The toxic waste from photovoltaic solar modules that could accumulate through 2050 is a “drop in the ocean” compared to the cumulative volume of municipal waste, coal ash, and plastic waste, yet concern about those life cycle impacts is still slowing down solar adoption, a team of five authors warns in a commentary for the journal Nature Physics.
“Harnessing the potential of photovoltaic (PV) electricity generation is a key part of the transition to less carbon-intensive energy sources,” writes the team led by Heather Mirletz, an engineer and PhD candidate working at the Colorado School of Mines and the U.S. National Renewable Energy Laboratory, in a paper last week that summarizes past research on the topic. Latest forecasts call for global solar capacity to reach a “massive” 75 terawatts (75 trillion watts) by 2050, the authors note.
But “PV modules are new to many people, so increasing PV deployment has led to growing concerns about the quantity of waste that may arise from decommissioning them (if they are not recycled), and their potential to leach toxic metals,” they add. So “debunking misinformation about PV modules and PV module waste is the first step in addressing these concerns that are unnecessarily slowing PV deployment.”
The paper projects solar modules world-wide producing 54 to 160 million tonnes of waste between 2016 and 2050. “Recycling PV modules is critical to decarbonizing the PV supply chain and minimizing waste and is the prominent circular strategy studied and implemented by the solar industry today,” writes the team of Mirletz, Henry Hieslmair, Silvana Ovaitt, Taylor L. Curtis, and Teresa Barnes. And there’s time to scale up PV module reuse and recycling programs, they say, with the projected lifespan of the devices increasing from 12 to 35 years since 2016.
But even if none of the material gets a second life, the total volume compares with 249 million tonnes of “oily sludge” from crude oil production, 1,876 million tonnes of e-waste, 12,355 tonnes of plastic waste, 45,550 tonnes of coal ash, and 70,350 tonnes of municipal wastes. Both coal ash and oily sludge are known to be toxic—and much more so than PV waste.
“By transitioning away from fossil fuels, a substantial reduction in waste mass and toxicity is possible and the remaining waste is well within our capabilities to manage responsibly,” the researchers say. But that hasn’t stopped the spread of “incorrect information” and “unsubstantiated claims” about PV modules’ potential impact on human health and the environment. The paper points to several state health department websites in the United States that list arsenic, gallium, germanium, and hexavalent chromium as potential toxins in PV waste, even though the two dominant forms of modules—crystalline silicon, which captured 97% of the global market last year, and cadmium telluride, which picked up another 3%—carry none of the four substances.
“The International Energy Agency confirmed that the only potential human health and environmental concerns in commercially produced PV modules are the trace amounts of lead in the solder” in both types of modules, the authors say, and that risk can be averted by using lead-free solders.
All of which means that “communities, government agencies, and policy-makers may be operating under outdated or false assumptions about PV module waste and toxicity hazards, resulting in delay or unnecessary impediments to the rapid deployment of PV needed to meet decarbonization goals,” the paper concludes.
“There is a difference between saying that some health concerns about solar are inaccurate and saying that there are zero concerns,” writes Inside Climate News reporter Dan Gearino, in a reaction piece on the Nature commentary. But even so, “if I was a solar developer, I would print thousands of copies of this three-page piece and hand them to everybody at local hearings.”