E-waste looms behind solar-power boom

Imagine a manufacturer that took back its products after 25 years of use.

That's exactly what watchdog group Silicon Valley Toxics Coalition is recommending that the solar industry do in a white paper released on Wednesday. (Click here for PDF.)

Solar is a renewable source of energy, and solar panels don't pollute when they are generating electricity. But the upstream process of making solar panels involves a number of toxic chemicals.

Most solar cells are made out of silicon, the same material embedded in billions of electronic chips. As a result, the burgeoning solar photovoltaics (PV) industry faces an electronic-waste problem.

The solar array at Applied Material's California headquarters. Where will the panels go after 25 years?

(Credit: Applied Materials)

In its white paper, the Silicon Valley Toxics Coalition recommends that manufacturers phase out harmful chemicals while it seeks out more benign materials and develops "environmentally sustainable practices." If the fast-growing solar business doesn't plan ahead, it risks "repeating the mistakes made by the microelectronics industry," according to the coalition.

"The electronics industry's lack of environmental planning and oversight resulted in widespread toxic chemical pollution that caused death and injury to workers and people living in nearby communities. The high-tech industry's legacy now includes the growing global tide of toxic electronic waste, or e-waste," the report says.

A report from China by The Washington Post brought attention to this solar-waste issue to many people for the first time. A reporter visited a village where toxic silicon tetrachloride, a byproduct of silicon cell manufacturing, was dumped, making the land unsuitable for growing and posing a health risk to residents.

The coalition recommends that manufacturers test materials for toxicity before they are used in manufacturing and to step up take-back programs so that materials can be recycled.

By keeping solar panels out of the waste stream, municipalities can eliminate health and environmental risks, such as water contamination. Silicon-based panels typically last 20 to 25 years.

Alternative thin-film solar cells using different materials pose their own health challenges.

For example, First Solar (which has a recycling program), which is considered the cost leader in solar power, makes cells from cadmium telluride. Although the toxicity of the cadmium telluride is not well understood, there is risk of exposure to toxic cadmium compounds during the manufacturing process, according to the report.

AUDIO

Solar power and e-waste
CNET News reporter Martin LaMonica tells CNET News editor Leslie Katz what kind of toxins are produced by solar panels, and what the recommendations are for dealing with them.
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[NocturnalCT]

As much as I like the idea of solar power I've been concerned about the environmental impact of creating traditional silicon based cells. I suspect (I'll admit I'm not certain) that PV cells are relatively inert once produced and can simply be dumped once they no longer produce enough electricity. As bad 'dumping' sounds, we're talking relatively small amounts of material compared to what we throw away or recycle every day. Since silicon PV cells use so much silicon it may even be possible to recycle them for new silicon. It may not be worth the trouble though if it takes more energy to purify the recycled material into workable raw silicon. In that case it's better just to put it on a pile and make new.

The same line of thinking needs to be applied to every wide eyed idea for producing power. Wind mills are great but is the production of these huge fiber composite blades clean enough? What about those batteries that the utilities have to install to give us power when there's no sun or no wind? What about maintenance costs? How much gas is burnt sending crews out to maintain remote wind parks?

I think the future of energy production will be created by multidisciplinary teams of engineers, physicists, economists, ecologists and whoever else is needed. So many angles that need to be reviewed. So many factors that, when swept under the rug, will come back to haunt us.

[Penguinisto]

Err, guys?

@ NocturnalCT: Correct - Solar cells are pretty much completely recyclable. The silicon can be re-melted and put back to immediate use as more solar cells (or semiconductor chips, or etc). Otherwise, it's about as chemically hazardous as sand. The plastic and glass used to make a solar panel are completely recyclable. Same with the copper used to wire it all together. I dare venture that less than 0.001% (if that, by weight) of a PV solar panel is not recyclable (basically, you'd have to scrape or melt off the PV cell coating).

As for the making of polysilicon, that is usually handled as a separate industry, and has no particular ties to the solar PV industry (which is why this whole report is kind of suspect in the first place). Toshiba (Intel's main supplier of silicon semiconductor wafers, among other folks IIRC) uses more polysilicon than most existing PV manufacturing sites... combined.

QED, I think these guys merely bolted the word "solar" onto (and into) the report to give it shock value, since polysilicon is far more heavily used by the semiconductor industry - which BTW is an industry that uses far nastier chemicals, and has far larger environmental hazards to deal with.

[hjecompany]

The problem with silicon-based cells is that recycling the silicon is not cost-effective. It is not as easy as remelting and reusing since there are many layers of other materials involved. The purity levels have to be at least 5-9's (99.999+%) and this material is quite expensive and VERY difficult to make from silicon scrap.
Also, not all photovoltaics are silicon-based. There are a CIGS cells (copper-indium-gallium-selenium), which will be next to impossible to recycle. And one of the commercially available systems is cadmium-based, which is very toxic.

[Penguinisto]

Actually, if the PV cells are made right, the cell coating comes right off after a short chemical bath and a cleaning. Most PV manufacturers do it right there in the plant if/when they find a defective cell during QA testing. (disclosure - I work in and around the PV industry). Now granted, this has yet to be tested with older cells and not on any large scale, but it is certainly possible, and even cost-effective for polysilicon providers when supplies are tight (as they are now).

You are correct in that not all PV cells are silicon-based, but silicon is the most common type made these days (be it poly- or monocrystal) due to low cost and simplicity of production. Also, the report doesn't whine about the non-silicon-based variety for some odd reason...

/P

[USDecliningDollar]

A friend of mine was a QA exec at a large (CdTe based) solar company. He started asking too many questions about toxicity, abatement, component recycling, and was shown the door - basically, it was the unwritten rule that questions about Cd were not mentioned.

[USDecliningDollar]

Very interesting.
The new "green" solar tech is CdTe based panels - Cadmium is terribly toxic and doesn't mix well with water. Ask AVA, First Solar or "I wish I had a product" Primestar Solar, what happens in the event of a fire say on your house and fire dept shows up to put it out.

"Burning material reacts violently with extinguishing agents such as water, foam, carbon dioxide, and halons"

That aside - cadmium is bad stuff, not the kind of thing that I want on top of my house, nor in a landfill. These solar companies can say what they want, but the current CEOs, investors, etc. will have cashed out by the time the cadmium waste starts to be a problem. Apparently the EU agrees - see tho RoHS directive.

I don't see how companies can build sustainable businesses off of CdTe. Cd is very toxic and Te is very rare - despite what the disinformation officers will tell you.