Approximately 11 months after the blackout on the Iberian Peninsula, on Friday 20th March 2026 the organisation ENTSO-E has released this Final Report into the ‘Grid Incident in Spain and Portugal on 28 April 2025’:

More, from ENTSO-E

The report (and other materials) are downloadable from the ENTSO-E sub-site here.  On that site, they introduce this second report as follows:

1)  It followed the ‘Factual Report’, which we noted here in October 2025 at its release;

2)  And they write:

‘In the second phase, which started immediately after the finalisation of the factual report, the Panel focused on the identification and analysis of the root causes of the incident. The Expert Panel specifically evaluated cascading disconnections of generation in the system, the voltage control and the oscillations’ mitigation measures. The Panel also assessed the performance of generators in regard to protection settings and contribution to voltage control, as well as the performance of the system defence plans and analysed the various steps of the restoration phase.

Based on the findings, the Panel sets out recommendations in its final report addressing each of the factors identified to help prevent similar events in the future.’

There’s also a Media Release ‘ENTSO-E Publishes Expert Panel Final Report on 28 April 2025 Blackout in Spain and Portugal’.

There’s already a growing amount of commentary about this burgeoning on various social media platforms – but worth particularly noting this update from the ENTSO-E organisation on LinkedIn, because readers here might be interested in the comments accumulating:

Lacking in ‘Resilience’!

At 472 pages, there’s obviously quite a lot to read through – but here are some quick observations …

1)  The Media Release features the word ‘resilience’ twice, and it’s mentioned in the Final Report 7 times … which might not seem much, over 472 pages!

2)  But this paragraph from p453/472 is particularly important to understand:

‘The increasing penetration of variable renewable and distributed generation, further market integration, broader electrification, and evolving environmental and geopolitical risks place the European electricity system under increasingly challenging operational conditions, requiring higher levels of resilience. The recommendations address voltage control and reactive power management, oscillatory stability, and generation disconnection behaviour. They further aim to enhance the effectiveness of system defence mechanisms and the robustness and preparedness of restoration processes’

3)  This need for ‘higher levels of resilience’ is (in my view) particularly important to understand:

(a)  not just in the Iberian Peninsular

(b)  but in grids across the world that are transitioning:

i.  from the old ‘Baseload + Peaking’

ii.  to the new ‘VRE + Shaping + Firming’ (i.e. explicitly calling out the need to think of Shaping separately from the need for Firming (such as for HILP events), as noted for the NEM in the Nelson Report).

4)  Implicit in the report, therefore, is the observation that there’d been insufficient level of resilience, and that the events on 28th April 2025 were a wake-up call.

5)  For our readers in the NEM, might be useful to think about the extent to which we’re adequately prepared with a Resilient* System to continue operating through this energy transition?

(a)  Remember that (*) ‘Reliability (as discussed in planning documents like the ESOO) is not the same as Resilience’.

(b)  We highlighted this:

i.  back in Key Observation #7/22 (*) back in 2021 in the report GenInsights21.

ii.  and briefly noted this again here on 31st August 2022.

Root Cause Tree

Page 452 contains a ‘Root Cause Tree’ that is worth copying in here, for ease of reader reference here:

Data Challenges … and so a Caveat

As also noted by others, there’s reference to the inherent challenges of assembling an accurate, complete, and synchronised set of high-speed data set … so (like others) I wonder how complete the Final Report actually is in the Root Cause Tree above?

1)  In page 8/472 the report notes:

‘Consequently, the Expert Panel collected a significant amount of data from DSOs and significant grid users. However, some data remain missing, particularly for generation trips that occurred before the blackout, which prevented the Expert Panel from identifying the cause of tripping for generation units due to missing or no fault recordings. The concerned parties (namely, the owners of those facilities) all cited the lack of fault record data as the reason they were unable to provide this information to the investigation.’

2)  in page 116/472 the report notes:

‘It is worth noting that many events occurred within a very short time frame, making it difficult to determine their exact sequence, as not all data is time-synchronised with sufficient accuracy. In addition, some of these events occurred in parts of the system that are not fully observable from the TSO perspective, requiring estimation of the imbalance caused by the disconnection of certain power plants. Therefore, the Table 3-1 reports the sequence of events based on the information available to the Expert Panel20, noting that some additional generation or load trips may be missing.’

Etc…