By Anders Lorenzen

In April, a severe power outage impacted Spain and Portugal.

In the immediate aftermath, some commentators and analysts were quick to blame the outage on renewables without supporting their claim with evidence. 

But last month, following an investigation of the Spanish and Portuguese blackout which shut down critical infrastructure for several hours, the Spanish government unveiled a different cause.

An overvoltage on the Spanish electrical grid had triggered a chain reaction, the government said in a statement.

According to Ecological Transition Minister Sara Aagesen, the Iberian power outage had multiple causes, and on the day of the outage, the Spanish energy grid system lacked sufficient voltage control capacity.

What is overvoltage?

Overvoltage occurs when there is too much electrical voltage in a network, causing it to overload equipment.  Failure can happen when there is an oversupply in networks, or if there are lightning strikes, or an insufficiency of protective equipment.

When a grid network is hit with overvoltage on protective systems, parts of the grid are shut down, leading to widespread power outages.

Aagesen criticises the Spanish electricity sector

Aagesen criticised the Spanish grid operator, REE, and individual energy companies, though she did not name them. She said they disconnected their plants inappropriately to protect their installations.

She added that, in theory, the Spanish energy grid should be robust enough to handle overvoltage problems, but a flaw in the programming prevented it from doing so.

Calling them misjudgements, she explained, “We reached a point of no return with an uncontrollable chain reaction”. She underlined that it would have been managed if only steps had been taken beforehand to absorb the overvoltage problems.

Aagesen said that the findings conclude an analysis by an inquiry commission launched by the Spanish Prime Minister, Pedro Sanchez, in the aftermath of the incident. 

Aagesen also stressed that the objective of the inquiry was not to point fingers but to examine the root causes and make recommendations.

Aagesen dismisses theories

Aagesen also wanted to rule out some of the speculations about the cause of the incident. In addition to unfounded theories and myths about excess renewable energy production, a cyberattack was also touted as an explanation. 

Aagesen dismissed those theories, acknowledging that vulnerabilities and deficiencies had been found in the Spanish grid’s security systems.

The power outage: A political football

The 28th of April power outage impacted Spain, Portugal, and briefly southwestern France. It had become a bit of a political football as the Spanish government scrambled to figure out the cause. The right-wing opposition had laid the blame on the phase-out of nuclear power and the over-reliance on renewables, arguing that this made Spain more vulnerable to blackouts.

This was also denied by the government, saying there was no evidence to back up such claims.

The report`s recommendations include stronger supervision and compliance requirements on operators, increasing overall electrical capacity, and boosting the country’s grid connections with neighbouring countries.

Critics have argued that the outage exposed Spain and Portugal’s relative lack of interconnections, especially as France and Morocco played a crucial role in restoring power.

Unconnected to the Spanish report, the European Investment Bank announced funding worth €1.6 billion last month for a significant electricity interconnection between France and Spain. Upon completion, it will deliver a doubling of power exchange capacity.

Anders Lorenzen is the founding Editor of A greener life, a greener world.