Tang Dehong is the author of "chorus image" and "future publishing".
One of the biggest challenges with solar power is what to do with the panels after they die.
Solar energy is important to solve climate change, but it needs to be recycled in order to be sustainable. When a solar panel dies, it will either be shredded or thrown away.
Arizona State University researchers are trying to change that through a new recycling process that uses chemicals to recover high- value metals and materials. The team received a grant from the DOE's Advanced Manufacturing Office earlier this month, which they hope will lead to a pilot recycling plant within the next three years. Matching funds are being provided by the two companies, and First Solar is an industrial adviser on the project.
If all goes well, a cleaner and more cost-effective solar recycling process could reach the market right as the first wave of solar panels hits the waste stream.
Diana Bauer, acting deputy director of the Advanced Manufacturing Office at DOE, says that thinking about recycling at the end of life becomes even more important as we ramp up clean energy manufacturing.
Most of the solar panels that have reached the end of their lives are likely to end up in a landfill. The world could face shortages of at least one of those metals, silver, long before we build all the solar panels needed to transition off fossil fuels, according to a solar researcher. The solar industry needs solar-grade Silicon more than once a year to keep up with electricity demands and its carbon footprint.
The economics could be improved by new solar recycling processes.
When solar panels are recycled, they are rarely recovered. Instead, recyclers typically remove the aluminum frame holding the panel together, strip the copper wiring off the back, and shred the panel itself, creating a solar hash that is sold as crushed glass. The three products that might fetch a recycler $3 per panel are aluminum, copper, and crushed glass. It costs up to $25 to recycle a panel after the costs of decommission and transit are taken into account.
The economics could be improved by new solar recycling processes. The process proposed by Tao and his colleagues would involve a hot steel blade being used to separate the envelope-sized Silicon cells inside the solar panels from the sheets of glass surrounding them. TG Companies developed a patent pending chemical that is used to extract silver, tin, copper, and lead from the cells.
While the recycling process uses harsh chemicals, Tao says those chemicals can be recycled and used again and again, reducing the amount of waste that is created. The process of recovering lead has the potential to eliminate an environmental hazard that would otherwise end up in recycling waste or landfills.
TG Companies has developed technology to recover 100 percent of silver, tin, copper, and lead in solar cells. The DOE grant will allow his team to further improve the recycling process for solar panels and verify if it can be done without the use of the Siemens process. The next step is to get private investors to finance a pilot plant that can recycle 100,000 solar panels a year.
Karsten Wambach, the founder of solar panel recycling nonprofit PV CYCLE, says that a green chemistry approach like the one proposed by Tao and his colleagues has a large potential to recover valuable secondary materials and contribute to protection of the environment.
The trash could become treasure.
Wambach notes that recovering all of the silver and other trace metals in solar panels might not be fully achieved due to the losses that occur during the process of separating the cells. The amount and quality of recovered metals will be adjusted according to the downstream user's specifications and cost savings potential in the treatment processes.
Cost savings will be important. Depending on the price of silver, Tao thinks his process could recover up to 15% of materials per panel. If manufacturers use less silver in solar panels, that could change. It is unlikely that even a small amount of money per panel will cover the full cost of recycling and defecit.
There aren't that many solar panels being pulled off rooftops today. The International Renewable Energy Agency has projected that the number of solar waste could rise to 8 million tons by the year 2030. We could throw out 6 million tons of dead solar panels every year by the year 2050.
According to the projections and data on the value of metals and minerals inside each panel, the solar e-waste will contain over a billion dollars' worth of harvestable materials by the year 2028. This high-tech trash could become treasure if anyone can crack the recycling challenge.
