Lisbon at night during a prolonged blackout

Power outages and blackouts

The most common emergency scenario in Portugal. Learn how to prepare and what to do when the lights go out.

28 April 2025: the day the Iberian Peninsula went dark

At around 11:33 (mainland Portugal time; 12:33 in Spain), a cascading failure in the Iberian electrical system shut down almost the entire grid in Portugal and Spain within seconds. More than 50 million people lost power: traffic lights out, trains stopped between stations, hospitals running on generators, payment terminals and ATMs offline, telecommunications degraded. Restoration took between 6 and 20 hours depending on the region. The lessons from this blackout are reflected throughout this guide.

Why power outages happen in Portugal

  • Storms and strong winds: the most frequent cause of power outages. Trees fall onto power lines and poles, interrupting supply
  • Wildfires: damage high and medium voltage lines, especially in inland areas during summer
  • Grid overload: heat waves cause consumption spikes (air conditioning, fans), which can overload transformers
  • Scheduled works and maintenance: the distributor may interrupt supply for network works, usually with advance notice
  • Distribution network failures: transformer breakdowns, damaged underground cables or substation problems
  • Iberian system-wide failures: frequency instability on the European grid or sudden loss of generation can trigger cascading blackouts (such as the one on 28 April 2025). These are very rare but affect millions at the same time
  • Cyberattacks on critical infrastructure: a growing threat. See the cybersecurity guide

Lessons from the 28 April 2025 Iberian blackout

The Iberian blackout was the largest power outage in Europe in two decades. These were the real failures that caught people in Portugal off guard, and the ones you should resolve before the next event:

What did not work

  • Payments: Multibanco, POS terminals and ATMs became unavailable. Anyone carrying only a card could not buy anything
  • Telecommunications: calls and data degraded as mobile towers ran out of power (batteries last 2-8 hours). Some areas lost coverage within 1-2 hours
  • Urban traffic: traffic lights out, chaos in the major cities. Trains and metro stopped (Lisbon and Porto)
  • Water in tall buildings: electric pumps stopped. From the 5th floor upwards, water started running out within a few hours
  • Fuel: petrol station pumps do not work without electricity. You could not fill up during the blackout
  • Toll payments: Via Verde kept the records, but many offline systems caused long queues

What kept working

  • Piped natural gas and bottled gas (cooking still possible)
  • Gravity-fed water on the lower floors (rooftop tanks)
  • Antena 1 FM and battery/wind-up radios: the main source of official information
  • Hospitals on emergency generators (but with limited autonomy of 24-72 hours)
  • Corded landline phones (not cordless ones) in some areas
  • Bicycles and walking: the only reliable way to get around the cities

3 changes to make right now

  1. Always keep €50-100 in small notes at home (notes of €5 and €10, not just €50)
  2. Fill 5-10 water containers if you live above the 4th floor (pumps stop in long blackouts)
  3. Never let your car fuel drop below half a tank. Refilling at half is a basic preparedness rule

Before the blackout: preparation

Lighting and communication

  • At least 2 torches with spare batteries (avoid candles, fire risk)
  • Battery or wind-up radio to listen to Antena 1 FM and receive official information
  • Charged power bank to keep your mobile phone operational

Backup power

Basic necessities

  • Water reserve: the water pump may stop without electricity (see water calculator)
  • Foods that don't need cooking: tinned food, biscuits, dried fruit, energy bars
  • Cash in notes: ATMs and payment terminals don't work without power
  • Extra blanket in winter: central heating stops working

During the blackout

DANGER: Carbon monoxide

Never use generators, barbecues or camping stoves indoors, in the garage or any enclosed space. Carbon monoxide is odourless and can kill in minutes. If using a generator, keep it at least 6 metres from the house, in a ventilated area.

Equipment and electricity

  • Unplug sensitive electronic equipment (computers, TVs, gaming consoles) to avoid damage when power returns
  • Leave one light on to know when power returns
  • Use torches instead of candles (fire risk, especially with children and pets)
  • If using a generator, keep it at least 6 metres from the house, in a ventilated area

Food and communication

  • Keep fridge and freezer closed: fridge safe for up to 4 hours, full freezer up to 48 hours (see calculator)
  • Don't open fridge/freezer doors unnecessarily
  • Listen to Antena 1 FM (regional frequencies) for official information
  • Keep at least one corded landline phone (works without electricity)

Check on vulnerable neighbours

Elderly people, those with reduced mobility or dependent on electric medical equipment (oxygen, CPAP) may be in danger during a prolonged blackout. Check if they need help, especially during cold or heat waves.

Timeline of a prolonged blackout

What to expect as the blackout drags on. Use this timeline to anticipate problems rather than react to them.

0 – 1 hour

  • Confirm it is not a tripped circuit breaker at home: check neighbours and street lighting
  • Report to E-REDES: 800 506 506 if the outage is local
  • Unplug sensitive electronics (computer, TV, gaming console)
  • Leave one lamp switched on so you know when power returns
  • Fill bathtubs and containers while water is still running (tall buildings lose pressure fast)
  • Turn on an AM/FM radio for official information (Antena 1)

1 – 6 hours

  • Telecommunications start to degrade (towers have limited battery)
  • Fridge still safe if you keep the door closed
  • Traffic chaos if it falls in rush hour (traffic lights out)
  • ATMs and POS terminals stop working — use physical cash
  • Reduce phone battery usage: aeroplane mode + minimum brightness
  • Cancel or postpone non-essential trips

6 – 12 hours

  • Fridge close to the safety limit (4 hours as a rule of thumb)
  • Hospitals still operating (generators), A&E departments overcrowded
  • Fuel starts running out (pumps stopped, tanks not being refilled)
  • Difficulty getting reliable information: social media unavailable
  • Water pumps in tall buildings may have stopped: save water
  • Night-time lighting becomes a problem if the blackout runs into the evening

12 – 24 hours

  • A half-empty freezer starts thawing (~24 hours without power)
  • Central heating/air conditioning off for hours: indoor temperature affects vulnerable people
  • Refrigerated medication (insulin) at risk — see techniques further down
  • Social tension rises in urban areas (supermarkets closed or cash only)
  • Check on elderly neighbours in person: phones do not work
  • Decide whether to relocate to relatives who still have power

24 – 48 hours

  • A full freezer approaches its 48-hour limit
  • Hospitals overstretched: generator fuel runs out if not resupplied
  • Basic sanitation systems may fail (sewage pumping stations)
  • Risk of gastrointestinal outbreaks if the water supply is no longer being treated
  • Cold washes or hygiene with wipes (save water)
  • Consider relocating to areas with power if contacts are available

48 – 72+ hours

  • Almost all refrigerated food has spoiled
  • Drinking water reserves critical — use purification techniques
  • Chronically ill patients (oxygen, dialysis) at serious risk
  • Consider reception centres (town hall, schools, churches)
  • Never use barbecues or generators indoors (CO kills in minutes)
  • See the guides on water purification and cooking without the grid

Communications when the towers go down

During the April 2025 blackout many people realised for the first time that a mobile phone does not replace other ways of communicating. Mobile towers have batteries lasting only 2-8 hours — after that, calls and data stop working even if your phone is fully charged.

AM/FM radio (essential)

  • Works for decades in a prolonged blackout
  • Antena 1 FM: regional frequencies vary (keep a printed list at home)
  • Battery-powered radios (AAA/AA) — keep 4-8 spare batteries
  • Wind-up radios: 1 minute of cranking = 30-60 minutes of listening
  • Solar radios: useful in a summer blackout
  • Cost: €15-40

Corded landline phone

  • Corded phones (not cordless) work without mains electricity — the traditional phone line carries its own power
  • Cordless DECT phones need power for the base station — they do not work
  • Check whether you still have an analogue landline (many homes only have VoIP, which goes down with the router)
  • Keep a corded phone in a drawer for emergencies
  • Cost: €10-20

PMR446 radios (family use)

  • Licence-free walkie-talkies, legal throughout the EU
  • Practical range: 1-3 km in urban areas, 5-10 km in open country
  • Communicate with family nearby (school, work within a short distance)
  • Agree on a channel and times in advance (e.g. channel 8, on the hour)
  • Rechargeable or alkaline AA batteries
  • Cost (pair): €30-60

Apps that work without internet

  • Offline maps: Google Maps (download the area beforehand), OsmAnd, Maps.me — they work with GPS without a network
  • Antena 1 / RTP Play: only work with a network. That is why a physical AM/FM radio cannot be replaced
  • Bluetooth mesh: apps such as Bridgefy or Briar create networks between phones without internet (Bluetooth range, a few dozen metres)
  • Notes, torch, calculator, compass, converter built into the phone all work offline
  • Scanned documents stored locally (not in the cloud) — save them as photos beforehand

Payments, water in apartment blocks, and gas

Payments without a terminal

  • Physical cash in small notes (€5 and €10) — without change, shops will turn you away
  • Recommended: €50 to €100 per adult, kept in different places
  • Withdraw cash before a severe weather warning is issued
  • ATMs with generators: central bank branches and shopping centres (but expect queues)
  • Some neighbourhood grocery shops kept manual tabs — a relationship of trust helps

Water in tall buildings

  • Most apartment blocks rely on electric pumps to push water above the 5th floor
  • Without electricity, water runs out within 2-6 hours on the upper floors
  • Fill the bath and water containers in the first 30 minutes of the blackout
  • Set aside at least 3 litres per person per day for drinking and cooking
  • For flushing the toilet: a bucket with water, 5 litres per flush
  • See the water calculator

Gas (cooking and heating)

  • Piped natural gas: normally keeps flowing during blackouts (the network has its own pressure)
  • Bottled gas (propane/butane): completely independent of electricity
  • Hobs with electric ignition: light with a match or lighter
  • Modern gas water heaters do NOT work without electricity (they need an electronic board)
  • Portable gas heaters: only in ventilated rooms (CO)
  • See cooking without the grid and heating without the grid

Food safety during blackouts

Safety timings

  • Closed fridge: food safe for up to ~4 hours
  • Full freezer: food safe for up to ~48 hours
  • Half-full freezer: food safe for up to ~24 hours
  • Food with ice crystals still visible can be safely refrozen

Safety rules

  • When in doubt, throw it out. Never taste to test if it's good
  • Meat, fish, dairy and eggs: discard if above 4 °C for more than 2 hours
  • Use a cooking thermometer to check food temperature
  • See complete guide: food safety

After the blackout

Immediate checks

  • Check food in the fridge and freezer (4h/48h rule)
  • Turn on equipment gradually, not everything at once to avoid overloading the grid
  • Check clocks and timers (they may have lost time)
  • Check for damage to electronic equipment (voltage spikes when power returns)

Restore supplies

  • Replace used batteries in torches and radio
  • Charge power banks and power stations
  • Restore water, food and generator fuel reserves
  • Note the duration of the blackout for future reference and complaints

Useful contacts

Distributors

  • E-REDES (national power grid operator): 800 506 506
  • SU Eletricidade (Endesa): 800 800 635
  • EDP Comercial: 800 505 505

Emergency

  • 112: European emergency number
  • ANEPC (Civil Protection): 214 247 100

More information

Related tools

Generator calculator

Select your equipment and find out what generator you need and how much it costs.

Battery runtime

Calculate how long your power station will power essential equipment.

Freezer runtime

Calculate how long frozen food will last without electricity.

Food safety

Complete guide on how to keep food safe during and after a blackout.

Emergency safety

Carbon monoxide, electrical safety, fire and document protection.

Be prepared, not scared

Most power outages in Portugal last just a few hours. But prolonged blackouts (24 to 72 hours or more) can happen during severe storms or fires. Having a plan and the right materials transforms an emergency into a manageable inconvenience. Start with the preparation checklist.