Spain’s grid crisis: A wake-up call for UK energy resilience

In April 2025, Spain experienced one of the most significant power outages in European history. Within seconds, nearly 60% of the country’s electricity vanished from the grid. This triggered a cascade of failures across the integrated Iberian Peninsula grid; leaving millions across Spain, Portugal, and parts of southern France without power. While power was eventually restored, the incident has sent shockwaves across Europe, especially to countries like the UK, which share similar grid vulnerabilities.

Are renewables the problem?

Contrary to some early speculation, Spain’s blackout wasn’t a failure of renewable energy. It was a failure of infrastructure and flexibility. With high levels of solar and wind generation feeding into the grid, the system lacked the agility to absorb or redistribute power effectively. Frequency dropped, nuclear plants shut down automatically, and backup systems couldn’t respond fast enough.

This wasn’t just a technical failure, it was a strategic one. Spain’s grid was overwhelmed by the pace of its energy transition, revealing a critical gap between ambition and infrastructure.

Following the April blackout, Spain’s government introduced Real Decreto-ley 7/2025, a legislative package aimed at reinforcing the grid. However, the law was rejected by Spain’s parliament in July 2025. This setback highlights that while legislative ambition is essential, it must be backed by broad stakeholder alignment, rigorous planning and robust implementation frameworks.

Why the UK should be paying close attention

The UK, like Spain, is undergoing a rapid energy transformation. Offshore wind capacity is set to quadruple from around 15 GW to 50 GW by 2030, including 5 GW of floating wind, making it a global leader in this sector. Solar is thriving too, with government targets aiming to more than double capacity to 45–47 GW by the end of the decade.

Meanwhile, hydrogen and battery storage are scaling up rapidly—battery energy storage systems (BESS) have already reached 5 GW, with a pipeline of over 120GWh planning approved BESS developments and the governments Clean Power 2030 Action Plan setting a goal of 23–27 GW by 2030. Plans also include 4–6 GW of long-duration storage to support dispatchable power.

But the UK is also an island nation with limited interconnections to mainland Europe, making it inherently more vulnerable to frequency deviations and voltage instability. Experts warn that peninsular and island grids, such as those in the UK and Ireland, must rely more heavily on internal flexibility and resilience. Without sufficient storage, inertia technologies, and fast-acting backup systems, the UK could face similar risks to those seen in other isolated grids.

Building a resilient, flexible grid

The good news? The UK is already taking steps to avoid Spain’s fate:

• integrated planning is underway, with the National Energy System Operator (NESO) overseeing a holistic approach that connects electricity, gas, hydrogen, and carbon networks which it is exploring through the Future Energy Scenarios (FES)
• storage expansion is accelerating, with increased investment in battery storage and pumped hydro to provide the fast-response capacity needed to stabilize the grid during fluctuations
• inertia technologies are being explored to help maintain grid frequency and prevent cascading failures
• smart forecasting and AI are being deployed to predict demand surges and generation drops, enabling proactive rather than reactive responses

The strategic imperative

Spain’s blackout is more than a cautionary tale - it’s a wake-up call for every nation accelerating its energy transition. It revealed that even countries leading in renewables can falter if infrastructure and flexibility don’t keep pace. For the UK, the lesson is clear: resilience must be built into the DNA of the energy system, not treated as an afterthought.

This means going beyond simply expanding wind and solar. It requires a grid that can think, adapt, and respond in real time. A grid that can absorb shocks, balance supply and demand instantly, and recover quickly from disruptions. The UK’s efforts - through integrated planning, storage expansion, inertia technologies, and AI-driven forecasting - are promising steps in the right direction. But the scale and speed of change demand continued urgency and coordination.

The energy transition is not just about hitting net-zero targets. It’s about building a system that is clean, secure, and resilient enough to power a modern economy under all conditions. Spain has shown what happens when ambition outpaces infrastructure. The UK now has a chance to show what it looks like when resilience leads the way.