Silicon: After the chip, another revolution? (BBC) {solar PV, Swanson's Law}

[eppur_se_muova]

By Justin Rowlatt
BBC World Service

Summer is upon us and you are almost certainly planning at least one trip to the beach. This year, as you lie back in the sun, put down your book or magazine and sift the sand through your fingers - and take a moment to reflect upon how much of the world economy is built on the stuff.

I don't mean "built on sand" in a philosophical sense, however true that may be. I'm talking about three technological revolutions that are literally based on sand, one of which is only just beginning and, if it lives up to its potential, has mind-boggling implications.

You've probably already guessed the element at the heart of these revolutions - silicon, the main component of sand.
***
Just as Moore's law forecast an exponential increase in the number of transistors on a chip, Swanson's Law predicts an exponential decrease in the price of solar. What he forecast is that every time the number of solar cells in the world doubles, the cost of making one would fall 20%.

And this law too has proved remarkably accurate. Prices have fallen like a stone since - from $100 per watt in the 70s, down to less than $1 per watt now.
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more: http://www.bbc.com/news/magazine-28600802




Interesting background, not really for science majors.

BTW, silicon is not really the "main ingredient in sand" -- oxygen is.

[DocwillCuNow]

1. This company uses beach sand instead of platinum to produce their fuel cell stacks and that is

a good thing, I think Ebay uses them iirc...

http://www.bloomenergy.com


What is an Energy Server?

Built with our patented solid oxide fuel cell technology, Bloom's Energy Server™ is a new class of distributed power generator, producing clean, reliable, affordable electricity at the customer site.

Fuel cells are devices that convert fuel into electricity through a clean electro-chemical process rather than dirty combustion. They are like batteries except that they always run. Our particular type of fuel cell technology is different than legacy "hydrogen" fuel cells in three main ways:

Low cost materials – our cells use a common sand-like powder instead of precious
metals like platinum or corrosive materials like acids.
High electrical efficiency – we can convert fuel into electricity at nearly twice the
rate of some legacy technologies
Fuel flexibility – our systems are capable of using either renewable or fossil fuels

Each Bloom Energy Server provides 200kW of power, enough to meet the baseload needs of 160 average homes or an office building... day and night, in roughly the footprint of a standard parking space. For more power simply add more energy servers.

[eppur_se_muova]

2. Their "common, sand-like powder" is not sand ...

I would have suspected cerium oxide, but it appears to be more complicated ...

Wired reported that the secret ingredient may be yttria-stabilized zirconia based upon US patent that was granted to Bloom in 2009; but this material is also one of the most common electrolyte materials in the field.[10] US patent 20080261099, assigned to Bloom Energy Corporation, says that the "electrolyte includes yttria stabilized zirconia and a scandia-stabilized zirconia, such as a scandia ceria stabilized zirconia". ScSZ has a higher conductivity than YSZ at lower temperatures, which provides greater efficiency and higher reliability when used as an electrolyte. Scandia is scandium oxide (Sc2O3) which is a transition metal oxide that costs between US$1,400 and US$2,000 per kilogram in 99.9% pure form.

http://en.wikipedia.org/wiki/Bloom_Energy_Server#Technology

While these materials are described as "found in beach sand", none of them -- cerium, zirconium, or scandium, the rarest -- is all that common, though still much cheaper than platinum metals.

[DocwillCuNow]

3. I sit corrected, thank you for that. nt