High yield, low cost, environmentally friendly process to recycle silicon solar panels: Technical, economic and environmental feasibility assessment

Abstract

The recycling of silicon photovoltaic modules is technically viable, but often not feasible economically due to reasons that vary from high processing cost to low waste volumes that do not justify investment cost. In this study, a novel, simple, cost-effective and environmentally friendly processing method is proposed. The process consists of module deframing, laminate shredding and material concentration using electrostatic separation. The latter outputs two fractions: a valuable mixture of silver, copper, aluminum and silicon, and a mixture of mostly glass, silicon and polymers. The valuable mixture accounts for only 2-3 wt% of the total module, which can be forwarded to the downstream industry for further refinement. This paper evaluates the technical aspects of the process (quantifies material separation, energy and time) while using life cycle assessment and life cycle costing to evaluate the environmental impacts and economic prospects, respectively. The results are compared to a full recovery alternative (FRELP) and to landfilling. Environmentally, a full recovery is preferred, followed by the proposed process, both of which have a net positive impact and are better than landfilling the whole module. Economic assessment shows the process has potential to be more profitable than FRELP i) at lower waste volumes (smaller than 4 kt/y), because of the smaller equipment capital cost, ii) if there is no market for the recovered glass, which is currently the case in many locations or iii) when the end-processing industry is located afar, since only the valuable mixture would require shipping.