Friday Dec 02, 2022

These scientists want to solve the solar e-waste crisis – The Verge


A new Department of Energy-funded research project seeks to solve one of the biggest challenges with solar power — what to do with solar panels after they die.

Solar energy is key to solving climate change, but for the technology itself to be sustainable it needs to be recyclable. Unfortunately, when a solar panel dies today, it’s likely to meet one of two fates: a shredder or a landfill.

Arizona State University (ASU) researchers are hoping to change that through a new recycling process that uses chemicals to recover high-value metals and materials, like silver and silicon, making recycling more economically attractive. Earlier this month, the team received a two-year, $485,000 grant from the DOE’s Advanced Manufacturing Office to further validate the idea, which they hope will lay the groundwork for a pilot recycling plant within the next three years. Matching funds are being provided by ASU and energy company First Solar, which is serving as 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.

“As we’re ramping up clean energy manufacturing, producing more clean energy tech, thinking about recycling at the end of life becomes even more important,” says Diana Bauer, acting deputy director of the Advanced Manufacturing Office at DOE.

While relatively few solar panels have reached the end of their life already, experts suspect most of those that have are winding up in landfills, where valuable metals and materials inside them are lost. Meng Tao, a solar sustainability researcher at ASU who’s leading the new recycling effort, has estimated that the world could face supply shortages of at least one of those metals, silver, long before we’ve built all the solar panels needed to transition off fossil fuels. Solar-grade silicon, meanwhile, takes tremendous amounts of energy to make, and using it more than once is important for keeping the solar industry’s electricity demands — and its carbon footprint — down.

New solar recycling processes could improve the economics considerably

Even when solar panels are recycled today, these materials 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’s sold as crushed glass. Those three products — aluminum, copper, and crushed glass — might fetch a recycler $3 per panel, Tao says. Companies Tao has spoken with say it costs up to $25 to recycle a panel, after decommissioning and transit costs.

New solar recycling processes that recover more metals and minerals could improve the economics considerably. Tao and his colleagues are proposing one such process, in which the envelope-sized silicon cells inside solar panels are first separated from the sheets of polymers and glass surrounding them using a hot steel blade. A patent pending chemical concoction developed by Tao’s recycling startup TG Companies is then used to extract silver, tin, copper, and lead from the cells, leaving behind silicon.

While the recycling process uses harsh chemicals, Tao says those chemicals can be “regenerated and used again and again,” reducing the amount of waste that’s created — a feature of his recycling method he believes to be unique. Tao adds that by recovering lead, the process …….


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