The Maxi Blackout which hit Spain, Portugal and the south of France paralyzed the air and rail transport for several hours, the Internet and the cellular network. Much of the Iberian peninsula, but also the territories beyond the Pyrenees, remained without electricity in just a few minutes, it would seem for a sudden collapse of photovoltaic production. To shed light on what the Blackout caused the Spanish government, the Spanish government has launched a commission of inquiry and the various hypotheses are currently being examined by the competent authorities. But why this “collapse” of the electricity grid was so extensive and so quick? To understand how it could have happened, beyond the possible causes that are still unknown and under consideration of the competent authorities, we must enter the mechanisms of the electrical network, one of the most complex and delicate infrastructures that exist.
The electricity grid is a gigantic balance system
We can imagine an electrical network like a dense spider web that must be managed in an extremely precise, quick and dynamic way. His balance is extremely delicate: Like a huge scale, he must constantly – second by second – balance on the one hand there is the production of energy (power plants, renewable systems) and on the other the consumption (homes, industries, hospitals etc.). It is so consumed, so much must be generated. If production exceeds consumption, or vice versa, network parameters such as frequency or tension are altered. And these alterations, if too large and incorrectly corrected, can put the entire system in crisis.
The cascade of events behind a blackout (also a question of seconds)
Contrary to what you think, a generalized blackout Like the one that happened yesterday is not literally instantaneous, like a switch that goes off suddenly. The effect perceived by the single person is that, but the lack of electricity is nothing more than the last act of a process which, albeit fast, develops in different phases:
- A local problem It begins to create imbalances to the network parameters;
- The network tries to reactby activating adjustment systems that try to restore balance;
- If the breadth of the imbalance is greatthe regulation cannot compensate;
- Emergency protocols are activated which involve the selective and controlled detachment of non -essential loads to try to quickly report the balance between production and consumption.
- If even the emergency protocols should fail or were not activated in time, protections take over, By turning off increasingly large portions, causing generalized blackouts.
- Finally, if multiple national networks are interconnected Among them as in the case of Portugal, an instability generated by a neighboring state can also spread to neighboring states.
This sequence of events can take place in some seconds until Tens of minutesdepending on how robust and interconnected the network is. The regulation systems to stabilize network imbalances act in a time ranging from a few minutes to the quarter of an hour. Around it reads that the blackout in Spain took place “In 5 seconds”but it is more likely that it happened in a time between 5 and 15 minutes – which is in any case a short time to cause such extensive damage.
How the blackout was triggered in Spain
It is not known what theinitial event which kicked off the accident: it may have been the failure of a central (even conventional, therefore not to renewable energy), the breakdown of a high voltage line, a maneuvering error or a sabotage to the infrastructures.
In addition, the Spanish electrical system stands out for thelarge contribution of energy produced by renewable sourcesin particular photovoltaic and wind. These technologies are essential to encourage energy transition, but involve new challenges for system stability. These systems, mainly of distributed size, are connected on average and low voltage and are equipped with interface protections designed to disconnect the system in the presence of anomalous values on the net. The important point to understand is that In case of network imbalances, renewable energy plants must disconnect from the network Because they cannot compensate for the disturbances of the parameters. And these initial detachments, even if localized, can propagate quickly to chain, and since photovoltaic systems were generating the 30% of the electricity requirement of the entire country, if the national electricity grid suddenly see almost a third of its production is not to compensate for the imbalance: a generalized blackout is created.
The sudden collapse of photovoltaic production following the imbalances on the network is in all likelihood contributed to accentuating the overall instability of the network. Having said that, photovoltaics and energy production from renewable sources in general they are absolutely not to demonize: represent a resource fundamental for the energy transition. For this reason their integration requires a profound awareness of its characteristics.
