Rong Deng

Postdoctoral Research Fellow

University of New South Wales

In my research I’m passionate about developing interpower our society in a I hold a Bachelor disciplinary and greener and more sustainable way. and PhD in of Engineering (Honours class I) transformable Photovoltaic technologies to Engineering and currently work as postdoctoral researcher at the University of New South Wales, Sydney. My major research interest is in the endofmissing technology that life recycling of silicon photovoltaic modules; will make solar ener Starting in 2018, I have published gy truly sustainable. the essential but currently ten academic journal papers, presented at ten international photovoltaic research conferences, won four best presentation awards, and hold two provisional patents. My research has attracted and universities. My paper " A research fund from local governments, international enterprise technoe conomic review of silicon photovoltaic module recycling" been recognised as the "textbook" among the industry and has inspired hundreds of has subsequent inventions and discoveries. 

End-of-life Recycling of Silicon Photovoltaic Modules: Towards A Circular Economy

Handling large volumes of silicon photovoltaic (PV) modules at the end of their 25-year lifetime is an emerging challenge. Circular economy strategies like recycling generate value from waste modules and avoid the environmental impact of producing new materials. Previous lab-scale studies have demonstrated feasible recycling technologies. Unfortunately, none are economically viable. This thesis explores various cost factors in silicon PV module recycling, using techno-economic assessment and innovative chemical recycling processes to illuminate the prevailing economic barriers. 
This work first associates feasible mainstream silicon PV module recycling technologies with a quantitative economic assessment framework to break down the cost structure. The comparative analysis of landfill, simple recycling, and high-value recycling reveals the main drivers of improving recycling costs; these include increasing landfill charges for waste solar panels, creating more effective waste collection networks, targeting high-value but low-quantity material recovery, improving the cost-effectiveness of recycling operations, integrating recycled materials for remanufacturing, and eco-designing new modules. The biggest hurdle is that the recycling alternative, landfill, is cheaper and more accessible. 
High-value recycling retains both bulk and low-quantity valuable materials within the waste module and exhibits the highest environmental benefits. Improving processing costs from the current $650-950/ton to $400-500/ton can make the technology viable for large-scale implementation. 
Circular chemical processes and prototypes are developed in this work to improve the recycling yield and processing cost, targeting valuable material recovery. Reverse electroplating can recover 96% silver at 99.9% purity, and subsequent etching processes can recover 99% silicon at 99.999% purity from waste solar cells at a cost of $6/module. 
The direct reuse of intact recovered silicon wafers for remanufacturing results in efficiency loss due to the poorer silicon bulk quality. A second-life characterisation and cost-efficiency trade-off analysis concludes that remanufacturing is only viable when it manages second-life efficiency within 2.5%abs compared to virgin solar cells. Further treatments are necessary to ensure closed-loop recycling is competitive and scalable. 
This work provides techno-economic insights to assist in implementing an affordable and sustainable PV end-of-life system.