Sign In or Create an Account.

By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy

Podcast

Spain’s Blackout and the Miracle of the Modern Power Grid

Rob and Jesse go deep on the electricity machine.

The blackout in Spain.
Heatmap Illustration/Getty Images

Last week, more than 50 million people across mainland Spain and Portugal suffered a blackout that lasted more than 10 hours and shuttered stores, halted trains, and dealt more than $1 billion in economic damage. At least eight deaths have been attributed to the power outage.

Almost immediately, some commentators blamed the blackout on the large share of renewables on the Iberian peninsula’s power grid. Are they right? How does the number of big, heavy, spinning objects on the grid affect grid operators’ ability to keep the lights on?

On this week’s episode of Shift Key, Jesse and Rob dive into what may have caused the Iberian blackout — as well as how grid operators manage supply and demand, voltage and frequency, and renewables and thermal resources, and operate the continent-spanning machine that is the power grid. Shift Key is hosted by Robinson Meyer, the founding executive editor of Heatmap, and Jesse Jenkins, a professor of energy systems engineering at Princeton University.

Subscribe to “Shift Key” and find this episode on Apple Podcasts, Spotify, Amazon, or wherever you get your podcasts.

You can also add the show’s RSS feed to your podcast app to follow us directly.

Here is an excerpt from our conversation:

Robinson Meyer: So a number of people started saying, oh, this was actually caused because there wasn’t enough inertia on the grid — that Spain kind of flew too close to the sun, let’s say, and had too many instantaneous resources that are metered by inverters and not by these large mechanical generators attached to its grid. Some issue happened and it wasn’t able to maintain the frequency of its grid as needed. How likely do you think that is?

Jesse Jenkins: So I don’t think it’s plausible as the precipitating event, the initial thing that started to drive the grid towards collapse. I would say it did contribute once the Iberian grid disconnected from France.

So let me break that down: When Spain and Portugal are connected to the rest of the continental European grid, there’s an enormous amount of inertia in that system because it doesn’t actually matter what’s going on just in Spain. They’re connected to this continen- scale grid, and so as the frequency drops there, it drops a little bit in France, and it drops a little bit in Latvia and all the generators across Europe are contributing to that balance. So there was a surplus of inertia across Europe at the time.

Once the system in Iberia disconnected from France, though, now it’s operating on its own as an actual island, and there it has very little inertia because the system operator only scheduled a couple thousand megawatts of conventional thermal units of gas power plants and nuclear. And so it had a very high penetration on the peninsula of non-inertia-based resources like solar and wind. And so whatever is happening up to that point, once the grid disconnected, it certainly lacked enough inertia to recover at that point from the kind of cascading events. But it doesn’t seem like a lack of inertia contributed to the initial precipitating event.

Something — we don’t know what yet — caused two generators to simultaneously disconnect. And we know that we’ve observed oscillation in the frequency, meaning something happened to disturb the frequency in Spain before all this happened. And we don’t know exactly what that disturbance was.

There could have been a lot of different things. It could have been a sudden surge of wind or solar generation. That’s possible. It could have been something going wrong with the control system that manages the automatic response to changes in frequency — they were measuring the wrong thing, and they started to speed up or slow down, or something went wrong. That happened in the past, in the case of a generator in Florida that turned on and tried to synchronize with the grid and got its controls wrong, and that causes caused oscillations of the frequency that propagated all through the Eastern Interconnection — as far away as North Dakota, which is like 2,000 miles away, you know? So these things happen. Sometimes thermal generators screw up.

Music for Shift Key is by Adam Kromelow.

Blue

You’re out of free articles.

Subscribe today to experience Heatmap’s expert analysis 
of climate change, clean energy, and sustainability.
To continue reading
Create a free account or sign in to unlock more free articles.
or
Please enter an email address
By continuing, you agree to the Terms of Service and acknowledge our Privacy Policy
Adaptation

This New Wildfire Risk Model Has No Secrets

CarbonPlan has a new tool to measure climate risk that comes with full transparency.

A house and flames.
Heatmap Illustration/Getty Images

On a warming planet, knowing whether the home you’re about to invest your life savings in is at risk of being wiped out by a wildfire or drowned in a flood becomes paramount. And yet public data is almost nonexistent. While private companies offer property-level climate risk assessments — usually for a fee — it’s hard to know which to trust or how they should be used. Companies feed different datasets into their models and make different assumptions, and often don’t share all the details. The models have been shown to predict disparate outcomes for the same locations.

For a measure of the gap between where climate risk models are and where consumers want them to be, look no further than Zillow. The real estate website added a “climate risk” section to its property listings in 2024 in response to customer demand only to axe the feature a year later at the behest of an industry group that questioned the accuracy of its risk ratings.

Keep reading...Show less
Yellow
AM Briefing

Endangered Finding

On BYD’s lawsuit, Fervo’s hottest well, and China’s geologic hydrogen

Lee Zeldin.
Heatmap Illustration/Getty Images

Current conditions: A midweek clipper storm is poised to bring as much as six more inches of snow to parts of the Great Lakes and Northeast • American Samoa is halfway through three days of fierce thunderstorms and temperatures above 80 degrees Fahrenheit • Northern Portugal is bracing for up to four inches more of rain after three deadly storms in just two weeks.


Keep reading...Show less
Red
Studying wildfire.
Heatmap Illustration/Getty Images

There were 77,850 wildfires in the United States in 2025, and nearly half of those — 49% — ignited east of the Mississippi River, according to statistics released last week by the National Interagency Fire Center. That might come as a surprise to some in the West, who tend to believe they hold the monopoly on conflagrations (along with earthquakes, tsunamis, and megalomaniac tech billionaires).

But if you lump the Central Plains and Midwest states of Minnesota, Iowa, Missouri, Arkansas, Oklahoma, and Texas along with everything to their east — the swath of the nation collectively designated as the Eastern and Southern Regions by the U.S. Forest Service — the wildfires in the area made up more than two-thirds of total ignitions last year.

Keep reading...Show less
Yellow