What is Grid-Forming (GFM) Inverter BESS?

A grid-forming inverter is a power-electronics controller for a battery energy storage system that generates its own independent voltage and frequency reference, rather than synchronizing to an existing signal the way conventional grid-following inverters do. This allows a grid-forming battery system to establish grid stability on its own, including energizing an isolated or weak grid, supplying short-circuit current, and providing rotational-inertia-like stability that older inverter designs cannot offer.