Experts speculate over cause of Iberian power outages

Nationwide power shortages brought chaos to Spain and Portugal this Monday (28^th April): crippling mobile networks, bringing airports and rail networks to a standstill and leaving millions without electricity.  

And whilst power is now gradually being restored across most of the affected areas, the initial cause of the blackouts remain unclear, with some experts cautioning that it could take many weeks, or even months, to complete a full investigation.

Unsurprisingly, when news of the outages broke many suspected foul play and whilst Spanish PM Pedro Sanchez confirmed that he had spoken to NATO secretary general Mark Rutte, his Portuguese counterpart Luis Montenegro, along with European Council president Antonio Cost, have played down the possibility of a cyberattack.

There has also been speculation - following a BBC interview with Portuguese energy company REN - that the outages may have been caused by a phenomenon called ‘induced atmospheric vibration,’ where extreme temperature variations cause oscillations (known as galloping) in high-voltage transmission lines that can alter their electrical properties and lead to potential mechanical failure and damage. 

According to David Brayshaw, Professor of Climate Science and Energy Meteorology, University of Reading,  if this is identified as a cause, it will underline the need for greater research into the impact of climate change on power systems. “If this event was indeed driven by atmospheric conditions, it underlines the urgent need for much deeper investigation into climate risks for power," he said.

However, experts have cautioned against jumping to conclusions that a single factor is to blame. “Due to the complexity of the interconnected power system, a proper investigation will take time, said Prof Keith Bell, Professor of Electronic and Electrical Engineering, at the University of Strathclyde. “The explanation of ‘induced atmospheric vibration’ still needs to be verified. The real cause could be very different. We must wait for detailed professional analysis.”

Whilst the cause is still unknown, what is clear is that the scale of the issue, and the speed with which it occurred is a direct result of the interconnected nature of the power grids in the EU, which - in normal circumstances - typically help boost the resilience of European energy supplies.

“Spain and Portugal’s electricity grids are highly interconnected with each other and with the wider European system,” said Prof Jianzhong Wu, Professor of Multi-Vector Energy Systems, University of Cardiff. “This interconnectedness provides resilience under normal conditions but can also allow disturbances to spread quickly if a major synchronisation failure occurs. In this case, the disruption appears to have propagated rapidly through the Iberian Peninsula.”

Prof Wu explained that in such a scenario it's possible that rather than a single incident the fault has been caused by a series of  small disturbances - such as equipment failures, human error, weather events and cyberattacks – which have interacted and cascaded across the grid.

Whatever the cause, the incident has brought into stark focus the challenges of managing increasingly complex power grids and engineers will be keen to learn lessons from the events of the past couple of days. “Incidents like this underline the complexity of managing modern energy systems, particularly as they integrate increasing levels of renewable energy…alongside traditional sources…., face growing energy demand, and contend with some ageing infrastructure,’ said Prof Victor Becerra, Professor of Power Systems Engineering at the University of Portsmouth. "Events like this are rare, but they demonstrate the importance of robust grid management, investment in infrastructure, and regional cooperation to ensure resilience against technical failures and external threats."