ECONOMYNEXT – A Spanish renewable energy advocacy has slammed suggestions that a high share of solar energy may have contributed to the cascading power failure that spread across the Iberian Peninsula and into parts of France.
The power outage came at around 1230 when solar energy is very strong.
“The fact that Spain has a high production of electricity from renewable sources has no link to the grid failures that occurred on Monday,” Fundacion Renovable said in a statement.
“We regret that an extremely serious situation is being taken advantage of to spread falsehoods and generate disinformation in an already very complex situation for all affected citizens.”
Some analysts had pointed to solar energy as a possible cause because large shares of solar tends to de-stabilize grids when the share of energy from generators with rotational inertia, which can absorb shocks to demand to maintain frequency – falls.
Unlike solar power, large hydro plants which are conventional old renewables, provide rotational inertia and are also widely used for frequency management.
Related : Spain, Portugal hit by Sri Lanka style cascading power failure
For imbalance to take place in the grid, there has to be a trigger event like an event that leads to a sudden fall in demand, which cannot be matched by a reduction in generation.
Spain, like the other European nations have a frequency of 50 Hertz (cycles per second). When the frequency falls (demand go up) or increases (supply goes up) beyond a tolerance level (say 49.5Hz/50.5Hz) the system has to adjust generation to match demand.
Sudden outages of demand can come from customers dropping off from the grid due to an equipment failure, lightning, or wild animal intrusion that shuts down part of the grid and take a significant amount of customers out of the system.
Solar power can also lead to uncontrolled supply (frequency moves above 50Hz).
If there aren’t enough plants to reduce the supply fast, the sections of the grid will start tripping to protect itself, leading to a cascading failure where both generators and ditribution and transmission lines trip in quick succession.
Other suggested triggers included a cyberattack.
Rooftop solar typically cannot be disconnected by system controllers when power demand fluctuates, and in some grids, they are not telemetered and not visible.
Invisible solar is generally described as a duck curve.
Read More : Electricity ducks being seen in Spain
There are however techniques like batteries which can mimic the effect of rotational inertia plants or automatic disconnection of solar plants under certain tolerances to maintain frequency.
Spain has long experience in handling renewable power.
It is not clear to what extent the Spanish grid had such buffers. Red Electra, the grid operator said on April 21 that solar power hit a new peak in a post on x.com.
📢21 de abril: Nuevo récord de producción fotovoltaica.
🌞A las 13.35 horas la potencia instantánea ha llegado a 20.120 MW en el sistema peninsular.
✅Es un 0,7% más que el anterior máximo histórico, que se registró el 12 de julio de 2024.
🥇A esa hora, esta #renovable ha… pic.twitter.com/4mFwFrQEkW
— Red Eléctrica (@RedElectricaREE) April 21, 2025
On April 16, Red Electra said renewable met the demand for the peninsular electrical system.
Spanish power officials have still not given an official explanation for the outage and are said to be still investigating the blackout. However, suggestions that a cyberattack was responsible has been denied.
Solar linked failure typically take place on weekends (Sunny Sunday blackouts) when overall demand falls, and solar share go up in a grid. (Colombo/Apr29/2025)
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