Some have raised concerns that metals and chemicals in solar panels could deteriorate and seep into soil and water. But that scenario is unproven.
Really there are two separate concerns: heavy metal leaching and PFAS leaching. Exposure to those latter chemicals, per- and polyfluoroalkyl substances, can lead to negative reproductive effects and cancers, hormone interference, and reduced ability to fight infections.
Leaching is “a topic that comes up in almost every case” Smith works on, she said.
Smith said she has worked with communities to oppose projects on areas the government determines “contributes to water supply.”
Of the six-odd years of largely residential solar permits analyzed, 1,575 certificates— a little less than 10%—are on those lands. Other types of permits do not have an address listed, so Vermont’s bigger projects could not be compiled.
Smith said she has asked the Vermont Agency of Natural Resources three times to test soil around panels to see if PFAS leaching is occurring.
The agency isn’t doing that kind of testing, said spokesperson Stephanie Brackin, but officials did look into it.
“Approximately a year ago, we conducted both a review of literature surrounding contaminants in solar panels and a data review of landfills that installed solar panels,” Brackin said in an email. “This is an emerging issue, but there were not observed groundwater impacts where solar panels were used, and we would not expect any runoff from a solar panel to exceed our soil standard. We will continue to monitor literature to determine whether additional work is required.”
Smith is still unsure, and she’s not alone in her concerns. Three federal officials— one, two and three— and a Connecticut senior drinking-water health official have all expressed concerns about PFAS leaching from solar panels in recent years.
“You place this kind of technology in a public drinking water supply area, that is a concern for us,” said Lori Mathieu, environmental and public-health chief for the Connecticut Department of Public Health’s drinking-water branch, in a November 2020 meeting. “Thousands (of PFAS) are out there that are new, that are not tested and could leach into our water supplies.”
Officials in New Hampshire, according to a 2018 state presentation, tested soil around three solar sites and found no PFAS, but they did not test if the panels had PFAS or list what compounds were tested. More than 9,000 PFAS compounds exist.
Michigan State University professor Annick Anctil has had research supported by the U.S. Department of Energy on whether PFAS is in solar panels.
“All current models that are being manufactured, we don’t necessarily know what they’re using,” she said. “But the most common materials used in manufacturing don’t contain PFAS.”
Still, she isn’t willing to rule out the possibility.
A 2018 article in the North State Journal newspaper in North Carolina quoted a federal scientist, Mark Strynar, citing 39 scientific records documenting PFAS in solar panels. “It appears PFAS are included in solar production and thus have the capacity to be sources of PFAS,” he said, according to the newspaper.
A 2021 report by the Green Science Policy Institute, a “team of science and policy experts,” cites 11 studies that document 14 types of PFAS in solar panels. The studies also show that there is a type of PFAS in every piece engulfing a panel’s solar cell. The report found no documentation that the chemicals have ever leached into groundwater.
Anctil said most studies, including that report, look at panels constructed in a non-commercial setting using atypical materials or commercial panels made before 2012.
Sterling, the Vermont industry rep, said PFAS “very well could be (in) solar panels,” but PFAS leaching is “highly unlikely” and would “take an exceptional occurrence, (but) not (that) it would never, ever, happen.”
Smith is unsure. She owns solar panels bought in 1989 and 2008 and said she has watched the older panels experience “infiltration” and “degradation.”
Smith is frustrated “that we don’t have better answers” over whether the chemicals are leaching into the soil.
There could be more clarity coming. According to a December 2022 federal regulation, domestic solar manufacturers must list in the federal toxic substance inventory whether they are using PFAS in solar panels.
McDougall, from the Shaftsbury opposition group, said that “some of the neighbors here are very concerned about it, and I don’t know enough to be very concerned, but I am cautiously concerned.”
Metals are certainly used in solar panels, and specific ones can have environmental and health impacts. Although, Anctil said, solar panels are less toxic than a phone battery.
An International Energy Agency study of PV solar panels, which comprise 95% of the solar market, says there is “low risk for the prioritized chemicals” of lead and cadmium on human and environmental health but did say findings are not representative of an additional six “environmentally sensitive” compounds.
Anctil says studies do show metals from panels can leach out as they break down, making them more of a potential environmental hazard in landfills but not in the course of normal operation. Studies also show panels leaching when they are smashed and left outside for an extended period of time.
But, the professor said, “I don’t know why someone would have a non-working solar panel broken in a million pieces and not clean it up or replace it.”
Sterling said panel breaks are “not a very common occurrence” and said that “solar developers take enormous care to make sure there aren’t trees nearby.”
McDougall remains worried about panel damage. In the case of the project next to his hilltop farm, he said 100 mph winds are not uncommon and expects the “panels will break in just a matter of time.”
Studies typically assume that panels very rarely break. But this study, which was described in a comprehensive literature review by the federal energy laboratory, said that “80% of decommissioned PV modules (studied) are younger than 4 years from the date of manufacture,” the literature review says.
Sterling said that if a panel did break, it would be quickly cleaned up as every panel is “monitored literally hourly” by a computer system.
If panels withstand the weather, how long do they last? Sterling said between 20 and 25 years. The federal lab says 30. And Smith’s 1989 panels are still kicking after 34 years of running her offgrid life.
Solar Waste
Officials and others predict that in 10 years, “most residential systems will be replaced for more efficient panels, so (we will) all want to be prepared to handle those (older panels),” said Brackin, the natural resources agency spokesperson.
The landfill might be an option. Or it might not.
“Businesses who have solar panel waste are considered regulated and must determine whether or not the panels are hazardous,” Brackin said, adding that state or local waste entities can help and that Good Point Recycling in Middlebury is willing to take decommissioned panels.
The federal government says the most common reason a scrapped panel can be considered hazardous waste is if a toxicity test determines its materials can leach into landfills. But the Agency of Natural Resources doesn’t do that kind of testing.
Sterling says solar waste is “not a problem for Vermont’s landfills” because “worst case scenario, broken panels can go into climate-controlled warehouses.” He added that those panels would not degrade for years.
Vermont might look to join states like Washington, New Jersey, and California taking different approaches that Anctil said “kind of deals with solar recycling.”
“Kind of” refers to the technical and economic challenges of solar recycling.
In a study she wrote, Anctil describes that entire panels could end up in landfills due to a lack of value in materials retrieved from recycling them—and the high cost and difficulty in doing it. She thinks recycling likely needs to be required to ensure this does not happen.
Vermont is considering two paths to achieving a robust solar recycling program: an effort between industry and the state to work toward a universal program and a bill putting recycling responsibility on solar installers. Smith said no one wants the cost of recycling, calling the situation a “real hot-potato.”
The first option is an explorative initiative by the Agency of Natural Resources alongside Renewable Energy Vermont. The parties are looking at options for reuse or recycling, such as shared warehouses between installers for scrap panels. But officials have no start date or specific recycling goals.
Rep. James Harrison (R, Rutland-11) offers a different approach, H.47, which would require every permit issued by the Public Utility Commission to include a plan to recycle panels when decommissioned.
The bill would also task the commission with setting guidelines for recycling programs. Harrison said he drafted the bill after a constituent asked him what they should do about solar waste.
But the measure has sat idle in committee.
Sterling’s group is proactive in dealing with solar waste, he said, but in his mind it’s a small problem compared to fossil fuels.
“What are we going to do in 20 years when we need to recycle a solar panel versus the problem (of climate change)?” he asked. “Let’s be honest: What we’re doing now is killing our planet.”
Logan Solomon is a UVM student reporting for the university’s Community News Service.