Environmentally improved CdTe photovoltaic recycling through novel technologies and facility location strategies

Abstract

Photovoltaic waste is projected to reach up to 78 million tons across globally dispersed locations through 2050. Current recycling infrastructure is inadequate to process these waste volumes responsibly. This necessitates commercializing novel, environmentally advantageous photovoltaic recycling technologies that improve upon incumbent industrial operations. CdTe photovoltaic recycling is a promising candidate for improvements as 25,000 tons of spent modules are recycled worldwide annually. This paper evaluates the operational performance and compares six novel technologies, the incumbent technology used in industry and one technology which extends the incumbent process across ten environmental impact categories. The tradeoff between incurring a transportation burden (ship or road) to recycle in a large-scale centralized facility with a higher operational efficiency and avoiding transportation by recycling in a smallscale decentralized facility with a lower operational efficiency is evaluated. Thermal delamination to eliminate the ethylene vinyl acetate and separate the photovoltaic glass panels is This article is protected by copyright. All rights reserved. This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1002/pip.3279 preferable to the incumbent mechanical process across nine environmental impact categories and decreases the climate-change impact of CdTe photovoltaic recycling by 23%. Bath and probe sonication are ineffective for delamination, and the use of organic solvents is more environmentally burdensome than the incumbent mechanical process. Centralized recycling with shipping is environmentally preferable than with road-based transportation. For every 100-km increase in road transportation from the decentralized to the centralized facility, the inventory requirement in the centralized facility should be 6% lower than the decentralized facility for centralized recycling to have a lower climate-change impact than decentralized recycling. The corresponding value for shipping is 0.4%.

Challenges and Solutions in Solar Photovoltaic Technology Life Cycle

“…Intensive R&D to improve the standard of recycled materials [237,247] Collection and delivery method Bring-in facilities for small-scale PV systems and pick-up services for large-scale PV systems, Decentralized recycling plant establishment. Operation by the PV industry group to gather and move discarded modules [248,249] PV waste input in insufficient amounts Collaboration through a shared treatment mechanism amongst nations with minimal PV waste flow. Recycling at current general recycling facilities or buildingadaptable recycling facilities that accept appropriate items Building a decentralized low-capacity recycling facility [247,248] Treatment procedure costs PV module treatment in a gaseous environment Al from silicon cells is extracted using aluminum chloride.…”

Environmental and Circular Economy Implications of Solar Energy in a Decarbonized U.S. Grid

“…74 For example, hazardous materials in c-Si PV modules (e.g., lead), 74 fluorine in the backsheet, and the challenges of removing the ethylene vinyl acetate (EVA) laminate can hinder efficient recycling of PV waste. [75][76][77][78] Design for circularity-which encompasses the use of novel PV module designs and materials in the manufacturing stage to enhance recyclability, transition away from supply-constrained materials to abundant materials, 79 and decrease risks to human health and the environment over the PV life cycle-can address these emerging sustainability challenges. Machine-learning (ML) and artificial intelligence (AI) methods can inform the selection of nonhazardous and environmentally benign materials during the design of PV modules.…”

“…245 Another key recycling challenge is delamination to eliminate the EVA and separate the glass and silicon wafer. 253 The use of organic solvents to dissolve the EVA is time intensive and increases human health risks, 75,254 mechanical processes increase energy consumption, 91 and hightemperature processes present the risk of releasing hazardous emissions. 77 While commercial processes use combinations of mechanical, thermal, and optical processes, there is scope to facilitate easier delamination through design for circularity approaches such as laminate-free design.…”

“…However, recycling in smaller-scale recycling plants forgoes the opportunity to realize efficiency gains from economies of scale in a centralized recycling plant. As a result, there is opportunity to optimally locate recycling facilities to minimize the economic and environmental cost of PV recycling, 75,[263][264][265][266] when transitioning to a CE for PV systems.…”