Media & news

Last month I wrote about the April 28 electrical blackout that affected most of Spain and Portugal. The primary theme of that article was that PowerSouth emphasizes electric reliability more than some states, regions, or countries. This month, I will discuss more about what happened with the Iberian blackout — and why it will happen again. But, first, I need to bore you for a few minutes.

Transmission grids are remarkable machines. They operate at very precise frequencies, and many are interconnected. Spain’s and Portugal’s transmission grids are interconnected. The U.S. has three separate transmission interfaces which are not interconnected with each other: ERCOT, which connects most of the electric utilities in Texas, the Eastern Interconnect that connects all utilities east of the Rocky Mountains, and the Western Interconnect that connects all utilities west of the Rocky Mountains. All generation within an interconnection not only operates at the same frequency — 60 Hertz in the U.S. and 50 Hertz in Europe —but the magnetic poles of the generators within an interconnected grid are completely synchronized.

The frequency and strength of the transmission grids are supported by the inertia of large, spinning, and synchronized generators — primarily powered by coal, natural gas, hydroelectric and nuclear generation. Solar and wind generation do not have the rotating mass of the spinning generators. Instead of synchronizing with the spinning generation, renewable energy is absorbed and accepted by the grid, so long as the grid’s frequency is not disrupted. The Mid-American Independent System Operator (MISO), which operates a large transmission grid in the Midwest, has expressed that introducing non-rotating generation, at levels of 30% of the total generation, can potentially disrupt or destabilize the transmission grid.  

Advanced synthetic frequency inverters and capacitors can be added to renewable generation facilities to provide a form of system inertia; however, these systems are costly, and most developers do not use them. If the power grid’s frequency deviates beyond normal limits, system protection devices step in and separate parts of the power grid to prevent the generators, or the grid itself, from being destroyed.

The Spanish government has pursued an aggressive renewable energy policy for years, forcing Spain’s electric utilities to build wind and solar generation and scale back fossil fuel and nuclear generation. Ironically, a week prior to the blackout, Spain bragged that, for the first time, renewable generation provided 100% of its electricity for a few minutes.

The Iberian blackout was the largest and most wide-spread blackout in European history, affecting approximately 55 million people in Spain and Portugal. People were stranded on trains for hours, traffic flows were thrown into chaos when traffic lights went out, hospital services were disrupted, many business transactions were interrupted and other critical services were abruptly cancelled in progress. Many people were panicked, thinking Spain had come under a foreign attack. Emergency service agencies were called on to rescue stranded people, straighten out traffic jams, and attempt to restore civil order in larger towns and cities. At least five people died due to the blackout and others suffered health issues without basic social services.

Prime Minister Sánchez acknowledged the seriousness of the situation and pledged to investigate the root cause of the blackout. He stated that the government was not ruling out any possible explanations, including cyberattacks. Despite employing criminal investigators and transmission grid experts, the Spanish government still hasn’t issued a statement on the blackout’s cause.    

However, Madrid was warned before the blackout. Red Electrica, the parent company of Spain’s grid operator, stated in February: “The high penetration of renewable generation without the necessary technical capabilities in place to keep them operating properly in the event of a disturbance . . . can cause power generation outages, which could be severe.” At the time of the collapse, the weather was mild, electric loads were relatively low, and the sun was shining. The Iberian grid was powered by 74% renewable energy – 55% of it provided by solar. With mild weather and low electric loads, the collapse was not caused by extreme, weather-driven loads with a power supply deficit, like what happened with Winter Storm Uri, which blacked out areas of Texas in 2021, or with the winter power supply shortage across TVA and MISO a couple Christmases ago.

There is almost no other reason for the blackouts other than the grid was totally dependent on non-rotating, renewable generation, which was disrupted for some reason. Without the spinning inertia that traditional generators provide to help stabilize the grid, the renewable generation was rejected by the grid, causing an under-frequency event across the transmission system. System protection devices deployed under-frequency actions in an effort to protect the grid by separating load from the grid, until there was a total collapse.

Yet the Spanish government is still in denial. While admitting that he didn’t know the cause of the blackout, Prime Minister Sánchez insisted there was no empirical evidence that renewables were to blame. He further stated that Spain is “not going to deviate a single millimeter” from its green energy ambitions.

And, that is why it will happen again. Despite evidence that the blackout was caused by too much renewable generation, the Spanish government will stick to its green energy programs, which will subject Spain (and Portugal because they are a part of the same transmission grid) to more blackouts in the future. Also, because the politicians’ futures are based on hiding the reasons for the blackout, this will be the last thing you will hear about it. I hope that if we are faced with similar decisions, we will have more honest answers than the Spanish government.

I hope you have a good month.