically searched for transparent conducting materials to little avail.

A new team claims it may have found the solution in one of the Earth's most abundant elements. Researchers at the Planck Institute have devised a new approach, utilizing graphene -- single 2D layers of carbon atoms, extracted from graphite -- 10 layers of which are applied to form an electrode. Each layer that comprises the electrode is a mere 5 nm thick.

The material has conductivity comparable or superior to indium and falls just slightly short of indium in transparent character. The current device is 80% transparent to visible light and 100% transparent to infrared light.

The team constructed a prototype using a process that will be drastically changed and refined. The prototype used graphite oxide flakes which were applied to form layers of surface coating between 10 nm to 100 nm thick. The coating was then heated to remove the oxygen, leaving behind a simple graphene-like material.

Assuming a better production process can be devised, mass produced solar cells made cheaply and with even better efficiency. The superior absorption of IR radiation would allow these cells to possibly surpass the production of traditional indium cells by capturing more of the EM spectrum. The team stated that they strongly believe that visible light efficiencies of 90 percent or higher are achievable.

The biggest challenge is that the formation of graphene is difficult and often leaves "creases" of extra carbon atoms. These creases distort light and lower the transparency. A sheet of perfect graphene would have nearly 100% transparency across the EM spectrum, including visible light. One positive, though is that the material is exceptionally stable and resistant to heat and acid, making processing much more viable.

While this discovery is likely 5 to 10 years from seeing serious production, it holds great promise to both provide unprecedented clean power and to provide a viable solution for electronics displays. With the inevitable depletion of indium, this may be one process that is forced to move from theory to mass production at an accelerated rate.

Odd that we've never heard of this before, although a potential solution is good. Strike one more up for Nuclear power I guess.

[Admiral Valdemar]

There are plenty of rare earth metals that are running out and absolutely vital to modern industry. The USGS did a report not long ago on this (or was it the UN?) and it was quite alarming. Metals you've never even heard of, but are absolutely mandatory in something like a computer chip or CCD or some chemical process are listed as having exhaustion rates in years and barely decades if demand keeps up.

[FSTargetDrone]

There are plenty of rare earth metals that are running out and absolutely vital to modern industry. The USGS did a report not long ago on this (or was it the UN?) and it was quite alarming. Metals you've never even heard of, but are absolutely mandatory in something like a computer chip or CCD or some chemical process are listed as having exhaustion rates in years and barely decades if demand keeps up.

Can such metals be recovered if more stringent computer and electronic recycling programs were mandated? I shudder to think of all the computers and components that end up in landfills.

[Admiral Valdemar]

I should think so. Recycling would help. The problem is that we aren't doing that and are more into keeping such things around and finding it cheaper to build brand new devices. There is a limit somewhere down the line where you simply have to rebuild old units, just as platinum exists in barely enough quantities to build fuel-cell cars to replace the current global population. Only platinum is relatively abundant.

Just running out isn't the issue. It's more along the peak oil problem of output production and cost. Phosphate from rocks, for instance, have peaked, they did so years ago, and phosphate is mandatory for all biological life. You can recycle it, but the vast bulk of it used to come from now exhausting deposits that were plentiful, like the bat guano the likes of the East India Company would prosper from.

As many who misunderstand the growth problem, we don't have to reach the point where every square metre holds a human. The planet is plenty stretched enough today even if we could all stand on Zanzibar.

[Sikon]

On the order of 1% of the mass of average biomass like plants and animals is comprised of phosphorus. As a necessary nutrient, phosphates are used in fertilizers. Of the thousands of quadrillions of tons of earth's crustal mass, on the order of 0.1% by mass is phosphorus. Phosphorus is not running out. There exist reserve figures based on a particular cutoff for the concentration of phosphate rock in the occasional regions where it is much better than average crustal abundance, considering the economics of production in a given area compared to the competition. An example is that here of a reserve base a few hundred times annual production, although fundamentally there are quadrillions of tons of phosphorus, millions of times more than world annual production.

The cost of U.S. phosphate production in 2006 was $850 million for 31 million tons of product, about 1 part in 15000 of the $13 trillion total economy. There's been reduced market demand for U.S. phosphate production due to competition from increasing, inexpensive production in regions such as China, which previously imported more from the U.S.

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The OP article leans a bit towards hyperbole. Not all forms of solar power use solar cells (such as solar-thermal being cheapest so far in large centralized installations); some types of solar cells use vastly less indium than others or none at all; etc. Besides, current indium production is more a matter of demand in the current economic market than fundamental limits (example). Despite the market price of indium itself having increased, the price of the best solar power has primarily been going down in recent history, although nuclear power is much less expensive per kilowatt-hour delivered.

[Admiral Valdemar]

Naturally, phosphorus is never going to "run out". It's never destroyed or shot into space beyond our grasp. The issue is a peaking in global production rates from phosphate rock deposits, meaning recycling will have to take priority if agriculture is going to continue even with expensive energy.

For solar, PV cells are getting better (though the NanoSolar and similar super cells that promise 40%+ efficiency are yet to make it to market), but in truly hot climes, it is best to use solar thermal farms than just PV cells. Europe is looking into making more such farms in the future, one has just recently come online in Spain, so I recall. No luck with that in areas that aren't prone to predictable sunshine and lack of cloud cover, but that's why the UK, for instance, can use wave and wind as a buffer to nuclear.