System Dynamics Modeling of Indium Material Flows under Wide Deployment of Clean Energy Technologies

• Indium supply is limited by the production of carrier metal zinc.
• CIGS solar PV will dominate indium consumption as its market expands.
• Annual indium demand may exceed supply thus shortage may occur.
• Technology advancement in CIGS solar PV can alleviate the shortage to some extent.

Clean energy technologies represent a promising solution to the global warming challenge. Many clean energy technologies, however, depend on some rare materials and concerns have been raised recently. Indium is one of these materials as it is critical for two emerging energy applications, that is, Copper indium gallium selenide (CIGS) photovoltaics (PV) and light-emitting diode (LED) lighting. This study analyzes the supply and demand of indium under different energy and technology development scenarios using a dynamic material flow analysis approach. A system dynamics model is developed to capture the time-changing stocks and flows related to supply and demand of indium over a 50-year time period, while considering carrier metal (i.e. zinc) production, price elasticity of demand, and indium usage in other applications (mainly liquid crystal display). Simulation results indicate that a shortage on indium is likely to occur in a short time period even under favorite case of indium supply. The rapid expansion of CIGS technology dominates indium demand in about 14 years, which outruns the growth of zinc mine production (thus indium supply). Sensitivity analysis suggests that model parameters related to solar PV market penetration, CIGS technology advancement, and price elasticity of indium demand have large effects on the total indium demand over simulation period. Eight scenarios combining projections on solar PV market growth, technology advancement, and zinc mine production are explored. It is observed that only under conservative estimates of solar PV market growth there is relatively enough indium supply to support the deployment. Even in these scenarios a shortage may occur toward the end of simulation.