Comments on: Jeremy Leggett, The Cheerful Edition

By: pj

pj — Sat, 03 Nov 2007 14:59:49 +0000

I never realised that you could measure the cost of silicon. Just the cost of moving it around. And if you were considering covering the Sahara with PV cells you wouldn’t have to move it very far.

Tim adds: Actually, the cost is in taking it from silica (sand or silicon oxide) to silicon (the metal). To get the high grade stuff, very energy intensive. Have to use zone refining techniques. What’s really happened in the market for solar cells is that they used to be made from material orginally intended for the computer chip market, but which failed the stringent testing and putiy standards. But now the cell market is much larger than that source.

One of the very best things someone could do for the renewablce energy market is work on the metallurgy of silica to silicon.

By: Dave

Dave — Sat, 03 Nov 2007 10:32:20 +0000

markbrinkley is right – the issue is the cost of silicon, which is PV’s key raw material and is rising very quickly as demand outstrips supply

By: markbrinkley

markbrinkley — Sat, 03 Nov 2007 08:32:16 +0000

The problem with this “20% cheaper a year” story is that it is simply not true. PV did follow this price reduction model until three or four years ago, since when demand has been outstripping supply and the price has started going up. Just because it’s vaguely hi-tech, people assume that Moore’s law will apply. Big mistake.

By: Mark Wadsworth

Mark Wadsworth — Fri, 02 Nov 2007 22:14:45 +0000

I think that this “cover the Sahara in PV cells’ idea is brilliant.

It gives NATO pilots a nice big easy target to blow to pieces the next time they start to piss us off.

By: pedant2007

pedant2007 — Fri, 02 Nov 2007 21:30:19 +0000

David Gillies: yes, but remember that these days “exponential” apparently just means “big”. At least if you have a journalistic gene.
Philip Thomas: ah yes, but how do you transmit the electricity from the Sahara to Shanghai? (I’m not saying it can’t be done at all). I imagine some of the governments there would be happy to lease a few million hectares for power generation if the price were right.

By: David Gillies

David Gillies — Fri, 02 Nov 2007 18:39:31 +0000

Errm, for a 20% decline every two years I get a per-decade figure of 1 – (0.8^5) ~ 67% decline. Or am I missing something?

By: windowlicker

windowlicker — Fri, 02 Nov 2007 18:23:12 +0000

His most recent book is called “The Empty Tank” in the US and “Half Gone” everywhere else. I guess Americans are harder to scare.

By: Philip Thomas

Philip Thomas — Fri, 02 Nov 2007 17:40:16 +0000

I did find it one of the more amazing figures in his book, that covering only a few percent of the Sahara in existing solar cells would provide the entire current energy needs of the planet. Obviously politically unviable but it clearly illustrated how these concerns on energy production and capacity were being exaggerated.