The major Iberian blackout: what happened and what lessons should we take from it?
Published on 5 May 2025 by Catarina Costa
- Storage & Backup
- Energy Transition
In this post
On Monday, 28 April 2025, Portugal and Spain experienced one of the largest power outages in recent decades.
In an instant, millions of people were left without electricity and the Iberian Peninsula revealed structural weaknesses that cannot be ignored, especially at a time when the energy transition is moving forward at a fast pace.
At Enbiente, we follow these events closely, because understanding the risks facing the energy sector is essential to ensuring a more sustainable, stable and secure future for everyone.
What caused the blackout?
According to information released by energy authorities, the blackout was caused by a sudden loss of around 15 GW of electricity generation in just five seconds.
That drop created a serious voltage fluctuation in the grid, destabilising the entire Iberian electricity system.
Investigations are still ongoing, but the first indications point to a combination of factors:
- Adverse weather conditions
- High injection of solar and wind energy, both intermittent sources
- Failure in backup response and frequency regulation
The result was a temporary collapse of the grid, with a direct impact on hospitals, transport, industries and thousands of homes.
Portugal and Spain’s energy interdependence
The blackout revealed a structural vulnerability: Portugal’s dependence on Spanish electricity.
At the time of the incident, Portugal was importing around one third of the electricity it consumed.
When the Spanish system collapsed, Portugal had to temporarily suspend interconnections and operate in isolation, with immediate costs.
Price volatility
With less energy available and no possibility of importing, electricity prices rose sharply.
For several days, the price of electricity in Portugal was up to four times higher than in Spain.
This impact was felt by both households and companies, especially those with high energy consumption.
The fragility of the Iberian “energy island”
Portugal and Spain are often described as an “energy island” because of their weak electrical connection to the rest of Europe.
Currently, the interconnection with France is only 2%, far below the European target of 15%.
This means that, in emergency situations, the Iberian Peninsula cannot rely on immediate support from other European countries.
The lack of redundancy and diversification makes the system more vulnerable to failures like the one we experienced.
What now? What can and should we do?
The blackout showed that the energy transition is not only about clean energy, but also about resilience, planning and stability.
At Enbiente, we believe the energy future depends on four fundamental pillars.
1. Strengthening electrical interconnections with Europe
More interconnections mean greater security and flexibility, reducing the risk of cascading failures.
2. Investing in energy storage
Residential and industrial batteries help stabilise the grid and guarantee energy even when there is no solar or wind generation.
3. Deploying decentralised and intelligent solutions
Self-consumption with batteries, energy management systems (EMS) and smart electric vehicle charging are key tools for a more balanced grid.
4. Educating and empowering consumers
Energy literacy is essential so that every citizen and company can contribute to a more stable and sustainable grid.
The future can be different
The major Iberian blackout is a warning, but also an opportunity.
It showed us that renewable energy needs intelligence, redundancy and storage to become truly sustainable.
At Enbiente, we work every day to build that future, developing and implementing solutions that combine generation, storage and intelligent energy management.
Because a prepared energy system is not one that never fails, but one that, even in the face of failures, continues to guarantee clean, affordable and reliable energy.
Shall we build a more resilient future together?
If you want to make your home or company better prepared for the energy future, talk to us.
We provide complete self-consumption, battery and intelligent energy management solutions, designed to deliver autonomy and security in any scenario.
