Toxicity of Photovoltaic Modules
A new ASTM International standard will aid in the recycling or safe disposal of solar photovoltaic modules that have reached their end-of-life due to failure, underperformance, or breakage resulting from extreme weather. ASTM International’s committee on solar, geothermal, and other alternative energy sources (E44) developed the new standard, soon to be published as E3325.
Photovoltaic modules are found in solar panels and other devices that convert sunlight into electrical energy. According to ASTM member Bulent Bicer, these modules contain various metals in the form of electrical contacts and/or semiconductor compounds that have a lifespan of 25-30 years.
“Broken PV modules may pose environmental and health risks through leaching of toxic chemicals and materials after landfilling,” says Bicer. “PV modules that contain hazardous materials such as lead and cadmium may contaminate ground and surface water.”
Modules that pass the toxicity characteristic leaching procedure (TCLP) test specified by the U.S. Environmental Protection Agency Method 1311 (and state protocols, if applicable) can be disposed of in regular landfills. Otherwise, modules would be classified as hazardous waste.
“Currently, there is no national or international standard available for removal of representative test samples from PV modules for toxicity testing per EPA 1311,” says Bicer. “The validity of the toxicity test results depends on the location of extracted samples in the module, specifically within the laminate area, and the particle size of the extracted samples.”
Bicer says that the new standard presents a representative and repeatable methodology to remove sample pieces from PV modules for later use in TCLP testing.
Bicer also notes that the new standard has its origins in a research project conducted under the leadership of Govindasamy TamizhMani at Arizona State University’ Photovoltaic Reliability Laboratory (ASU-PRL) in collaboration with the Electrical Research Institute, First Solar, Salt River Project, and Arizona Public Service. ASU-PRL has been conducting performance, reliability, and end-of-life research on PV modules, microinverters, optimizers and related components for over 30 years.
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