Resilience

Iberian Grid Blackout: Microgrids and Backup Power Helped Mitigate the Harm for Some Mission Critical Sites

April 29, 2025

Spanish airport network AENA reported that backup power kept many terminals operating despite the peninsula-wide outage.

Rod Walton

6810fccc06fb1036b638e07a Iberian Map Dreamstime

The sudden and nearly cataclysmic grid blackout across Spain and Portugal this week is one of the worst power outages in history in terms of capacity knocked offline and lives impacted.

The potentially deadly and economically devastating impact, however, was somewhat muted compared to historic grid outages such as the Northeast Blackout in the U.S. 22 years ago and the India blackout of 2012. More than 50 million customers and businesses throughout Spain and Portugal were forced into a standstill without power, but a host of mission critical facilities carried on despite the broken interconnection.

Why? Quick and decisive action by grid operators, but also some impact from deploying microgrids and backup power at least in the service of air travel. A report on The Conversation website noted social media tweets by Spanish airport network AENA indicating that its airports were operating with backup power, although the outage invariably caused delays.

The Conversation story also highlighted the fast intercommunication between Spanish and Portuguese grid operators to isolate the blackouts for the benefit of the entire system. Exact cause of the Iberian Peninsula-wide outage was not certain, although some leaders pointed to “atmospheric vibration” and voltage fluctuation.

Four years ago, the Texas grid, managed by the Electric Reliability Council of Texas, was minutes away from a systemwide outage after close to 52 GW of power generation—including gas-fired, renewable and nuclear power—was knocked offline due to freezing weather conditions and other factors. The Atlanta airport power blackout of 2017 caused a ripple effect throughout the U.S. and some $100 million in losses for Delta Airlines and others. This led to a nationwide move toward investing in airport microgrids.

Since then, Texas has scaled up its installation of distributed energy, battery storage and commercial microgrids. The 2025 Microgrid Knowledge Conference earlier this month was held in Dallas.

Across the Atlantic, Spain Prime Minister Pedro Sanchez estimated the nearly instantaneous loss of power capacity on the grid at close to 15 GW, more than half of national demand. Both Spain and Portugal have been proponents of renewable energy projects, and various news reports indicate that both national grids were sourcing most of their power capacity from solar and wind.

The intermittency of these resources can cause variances in capacity and threaten voltage regulatory and frequency on the transmission and distribution grids. Only a few days earlier, Spain celebrated a milestone with powering 100 percent from wind, solar and hydro on April 16.

The grid outage, if attributable primarily to fluctuations renewable energy capacity, may point to the need for a scaling up of battery storage capacity on the Iberian electricity delivery systems.

Spain reportedly has only 60 MW of battery storage capacity which could help respond to intermittencies in the renewable generation, while the United Kingdom has nearly 6 GW and the U.S. has close to 26 GW of installed battery storage capacity, according to a new story in the journal National Interest. Spain has plans to increase that battery installed capacity to 22 GW by 2030, although that will require billions in investment.

Portugal’s mainland also suffered from the blackout, as well, but the energy provider Electricidade dos Açores several years ago installed a microgrid on the Azores island of Terceira. The microgrid project included Siemens' Spectrum Power Microgrid Management System (MGMS) software and a 15-MW battery-based energy storage system from Fluence.

About the Author

Rod Walton | Managing Editor

For Microgrid Knowledge editorial inquiries, please contact Managing Editor Rod Walton at [email protected].

I’ve spent the last 15 years covering the energy industry as a newspaper and trade journalist. I was an energy writer and business editor at the Tulsa World before moving to business-to-business media at PennWell Publishing, which later became Clarion Events, where I covered the electric power industry. I joined Endeavor Business Media in November 2021 to help launch EnergyTech, one of the company’s newest media brands. I joined Microgrid Knowledge in July 2023.

I earned my Bachelors degree in journalism from the University of Oklahoma. My career stops include the Moore American, Bartlesville Examiner-Enterprise, Wagoner Tribune and Tulsa World, all in Oklahoma . I have been married to Laura for the past 33-plus years and we have four children and one adorable granddaughter. We want the energy transition to make their lives better in the future.

Microgrid Knowledge and EnergyTech are focused on the mission critical and large-scale energy users and their sustainability and resiliency goals. These include the commercial and industrial sectors, as well as the military, universities, data centers and microgrids. The C&I sectors together account for close to 30 percent of greenhouse gas emissions in the U.S.

Many large-scale energy users such as Fortune 500 companies, and mission-critical users such as military bases, universities, healthcare facilities, public safety and data centers, shifting their energy priorities to reach net-zero carbon goals within the coming decades. These include plans for renewable energy power purchase agreements, but also on-site resiliency projects such as microgrids, combined heat and power, rooftop solar, energy storage, digitalization and building efficiency upgrades.