Life cycle assessment of recycling strategies for perovskite photovoltaic modules

Effective recycling of spent perovskite solar modules will further reduce the energy requirements and environmental consequences of their production and deployment, thus facilitating their sustainable development. Here, through ‘cradle-to-grave’ life cycle assessments of a variety of perovskite solar cell architectures, we report that substrates with conducting oxides and energy-intensive heating processes are the largest contributors to primary energy consumption, global warming potential and other types of impact. We therefore focus on these materials and processes when expanding to ‘cradle-to-cradle’ analyses with recycling as the end-of-life scenario. Our results reveal that recycling strategies can lead to a decrease of up to 72.6% in energy payback time and a reduction of 71.2% in greenhouse gas emission factor. The best recycled module architecture can exhibit an extremely small energy payback time of 0.09 years and a greenhouse gas emission factor as low as 13.4 g CO2 equivalent per kWh; it therefore outcompetes all other rivals, including the market-leading silicon at 1.3–2.4 years and 22.1–38.1 g CO2 equivalent per kWh. Finally, we use sensitivity analyses to highlight the importance of prolonging device lifetime and to quantify the effects of uncertainty induced by the still immature manufacturing processes, changing operating conditions and individual differences for each module. Effective recycling of worn-out perovskite photovoltaic modules could improve their energy and environmental sustainability. The authors perform holistic life cycle assessments of selected solar cell architectures and provide guidelines for their future design.