So renewables, the European Network of Transmission System Operators for Electricity (ENTSO-E) confirmed last week, were not to blame for the electricity blackout in the Iberian peninsula last April. The blackout affected large parts of Spain and Portugal, and briefly affected southwestern France. At one stage on April 28, 2025, as many as 60 million people were without electricity.
Knee-jerk reaction to the blackout suggested that Spain’s heavy reliance on renewable energy for what was Europe’s most severe blackout incident in over 20 years, and the first ever of its kind. Portugal relies on renewables (including hydropower) for more than 80 per cent of electricity generation, while more than half of all Spain’s electricity is derived from renewable sources.
ENTSO-E’s report, prepared by a 49-member panel of experts, concludes that the blackout resulted from a combination of many interacting factors, including oscillations, gaps in voltage and reactive power control, differences in voltage regulation practices, rapid output reductions and generator disconnections in Spain, and uneven stabilisation capabilities. These factors led to fast voltage increases and cascading generation disconnections, resulting in the blackout in continental Spain and Portugal.
The report’s recommendations emphasise that renewable energy remains central to both energy security and climate objectives, but needs to be supported with a modern, resilient infrastructure.
Indeed, it can be argued that the report, as well as the current energy crisis and the sharp rise in oil and gas prices, only improve the case for expanding domestic renewable energy. However, Spain, and Europe more broadly, face limitations under the existing grid conditions. This is why urgent investment in grid modernisation and expansion is not optional, but essential.
“This report confirms that the main cause of the Iberian blackout was grid failure, not renewables. Right now, Spanish customers are among the least exposed to energy price surges in Europe thanks to sustained investment in renewables in recent years,” says Tara Connolly, energy campaigner at Beyond Fossil Fuels.
“Solar and wind remain the best hedge against unstable global gas markets, while strengthening energy security. Governments in Europe must accelerate investments in clean technologies to update our aging power grids to be more resilient, modern and flexible, and avoid repeating the same mistakes again.”
Wired wrong
The impulse to blame wind and solar for power failures is not new, and it surfaces with tiresome reliability whenever a grid wobbles. What made the Iberian case distinctive, according to the ENTSO-E panel, was that it was the first blackout ever caused not by too little power, but by too much voltage. At 12:33 on April 28, a surge of overvoltage in southern Spain cascaded through the system in under 30 seconds. Fossil, nuclear and renewable plants alike disconnected automatically to protect their equipment. The grid lost synchronisation with France and Morocco. Voltage dropped to zero.
Renewables bore a specific technical vulnerability, and the report was candid about it. Solar and wind installations using converter-based technology were, at the time, not legally permitted to contribute to voltage control. They could not help stabilise the very instability that triggered their disconnection. Spain updated its operational procedures in June 2025 to fix this.
The full implication is almost the reverse of what the critics claimed: the problem was a regulatory framework that had not caught up with the generation mix it was meant to govern.
Back on the gas
The months after the blackout offered a sharper demonstration of what fossil fuel dependence actually costs. Nervous grid operators responded by mandating more gas-fired generation to stabilise the system. The cost of grid balancing services doubled in May 2025 compared with the previous year. Gas ended up accounting for 57 per cent of the final electricity price that month, up from an average of 14 per cent in the year before the blackout. Renewable curtailment tripled, from 1.8 per cent to 7.2 per cent between May and July, as grid operators opted for thermal backup over cheap, available clean power.
Spain had spent years building exactly the generation fleet that breaks the link between gas markets and electricity prices. The blackout snapped that link temporarily back into place. The scale of what had been achieved is worth stating plainly: since 2019, the country doubled its wind and solar capacity, and its wholesale electricity price was 32 per cent below the EU average in the first half of 2025. New solar and wind capacity added in the past five years avoided some 26 billion cubic metres of gas imports, saving around 13.5 billion euros. That is almost five times what Spain invested in its transmission grid over the same period. The imbalance is the real story.
Europe’s electricity grids were designed for large, centralised thermal plants. They were not built for dispersed, variable renewable sources without significant investment in storage, interconnection, and voltage management. Spain, despite generating more than 55 per cent of its electricity from renewables in 2025, has only 120 megawatts of battery storage, ranking 13th in Europe. Denmark, for comparison, manages a 69 per cent renewable share without comparable grid instability.
Gas prices rose 55 per cent in a single day following the escalation of conflict in the Middle East, and have continued climbing. Countries with fossil-heavy grids are most exposed. The ENTSO-E report’s recommendations point toward infrastructure, not ideology: stronger operational practices, improved monitoring, updated regulatory frameworks.
The European Commission’s Grid Package, announced last year, provides a framework for accelerating such investment. Frameworks and actual capital, however, are different things. The blackout was a grid failure. Treating it as a renewables failure risks the worst possible outcome: a retreat from the only energy strategy that durably reduces dependence on volatile global fuel markets.
Photo: Dreamstime.
