Questions over power supply remain as Spain recovers from blackout

RTÉ News​

29-04-2025

At around 12.30pm local time, there was a sudden and devastating problem on a Spanish power line.
In five seconds, the Iberian network lost 15 GW of power, approximately 60% of normal consumer demand.
The sudden blackout crippled transport networks, shut cash machines, knocked out traffic lights and switched off thousands of computers.
The problem spread to Portugal and France.
Spain's main business lobby CEOE estimates the outage will cut €1.6 billion of GDP with the meat industry estimating losses of up to €190 million as fridges lost power.
The slump in power generation went beyond what the electrical systems are designed to handle and the Spanish grid was disconnected from the European system.
The system then collapsed, leading to voltage losses in the supply points of both the Spanish and Portuguese Peninsula's electrical systems, according to grid operator Red Eléctrica.
The authorities have been adamant that they will get to the source of the problem.
Eduardo Prieto, operations director for Red Eléctrica, said there was no evidence of a cyber attack.
"We have been able to conclude there was no intrusion in our electricity grid control system that could have caused the incident," Mr Prieto said.
Despite this, the country's High Court said it would investigate whether the grid had suffered a terrorist strike.
Spanish Prime Minister Pedro Sanchez has not ruled out any possible cause at this point.
Europe's energy providers are tightly integrated, with power flowing back and forth across the continent according to generation and demand.
Spain and Portugal have a series of interconnectors with France, although both sides of the Pyrenees have been in negotiation for years over increasing that number.
The most common cause of unplanned and large scale power cuts is extreme weather such as storms, lightning strikes or high winds.
Faults at power stations, power distribution lines, substations or other parts of the electricity transmission system or grid can also trigger major outages.
The initial suggestion by Spain's energy network is that exceptional temperatures on one part of the grid may have triggered what are called "induced atmospheric vibrations".
A surge in power caused by such "oscillations" can cause one line to "trip".
If that happens, then the current running through the line is split and diverted into two adjacent lines.
Those lines in turn are suddenly carrying more electricity than normal and the currents are split again, this time over more adjacent lines, with the same build up of excess power.
This results in a cascading effect which can ripple through a region and across borders.
"What happens in Spain can have an impact on other countries and what happens on the other side of continental Europe can have an impact on Spain," says a senior EU official.
On 21 June 2024, two separate incidents hit power lines in the Balkans, causing three hour outages in Montenegro, Bosnia and Herzegovina, Croatia and Albania.
Following an investigation, the European Network of Transmission System Operators for Electricity established that the outages were caused by vegetation touching power lines.
Astonishingly, the incidents happened just 15 minutes apart: one on an overhead line near Podgorica in Montenegro, and the second on a line linking Greece and Albania.
Due to exceptionally high temperatures of over 40 degrees Celsius that month, vegetation had grown beyond the level at which it should have been trimmed.
As a result of the investigation, new recommendations were introduced on the need to properly keep vegetation away from power lines.
The initial reports so far suggest that a dangerous cascade is what swept through the Iberian energy network.
Red Eléctrica said there was "strong oscillation in power flow," which triggered "a very significant loss of generation."
Spain is one of Europe's biggest producers of renewable energy and yesterday's shutdown has already sparked debate about whether the volatility of supply from solar or wind made its power systems more vulnerable to such an outage.
Red Eléctrica data showed solar photovoltaic (PV) energy was providing almost 59% of Spain's electricity at the time of the blackout, while wind power was providing nearly 12%.
Energy systems can be vulnerable when combining intermittent renewable power such as wind and solar with traditional sources such as gas and nuclear plants, according to Victor Becerra, a professor of power systems engineering at the University of Portsmouth.
"Whatever the cause, a major failure in one area can place sudden pressure on neighbouring systems, causing protective shutdowns to prevent further damage," he told Reuters.
The Spanish prime minister has ruled out renewable energy as the cause of the problem, while the European Commission has been reticent in attributing blame.
Eduardo Prieto, operations director for Red Eléctrica, said it was "very possible" the outage was linked to solar energy production, according to Spanish media reports.
Either way, the revolution in renewables means national grid operators and EU authorities are having to adapt.
"We need to look at what the causes have been in this case," says one EU official.
"There is the experience we are gaining in new systems as we evolve in the energy transition. These systems are different from the previous ones - that's why you need to manage them in a different manner."
EU officials have said that the evidence coming in so far suggests that whatever happened on the Spanish grid caused the interconnector with France to "trip" as well as local lines, accentuating the problem across the Iberian Peninsula.
When such an outage occurs, the European network is triggered to provide an emergency response to gradually restore power in carefully coordinated phases.
In this incident, Spain relied on the interconnectors with France and Morocco, as well as hydroelectric power, due to its flexibility, to start gradually phasing in energy to reboot the system.
"Typically you start energizing small areas, called islands, and then you start connecting them to each other until the whole system is up [and running]," says one EU official.
Under EU rules, two investigations must now take place.
Having notified the Commission of the emergency, Spain will have to file a report within three months, explaining the cause, the impacts and what remedial measures have been put in place.
In parallel, a technical report is carried out by a panel of experts. This investigation is led by the Transmission System Operators (TSOs) of a member state not affected, with the TSOs from Spain, France and Portugal joining the investigation, as well as other operators interested.
Once both reports have been finalised, the European Commission can make recommendations on lessons learned and any changes which might be needed to the rules operating the European network.
There have been complaints that Spain and France have dragged their feet in boosting the number of interconnectors between the Iberian Peninsula and the rest of the European energy zone.
The EU's High-Level Group on Interconnections for South-West Europe, comprising officials from France, Spain, Portugal as well as neighbouring TSOs, has been attempting to boost the construction of interconnectors.
Interconnection capacity between France and Spain was doubled following the completion of the Santa-Llogaia-Baixas electricity line in 2015, while a transformer in Arkale, Spain, in 2017 brought the line into full capacity during the winter of 2017.
Other interconnectors remain to be completed, including one between Spain and Portugal, expected to be finished by the autumn, and the Biscay Bay electricity interconnection, which is under construction and expected to be commissioned by 2028.
These will double the capacity between France and Spain to 5000 MW when completed.
Two further interconnectors are planned between the Pamplona area in Spain and Cantegrit in France, and between Marsillon in France and the Aragón region.
"Having a more interconnected system in the EU is better for everyone, for market integration, for security of supply," the official said.