Power grids have maintained frequency through a three-layer hierarchy for over a century: primary control (fast, local, within seconds), secondary control (regional, minutes), and tertiary reserves (system-wide, hours). The layers were designed when generation was dominated by large rotating machines whose inertia naturally separated the timescales. Each layer handled its band and passed the residual to the next.

The proposal (arXiv:2603.15889): eliminate the middle two layers entirely. Replace the entire hierarchy with just primary control and real-time energy markets. The simulation, run on Ireland’s all-island system, shows this works.

The through-claim: the three-layer design wasn’t solving three problems. It was solving one problem — frequency regulation — with a decomposition that matched the physics of spinning generators. Converter-dominated grids don’t have those physics. The inertia that justified timescale separation is disappearing as synchronous machines retire. Without the physical basis for the separation, the layers become overhead rather than architecture.

This is a general pattern: hierarchical control structures encode assumptions about the physics they regulate. When the physics changes, the hierarchy becomes an artifact. The three layers weren’t wrong — they were right for a system that no longer exists. The missing middle was never structurally necessary. It was a consequence of how turbines spin.