Grid-Forming Green Hydrogen Microgrids: Virtual Inertia Synthesis via Electrolyzer Control

Abstract

As power grids transition toward fully renewable, inverter-based generation, the loss of mechanical rotational inertia threatens frequency stability, and dedicated battery energy storage systems (BESS) traditionally deployed to supply synthetic inertia add substantial capital cost to microgrid projects. We propose instead using megawatt-scale proton exchange membrane (PEM) electrolyzers within green hydrogen facilities as grid-forming assets, and formulate a virtual synchronous machine (VSM) control topology for the electrolyzer's power electronics that modulates its multi-megawatt power draw within milliseconds. Time-domain simulation of a 100% renewable islanded microgrid shows that grid-forming electrolyzer control reduces the rate of change of frequency by 68% during a severe contingency, matching or exceeding a dedicated BESS while reducing daily hydrogen yield by less than 0.4%.