As lucid as ever, Joaquín Coronado wrote a few days ago on a topic that often lends itself to easy headlines: the stability of the Spanish electricity grid.
And, as usual, he did so without resorting to simplifications or technological nostalgia. His thesis is clear: The problem with the current electrical system is not the lack of inertia, but the lack of speed and coordination..
In other words, we don't need more spinning mass, but more reacting intelligence.
For decades, network stability relied on the physical inertia of large synchronous generators. When there was a disturbance, their tons of rotating steel naturally absorbed or released energy, damping frequency imbalances. But the energy transition has changed that balance: more and more renewables are connected through electronic inverters, which they do not provide inertia and therefore leave the network “lighter” and more sensitive.
However, to think that the solution lies in recovering that lost momentum is—as Coronado says—looking in the rearview mirror.
Today we have something that might be the answer: digital control capable of reacting thousands of times faster than any turbine.
From following the network to creating it
This is where a technology we've been hearing about since the blackout comes into play: el grid forming.
I confess that for a long time I felt a bit repulsed by it, perhaps because it always seemed almost magical. "New inertia-generating inverters," "virtual inertia," "digital synchronous machines"… too many labels for something that seemed intangible.
But behind the jargon is a simple and powerful idea.
An investor grid forming It does not limit itself to following the frequency and voltage of the existing network, as a conventional investor does (grid following).
Instead, generates its own voltage and frequency reference, behaving as if it were a virtual synchronous machine. That is, creates the network to which others synchronize.
To achieve this, the inverter synthetically produces the voltage and current necessary to maintain balance, being able to generate or consume active and reactive power playing with the phase shift of the waves.
In this way, it acts as a controllable “complex power source,” capable of stabilizing the grid even in the absence of traditional generators.
It's not magic: it's control, and it has limits
El grid forming solves part of the problem, but not all of it.
By replacing physical inertia with a virtual inertia, response speed is gained, but new challenges also arise.
- Lack of energy.
If the source behind the inverter (a battery, for example) does not have enough power available, the system may lose its ability to maintain frequency and voltage, causing sudden synchronization disconnections.
Simply put: without “electric fuel,” the resulting grid collapses.
- Unequal qualities.
The stability of a grid forming depends largely on the quality of digital control and its dynamic adjustment (the parameters of drop, cushioning, etc.).
A poorly calibrated inverter can generate oscillations in voltage or frequency, affecting not only itself, but the entire local network.
- Lack of standards.
Each manufacturer implements its own control model. This means that two inverters grid forming of different brands can respond differently to the same disturbance, even reaching “compete” with each other to impose the frequency.
Por eso ENTSO-E, IEEE and other agencies are working to define Specific grid codes for grid-forming inverters, something that will be essential for its mass deployment.
The network of the future
Coronado's article points in the right direction: The stability of the electrical system no longer depends on the inertia of steel, but on the intelligence of silicon..
Technologies like grid forming, combined with storage and active demand management, mark a new paradigm: electricity grids that are stabilized not by their weight, but by their adaptability.
In this paradigm shift, we are no longer talking only about large power plants or operators, but about a network composed of thousands of active nodes—homes, batteries, electric vehicles—that can dynamically contribute to maintaining system stability.
And this is what's cool, because it's not magic: it's real-time engineering.
