Solar Waste Recycling: Can the Industry Stay Green?

In recent years, the electronics industry has gained notoriety for creating an endless stream of disposable products that make their way at life's end to developing countries, where poor people without safety gear cut and burn out valuable materials, often spilling contaminants into their water, air and lungs in the process.

Solar modules contain some of the same potentially dangerous materials as electronics, including silicon tetrachloride, cadmium, selenium and sulfur hexafluoride, a potent greenhouse gas. So as solar moves from the fringe to the mainstream, insiders and watchdog groups are beginning to talk about producers' responsibility and the prospect of recycling in an attempt to sidestep the pitfalls of electronic waste and retain the industry's green credibility.

Solar modules have an expected lifespan of at least 20 years, so most have not yet reached the end of their useful lives. But now, before a significant number of dead panels pile up, is the perfect time to implement a responsible program, said Sheila Davis, executive director of the Silicon Valley Toxics Coalition.  

The nonprofit environmental group has been a leader in recognizing the problems of e-waste, including hazardous disposal sites in the Bay Area left by the semiconductor industry. Now it is focused on the solar boom in Silicon Valley. Last year, the group published a report calling for a "just and sustainable" solar industry, and this year it issued a scorecard of solar companies. The scorecard evaluates recycling and extended producer responsibility for the product's end of life, called takeback; supply chain and green jobs; chemical use and lifecycle analysis; and disclosure. 

Vastly expanding industry

Solar energy is the most widely available resource we have. Every hour, enough solar energy strikes Earth to meet human energy needs for more than a year, according to NASA. Now the solar industry is poised for huge growth in the United States, thanks to policy changes, incentives, technological improvements and economies of scale. Solar photovoltaics have recently become less expensive than nuclear energy on a per-kilowatt-hour basis, according to a new report from Duke University. Also, solar is widely expected to reach cost parity with fossil fuels in most markets by 2013.

In 2009, Greentech Media estimated that U.S. solar demand will continue to increase about 50 percent annually through 2012. The report said the U.S. capacity installed during 2008 was about 320 megawatts, and it predicted that about 2,000 megawatts would be installed during 2012. Such growth would put U.S. capacity ahead of solar leader Spain and potentially ahead of Germany, as well. 

While most of the new modules will likely have a long, productive life, factory scrap, transport breakages and field failures are ready for recycling now. Jennifer Woolwich is collecting these broken solar modules in a warehouse near Phoenix.

She founded her company, PV Recycling, in February 2009 after estimating that she could harvest 500 panels a week from these sources. She is not yet collecting at that capacity, nor does she have enough panels to begin recycling them, but she is talking with solar manufacturers in an effort to win their recycling business. 

"Of those we interviewed, 100 percent want recycling," she said. "Eighty percent want an independent third-party doing the recycling."  

Woolwich said she has seen a quick evolution in solar manufacturers' attitudes toward recycling: "Last year, there was kind of a 'wait and see, we're not sure how this is going to work' attitude. Over the past 12 months, I've seen a 180. I've seen companies who are hiring consultants to research their whole value chain to identify waste, including the end of life of modules. We've received calls from consumers asking us which companies have takeback programs in place."

Solar companies tend to be secretive about their product recipes, making some manufacturers cautious about, yet conceptually open to, third-party recycling.

"We guarantee that intellectual property will not be put at risk," Woolwich said. "We're not interested in reverse engineering or selling company secrets. We have certificates of destruction that we provide."

For now, though, some companies are doing their own recycling.

SolarWorld, which received an 88 out of 100 on the toxics coalition's scorecard, has been recycling its own panels since 2003 at its main factory in Freiberg, Germany. That factory now receives broken panels from its U.S. plants in Cabrillo, Calif., Hillsboro, Ore., and Vancouver, Wash.

"The fact is, there isn't much to recycle," said Ben Santarris, a spokesman for SolarWorld. "In the future we might expand recycling to our U.S. plants or contract with a third-party recycler."

First Solar earned a rating of 67 on the scorecard. Headquartered in Tempe, Ariz., it has recycling facilities at its manufacturing sites in Perrysburg, Ohio; Frankfurt (Oder), Germany; and Kulim, Malaysia. Lisa Krueger, vice president of sustainable development, said that so far the company is primarily recycling manufacturing scrap.

"It's our intention that there would be other recycling facilities worldwide as you get into those volumes," she said.

Materials of interest

Solar modules employ a variety of technologies, and even models within the same technology can have different ingredients. These materials may or may not be classified as toxic depending on who is regulating them.

Dustin Mulvaney is a scientist who works on solar issues at the University of California, Berkeley, and serves as a consultant to the Silicon Valley Toxics Coalition. He has analyzed solar modules currently on the market and has outlined for each its key ingredients, including potentially toxic elements and materials that would be valuable to recover in recycling.

Used in SolarWorld modules, crystalline photovoltaic is the oldest and most widespread solar technology in the United States, holding 57 percent market share in 2009, according to Greentech Media. "As far as hazardous materials go, you're primarily talking about lead," Mulvaney said.

A thin film technology called cadmium telluride makes up about 21 percent of the U.S. market. First Solar panels use this technology.

Cadmium may be carcinogenic. Exposure affects the lungs and kidneys and can be fatal. "It's gene toxic and a mutagen, so it has the ability to affect DNA, meaning it could affect reproduction and future generations' DNA," Mulvaney said.

Cadmium is technically banned by the European Union's Restriction on Hazardous Substances directive, although the policy currently allows an exemption for its use in solar modules.

Still, there's not a lot of data about whether cadmium is toxic in the alloy form in which it's used in thin film. And cadmium isn't likely to go away anytime soon, as it is uniquely efficient at absorbing light.

Another thin film material, copper indium gallium selenide (CIGS), also has a cadmium layer. Indium is a potentially hazardous substance, too, particularly in the form of indium tin oxide, Mulvaney said. Studies have linked it to pulmonary disease in flat-screen TV recycling facilities. And selenium has been documented to be a hazardous material.

While CIGS currently has a market share of just 6 percent, amorphous silicon, which also has an indium tin oxide layer, holds 16 percent of the market.

California's Department of Toxic Substances Control has taken note of the European Union's concern about cadmium and is researching the chemical and physical makeup of various types of modules.

"We think some solar panels, probably the cadmium thin-film type, might be hazardous waste when shredded or disposed of in a landfill," said Charles Corcoran, a hazardous substances scientist at the department.

Only panels classified as hazardous would fall under the jurisdiction of the department. It is considering regulatory options to try to steer end-users toward recycling rather than disposal.

"That gets a little complicated, because California and U.S. regulations aren't necessarily in sync," Corcoran said. "An option might be to transport it out of state where disposal is legal."

Today, California has no solar module recycling facilities. But recycling locally is an important tenet of an ethical, sustainable industry, said the Silicon Valley Toxics Coalition's Davis. Recycling locally reduces the process' carbon footprint.

"It would also make people more conscious about what goes into the products," Davis said. "And it would create local jobs."

Designing with recycling in mind

Extended producer responsibility, including module recycling, is currently an expense rather than a source of profit for companies, including Solar World and First Solar.

"As we get to scale, we hope those costs will come down," Krueger said.

A dedicated recycler like Woolwich is counting on economies of scale. Her business plan also includes various revenue streams, including reclaiming and selling materials and providing a service of managing manufacturers' collection and recycling systems.

Davis said recycling costs could be reduced if manufacturers would take the notion of extended producer responsibility to the next level: the design phase.

"If you don't look at the recycling when you're designing the product, then it's really, really difficult to recycle," Davis said. "But if you know you're going to have to pay for the recycling at the end of life, you might make the necessary design changes in your product now to reduce that cost."

Mulvaney said that if the government were to set a price on carbon emissions, that would also help make solar recycling more affordable. Because turning sand into crystals takes 70 to 80 percent of the energy used to make crystalline photovoltaics, he said recycling silicon would "save so much energy in production, it could become a money saver."

Still, most companies that are beginning recycling programs today are proceeding under the assumption that recycling will be a cost. They are preparing for that expense by creating a variety of funding mechanisms based on the principle of producer responsibility.

Via her surveys, Woolwich has found that solar companies are using an annuity program, escrow, maturity bonds, annual fixed contracts, and pay-as-you-go.

Krueger said First Solar uses a trust: "First Solar doesn't have access to those funds except for collection and recycling," she said. "It's designed that way because of the long product life. If something happens to First Solar, the industry won't have to deal with orphan waste."

Some materials in solar modules such as silicon and rare metals could be more valuable in the future, providing an additional incentive to recycle. Material price spikes have caused industry turmoil in recent years. For example, polysilicon shot to $400 per kilogram between 2006 and 2008. It is now down around $55.

Krueger said First Solar currently harvests cadmium and tellurium from its recycling program to use in new modules, even though buying it from a supplier is currently less expensive. She said she expects harvesting costs to come down as recycling scales up.

Mulvaney said that the industry would do well to plan now for the recovery of rare metals such as indium and tellurium.

Of course, materials recovery has an environmental benefit, as well. "We'll be able to reduce impact from mining and other environmental hazards by collecting a lot of the metals and other valuable minerals that are being used in panels," Davis said.

Being truly sustainable -- and maintaining that green credibility -- is a powerful motivator for renewable energy companies.

Santarris said the Silicon Valley Toxics Coalition's scorecard was an "important step" toward figuring out which manufacturers are the most environmentally benign.

"There's not a lot of sophistication in the marketplace to differentiate among products and manufacturers of varying environmental performance," Santarris said. "Are solar modules all the same? They're not."

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This article was originally published at the SF Public Press.