Assessment of the environmental toxicity of four photovoltaic module technologies in accordance with waste leaching standards

ABSTRACT In 2022, global solar energy capacity reached 1 TW and is expected to double by 2026. Predictions suggest that photovoltaic waste, which contains environmentally harmful elements such as lead and cadmium, could exceed 70 million tons by 2050. Therefore, this study aimed to assess the hazardous nature of four photovoltaic module technologies: polycrystalline silicon (p-Si), cadmium telluride (CdTe), amorphous silicon (a-Si), and copper indium gallium selenide (CIGS). This work involved chemical characterization and leaching tests for solid waste classification. The leaching procedures strictly adhered to American (TCLP 1311), European (EN 12457-2), and Chinese (HJ/T299) standards. Results indicated that the p-Si module was deemed hazardous as it exceeded the Pb tolerance limits of both the TCLP 1311 (8.69 mg/L) and HJ/T299 (7.35 mg/L) standards. The CdTe module was considered hazardous as it surpassed Cd tolerance limits in all the studied standards: TCLP 1311 (1.01 mg/L), EN 12457-2 (1.86 mg/L), and HJ/T299 (4.74 mg/L). The CIGS module was identified as hazardous according to the EN 12457-2 standard, exceeding a Se tolerance limit of 0.56 mg/L. The a-Si module did not exceed the maximum concentration levels set by the standards for the analyzed elements, although traces of toxic metals were observed in the leachate.