Towards a sustainable PV waste policy: Exploring the management practices of end-of-life solar photovoltaic modules in Australia

Abstract

Solar photovoltaic (PV) systems are effective measures to reduce the greenhouse gas emissions. However, the large exploitation of solar PV modules, leads to undesirable waste accumulation, affecting the environment. Solar PV waste management research is an emerging field that has received more attention recently, affected by the increase volume of solar PV disposals. However, only a few studies have examined the current practices in solar photovoltaic waste management. In Australia, because of social and economic factors (such as the replacement of small-scale PV systems come with new rebates), residential solar systems are decommissioned earlier than expected before reaching their end-of-life (EoL). 70% of the market share of PV systems are predominately dominated by the residential market in Australia as of 2020. The average practical lifetime of PV modules instead of 20-30 years is 15-20 years in Australia. Therefore, the volume of EoL PV from the residential sector entering the waste stream in the coming decade will be higher than previously predicted. This study aims to assess the environmental impacts of waste from rooftop solar photovoltaic panels in Australia to inform sustainable policies. To achieve the aim of the research, the following objectives are investigated: 1) exploring the current practices of managing end-oflife rooftop solar photovoltaic panels in Australia; 2) developing an optimised system approach in dealing with solar photovoltaic waste in Australia; and 3) assessing the environmental impacts of end-of-life rooftop solar photovoltaic panels in Australia within the developed assessment framework. To achieve the research objectives, several methods are adopted to analyse the primary and secondary data for this research. A modified Fuzzy Delphi Method (FDM) is adopted in gathering data through interviews and questionnaires from experts in the field. The results show that, crystalline silicon panels were the most common panels on the Australian market and the ones that are being installed frequently. On policies, although the Australian government has banned PV waste from going to landfill since 2014, there were no regulations or action plans to manage PV waste. The absence of policies and regulations results in unregulated movement and tracking of solar PV waste in and out of Australia as well as within and across the states. The extent of the PV recovery and recycling warrants further investigation. Moreover, infrastructure and logistics has been a significant problem because of the geographical spread of the country and how it affects transportation and the supply chain. Findings led to the establishment of a conceptual framework for the current treatment of solar PV waste in Australia. Furthermore, a Weibull distribution model is employed to forecast the PV waste in the next three decades in South Australia. The study further estimates the pollutant emission associated with the collection and transportation of the waste for recycling and recovery. Results indicate that, there will be 109,007 tons of PV waste generated in urban and suburban context in South Australia by 2050. Among the three routing scenarios generated, the third scenario with optimised transfer stations and an additional recycling facility showed more than 34% reduction in pollutant emission. This study evaluates the environmental impacts of three policy options for mono and multi crystalline silicon (c-Si) solar panel waste modules. The impact of transport distance from transfer stations to the recycling centre is also assessed. The life cycle assessment revealed that, -1E+06 kgCO2eq and -2E+06 kgCO2eq are associated with the mandatory product stewardship scenarios under global warming potential for mono and multi c-Si solar modules respectively. However, the non-existence of a product stewardship will produce a global warming impact of 1E+05 kgCO2eq for both modules. The global warming effects revealed that, collecting and recycling most of the multi c-Si panels were not effective (-365 kg CO2-eq, -698.4 kg CO2-eq, -1032 kg CO2-eq) compared to keeping them away from the landfills and fully recycling (- 2E+06 kg CO2-eq) them. It was also highlighted that, the highest environmental impact regarding the transport distances was the scenario of one recycling centre serving over 107 transfer stations with a global warming potential of 1E+06 kgCO2eq. In conclusion, this study contributes to the management of the supply market of solar PV technologies, using Australia as a case study. The recommendations derived from the study include: creating collection centres for EoL PV modules in South Australia, developing a logistic network to for the collection of EoL PV modules, creating and enhancing the PV recycling market for recovered materials, issuing a regulatory landfill ban for EoL solar PV module in South Australia, developing a mandatory product stewardship for PV waste in Australia, promoting and providing financial incentives to current and future infrastructure for PV recycling, minimising the exportation of PV waste overseas and interstate, encouraging industry led research on new innovations to improve the recovery of different PV technology families, developing sustainable measures to cut emissions for recycling through research and development in South Australia, and building the capacity and promoting awareness on the benefits of PV recycling in South Australia.