Supplier diversification at Tier 1 can still hide a single point of failure upstream. This article explains how three qualified suppliers across three countries can depend on the same processor, equipment, or critical material. It uses IEA data on battery-grade graphite and rare earth magnets to show how concentrated processing capacity remains a bottleneck for clean energy supply chains. For procurement teams, the practical takeaway is to trace dependencies beyond supplier count: where production actually happens, whether suppliers share sub-tier inputs, and how long a substitute would take to qualify. The same logic applies to anyone building solar, storage, or EV supply chains. Counting vendors is not the same as proving independent production pathways exist.
