Challenges of variable energy resource integration and power system security: Lessons from the 2025 Iberian system blackout

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.