(LinkedIn: https://www.linkedin.com/pulse/renewables-reliability-reflection-power-outage-spain-portugal-benoit-3trle/)

I was in Spain during the major power outage on April 28, 2025. And no, it wasn’t my fault! Eleven hours without electricity is a memorable experience, even in a country with a modern grid like Spain’s. Since then, several commentators have blamed the high levels of wind and solar generation present at the time. I believe this interpretation is mistaken.

Events like this should not cast doubt on the reliability of renewable-rich grids. Rather, they remind us that such systems must be designed and planned differently.

A renewable grid is different—not less reliable

Legacy power systems were built around large thermal or hydro plants that provided natural inertia, centralized control, and predictable output. Modern grids, enriched with renewable resources, require a different approach:

·       Frequency, voltage, and stability must be ensured through technologies like battery storage, dynamic controllers, and synthetic inertia.

·       Planning must account for the production profiles of solar and wind, their variability, and their geographic complementarity.

·       Interconnections must be strengthened to allow the system to self-balance on a larger scale.

Don’t confuse a grid outage with a technology failure

Even though the April 28 incident occurred during high renewable output, that doesn’t mean renewables were to blame. Major outages almost always stem from systemic issues: poorly coordinated protection systems, the loss of critical transmission lines, insufficient inertia due to equipment failure, or a poor response to a localized disturbance.

What this really shows is that our planning approach must evolve. We can’t simply add solar and wind to an architecture built for centralized thermal or hydro power. We need to rethink the foundations of the system.

Storage: a critical ally

Large-scale storage, deployed intelligently, can serve several critical functions:

·       Frequency support

·       Black start capability

·       Smoothing variable generation

·       Fast-acting power reserve

It’s also worth noting that the sudden loss of a major load, such as a large data or AI center, can disrupt the grid as much as the shutdown of a power plant — a risk often underestimated in traditional planning.

Storage comes in many forms — pumped hydro, thermal, chemical (batteries) — and can be complemented by other flexibility sources like demand-side management. That said, batteries, with their rapidly falling costs and high operational flexibility, are likely to play an increasingly central role. They are a key element in a technological ecosystem capable of ensuring the stability, flexibility, and resilience required by a modern, renewables-rich grid.

Conclusion

It’s not the presence of renewables that makes a grid fragile — it’s the lack of adaptation to this new reality. Tomorrow’s grids cannot be based on yesterday’s models. They must be designed with the right tools, the right signals, and planning oriented toward resilience.

Reliability is not a legacy — it’s something we build.