The Iberian Blackout Didn’t Stop the Energy Intelligence

On Monday, April 28, 2025, at 12:33 pm local time, an exceptional blackout struck the entire Iberian Peninsula. Approximately 55 million people across Spain and Portugal were left without electricity, with ripple effects felt in southwestern France and disruptions to internet networks in Morocco. The outage, for which the cause is still under investigation, appears to have been triggered by a series of fluctuations in the power grid, which led to the disconnection of the Spanish electrical system from the European network, causing the collapse of the entire Iberian grid.

The consequences were immediate and paralyzing: halted transportation, grounded airports, disrupted communications, and essential services rendered inoperative. Authorities estimated a full restoration time of 6 to 10 hours, declaring a state of emergency and advising residents to stay indoors. Normalcy was gradually restored by the following morning.

This event powerfully highlighted the importance of having energy solutions capable of ensuring continuity, even in the face of widespread grid failures. In this context, residential photovoltaic systems equipped with storage and integrated backup demonstrated their true value, continuing to deliver power throughout the blackout.

The Reliability of the Tigo EI Residential Solution

We examined a sample of ten PV installations in Spain, all equipped with the Tigo EI Residential all-in-one system featuring integrated backup, and monitored through the Energy Intelligence portal. Data from each system clearly shows the exact moment the grid went down, at which point the powerful backup system automatically activated to support the household loads in use at the time.

What makes this solution particularly effective is its ability to allow solar modules to keep producing energy in sunlight, even when the grid is offline. This not only helped reduce the strain on batteries but, in some cases, kept them fully charged and ready for a prolonged outage.

Two Exemplary Cases: EI Residential Installations in Tarragona and Barcelona

Among the systems analysed, two stood out for their particularly noteworthy behaviour:

• In Tarragona: the installation successfully powered the entire home using solar production alone. Additionally, excess energy was used to recharge the batteries (between 3 an 4pm, as shown in the image below), delaying their discharge and maximizing the overall autonomy of the system.

• In Barcelona, the EI Residential system’s batteries remained unused until sunset, thanks to excellent weather conditions that allowed solar production to cover all domestic loads during the day. Only in the early evening did the system begin discharging the batteries, while the grid was still offline. Once grid power returned during the night, the homeowner proactively chose to recharge the batteries from the grid, making the most of the smart battery modes of the Tigo system to prepare for any potential future outages.

Being Prepared Makes All the Difference

The April 28, 2025 blackout was a real-life stress test – not a simulation – of the reliability of photovoltaic solutions with storage and integrated backup. Systems equipped with the Tigo EI Residential Solution proved capable of withstanding a large-scale emergency, keeping essential home loads running, ensuring autonomy, and providing peace of mind to homeowners.

In an era where energy resilience is no longer optional but essential, this event reinforces a clear truth: being prepared makes all the difference. And in the field, Tigo Energy’s all-in-one solution has decisively proven to be up to the challenge.