Recycling Solar Panels
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,spilling contaminants into their water, air and lungs.
Solar modules contain some of the same potentially dangerousmaterials as electronics, including silicon tetrachloride, cadmium,selenium and sulfur hexafluoride, a potent greenhouse gas. So as solarmoves from the fringe to the mainstream, insiders and watchdog groupsare beginning to talk about producer responsibility and recycling in an attempt to sidestep the pitfalls of electronic waste and retain theindustry’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 asignificant number of dead panels pile up, is the perfect time toimplement a responsible program, said Sheila Davis, executive directorof the Silicon Valley Toxics Coalition.
The nonprofit environmental group has been a leader in recognizingthe problems of e-waste, including hazardous disposal sites in the BayArea 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 andextended producer responsibility for the product’s end of life, calledtakeback; supply chain and green jobs; chemical use and lifecycleanalysis; and disclosure.
Vastly expanding industry
Solar energy is the most widely available resource we have. Everyhour, enough solar energy strikes Earth to meet human energy needs formore than a year, according to NASA. Now the solar industry is poisedfor huge growth in the United States, thanks to policy changes,incentives, technological improvements and economies of scale. Solarphotovoltaics have recently become less expensive than nuclear energy on a per-kilowatt-hour basis, according to a new report from DukeUniversity. Also, solar is widely expected to reach cost parity withfossil fuels in most markets by 2013.
In 2009, Greentech Media estimated that U.S. solar demand willcontinue 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 during2012. Such growth would put U.S. capacity ahead of solar leader Spainand potentially Germany as well.
While most of the new modules will likely have a long, productivelife, factory scrap, transport breakages and field failures are readyfor recycling now. Jennifer Woolwich is collecting these broken solarmodules 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 istalking with solar manufacturers in an effort to win their recyclingbusiness.
"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 andsee, we’re not sure how this is going to work’ attitude. Over the past12 months, I’ve seen a 180. I’ve seen companies who are hiringconsultants to research their whole value chain to identify waste,including the end of life of modules. We’ve received calls fromconsumers 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 sellingcompany secrets. We have certificates of destruction that we [will]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 inFreiberg, 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, aspokesman for SolarWorld. "In the future we might expand recycling toour 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 modelswithin the same technology can have different ingredients. Thesematerials may or may not be classified as toxic depending on who isregulating them.
Dustin Mulvaney is a scientist who works on solar issues at theUniversity of California, Berkeley, and serves as a consultant to theSilicon 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 torecover in recycling.
Used in SolarWorld modules, crystalline photovoltaic is the oldestand most widespread solar technology in the United States, holding 57percent market share in 2009, according to Greentech Media. "As far ashazardous materials go, you’re primarily talking about lead," Mulvaneysaid.
A thin film technology called cadmium telluride makes up about 21percent of the U.S. market. First Solar panels use this technology.
Cadmium may be carcinogenic. Exposure affects the lungs and kidneysand can be fatal. "It’s gene toxic and a mutagen, so it has the ability to affect DNA, meaning it could affect reproduction and futuregenerations’ 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 inthe 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 absorbinglight.
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 hazardousmaterial.
While CIGS currently has a market share of just 6 percent, amorphous silicon, which also has an indium tin oxide layer, holds 16 percent.
California’s Department of Toxic Substances Control has taken note of the European Union’s concern about cadmium and is researching thechemical 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 thedepartment.
Only panels classified as hazardous would fall under the jurisdiction of the department. It is considering regulatory options to try tosteer 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. Butrecycling locally is an important tenet of an ethical, sustainableindustry, said the Silicon Valley Toxics Coalition’s Davis. Recyclinglocally 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, iscurrently 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, includingreclaiming and selling materials and providing a service of managingmanufacturers’ collection and recycling systems.
Davis said recycling costs could be reduced if manufacturers wouldtake 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 theproduct, 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 theend 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 carbonemissions, 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. Theyare preparing for that expense by creating a variety of fundingmechanisms 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, andpay as you go.
Krueger said First Solar uses a trust: "First Solar doesn’t haveaccess to those funds except for collection and recycling," she said."It’s designed that way because of the long product life. If somethinghappens to First Solar, the industry won’t have to deal with orphanwaste."
Some materials in solar modules such as silicon and rare metals could be more valuable in the future, providing an additional incentive torecycle. Material price spikes have caused industry turmoil in recentyears. For example, polysilicon shot to $400 per kilogram between 2006and 2008. It is now down around $55.
Krueger said First Solar currently harvests cadmium and telluriumfrom its recycling program to use in new modules, even though buying it from a supplier is currently less expensive. She said she expectsharvesting 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 environmentalhazards by collecting a lot of the metals and other valuable mineralsthat 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 todifferentiate among products and manufacturers of varying environmental performance," Santarris said. "Are solar modules all the same? They’re not."
This piece is made possible by the reporter Erica Gies, the editing of the SF Public Press and funding from Spot.Us. This piece is free to be republished but must give credit to all parties. We have reprinted it from The Daily Green.
Search 26k+ Solar Articles
- In Focus: Vertical Farming
- Why Green Buildings Work
- FUTUREWATCH: 3D NAND Flash Memory
- STUDY: Humans Caused Climate Change
- Nickel Iron Battery
- The Solar Vineyard House by Michael Jantzen
- Report: Solar PV Market to Recover by 2015
- Green Design Standards and the Construction Industry
- Converting Waste Heat Into Electricity Through Osmosis
- The Solar Canals of India
- In Focus: Sustainable Base
- New CPV Efficiency Record for Amonix