Preventing future electricity blackouts requires thorough analysis

To a great extent, mystery still surrounds the highly disruptive and damaging 28 April power blackout on the Iberian peninsula. Information about the sequence of events that resulted in the blackout is emerging only slowly. Some data circulated early on was likely wrong (such as Spanish electricity generation data). And media overstated quotes from senior government officials and network companies. These range from confidently ruling out a cyberattack to attributing the incident to temperature-driven oscillations, or framing the role of renewables as either negligible or decisive – depending on the narrative.

Amid this noise, a clear understanding of what went wrong is currently lacking. In a politicised environment, even innocent technical speculation about the potential causes of the incident is immediately used to form narratives that blame certain parties or technologies, and to identify ‘better’ solutions. In this situation, those that might have some deeper understanding – especially within the system operator – are stopping all communication to avoid politicisation and legal risk.

In particular, increasing shares of wind and solar power in the Iberian electricity system have been singled out as a major contributor to the blackout. There was no lack of generation from renewables in the hours of the blackout, but speculation has included reduced resilience of the system (eg too little inertia that has historically been provided by conventional power plants, to quickly dampen frequency oscillation), or badly calibrated large-scale solar farms that all switch off at the same trigger point.

These are known and real challenges that need to be addressed when increasing the share of renewables in the system – and in principle the Iberian grid operators were aware of them. In other countries, these issues are effectively addressed. It is too early to tell if some wilful negligence of those elements contributed to the blackout. 

A large power system is not meant to fail – especially not because of a single incident. Systems are built with multiple layers of redundancy (for example, the N-1 principle, which requires the system to withstand the failure of any single component), self-stabilising mechanisms and both automatic and manual defence tools. Severe blackouts are rarely the result of a single shock. Rather, such blackouts point to a combination of technical and operational design shortcomings, a lack of preparation for such contingencies, possible design flaws that amplified the initial disturbance and likely failure to effectively deploy available stabilisation tools.

As it is likely that different elements contributed to the Iberian blackout, even once the chain of events leading up to it is understood, specific interest groups will likely point to particular failures to promote their preferred technical/managerial solutions.

Furthermore, whatever the cause of the blackout, a new energy-security paradigm is needed. As the low-carbon energy transition proceeds, the challenges of ensuring security of the electricity system are changing. In a system dominated by conventional generation, risks related to the availability of cooling water and fuels, or on the failure of large individual power plants. These risks are well understood and managed through sound system design and operational practices, resulting in very few large-scale blackouts over recent decades.

The shift towards a net-zero electricity system need not increase the risk of power outages. But both the system architecture and its operational logic must evolve to reflect the new systemic challenges posed by a grid dominated by wind and solar. Proper management of a structurally transforming system is needed to ensure energy security in the future. This includes appropriate incentives for the provision of inertia and flexible capacities, effective cross-border coordination, good management of decentralised generation, storage and production assets and the right grid development.

And while the energy transition undoubtedly introduces different energy-security challenges, this does not imply that transition-related factors are to blame for the Iberian blackout.

What’s needed now is not politicised finger-pointing, but a comprehensive, evidence-based investigation of the blackout. Only by clearly understanding all elements that contributed to the blackout can solutions be developed that holistically, sustainably and efficiently reduce the risk of future blackouts. Whatever the causes of the blackout, future energy security requires continuous monitoring and measures to address the changing technological and managerial challenges involved in transforming energy systems. All relevant decision-makers must do everything necessary to prevent such a dire situation from reoccurring, not only on the Iberian Peninsula but all over Europe.