4 December 2019

Scientific American: The Downside of Solar Energy

The Downside of Solar Energy Credit: Gerard Julien Getty Images The solar economy continues its dramatic growth, with over a half-terawatt already installed around the world generating clean electricity. But what happens to photovoltaic (PV) modules at the end of their useful life? With lifespans measured in decades, PV-waste disposal may seem to be an issue for the distant future. Yet, the industry ships millions of tons every year, and that number will continue to rise as the industry grows. Total e-waste—including computers, televisions, and mobile phones—is around 45 million metric tons annually. [...]

At the same time, demand for everything from sand to rare and precious metals continues to rise. While supplying only about 1 percent of global electricity, photovoltaics already relies on 40 percent of the global tellurium supply, 15 percent of the silver supply, a large portion of semiconductor quality quartz supply, and smaller but important segments of the indium, zinc, tin, and gallium supplies. Closing the loop on these metals and embracing circular economy concepts will be critical to the industry’s future. [...]

The primary challenge to recycling PV today is finding value in the recovered materials compared to the costs of collection and recovery. The International Renewable Energy Agency reported that recovered materials could exceed $15 billion dollars (U.S.) by 2050. But a cost-effective PV-waste collection and recovery system capable of high-value material recovery remains elusive. Most of the value in PV-waste is in the aluminum frame and the silver in the metallization paste. Getting higher-value PV recycling will require expertise in managing glass. 80–90 percent of a module by weight is made from glass.

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