The rational decommissioning of solar photovoltaic (PV) technologies: evidence from Australia

• 95 % of Australian small-scale PV system users will adopt early replacement. • PV lifespan averages 20.4 years; cost variables affect decommissioning differently. • PV waste will increase substantially and eventually surpass installation capacity. • Marked spatiotemporal heterogeneity is observed in PV lifespan and waste generation. • Scenario-based heterogeneity varies at multi-scales in PV lifespan and waste generation. PV technology is being rapidly deployed worldwide to meet climate goals, yet the resulting PV waste poses a growing challenge to global decarbonization commitment. This study addresses the unresolved question of future PV waste magnitude and its spatial-temporal characteristics by proposing a rational decommissioning model. Incorporating multiple factors, the model captures the complex drivers of PV lifespan and waste generation. Validated using Australia—global leader in residential PV—the results show that from 2008 to 2079, over 95 % of Small-scale PV System (SPS) users would opt for early replacement to maximize financial return, causing PV waste to emerge nearly a decade before warranty and eventually outpace new installations. Under the fastest decarbonization scenario, PV waste will be 1.8 and 2.8 times higher than under baseline and slowest pathways, respectively. Results reveal obvious spatio-temporal heterogeneity and scenario sensitivity across multi-dimensional scales. The paradigm provides transferable insights for global PV waste management.