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2025 Iberia Blackout Report [pdf]

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Re: 2025 Iberia Blackout Report [pdf]

#121

Post by shakow »

stephen_g wrote: post #56
shakow wrote: post #23

Earlier quoted context omitted.

True, but the market moves fast because renewables (or, more precisely, wind & solar) move fast. There is not much fast trading to be done on a nuke/gas/coal/hydro powerplant ramping up or down, but there is a lot of instability (and thus market volatility) to be found in fast varying solar/wind conditions.

That's inaccurate on the whole though, because while those big generators can't move fast, demand can move fast! Which is a difficult problem to manage in baseload grids. Renewables just change one set of challenges for another set, at the end of the day it's all manageable.

It is a problem in baseload grid, but this is a global issue is shared with wind/solar – unless we find a way to sync demand peaks with wind/Sun peaks, that is solved by other means of energy buffering.

Re: 2025 Iberia Blackout Report [pdf]

#123

Post by icar »

It's a difficult read, so let me paste here what Claude Sonnet 4 summarised:

Based on this comprehensive report on the April 28, 2025 electrical blackout in Spain, I can summarize the key reasons why it happened:

## Primary Cause: Voltage Control Crisis

The blackout was fundamentally caused by *insufficient dynamic voltage control capacity* in the system, which led to a catastrophic "chain reaction" of overvoltages. Here's how it unfolded:

### The Perfect Storm of Contributing Factors

*1. Inadequate Voltage Control Resources* - Only 11 thermal power plants were coupled with voltage control obligations (the lowest number recorded in 2025) - One planned voltage control plant in the southwest failed the previous evening and wasn't replaced - Several connected plants didn't provide expected reactive power absorption during critical moments

*2. System Oscillations Weakened the Grid* - Multiple oscillations occurred throughout the morning (starting at 5:49 AM) - Two major oscillations at 12:03 PM (0.6 Hz) and 12:19 PM (0.2 Hz) significantly stressed the system - The first oscillation was traced to anomalous behavior at a specific photovoltaic installation - Measures taken to dampen these oscillations (increased grid meshing, reduced interconnection flows) inadvertently contributed to voltage increases

*3. The Fatal Chain Reaction (Phase 2-3)* Starting at 12:32 PM: - Voltages began rising rapidly across the transmission network - Generation facilities started disconnecting due to overvoltages, beginning with renewable plants - Each disconnection removed reactive power absorption capacity and reduced line loading - This caused further voltage increases, triggering more disconnections - The process accelerated into an unstoppable cascade

### Key Timeline - *12:32 PM*: Sustained voltage increases begin - *12:32:57*: First major generation loss (355 MW at Granada) - *12:33:16*: Second major loss (730 MW at Badajoz) - *12:33:17*: Third major loss (550 MW at Sevilla) - *12:33:30*: Complete system collapse to zero voltage

### Why Couldn't It Be Stopped?

Once the chain reaction began, stopping it would have required massive reactive power absorption capacity that simply wasn't available. The system's protective mechanisms (like demand disconnection) actually made the overvoltage problem worse by further reducing grid loading.

## Broader Context

The report emphasizes this was a *multifactorial event* - no single failure explains it entirely. Contributing factors included: - Low electrical demand creating capacitive effects in the highly meshed grid - Quarter-hourly market changes causing rapid generation adjustments - Spain's weak interconnection with Europe (only 3% vs. 15% target) - Complex renewable evacuation infrastructure with inadequate protection settings

The restoration process took until 7:00 AM the next day to reach 99.95% supply restoration, though it was considered exemplary by international standards.

Re: 2025 Iberia Blackout Report [pdf]

#124

Post by scrlk »

amluto wrote: post #104
diggan wrote: post #35

Seems the money shot starts at page 131: > The ultimate cause of the peninsular electrical zero on April 28th was a phenomenon of overvoltages in the form of a "chain reaction" in which high voltages cause generation disconnections, which in turn causes new increases in voltage and thus new disconnections, and so on. > 1. The system showed insufficient dynamic voltage control capabilities sufficient to maintain stabl…

I’m a bit mystified as to how the grid controls voltage at all. The non-renewable plants follow the rules here: https://www.boe.es/buscar/doc.php?id=BOE-A-2000-5204 7.1(b) seems to be saying that generators connected at 200kV adjust their reactive power generation/absorption in real time according to the voltage they observe, based on a lookup table provided by the grid operator. This seems sort of sensible according…

The automatic voltage regulator (AVR) of the generator and the on-load tap changer (OLTC) operate on different timescales (AVR = quick; OLTC = slow). OLTCs are typically set up with a voltage deadband and a time delay to prevent 'hunting' (i.e., repeatedly tapping up and down).

Re: 2025 Iberia Blackout Report [pdf]

#125

Post by pjc50 »

londons_explore wrote: post #12
AnotherGoodName wrote: post #10

Reads very similar to some blackouts we had in Australia. Weakly connected grids with vast geographical distances leading to oscillations that took down the grid. https://en.wikipedia.org/wiki/2016_South_Australian_blackout Completely solved with lithium based grid storage at key locations btw. This grid storage has also been massively profitable for it's owners https://en.wikipedia.org/wiki/Hornsdale_Power_Reserve#R…

> nor are brief periods of multi-gigawatt draw/dumping as needed. Actually this is typically an issue for grid batteries. Spinning generators can easily briefly go to 10x the rated current for a second or so to smooth out big anomalies. Stationary batteries inverters can't do 10x current spikes ever - the max they can get to is more like 1.2x for a few seconds. That means you end up needing a lot of batteries to prov…

> Spinning generators can easily briefly go to 10x the rated current for a second or so to smooth out big anomalies.

I'm very suspicious of this, because it would also imply 10x overcurrent on the associated transmission gear. There's limits on how much you can overcurrent a transformer before the core magnetically saturates, for example. Also I would expect protection systems to trip out at such a huge divergence from rated current. Do we have a citation?

Re: 2025 Iberia Blackout Report [pdf]

#126

Post by pjc50 »

jakewins wrote: post #112
amluto wrote: post #104

Earlier quoted context omitted.

I’m a bit mystified as to how the grid controls voltage at all. The non-renewable plants follow the rules here: https://www.boe.es/buscar/doc.php?id=BOE-A-2000-5204 7.1(b) seems to be saying that generators connected at 200kV adjust their reactive power generation/absorption in real time according to the voltage they observe, based on a lookup table provided by the grid operator. This seems sort of sensible according…

I don't claim to know the details of reactive power management, but the primary mechanisms for grid stability in the EU is the "cascade" of services the TSOs procures: - Fast Frequency Response (FFR), sub-second power adjustment following frequency table - Frequency Containment Reserve (FCR), ~second power adjustment following frequency table - Automatic Frequency Restoration Reserve (aFRR), ~second energy production…

> 9 separate synchronous plants that had sold aFRR(?) to the TSO then failed to deliver, so when the TSO algorithms tried to adjust the oscillations, nothing happened.

Oof. This sounds like a classic of "it's only needed in emergencies, so it's only in emergencies that we find out it doesn't work".

Re: 2025 Iberia Blackout Report [pdf]

#127

Post by ajross »

bob1029 wrote: post #117
AnotherGoodName wrote: post #40

Earlier quoted context omitted.

Agreed. The relatively small battery substation linked above can output 2GW of equivalent inertia generation (a measure to align batteries to inertial power systems) when needed. That's an entire power station they can match for short periods of time. Link: https://www.energymagazine.com.au/sa-approves-world-first-ba... Australia's largest power plant has 2.9GW of inertial generation assuming all generators are runni…

The article does not describe an inertia constant. Without the time component, any comparison to traditional systems is meaningless. Inertia is a measure of energy, not power. Large spinning masses can provide several seconds of inertia. For 2GW of traditional turbine, you would have between 10-20 gigawatt-seconds of energy that is instantly available at any moment to resist RoCoF.

The switching rate of a good power MOSFET has a bandwidth in megahertz. It's... all solid state electronics. Again, this is just wrong, absent someone showing a cite. It's very weird seeing this kind of seeming ignorance of basic electrical engineering on a hacker site of all places.

Re: 2025 Iberia Blackout Report [pdf]

#128

Post by ajross »

bob1029 wrote: post #105
ajross wrote: post #38

Earlier quoted context omitted.

That... doesn't sound correct. Inverters are the cheap part, you can literally wire as many as you want in parallel. Batteries have immense power availability, with most chemistries you can trivially deliver the entire capacity in half an hour or so (more like 5 minutes with lithium cells). Basically I'm dubious. I'm sure there are grids somewhere that have misprovisioned their inverter capacity, but I don't buy that…

> Inverters are the cheap part The whole point with actual inertia is that you get a large multiple of your maximum capacity without any redundant parts or added system complexity. Keeping around 10x+ more semiconductors than you need to cover a tiny fraction of operational scenarios is difficult economics. A semiconductor device cannot be overloaded like a spinning generator or transmission infrastructure can. You c…

> Keeping around 10x+ more semiconductors than you need to cover a tiny fraction of operational scenarios is difficult economics.

Not according to the prices I see. Digikey tells me I can switch a MW of power for about the price of a MBP. I ask again, is there a citation for this nonsense?

Re: 2025 Iberia Blackout Report [pdf]

#129

Post by rsynnott »

decimalenough wrote: post #20
rcarmo wrote: post #11

Page 130 is where the actual human readable summary is. Although the previous pages were pretty detailed in explaining the cumulative instabilities. Sadly, some news outlets are probably only going to look at the recommendations and read "cybersecurity" and (even though they are common sense recommendations) assume there might be more to say about the matter.

Don't worry, some news outlets will summarize this as "renewables = bad" regardless of what the report actually says. Oh wait, they already did: https://www.telegraph.co.uk/business/2025/06/18/renewable-en... Ed: Do I need a /s tag here or something? My point was that we shouldn't worry too much about about the presentation of the report, its actual contents will be spun to suit any narrative regardless.

I mean, that's the Telegraph; it's just not a serious newspaper these days. (Brexit really did a number on it; in the last decade or so it's gone from a right-wing but fairly normal broadsheet to just complete raving nonsense.)

Re: 2025 Iberia Blackout Report [pdf]

#130

Post by Paradigma11 »

Maxion wrote: post #101
perching_aix wrote: post #96

Earlier quoted context omitted.

This makes sense to me to an extent, however, I do not entirely follow. You say: > Properly accounting for those externalities and adding them to the cost of renewable generation is possible, but politically unappealing. Implying this was/is not done and should be done. As a certified fan of looking out for (cost) dependencies, I agree with this to put it very mildly. I find it unlikely this wasn't done however, rath…

> We need to remove the existing subsidies on renewables which made sense in the early days, but not now. Let the generation sources play at the even field. This is also factually incorrect (unless Spain are now doing some country level subsidies on renewables). Fact is, new solar and new wind offer the lowes average power generation costs of any method. Regular market forces (without susidies) will favor renewables…

It is the total cost of the system that is relevant. If one producer is able to produce cheap energy while making the system more unstable and expensive that would usually be frowned upon and called parasitic.
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