Half a million Portuguese customers lose power at once
The test Between 28 Oct 2026 and 27 Oct 2027, at least 500,000 electricity customers (delivery points) in mainland Portugal are without power at the same time, from any cause (weather, grid failure, cyberattack or sabotage), as reported by E-Redes, REN or the government.
Not under way · Confidence: medium · Reviewed 28 Oct 2026 · Scores from 1 to 10
This page answers: What could happen, how it is scored, and who is exposed?
Using this page
- Read the two scores: Likelihood and Impact are kept apart.
- Check what is happening, each fact with its source.
- Use the calendar for the dates to watch.
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Impact is the average of the four parts, rounded, plus one point when Canada is directly hit on two or more channels, up to 10.
Two separate scales from 1 to 10. Strature never multiplies or merges them.
Why it matters
Mainland Portugal has had two mass outages in 18 months: the Iberian blackout of 28 Apr 2025 and Storm Kristin, which left about one million customers without power at its peak in late January 2026. The ENTSO-E experts' final report found voltage-control gaps; Lisbon is adding black-start plants and weighing about EUR 4bn of grid spending.
Why Likelihood 4 Pushes: winter storms; voltage-control gaps found by ENTSO-E experts; voluntary recommendations. Brakes: four black-start plants, battery tender, REN says the fixes are in hand. Two drivers with blockers holding: 4; no cited source on the event side for a 5.
Why Impact 4 Threshold case: 500,000 customers without power for hours to a few days.
The other facts on file (12)
- More than 550,000 customers without power in mainland Portugal on 28 Jan 2026 (headline report, low-confidence source) [1] (28 Jan 2026)
- About one million customers without power at the peak of Storm Kristin (28 Jan 2026); Leiria about 300,000; Kristin brought down 61 pylons and 774 km of very-high-voltage line; distribution grid left 450,000 without power on 29 Jan [2] (29 Jan 2026)
- About 9,000 customers still without power on 17 Feb 2026 (headline report, low-confidence source) [3] (17 Feb 2026)
- E-Redes repair cost after the storms about EUR 110m [4] (24 Jul 2026)
- Electricity back for four million consumers on 28 Apr 2025 (headline report, low-confidence source) [5] (28 Apr 2025)
- E-Redes chair: last 60 kV substation energised 01:00, restoration complete 03:00 on 29 Apr 2025; 95% back by end of day; 'once in a lifetime' [6] (29 Apr 2025)
- ENTSO-E final report: 22 recommendations; more than 2.5 GW tripped; loss of synchronism 12:33:19; several conventional plants below 75% of requested reactive power at critical moments [7] (20 Mar 2026)
- ENTSO-E published the expert panel's final report on the 28 Apr 2025 grid incident in Spain and Portugal on 20 Mar 2026 [12] (20 Mar 2026)
- Portuguese and Spanish voltage ranges differ; experts recommend harmonising them [8] (21 Mar 2026)
- ERSE: ENTSO-E final report published 20 Mar 2026; recommendations voluntary [9] (20 Mar 2026)
- All four black-start plants kept in service, where REN's earlier tender would have replaced two; battery tender raised to EUR 180m with recovery-plan money; about EUR 4bn grid investment on the table, not decided; minister: no country is prepared to remove the risk [10] (15 Apr 2026)
- REN: no Portuguese plant tripped before the point of no return; REN: none of the panel's recommendations (about 20, in REN's count) is new for Portugal; REN said the blackout began in Spain [11] (20 Mar 2026)
Where it sits
Where this risk sits
Size shows Impact. Colour shows the Likelihood band. The two scores are never combined.
- Low 1–3
- Elevated 4–6
- High 7–8
- Severe 9–10
- Bigger circle: higher Impact
- Solid ring: under way
- Red ring: highest Impact on this map
- Where it starts
- Who it reaches
The risk on this map
- Half a million Portuguese customers lose power at onceImpact 4 of 10, Elevated. Likelihood 4 of 10, Elevated. · Portugal
How it spreads
Between 28 Oct 2026 and 27 Oct 2027, at least 500,000 electricity customers (delivery points) in mainland Portugal are without power at the same time, from any cause (weather, grid failure, cyberattack or sabotage), as reported by E-Redes, REN or the government.
Not under wayChannels 5 on the card
- CanadaNo Canadian exposure found.
- Daily life and healthHospitals, care homes and fire stations need backup power [10].
- BusinessRetail, payments, factories, rail and telecoms stop [11].
- Grid billsGrid programme and black-start contracts carry tariff costs [10].
- SpainA grid-borne event would likely be Iberian; REN said on 20 Mar 2026 that the 2025 blackout began in Spain [11].
Three scenarios and their signposts
- S1
A quiet year
Storms cause local outages below the line; grid upgrades proceed.
- S2
Storm repeat
A winter storm cuts power to 500,000 or more for hours to days, as Kristin did.
- S3
Grid event
A voltage or protection failure trips a large part of the Iberian system again.
| Path | Signpost |
|---|---|
| S1 | No E-Redes count above 500,000 |
| S2 | An IPMA red warning for wind over the centre |
| S3 | A REN or Red Electrica incident report on voltage swings |
No probability is given for the three paths.
Dates to watch
The dates to watch
A dot is a day, a bar a month or a year; a hollow mark is tentative. The line marks today.
- Nov 2026 Winter storm season opens (Kristin struck on 28 Jan 2026) [2] Tentative · Window
- 27 Oct 2027 End of the scored window Declared · Strature date
Sign in, with alerts on, for an email 7 days and 1 day before.
The other side
Grid spending, batteries and black-start plants are a market for Portuguese contractors and storage makers. Better voltage control from solar plants lets more renewables run safely.
Connected in Strature
- Portugal
- Spain
- A state-linked cyber attack cuts power, water or a port for a day or more Shares a channel: An attack on grid control systems is one cause that counts.
- Ransomware halts a major port, hospital network or pipeline for three days or more Shares a channel: Same channel: utilities as targets.
Sources
12 sources, numbered as the text cites them
- Mais de 550 mil clientes estao sem eletricidade em Portugal continental. Radio Renascenca · 28 Jan 2026 · News · confidence low · retrieved 2026-10-28 (headline only)
- Kristin deitou abaixo 61 postes e 774 km de rede de muito alta tensao, mas e a rede de distribuicao que deixa 450 mil sem luz. Observador · 29 Jan 2026 · News · confidence medium · retrieved 28 Oct 2026
- Tres semanas depois, cerca de 9 mil clientes continuam sem luz nas zonas afetadas. Radio Renascenca · 17 Feb 2026 · News · confidence low · retrieved 2026-10-28 (headline only)
- Mau tempo: E-Redes com custo de cerca de 110 milhoes de euros na reposicao da rede de energia. Observador (Lusa) · 24 Jul 2026 · News · confidence medium · retrieved 28 Oct 2026
- Apagao em Portugal. Eletricidade regressou para 4 milhoes de consumidores. Radio Renascenca · 28 Apr 2025 · News · confidence low · retrieved 2026-10-28 (headline only)
- Apagao. E-Redes afasta responsabilidades na distribuicao de energia e aponta dependencia da REN. RTP · News · confidence medium · retrieved 28 Oct 2026
- Entso-E report finds systemic failures behind 2025 Iberian blackout. pv magazine · 23 Mar 2026 · Industry · confidence medium · retrieved 28 Oct 2026
- Without blaming anyone for the blackout, experts recommend improving monitoring, coordination and regulation. ECO News · 21 Mar 2026 · News · confidence medium · retrieved 28 Oct 2026
- Investigacao do Grupo de Peritos da ENTSO-E ao apagao iberico de 28 de abril de 2025: relatorio final. ERSE · 20 Mar 2026 · Official · confidence high · retrieved 28 Oct 2026
- Minister on blackout measures, black-start plants and grid investment (Lusa). Lusa via AMAN Alliance · 16 Apr 2026 · News · confidence medium · retrieved 28 Oct 2026
- REN says ENTSO-E report confirms blackout began in Spain (Lusa). Lusa via AMAN Alliance · 21 Mar 2026 · News · confidence medium · retrieved 28 Oct 2026
- Final Report on the Grid Incident in Spain and Portugal on 28 April 2025. ENTSO-E · 20 Mar 2026 · Official · confidence high · retrieved 28 Oct 2026
Reviewed 28 Oct 2026 · version 1 · last change: first review · All risks