Key Takeaways & Executive Findings
- •• • China's PV installed capacity reached 277.57 GW in 2024 (28.5% YoY growth), with projected retired PV volumes of 24 MW (2025), 65 MW (2030), and 2 GW (2036), underscoring an urgent need for scalable recycling infrastructure. • • Cumulative recoverable materials by 2030 are estimated at 1.1×10^6 t glass, 5.4×10^5 t plastics, 2.6×10^5 t aluminum, 1.7×10^5 t silicon, 5×10^4 t copper, and 550 t silver, highlighting the economic and resource security value of recycling. • • Crystalline silicon modules dominate the market (90–95%), while thin-film modules (CdTe, CIGS, a-Si) account for 5–10%, with CdTe representing 65% of thin-film market share; this composition dictates the need for tailored recovery processes. • • Existing national standards (e.g., GB/T 39753—2021, GB/T 43752—2024) are only recommended, not mandatory, reflecting the early-stage development of PV recycling technology and the lack of mature industrial systems.
Abstract
The rapid expansion of photovoltaic (PV) installations and the impending retirement of early-stage modules have made the recycling of end-of-life PV modules an urgent issue. This review systematically examines the types and structures of retired PV modules, with a focus on crystalline silicon (c-Si) and thin-film technologies. It critically evaluates the principles, processes, and pros and cons of physical, chemical, pyrolysis, biological, combined, and emerging methods for recovering c-Si modules. The current status of silicon, metal, and valuable component recovery processes is summarized. For thin-film modules, the core technologies for recovering valuable components via pyrometallurgical, hydrometallurgical, biological, and novel approaches are analyzed in depth. Results indicate that conventional methods (physical, chemical, pyrolysis) remain dominant but suffer from high energy consumption, pollution, and chemical usage. Emerging technologies such as biological and green leaching are identified as key research directions, though they face challenges of low technical maturity and high costs. Finally, policy orientations and existing challenges are discussed, and future development directions are proposed, providing significant guidance for the sustainable and large-scale green development of the PV industry.
1. Introduction
The exponential growth of photovoltaic (PV) installations, driven by global energy transition demands, has set the stage for a massive wave of module retirements. China alone added 277.57 GW of PV capacity in 2024, a 28.5% increase from 2023, yet this rapid expansion masks an impending crisis: the lack of commercially viable, environmentally sound recycling technologies for end-of-life modules. Current recycling practices are dominated by energy-intensive and polluting physical and chemical methods, which not only undermine the environmental benefits of solar energy but also fail to recover high-value materials such as silver, silicon, and rare metals efficiently. The absence of mandatory standards and mature industrial chains further exacerbates the problem, leaving the sector in its infancy despite the urgent need for scalable solutions.
This review addresses the critical bottleneck by systematically analyzing the state-of-the-art in PV module recycling, from mechanical dismantling to advanced hydrometallurgical and bioleaching approaches. It provides a comprehensive comparison of recovery efficiencies, energy demands, and environmental impacts across methods, while highlighting emerging green technologies that promise to reduce chemical consumption and secondary pollution. By synthesizing recent research and policy developments, this work offers a roadmap for overcoming technical and economic barriers, thereby supporting the sustainable scaling of the PV industry and the circular economy.
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LI Yamin, ZHAO Guangjin, ZHANG Yunxiao, DONG Ruifeng, HU Yuxia, ZHANG Shaofeng (2026). Research Progress on Recycling Technologies for Retired Photovoltaic Modules. Chinese Journal of Environmental Engineering. https://doi.org/10.12030/j.cjee.202509078
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Frequently Asked Questions
What are the main technical bottlenecks in current crystalline silicon PV module recycling, and how do they affect recovery efficiency and cost?
The primary bottlenecks are the high energy consumption and chemical usage in delamination and metal recovery steps. Physical methods like mechanical crushing are energy-intensive and yield impure fractions, while chemical methods (e.g., nitric acid for silver) generate hazardous waste. Thermal methods require temperatures above 400°C, leading to high energy costs and potential degradation of silicon. These inefficiencies result in recovery rates for silver and silicon often below 90%, with costs that are not yet competitive with virgin material production, hindering industrial adoption.
How do emerging biological and green leaching methods compare to conventional hydrometallurgical processes in terms of recovery efficiency and environmental impact?
Biological methods, such as bioleaching using Acidithiobacillus ferrooxidans, can achieve silver recovery rates of up to 98% under optimized conditions (e.g., pH 1.5–2.5, 30–35°C), but require longer processing times (days) and careful control of microbial activity. Green leaching using deep eutectic solvents (e.g., ethaline) offers a non-toxic alternative, with reported silver recovery of ~95% at 60°C, but faces challenges in solvent recycling and scale-up. Compared to conventional HNO3 leaching, these methods reduce chemical waste and energy consumption, but their lower technology readiness level (TRL) and higher reagent costs currently limit industrial deployment.
What are the key differences in recycling strategies between crystalline silicon and thin-film (CdTe, CIGS) modules, and what challenges arise from their material compositions?
Crystalline silicon modules require delamination of EVA encapsulant and separation of silicon wafers, often via thermal or chemical processes, followed by acid leaching for metal recovery. Thin-film modules, particularly CdTe, contain toxic cadmium, necessitating careful handling and specialized hydrometallurgical processes to recover Cd and Te. CIGS modules contain indium, gallium, and selenium, which are rare and valuable, but their low concentrations (typically <1% by weight) make recovery economically challenging. The layered structure of thin-film modules also complicates mechanical separation, requiring more sophisticated methods like laser scribing or ultrasound-assisted delamination.
What policy and standardization gaps exist in China's PV recycling sector, and how do they impact technology deployment?
China has issued several national standards (e.g., GB/T 39753—2021, GB/T 43752—2024) but they are all recommended, not mandatory, leading to inconsistent practices and low adoption rates. There is no extended producer responsibility (EPR) legislation specifically for PV modules, and the lack of economic incentives (e.g., subsidies for recycled materials) discourages investment in advanced recycling infrastructure. This regulatory uncertainty hampers the scale-up of innovative technologies and perpetuates reliance on less efficient methods.
What are the projected economic and environmental benefits of large-scale PV recycling, and what are the main barriers to achieving them?
By 2030, cumulative recovery of glass, plastics, aluminum, silicon, copper, and silver could reach 1.1×10^6 t, 5.4×10^5 t, 2.6×10^5 t, 1.7×10^5 t, 5×10^4 t, and 550 t, respectively, potentially generating significant revenue and reducing import dependence for critical metals like tellurium and indium. Environmentally, proper recycling prevents toxic material leakage and reduces the carbon footprint of PV manufacturing. However, barriers include high collection and processing costs, lack of efficient collection networks, and the need for technological breakthroughs to achieve cost parity with virgin materials.
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