Major challenges and opportunities in silicon solar module recycling

Abstract

This article examines some of the basic questions about silicon module recycling: (1) What can be recovered from silicon modules? (2) What recycling technologies are needed? (3) What are the potential revenues for different recycling scenarios? And (4) what are the major challenges for different recycling scenarios? Three recycling scenarios are considered: module reuse, component extraction, and material extraction. Recycling process sequences for different scenarios are outlined. The discussions conclude that module reuse generates the highest revenue with the fewest processing steps, while material extraction leads to the lowest revenue with the most processing steps. It is suggested that gentle and clean separation of silicon solar cells from the glass pane is a critical technology for silicon module recycling. It is also argued that two low‐concentration metals must be recovered from silicon modules: silver as a scarce material and lead as a toxic material. Their recovery requires chemical methods, while bulky materials including glass cullet, aluminum frame, and copper wiring can be recovered with physical methods. The silicon in the cells can be extracted with different qualities: ferro‐silicon, metallurgical‐grade silicon, or solar‐grade silicon, with a higher revenue and more complicated recycling process for purer silicon. Markets outside the solar industry for the recovered silicon should be explored. The biggest challenge for module reuse is to find a large and sustained market for hundreds of gigawatts peak of decommissioned modules a year, and the biggest challenge for component extraction is the many different module and cell structures on the market and cell efficiency variability. For all the three scenarios, the cost of collecting and processing waste modules is a common challenge.

Integrating sociotechnical factors to assess efficacy of PV recycling and reuse interventions

“…Thus, CE programs should be based on adoption rates for all circular pathways rather than focusing on one CE strategy. Second, for reuse to be effective, the used product supply must match demand, and therefore secondary markets must be mature 39 . For example, only when PV owner attitudes toward used modules improve (e.g., through warranties) does demand grow and start substantially absorbing used module supplies.…”

Photovoltaic Module Recycling: Thermal Treatment to Degrade Polymers and Concentrate Valuable Metals

“…PV modules have a useful life estimated of about 25 -30 years (Paiano, 2015). However, an increasing number of modules will reach the end of their lifespan before that time due to the damage during installation or storms, component failures, or economic incentives to replace older modules by new modules with higher efficiency (Tao et al, 2020).…”

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“…Some glass suppliers state that their products are 100% recyclable, although it is valid only till the component is assembled to the solar panel. From that moment it is not possible with current recycling technologies to recover the same quality glass suitable for the same purpose due to impurities (Tao et al 2020). Plastics are usually incinerated for energy generation as they cannot be recycled (D'Adamo et al 2017;Latunussa et al 2016).…”