[atemerev]

Solar panels production. Currently, they are mostly produced from scraps of semiconductor industry, and it's already close to capacity. This process is energy inefficient and environmentally unfriendly (silicon tetrachloride is an intermediate stage).

Pushing for more silicon solar panels beyond what's possible as semiconductor industry byproduct is unsustainable, both economically and environmentally.

[philipkglass]

Most high purity silicon is now destined for solar PV; PV's "scraps of semiconductor industry" phase was a decade or more ago.

http://www.upi.com/Business_News/Energy-Industry/2007/05/22/...

"In 2006, for the first time, more than half the world's polysilicon was used to produce solar PV cells."

It's true that the intermediates in silicon refining like are quite hazardous, but in a well-run production facility those intermediates don't get released to the biosphere. They affect the toxicity of the end product no more than the intermediate use of acetic anhydride in aspirin production, or the intermediate use of uranium hexafluoride in nuclear fuel rod production. There was a famous story in 2008 about a Chinese silicon production facility that was illegally dumping SiCl4, but if you're going to pick the most horrifying Chinese examples you'd think that nothing at all can be made safely.

[atemerev]

It is not that it is impossible to run photovoltaic panels production de novo (and it is done in large scale these days, as you have correctly stated). The problem is that it is economically unsustainable and have to be financed by government subsidies (or, alternatively, moved to cheap Chinese factories disregarding environmental costs completely).

Photovoltaics: scalable, green, economically sustainable (choose two).

[CountSessine]

There was a famous story in 2008 about a Chinese silicon production facility that was illegally dumping SiCl4, but if you're going to pick the most horrifying Chinese examples you'd think that nothing at all can be made safely.

There are some interesting moral gymnastics required there, no? The Chinese lead the world in PV manufacturing right now. Is this PV-revolution necessarily built on dirty manufacturing? Would we still have a PV-revolution if we weren't so accepting of an environmental disaster that takes place in a distant country?

[philipkglass]

My guess is that there would still be a PV revolution even without the Chinese factories, though the cost drops might have a come a bit slower. Costs were dropping at about the same year-over-year rate for decades before China leapt to the top of the PV manufacturing ranks.

Silicon refiners in the US actually had lower production costs than Chinese refiners even with the extra labor and environmental costs in the US. Unfortunately, a few years ago China imposed punitive trade barriers against silicon imported from the US. It was in retaliation for trade barriers the US put up against imports of Chinese solar modules. Until both sides erected their dueling trade barriers, the value of US-to-China silicon exports just about balanced the value of China-to-US modules. It was like a textbook example of comparative advantage. Now Chinese manufacturers get higher priced silicon made with fewer environmental protections, and US buyers get higher priced modules :-/

[xg15]

My impression is that most large-scale clean energy projects go for wind power, indirect solar energy (use sunlight to heat up some medium which then drives turbines or rotors) or bio fuel - with more exotic stuff like geothermic energy where it's applicable.

Solar panels seem to be one of the most inefficient clean energy solutions - so are they actually relevant here?