The global expansion of solar energy presents a paradox: while it is a key sustainable technology, a comprehensive waste management strategy for decommissioned solar panels remains insufficient. Previous studies have examined this issue, yet waste volume estimations remain incomplete due to the exclusion of early waste streams and the failure to account for temporal fluctuations in key variables. This study addresses these gaps by employing System Dynamics Modelling (SDM) to capture a more nuanced understanding of the heterogeneity of decommissioned panels. The findings reveal significant discrepancies between projections from conventional static models and those generated by the developed model, underscoring the need for more adaptive forecasting methods that account for temporal variations and the evolving characteristics of decommissioned panels. Furthermore, this paper highlights the inefficiencies of uniform waste management approaches, emphasizing the need for differentiated strategies based on panel characteristics. Crucially, the findings challenge the recycling-centric paradigm by exposing the overlooked potential of functional discarded panels, advocating for circular strategies that prioritize reuse and secondary markets.