From Electric Grid to Electronic Grid

The verdict is in, and it isn't the one the headlines wanted

For eleven months after the lights went out across Spain and Portugal on 28 April 2025, the blackout did double duty as a morality tale. Renewables were too much, too fast; the grid had been hollowed out in the name of net zero. Then, on 20 March 2026, ENTSO-E's expert panel published its final report, and the story it told was duller and far more useful. The collapse came from oscillations, weak voltage control, fixed power-factor schemes that should have been dynamic, reactive-power resources that fell short, and generators that delivered less than three-quarters of the voltage support the operator asked for at the worst possible moment. It was an engineering failure of grid strength, not a verdict on solar panels.

ATA Insights and RENMAD had reached the same conclusion months earlier, in a webinar built for engineers rather than commentators: "Claves técnicas de los recientes apagones en el sistema eléctrico español." Two speakers walked an audience through the physics the official summaries had skipped. Adolfo Pérez, managing partner at the consultancy eselec and a power-systems engineer, supplied the technical anatomy. Raúl García Posada, director of ASEALEN, the Spanish energy-storage association, supplied the market argument. A year on, with the report out and Spain's new rulebook in force, their debate has become the spine of the only question that still matters.

A different machine wearing the same clothes

Pérez opened with a frame that has aged well. "What we have today is not an electrical grid. It is an electronic grid based on converters," he told the audience. The point is not poetic. For a century, power came from synchronous machines — hydro, thermal, nuclear — spinning iron that holds frequency steady through sheer physics and pours short-circuit current into faults. Solar, wind and batteries arrive instead through power-electronic converters that measure, process and follow. They are governed by control algorithms, not inertia.

That swap changes how the grid behaves under stress, and Pérez reached for Mike Tyson to explain why nobody noticed sooner. "Everyone has a plan until they get punched in the face," he said. The comfortable axiom — that a megawatt is a megawatt once it reaches the wires — held right up until 28 April. Converters carry almost no overload capacity, contribute little short-circuit power, and the older fleet of them emulates no inertia at all. As synchronous plant is pushed out, the system's short-circuit ratio drifts down, and with it the grid's strength: its ability to hold the voltage waveform clean at every node. Drop the ratio far enough and following-converters lose the firm reference they need to stay synchronised. The new failure modes — resonance instability, converter instability — play out in milliseconds, not the comfortable seconds of classical frequency and voltage transients.

The cavalry that was sent to the wrong battle

Spain's problem, Pérez argued, has long been the opposite of what people assume: not falling voltage but rising voltage, driven by lightly loaded transmission lines — increasingly buried cables with a strong capacitive effect — that push voltage up when renewable output drops. For years the operator has leaned on a small set of conventional plants to absorb that excess reactive power, and combined-cycle gas turbines drew the short straw.

Here Pérez was blunt about the cost. The CCGT fleet was built as baseload, designed to run five or six thousand hours a year. "That business case broke years ago. Those plants have been through a calvary, because overnight they were displaced in the marginal market and turned into peaking plants they were never designed to be." Run a few hundred hours instead of thousands, swap twenty starts a year for a hundred, push the machine into a reactive-absorption region that overheats its windings — and the per-hour price has to climb to recover the investment. That, in a sentence, is why gas-fired voltage support is expensive. And it is exactly the muscle the grid leaned on hardest on the day it failed.

Pérez ran the numbers on what the operator has now chosen. Red Eléctrica has committed to eight large synchronous condensers — spinning machines with no turbine, sized at 250 MVAr and roughly six seconds of inertia — adding about 2,000 MVAr of dynamic voltage control and lifting the system's short-circuit ratio so it can absorb more renewables without leaning on costly gas. The steel works. The question Raúl García Posada raised is whether buying it outright was the right call.

Pay for the muscle, don't pour it in concrete

García Posada's case is that Spain already owns much of the capability it is about to build. "What sense does it make to spend 500, 600 million on condensers," he asked, "when there are machines on the grid today that could provide those services — if you pay me for them?" His complaint is not anti-condenser. It is that an asset owner will not start a plant to supply short-circuit power, or hold a hydro unit ready for dynamic voltage control, on a regulatory instruction that carries no payment. "I'm not going to start up to give you short-circuit power, if that's what you need, or extra voltage control, if you don't pay me for it."

He was careful, too, to widen the word "storage" beyond lithium. ASEALEN — more than fifty companies, over five years of history — counts pumped hydro, thermal storage at concentrated-solar plants, and converter-based batteries as one family, some of it synchronous and some not. Modern pumped-hydro designs pair a full-power converter with the synchronous machine to get "the best of both worlds": spin when the system needs firmness, switch to power electronics when it needs speed. Thermal storage, he noted, can be retrofitted into combined cycles and even coal plants, using surplus midday solar to charge heat rather than spill it — turning a stranded asset into something that cuts its own emissions.

The two speakers landed in the same place from opposite directions. Pérez laid out the international split cleanly: in Italy, Germany and others the network operator buys and owns the condensers; in Britain and Australia the operator runs a market and the private sector invests against clear availability contracts. "In England they've built batteries, grid-formers and synchronous condensers by the dozen," he said, on their fourth stability-services pathfinder. Spain, he noted drily, did neither for years — the operator refused the condensers on the mainland and told generators to install reactances, while generators refused to spend tens of millions with no extra revenue. "If you tell an asset owner by decree to provide it, nobody will do it. It's pure economic and financial logic."

The rulebook that finally arrived — and the gas price chasing it

When the webinar was recorded, the spine of that market still didn't exist. The speakers were reacting, almost in real time, to a royal decree-law that had failed to clear parliament the day before — García Posada admitted he had spent the morning "crying, and then we got to work." The capacity mechanism, the flexibility target, the demand-response rules: all left hanging.

That gap has since closed, in a way that sharpens their argument rather than settling it. RDL 7/2026, published on 21 March 2026 as part of the government's response to the Middle East crisis, finally carried the storage and electrification measures the sector had waited years for, recognising both electrochemical and pumped storage as essential to integrating renewables. Ten weeks later, on 29 May, the European Commission cleared Spain's €9bn capacity market — ten years, roughly €900m a year, open to generation, demand response and storage through competitive auctions, run by Red Eléctrica against a national reliability standard. The market García Posada wanted is, at last, being built.

The timing carries a second edge the speakers could not have scripted. RDL 7/2026 exists because a war in the Middle East sent gas prices through the roof: Dutch TTF nearly doubled toward €60–70/MWh in mid-March before easing back. Every euro on the gas curve makes running combined cycles as voltage-stabilising peakers more expensive — precisely the "calvary" Pérez described, now with a fuel bill attached. The case for paying existing hydro and storage to supply firmness, and for grid-forming converters that can stand in for spinning iron, gets stronger each time the gas market lurches.

Clear the renewables, fix the wiring

What both men kept returning to was not technology but signal. Spain, García Posada said, runs its energy sector like an accordion — a few years of frantic installation, then a sudden brake while everyone rethinks. Pérez agreed: contradictory regulation tells investors the country is unreliable, "and nobody knows which way to pull." The blackout did not prove that renewables are too risky. It proved that connecting them through electronics, without buying the grid strength that synchronous iron used to give away for free, leaves a system that can be punched in the face.

The fix is now half-bought in steel and half-promised in a market that has only just opened. Whether Spain pays for the muscle it already owns or keeps pouring it in concrete is the debate the next eighteen months will settle — and it is the debate RENMAD Almacenamiento will carry to Seville on 17–18 March, where, as the host put it, the blackout "is probably going to come up again." On current form, it will. The grid stopped being electrical a decade ago. The rulebook is only now catching up to the machine.