What's wrong with our electrical system?

BarcelonaThe Spanish and Portuguese governments, the National Court, the European Commission, the Competition Authority and the European network of electric transport managers They have already launched investigations to clarify what happened on Monday, when the entire Iberian Peninsula suddenly lost power. For now, everyone agrees that time will be needed to gather data, analyze the events, and understand why the Spanish electricity system went down so massively and unexpectedly. The blackout has once again brought the ideological debate between nuclear and renewable energy to the forefront, but—beyond lobbying interests and political discourse—there are technical reasons that point to the possible causes of such a collapse.

In a changing system in the midst of an ecological transition, it's not only how energy is generated that matters, but also how it's managed and how it's transported through the grid. While waiting for Red Eléctrica to provide more details about the origin of the outage—for now, it has only ruled out a cyberattack—the consensus in the sector is that Monday's incident has highlighted our fragility in the face of random imbalances between generation and demand. The episode has reopened issues such as the need to invest in stabilization, storage, and digitalization systems to ensure a more flexible and resilient infrastructure.

"The initial diagnosis is that the grid has changed in a very short time. There are now many renewables, and this has certain implications for management. Progress and improvements have been made, but it remains to be seen whether they are sufficient or whether they should be different," explains Daniel Montesinos, director of the Center for Research in Energy, Power Systems, and Electronics (CITCEA-UPC). What appears to be happening so far is that some photovoltaic plants in the southeast of the Iberian Peninsula may have self-disconnected to protect themselves from possible frequency or voltage deviations. But it remains to be seen why the firewalls that were supposed to prevent these contagions did not work. The president of the energy committee of the Industrial Engineers of Catalonia, Lluís Pinós, points to a sequence of three events, with a massive drop in photovoltaic generation, which triggered "the complete degradation of the grid."

Mar Reguant, an Icrea researcher at the Institute for Economic Analysis and a professor at Northwestern University, recalls that many hydroelectric plants were undergoing maintenance, some nuclear plants were shut down, and most renewables were unprepared to assist in these cases. The president of the Efficient Energy Cluster of Catalonia, Joaquim Daura, uses the metaphor of a human chain: when too much power suddenly drops, there isn't enough capacity to react, and that drags down the entire system. "We are victims of our own history. We have been developing a grid that grows vegetatively, but conceptually we have not moved from the 19th century," explains Josep Ballart, an emergency operational plans engineer and former director of operations at Endesa.

Storage, a critical element

How can we make a system more robust and flexible so that it doesn't suffer if the sun is dimming or the wind is weak? Experts agree that storage is a critical element to compensate for the intermittency of renewable energy. "The solution is batteries, and there are many overdue investments in them. We need this storage at different time levels: instantaneous, daily, seasonal," remarks Montesinos, from the UPC. Researcher Mar Reguant also sees an opportunity in installing oversized batteries in public buildings such as health centers or institutes to ensure resilience in the event of a blackout. "Hospitals were already prepared because they are critical infrastructures, but with climate change we must think beyond and extend that resilience," she adds.

Another card that can be played is to reversible or pumping hydraulicsThese facilities operate with two reservoirs at different levels: when there is excess energy, they pump water from the lower level to the upper level; and when needed, they release it again to generate electricity through turbines. "In Catalonia, the Estany Gento and Moralets power plants already operate with this system," says Ballart. In this sense, he also believes that old reservoirs can be used, adapting them for pumping, to increase capacity without needing to create new ones.

In this effort to enable the electricity grid to incorporate large volumes of renewables without endangering its stability, another concept appears in English: grid-forming. Montesinos recalls that only a few decades ago photovoltaic and wind installations were symbolic and responded passively, following the frequency – that is, in mode grid-following– in the face of a scare. They then shut down themselves to protect themselves rather than to contribute to system stability. However, this is already beginning to change with the introduction of grid-forming and renewable energy inverters that simulate the mechanical inertia of conventional generators can thus contribute to grid stability.

Dora also emphasizes that with a more digitalized network, errors could have been detected and confined ("as if we all had a GPS and headlamps that showed us where the breach was"), and even cyberattacks or anomalous fluctuations could have been anticipated, thanks to artificial intelligence systems. That's why the sector also sees essential investments in digitalization, such as installing meters and sensors that send data in real time and implementing monitoring platforms. digital twins, which allow some of these critical scenarios to be simulated in a controlled environment to test the response.

The fact that the Iberian Peninsula is practically an energy island—interconnections are still pending development and are at 3% of the 10% recommended by the European Union—doesn't help in incidents like Monday's. "There are many difficulties and opposition to building the corresponding lines. France hasn't been very supportive of the idea of continuing to improve interconnection," says Lluís Pinós, of Industrial Engineers of Catalonia. Reguant acknowledges that this uniqueness of the peninsular market has "advantages and disadvantages," but emphasizes that it is necessary to move toward acting as a single European market to gain strength.

The Spanish electricity system is based on a marginalist business model. Prices are assigned so that every fifteen minutes, the market operator OMIE accepts offers from energy companies, starting with the cheapest—usually renewables—until demand is met. The last one accepted is the one that sets the price. However, this model also has consequences in situations like Monday's. "It incentivizes investment in low-cost energy," explains Ballart. At a time of so much renewable energy production, this dynamic also means that during hours when the sun and wind are at near-zero cost, it's unprofitable for energy companies to activate conventional power plants and discourages them from adding extra backup power, such as combined cycle plants. "The negative price scenario is sending a signal to the model that something isn't quite right," concludes Ballart.