Solar energy is crucial and unquestionably the most applicable and affordable solution leading the energy transition and climate change throughout the world. Although Photovoltaic (PV) systems provide zero-emission power generation through their lifespan of 25-30 years, it is crucial to ensure sustainable products over the whole life cycle. While strong efforts have been invested for the manufacturing stage to reduce environmental impacts, the End-of-Life (EoL) of PV devices has not been adequately addressed.
The upcoming PV waste has been estimated with substantial cumulative volumes of ~10 Million tons (Mtons) in Europe and 60-78 Mtons worldwide expected by 2050. Nowadays, 80-90% of PV wastes are recycled, while the remaining 10-20%, that also contains high-value materials, is landfilled, which is not a satisfactory solution, especially in the context of the projected Mtons of PV EoL modules forthcoming.
The baseline recycling scenario is considered representative of average practices in Western European WEEE recycling plants not equipped with specialized technologies for PV recycling. This scenario starts with manual dismantling of the panel’s frames and cables, which are subsequently sorted for recycling. The remaining parts of the panel are then treated with simple techniques (e.g. hammered or ground to partially separate the glass) or directly shredded with other WEEE. Due to the heterogeneity of the PV panel (including glass, encapsulations, silicon cells and multi-polymer backsheet), this process is not able to efficiently separate different materials.
Innovative technologies, that allow the recovery of SRM (secondary raw materials), focusing on Silicon, Indium, Silver and Copper, avoiding disastrous consequences of RM permanent loss due to current landfilled or shredding practices, will provide an answer to this new environmental challenge, giving the opportunity to transform it into a new opportunity to create value.
The benefits due to the recovery of these materials counterbalance the larger impacts of the high-efficiency recycling process. Considering the full life cycle of the panel, the energy produced by the panel grants the most significant environmental benefits. However, benefits due to high-efficient recycling are relevant for some impact categories, especially for the resource depletion indicator. These treatments have to be carefully assessed since they can be responsible for the emissions of air or water pollutants.
Enel Green Power (EGP) is looking for the best – from a sustainability, effectiveness, and cost perspective – available technology or process to recover SRM, focusing on Silicon, Indium, Silver and Copper, from End-of-Life PV modules, in order to define a proper sustainable business chain, under a circular economy perspective. The solution shall be applicable in the most relevant countries in which Enel Green Power is developing its business and business cases shall consider local rules and logistic issues.
Submissions must address the following Solution Requirements.
The solution must:
- be cost-effective, targeting operating costs in the order of magnitude of 100 €/ton of waste treated and take into account the total cost of recycling (life cycle analysis, LCA) compared to the actual recycling process;
- be a process targeting zero waste (recycle and reuse 100%);
- not produce pollutants (or must reduce pollutants compared to the standard process) that could have a negative effect on the ecosystem. Generally, chemical processes are used to treat the solar cells’ fraction to recover metals and silicon (Si). The processes are based on successive stages using hydrofluoric (HF) and nitric acid (HNO3), sodium hydroxide (NaOH) and/or hydrochloric acid (HCl), and hydrogen peroxide (H2O2), which are mostly toxic and hazardous. Moreover, the use of aqueous acids or alkalis involves the consumption of important reactants, thus generating large chemical waste streams;
- be capable of dealing with large amounts of materials (recycling capacity > 5000 tons of EoL PV modules per year);
- use a recycling process able to recover materials (Silicon, Indium, Silver and Copper) with a purity >99%;
- address, as much as possible, geographically local opportunities for recycle, in order to avoid or minimize transporting for long distances due to the size, weight and scale of the materials (even if cut into pieces). In particular we are looking for solutions to be applicable in Europe (with focus on Italy and Spain), US, Chile, Brazil and Mexico.
Additionally, the solutions should:
- use recovered materials in solar PV panels production or other sectors, in which their value can be maintained. Other uses will however be taken into account with lower priority;
- be capable of being deployed globally, hence following environmental and safety best practices and taking into consideration laws and regulations for material handling and disposal;
- be capable to process PV manufacturing wastes (cell and precursors, assembled modules) coming from PV cell/module producers.
The submitted proposal should include the following:
- Detailed description of the proposed method or process that allows for a feasibility assessment by Enel Green Power and includes (but is not limited to):
- analysis of the performance of different processes for the recycling of crystalline silicon PV waste, in a life cycle perspective;
- comparison of the life cycle impacts of the innovative solution with current standard processes evaluating the environmental benefits of secondary raw materials recovery;
- a description of all chemical/mechanical/physical processes involved;
- details on the materials/components streams resulting from the process, from a chemical/mechanical/physical point of view and how they shall be used;
- a description of any potential waste product resulting from the proposed process and how it should be disposed (the proposed solution should avoid the production of waste);
- a detailed description of the overall cost of the process, including energy consumption, with a focus on its cost-effectiveness.
- Data, case studies, patent and journal references or any additional material that supports the proposed solution.
- SDG 9: Industry, Innovation and Infrastructure
- SDG 12: Responsible Consumption and Production
- SDG 13: Climate Action