Published in La Tribune on April 9, 2026
Countries striving to be environmentally responsible are increasingly turning to (green) electricity as a means of meeting most of their energy needs. This is not without risk, since, by being connected to a common grid, each of us can be affected by incidents or operational errors at various nodes in the network. Ensuring the reliability of the power system is therefore a necessity in modern economies. How can the lessons learned from the major blackout that occurred in Spain and Portugal on April 28, 2025, help us improve the safety of our power systems?
The facts and their interpretation(s)
Since the blackout of April 28, 2025, experts from the European Network of Transmission System Operators for Electricity (ENTSO-E) have gathered information from the generators, transmission operators, distributors, and system operators involved to understand the sequence of events that caused this massive blackout.
The first report, published on October 3, 2025, is purely descriptive. Its purpose is to “provide a technical and objective account of the incident, based on factual evidence” and not “to allocate liability or responsibility to any party.” It is worth noting that, given the speed at which electrical energy travels, incidents at a single point in the grid have nearly instantaneous consequences for all generators and consumers connected in the affected area and, within a short time, for those in interconnected areas.
Grid operators naturally have equipment and procedures to mitigate the negative effects of such incidents, the simplest of which involve reducing power deliveries to certain consumers and/or increasing power generation from already active power plants. However, these marginal adjustments may prove insufficient, and to limit the spread of failures, it may be necessary to disconnect certain sub-grids and/or international interconnections. Thus, Spain and Portugal were disconnected from the rest of Europe.
Nevertheless, it is suspected that if the blackout of April 28, 2025, reached the scale observed in the Iberian Peninsula, it is because the solutions mentioned above were not implemented in a timely manner, or even proved inadequate for the problem at hand. In fact, in its final report of March 20, 2026, ENTSO-E highlights “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..”
Simply put, no one is entirely to blame, and everyone is partly to blame. The technical failures observed (oscillations, voltage fluctuations, poor reactive power management, and untimely automatic disconnections) could not be corrected by implementing the protocols designed for that purpose. This raises questions about their full effectiveness.
Economic Principles and Electrical Constraints
The authors of this post are not engineers. Beyond all the technical explanations that punctuate the report’s 472 pages, their attention was instead drawn to a remark in the March 20 press release calling for the upgrades to the Iberian power system to be carried out “while ensuring that market mechanisms, regulatory frameworks and energy policies remain aligned with the physical limits of the system.” This reminder of the tyranny of the laws of physics is not insignificant in a world where political promises and attacks regarding energy dominate the media headlines and are amplified on social media.
The current organization of the European electricity system is a compromise between centralization and the market economy. To understand how it works, it is important to remember that, to date, electrical energy can only be stored on a very small scale relative to the needs of modern economies (and only after temporary conversion into another form of energy, such as chemical, thermal, or potential energy in pumped-storage power plants), so that a constant balance must be maintained between the amounts fed into the grid and those drawn from it. Following the general trend toward introducing competitive mechanisms in all network industries at the end of the last century, market activities (production and sales) were separated from network activities (transmission and distribution), whose natural monopoly characteristics do not efficiently accommodate a multiplicity of actors.
For the competitive aspect of electricity generation, the “copper plate” principle was adopted: a single market in which all producers and wholesale buyers submit bids on an equal footing, regardless of their injection or withdrawal location. Based on these bids, within the limits of interconnections between different countries, the market software calculates the equilibrium price and the quantities that each bidder must inject or withdraw. However, it remains to be verified that the grid can handle the energy flows resulting from this draft dispatch. This is the task of the system operator, most often the transmission system operator. If the flows are incompatible with the technical characteristics of the lines and transformers, the grid operator organizes a “redispatching,” increasing or decreasing injections or withdrawals at specific nodes in the grid, which will result in financial settlements between rejected and called-up agents (for the costs of redispatching in Spain, see HERE).
This separation offers “political benefits” since everyone is initially placed on an equal footing, thereby perpetuating the myth of the great single market. But it has its drawbacks. Sequentiality complicates real-time operations and shifts responsibility away from buyers and sellers. With this structure, we overlook the fact that the price of a good depends not only on its characteristics, its availability date, and the state of nature under which it is available, but also on where it is available—and thus on transmission line congestion. Other organizational models exist. For example, in the northeastern United States, the Pennsylvania-New Jersey-Maryland (PJM) power system calculates and publishes nodal prices every five minutes—that is, the prices prevailing at several hundred nodes across the grid. This information allows producers and consumers to assess local indicators of electricity scarcity but also informs the choices of connection applicants regarding the best location and the plans of infrastructure investors to determine which nodes to connect first.
Without going so far as to suggest the use of nodal prices, by applying the recommendations for the Iberian Peninsula contained in Chapter 9 of the ENTSO-E report, we can reasonably hope to reduce the risks of a major blackout. However, given the complexity of electrical systems, we cannot eliminate them entirely. Mark Twain wrote, “The calamity that comes is never the one we had prepared ourselves for.” In its modern version, this idea is expressed as “Anything that can go wrong will go wrong” (Murphy’s Law). It is with this logic that crisis plans must be designed. It would therefore be prudent to keep some cash on hand for times when payment systems are down, candles and matches for when electric lighting fails, and to stay fit enough to walk and climb stairs during periods when traffic lights and elevators are no longer powered.
Photo Fahrul Razi Unsplash
