This editorial explores the challenge posed by the growing integration of variable energy resources (VERs) into power systems, referencing the April 28, 2025 blackout in the Iberian grid as a case study. Despite robust grid infrastructure and dispatchable generation capacity, a sharp solar ramp, low demand, and limited voltage control led to system collapse. The event underscores the need for improved ancillary services, real-time visibility of distributed generation, and greater demand-side flexibility to ensure reliable operation under high VER penetration.
