When is Green Really Green? A Pilot Investigation of Time Effects Using LCA Data

A pilot model using Simulink™ of three interlinked industrial sectors leading to painted automotive bodies was constructed for the purpose of observing time based effects on an Life Cycle Analysis (LCA). Current LCA neglects time under an implicit assumption that material inventory data is steady state. In this study, process models were built which included time as a parameter in addition to LCA material inventory data. The results show that time is a critical factor in the overall material inventory. If the transient behavior due to demand or regulatory control results in an industry instability, material supplies may be interrupted or overproduced depending on the timing and strength of the control. Furthermore, potentially greater inventories of undesirable materials could occur. These effects are not currently captured by LCA Inventory Analysis procedures. However, this paper shows that use of dynamic modeling can correct this situation.