Scaling Renewables Reliably: What U.S. Utilities Can Learn from the 2025 Iberian Peninsula Blackout One Year Later
Research

Scaling Renewables Reliably: What U.S. Utilities Can Learn from the 2025 Iberian Peninsula Blackout One Year Later

  • Operational lessons from the April 2025 Iberian blackout
  • How high inverter-based resource grids differ from traditional power systems
  • Why flexibility has become a core reliability requirement
  • Where market design falls short of procuring critical stability attributes
  • Transferable recommendations for U.S. utilities

Portugal offers one of the clearest examples of large-scale renewable integration in the world—reaching 85% renewable electricity in 2024, with a national target of 93% by 2030. Its experience also illustrates what happens when inverter-based resources (IBRs) scale faster than the operating models, market structures, and analytical tools designed to manage them. The April 28, 2025 blackout—which interrupted service for more than 55 million people across Spain, Portugal, and parts of France—brought those gaps into focus.

SEPA’s 16th Executive Fact-Finding Mission brought 13 U.S. utility executives to Lisbon in the months following the blackout, engaging directly with Portuguese grid operators, regulators, transmission planners, and distribution system operators—grounding every conversation in immediate operational reality.

For U.S. utilities managing growing IBR penetration, participating in RTO/ISO market reform, or modernizing operational tools and workforce training, Portugal’s experience provides directly applicable reference points. This brief documents what SEPA’s delegation observed and heard and translates those findings into recommendations for U.S. utility leaders.

Download the full report to explore findings, host organization insights, and actionable recommendations for U.S. utility leaders.

For more context about the 2025 Iberian Peninsula Blackout, read SEPA’s initial analysis here.

Learn more about SEPA’s upcoming Fact Finding Mission to Norway here.

Authors

SEPA Research Report: Operational and market design lessons from a high inverter-based resource grid