Stage-wise modelling of energy, emissions, and economic trade-offs in recycling end-of-life photovoltaic panels for circular economy decision-making

As the global adoption of photovoltaic (PV) technology accelerates, the end-of-life (EoL) management of PV panels has become a key priority for sustainable and circular economy planning. This study introduces a stage-wise mathematical modelling framework to evaluate energy consumption, CO2 emissions, and revenue generation associated with recycling crystalline silicon (c-Si) PV panels. The recycling process is divided into three stages: Stage 1 (dismantling), Stage 2 (layers separation), and Stage 3 (metals extraction). The model is first applied to 1,000 kg of EoL PV panels, then scaled to a real-world case involving 285,450 tonnes of projected PV waste from large-scale solar farms in Queensland, Australia. The results show that Stage 1 and Stage 2 are environmentally efficient, offering energy savings of up to 99.8% for extracting aluminium and 95.4% for glass compared to primary production. These stages contribute 40.4% and 4.4% of total revenue, respectively, while generating a combined 43.84% of total emissions. Stage 3, although it processes only 4.4% of the panel’s initial mass, contributes 55.2% of the total revenue due to the recovery of silver and silicon. However, it also accounts for 56.16% of total emissions, 59% of the processing cost, and 92% of the disposal cost, making it the most environmentally and financially intensive stage. As material price fluctuations and emissions intensity substantially influence recycling outcomes, EoL management strategies may shift accordingly: under high-emission and economically unfavourable scenarios (Ch-Eu), limiting processing to Stage 1 and Stage 2 may provide a more balanced outcome, while low-carbon and economically favourable conditions (Cl-Ef) justify full-stage recovery, including Stage 3. Across these scenarios, carbon-revenue efficiency varies significantly, with each kilogram of CO2 emitted earning between 1.60 and 6.03 USD. The novelty of this work is in quantifying the correlation between energy consumption, CO2 emissions, and economic return at each stage of the recycling process, an aspect previously unaddressed in EoL PV panel recycling studies. This trade-off serves as a practical reference for decision-making by enabling material-specific evaluation and balancing environmental and financial outcomes to advance circular economy goals.