Can the Spain/Portugal Blackout Happen Here?

Yes. But it's less likely (today) and should be more limited

If you want to read some very good discussions on the issue, I suggest r/EnergyAndPower and r/Grid_Ops. And if the below has you wishing for a primer on the basics, please read:

• Electricity 101

• Load Balancing the Grid

I’m not going to add my $0.02 to what started the problem. There are a lot of different possible causes and it’ll likely take some time to figure it out. The key takeaway is there are numerous natural events & system events that can trigger this.

First off, the problem is less likely to be significant here because, since a tree branch caused a blackout of the Northeast, FERC has been diligent making sure issues like that are isolated. It still happens here,¹ but each time it does they work on addressing the new issues found.

Inertia

Second, we² still have significant inertia in our grid. Spain & Portugal do not. (This post is not anti Solar & Wind, read through to the end.) That matters - a lot.

Inertia: Think of being on an exercise bike where the pedals spin with the wheels. To slow down you have to gently push against the moving pedals. If you try to stop them it will likely throw you off the bike or the bike will tip over. Now imagine being on a 10 person exercise bike where the other 9 people are pedaling at the same speed - you have no choice but to pedal at that speed. Those other 9 people - that’s inertia.

The grid is this amazing machine where it must constantly balance between generated power & demand. Not every minute or every second, but constantly because energy moves on the lines at the speed of light.

Now it’s impossible, with today’s technology, to deliver exactly 120v @ 60Hz to every device. This is why you will see lights temporarily dim when something using a lot of power is switched on. The key to this is to stay at 60Hz³ while the voltage will bounce up/down a little bit as the grid is constantly being balanced.

To make this work there are generators that set the phase & frequency. These historically are large hydropower, nuclear, and coal. These set the cycles because they tend to generate gigawatts of power. The grid operators focus diligently on keeping these large generators in sync.

All other generators are followers. They match themselves to the phase & frequency of the grid and will constantly adjust to match the grid. They will disconnect if the grid gets too far from 60Hz, but while connected they will always follow.⁴

Key to inertia is that the phase setting generators are producing a lot of power.

Minimal Inertia

So what happens when you have almost all power generated by solar, which is what was happening in Spain when this event triggered? You don’t have much in the way of inertia.

Spain has some nuclear power and they have an intertie to France⁵ which is heavily nuclear. That provides inertia, but not much as they aren’t delivering that much power. Spain also has gas for backup, evenings, etc. But if that’s not on it takes time to get them running, synced up, and connected.

And key to all this is when the system gets enough out of phase, generators have breakers that open to save the generator. Once this problem got large enough most generators were taking themselves offline.

In short, as soon as the inertia in their grid was overpowered, the shutdown was inevitable. If the conductor of the orchestra suddenly disappears, the music falls apart.

There is a substation in the San Jose area that was tripping a breaker every night at 1:00am. They investigated and found a substantial number of homes there have a Tesla set to charge at 1:00am. The instantaneous jump in demand caused too large an imbalance. The fix? Have each home set a different start time. One minute apart is sufficient.

Inertia in a VRE World

So does that mean we can’t have solar & wind delivering 99% of our power at times? No. What it means is we need to provide strong inertia for a VRE centric system.

One of the easiest ways is to have the solar/wind spin up large flywheels. Those flywheels are connected to a generator. And so the solar/wind deliver power indirectly through the flywheel. Have enough flywheels and you have strong inertia.⁶

Another approach being developed is to do this with BESS.⁷ The BESS is managed to deliver power as needed to get the grid back to the desired phase & frequency. Batteries can be used instantly so they can do double duty as both the backup for low VRE output and as inertia for high VRE output.

What’s critical, if we go the VRE route, is to add substantial inertia before we disconnect the remaining coal plants from the grid. I don’t think I’ve seen much mention of this⁸ in either the CEO or PUC discussions.

And of course, if we instead use nuclear for baseload power, then we have really solid inertia.

Also, kudos the the Spanish & Portuguese power companies. They performed a black start in under 24 hours. Granted they could use the intertie to France but still, very impressive.

1. Odessa Event

2. Colorado. Although everything here holds for any region aiming for 40% or more VREs.

3. 50Hz in Europe

4. A turbine based generator (gas, coal, hydro, nuclear), if they connect to the grid out of phase, will shake itself to death. Matching is not optional.

5. Which opened a breaker when the insanity started to protect France’s grid.

6. And yes, this is expensive.

7. It’s expensive

8. It is mentioned in passing in a couple of places.