You should read the report, its a good description of a complex system failing complexly. (well the reasons leading up to it failing were complex)
The interesting thing about spain's grid is that it doesn't have that much battery compared to say the UK (the uk has about 11 gwhr which is about enough to power the entire uk for around 20mins)
The Iberian grid has <100Mw (I know mixed units) battery at the moment. This is interesting because the economics of the iberian grid means that most solar plants are in curtailment (ie told to turn off) at solar mid day prices are normally negative, at 18:00 prices are very high.
There is currently a large lucrative market in grid scale batteries being paid to charge at solar noon and getting a 30-50% premium to release the power at peak.
There are only a few companies that are able to vertically integrate solar and battery, so it'll be interesting to see how the prices shape up in the next 5 years. I expect a bunch of batteries to be built and then sold as the market changes shape.
Because you'd have to have engineered the whole thing for that purpose right from the get go. In theory you can run the generators in reverse and push water up the hill into the basin. In practice this may not work for a multitude of reasons (priming, encasement, rotation reversal, cavitation, impeller and impeller housing design).
Also missing in vast majority of the dams is a lower reservoir. Pumping up the water from a river/canal below the dam would result in a dry river bed just below the dam rather quickly
Spain does have few (probably 4 according to ESP Wikipedia) pumped-storage hydroelectricity plants. Supposedly these are being used nowadays to store excess of energy produced by fotovoltaic plants. No idea how fast these can switch from storing energy to producing it and if these were used to help during the blackout.
> No idea how fast these can switch from storing energy to producing it and if these were used to help during the blackout.
Typically ~10 seconds.
The bigger issue is if these have blackstart capability. (IE, if they can switch to generation when there is a blackout, or if they need power from the grid to start.)
Unrelated to the cause but I just want to say, actually experiencing it in Barcelona was thrilling. No lights in the streets, just illuminated by strategically placed police cars. Everyone out meeting their neighbours, playing music on their phones, playing card games, bars giving away their drinks.
It was a real communal event. Like going back to a simpler time that hasn't actually existed in modern times. Maybe we should do it again.
If you would have a family member having a scheduled chemotherapy treatment for that day the thrill would be gone. Not every day is great for the chill out.
A quick check at comment history shows a few replies with cancer as the main topic. My guess would be the nature of the topic being on top of op's mind; adding the worst-case scenario of how a city-wide power outage would affect them (painting a realistic picture of life that is not all song and dance and free drinks as laid out by the original op).
Thank you for your kind words. Sorry for the Captain's Obvious a bit rude comment. It just happened that me and my partner were battling traffic using rickety road through the hills above the Barcelona to get on time for a chemotherapy session. Just to be told that due to the blackout it must be postponed for a few days. Luckily nothing serious in the long run, but nevertheless rather annoying. Because of the traffic jams and lack of mobile coverage for many hours in various locations in Spain I am quite sure there were some extra fatalities.
Thinking about it, there is nothing wrong writing about unexpected pleasures of that day. Just that we keep in mind the fact that blackouts have this non-hipstery, rather serious aspects.
PS I am doing ok-eish, splendid even considering the initial diagnosis (pancreatic cancer 1b stage diagnosed in December 2024). Maybe still way too touchy about some topic apparently triggering me.
The big thing with renewables is that they don't really require ongoing fuel shipments. Spain is not a large producer of any of the major fossil fuels like oil, gas and coal.
While there are certainly issues with the supply chain of certain components of renewables, those effectively cease after installation. And even hydro is not totally immune from supply issues given increasing drought frequencies across the world.
That report concentrates on the forensics, but it doesn't really look at any of the root causes which were failures at the regulatory or political level. The Spanish electricity network was designed such that it would fail.
Working out why the regulator failed is no easy task. And fixing regulators is highly political.
You might compare against another country that successfully integrated massive solar systems such as Australia. They had a functional regulatory environment that designed their systems to handle the supply changes. Some of that was through world leading deployment of battery systems to help regulate their network.
There is a lot of specialist expertise (e.g. nera.com economic consultants) that is paid by a countries network operator to design their networks and markets. The staff within individual countries either lack sufficient analytical skills or lack sufficient political clout to make their networks deeply resilient.
The proximal cause of the blackout was a single faulty solar inverter in a PV plant. The distal cause, however, was inappropriate disconnection of wind/solar generation and widespread cascading failure of reactive power support across the grid. Add to that a whole bunch of noncompliant transformers which tripped inappropriately, and Spanish grid operators inability to react appropriately.
It looks like you know way more than the entso report. Which mostly blamed it on governance. Mostly because a small change in a complex system can lead to cascading failures. They also included data to prevent it in the future. And yes solar and wind power makes these failures more complex but they are certainly not to blame. (Just read the article…)
I already said REE (the operator) was partly to blame, but they were reacting to something their grid was ill equipped to deal with.
Perhaps you should understand the difference between distal and proximal causes of events? Both are important. Voltage oscillation was the proximal cause. Where did this come from? It's explained in the operators own report:
> During the incident analysis, it was determined that the oscillation was not natural to the system but rather
forced. This oscillation is observed with significant amplitude at a Photovoltaic Plant located in province of
Badajoz (PV Plant A). At the time of the oscillations, the plant was generating approximately 250 MW. Since
the oscillation was forced, it ceased once the plant stabilizes it.
The reason is that classical grids are mostly self-correcting. Rotating inertia can stabilize frequency and can produce or absorb reactive power.
"Reactive power" sounds fancy, but it just means that motors can create a drag. The power lines are giant capacitors, and capacitors have the lowest effective resistance when they are discharged. So the current is greatest when the voltage crosses the zero mark. Inductive (rotating) loads are the opposite, their effective resistance is greatest when the current starts to rise or fall. So this limits the initial inrush of the current.
But there's more! When you have a transformer and a long line, you can essentially get a boost converter. The voltage from a transformer travels through a low-resistance wire until it reaches the end, and because the line can be modeled as a series of capacitors, you essentially get a "charge pump" ( https://en.wikipedia.org/wiki/Charge_pump ). From the viewpoint of the generator you have one large capacitor, but from the viewpoint of a consumer in the middle of the line, you have two capacitors in series.
As a result, the voltage in power lines can _spike_ if there's not enough rotating load. This is called Ferranti effect, and in Spain it was the primary reason for the faults.
This is all fixable, but it requires investment and regulation. And Spain (and other countries) have been neglecting that, by incentivizing the cheapest possible generation.
That article is a piece of horseshit. It was indeed the renewables (too much of them) that caused the blackout, as independent and regulatory investigations have revealed.
The rate of new solar capacity is falling though, according to that graph.
And:
"With annual additions now around 1 GW, UNEF is calling for stronger momentum to maintain progress towards 2030 targets"
"Growth, however, has slowed, with only around one gigawatt added last year. To reach the national target of 19 gigawatts by 2030, deployment will need to accelerate, the association" [0]
The 2026 Ember report said that 99% of new global electricity demand was met by solar+wind (solar 75% alone). Solar broke its previous records on relative and absolute installed numbers. Fossil fuel usage shrank. There might be regional changes, but there is no stopping solar.
Good news. But "there is no stopping solar" is a straw-man. Nobody said it's stopping.
(Also, I'm discussing an apparent slowdown in Spain's rate of new solar capacity (given the article is about Spain). And global trends are not too relevant to that topic. We all know it's easy to hide issues in global stats – domestic consumers Spain won't care if China increases their solar by 1000000%, for example.)
Yup, hopefully the Spanish Government will address the slow down and announce a commitment to keep up the pace (if not already). Though of course they are already doing very, very well.
You should read the report, its a good description of a complex system failing complexly. (well the reasons leading up to it failing were complex)
The interesting thing about spain's grid is that it doesn't have that much battery compared to say the UK (the uk has about 11 gwhr which is about enough to power the entire uk for around 20mins)
The Iberian grid has <100Mw (I know mixed units) battery at the moment. This is interesting because the economics of the iberian grid means that most solar plants are in curtailment (ie told to turn off) at solar mid day prices are normally negative, at 18:00 prices are very high.
There is currently a large lucrative market in grid scale batteries being paid to charge at solar noon and getting a 30-50% premium to release the power at peak.
There are only a few companies that are able to vertically integrate solar and battery, so it'll be interesting to see how the prices shape up in the next 5 years. I expect a bunch of batteries to be built and then sold as the market changes shape.
Spain is a leader in Hydro. Why they don’t use their dams for storage ?
Because you'd have to have engineered the whole thing for that purpose right from the get go. In theory you can run the generators in reverse and push water up the hill into the basin. In practice this may not work for a multitude of reasons (priming, encasement, rotation reversal, cavitation, impeller and impeller housing design).
Also missing in vast majority of the dams is a lower reservoir. Pumping up the water from a river/canal below the dam would result in a dry river bed just below the dam rather quickly
*edit* spell
Yes, excellent point. Cruachan dam is a nice example of such a double storage setup.
https://www.visitcruachan.co.uk/
Spain does have few (probably 4 according to ESP Wikipedia) pumped-storage hydroelectricity plants. Supposedly these are being used nowadays to store excess of energy produced by fotovoltaic plants. No idea how fast these can switch from storing energy to producing it and if these were used to help during the blackout.
> No idea how fast these can switch from storing energy to producing it and if these were used to help during the blackout.
Typically ~10 seconds.
The bigger issue is if these have blackstart capability. (IE, if they can switch to generation when there is a blackout, or if they need power from the grid to start.)
Reconfiguring dams for storage isn't easy, quick or possible.
Non-storage dams don't have lower lakes to pull from, and the surrounding area might not be able to support it.
plus they also need water when there are droughts, which spain is also prone to.
they do it all the time
Unrelated to the cause but I just want to say, actually experiencing it in Barcelona was thrilling. No lights in the streets, just illuminated by strategically placed police cars. Everyone out meeting their neighbours, playing music on their phones, playing card games, bars giving away their drinks.
It was a real communal event. Like going back to a simpler time that hasn't actually existed in modern times. Maybe we should do it again.
If you would have a family member having a scheduled chemotherapy treatment for that day the thrill would be gone. Not every day is great for the chill out.
Yes obviously
what is the point of this comment?
A quick check at comment history shows a few replies with cancer as the main topic. My guess would be the nature of the topic being on top of op's mind; adding the worst-case scenario of how a city-wide power outage would affect them (painting a realistic picture of life that is not all song and dance and free drinks as laid out by the original op).
Be safe and well op.
Thank you for your kind words. Sorry for the Captain's Obvious a bit rude comment. It just happened that me and my partner were battling traffic using rickety road through the hills above the Barcelona to get on time for a chemotherapy session. Just to be told that due to the blackout it must be postponed for a few days. Luckily nothing serious in the long run, but nevertheless rather annoying. Because of the traffic jams and lack of mobile coverage for many hours in various locations in Spain I am quite sure there were some extra fatalities.
Thinking about it, there is nothing wrong writing about unexpected pleasures of that day. Just that we keep in mind the fact that blackouts have this non-hipstery, rather serious aspects.
PS I am doing ok-eish, splendid even considering the initial diagnosis (pancreatic cancer 1b stage diagnosed in December 2024). Maybe still way too touchy about some topic apparently triggering me.
The big thing with renewables is that they don't really require ongoing fuel shipments. Spain is not a large producer of any of the major fossil fuels like oil, gas and coal.
While there are certainly issues with the supply chain of certain components of renewables, those effectively cease after installation. And even hydro is not totally immune from supply issues given increasing drought frequencies across the world.
When you consider the intermittency of renewables, and you should, fuel suddenly becomes an issue again.
But you need less than if you were to go fully fueled. One hedges the other.
Absolutely, and that's different than saying « they don't really require ongoing fuel shipments ».
If you have batteries, those also don’t need fuel shipments.
But the evidence is literally in the article.
Nope, it is not perfect, so should never install any renewables ever.
/s
I found this video by Modo Energy interesting on why Spain has so little battery right now:
https://www.youtube.com/watch?v=8CwB38oLEYM
Solar Saturation & Grid Collapse: Spain's BESS Opportunity - Modo Energy
Absolutely fascinating. Now watching some of the others in the series.
So renewables didn't cause the blackout per the author, but according to the neutral report [0], solar and wind exacerbated the blackout.
As these renewables and grid change to a different configuration/inverter technology, this problem shouldn't happen again?
[0] https://www.entsoe.eu/publications/blackout/28-april-2025-ib...
> So renewables didn't cause the blackout per the author, but according to the neutral report [0], solar and wind exacerbated the blackout.
So, what caused the blackput?
It is a complex system. There is no single cause. There's a multitude of causes.
The root cause tree with its multiple roots on page 23 is a good start.
That report concentrates on the forensics, but it doesn't really look at any of the root causes which were failures at the regulatory or political level. The Spanish electricity network was designed such that it would fail.
Working out why the regulator failed is no easy task. And fixing regulators is highly political.
You might compare against another country that successfully integrated massive solar systems such as Australia. They had a functional regulatory environment that designed their systems to handle the supply changes. Some of that was through world leading deployment of battery systems to help regulate their network.
There is a lot of specialist expertise (e.g. nera.com economic consultants) that is paid by a countries network operator to design their networks and markets. The staff within individual countries either lack sufficient analytical skills or lack sufficient political clout to make their networks deeply resilient.
The proximal cause of the blackout was a single faulty solar inverter in a PV plant. The distal cause, however, was inappropriate disconnection of wind/solar generation and widespread cascading failure of reactive power support across the grid. Add to that a whole bunch of noncompliant transformers which tripped inappropriately, and Spanish grid operators inability to react appropriately.
It looks like you know way more than the entso report. Which mostly blamed it on governance. Mostly because a small change in a complex system can lead to cascading failures. They also included data to prevent it in the future. And yes solar and wind power makes these failures more complex but they are certainly not to blame. (Just read the article…)
I already said REE (the operator) was partly to blame, but they were reacting to something their grid was ill equipped to deal with.
Perhaps you should understand the difference between distal and proximal causes of events? Both are important. Voltage oscillation was the proximal cause. Where did this come from? It's explained in the operators own report:
> During the incident analysis, it was determined that the oscillation was not natural to the system but rather forced. This oscillation is observed with significant amplitude at a Photovoltaic Plant located in province of Badajoz (PV Plant A). At the time of the oscillations, the plant was generating approximately 250 MW. Since the oscillation was forced, it ceased once the plant stabilizes it.
The reason is that classical grids are mostly self-correcting. Rotating inertia can stabilize frequency and can produce or absorb reactive power.
"Reactive power" sounds fancy, but it just means that motors can create a drag. The power lines are giant capacitors, and capacitors have the lowest effective resistance when they are discharged. So the current is greatest when the voltage crosses the zero mark. Inductive (rotating) loads are the opposite, their effective resistance is greatest when the current starts to rise or fall. So this limits the initial inrush of the current.
But there's more! When you have a transformer and a long line, you can essentially get a boost converter. The voltage from a transformer travels through a low-resistance wire until it reaches the end, and because the line can be modeled as a series of capacitors, you essentially get a "charge pump" ( https://en.wikipedia.org/wiki/Charge_pump ). From the viewpoint of the generator you have one large capacitor, but from the viewpoint of a consumer in the middle of the line, you have two capacitors in series.
As a result, the voltage in power lines can _spike_ if there's not enough rotating load. This is called Ferranti effect, and in Spain it was the primary reason for the faults.
This is all fixable, but it requires investment and regulation. And Spain (and other countries) have been neglecting that, by incentivizing the cheapest possible generation.
https://archive.ph/zPv2u
The guardian is free to read. Why post an archive link ?
Their script is over active. Not sure why people are harvesting HN likes.
So you can select all images with traffic lights.
That article is a piece of horseshit. It was indeed the renewables (too much of them) that caused the blackout, as independent and regulatory investigations have revealed.
https://en.wikipedia.org/wiki/2025_Iberian_Peninsula_blackou...
From the specific section you linked:
> Chair of the ENTSO-E Board of Directors, stated: "The problem is not renewable energy, but voltage control, regardless of the type of generation"
True, but it conveniently hides the fact that voltage control becomes more of a problem in a low inductance environment.
The rate of new solar capacity is falling though, according to that graph.
And:
"With annual additions now around 1 GW, UNEF is calling for stronger momentum to maintain progress towards 2030 targets"
"Growth, however, has slowed, with only around one gigawatt added last year. To reach the national target of 19 gigawatts by 2030, deployment will need to accelerate, the association" [0]
[0] https://www.pveurope.eu/markets/spains-solar-market-hits-93-...
The 2026 Ember report said that 99% of new global electricity demand was met by solar+wind (solar 75% alone). Solar broke its previous records on relative and absolute installed numbers. Fossil fuel usage shrank. There might be regional changes, but there is no stopping solar.
https://ember-energy.org/latest-insights/global-electricity-...
Good news. But "there is no stopping solar" is a straw-man. Nobody said it's stopping.
(Also, I'm discussing an apparent slowdown in Spain's rate of new solar capacity (given the article is about Spain). And global trends are not too relevant to that topic. We all know it's easy to hide issues in global stats – domestic consumers Spain won't care if China increases their solar by 1000000%, for example.)
Data from last year may show a slowdown, but I’d bet that the Iran situation may be pushing demand up
Yup, hopefully the Spanish Government will address the slow down and announce a commitment to keep up the pace (if not already). Though of course they are already doing very, very well.