I’ve seen lots of posts lately on Texas being “minutes and seconds away” from months long blackouts. What could’ve happened, what was avoided that caused that?
In: Engineering
Imagine one of those [rides at the fair](https://en.wikipedia.org/wiki/Kamikaze_(ride)) where you have a car full of people swinging back and forth. That’s the electrical grid, and the people on the ride are the load on the electrical grid – if you add more people it’s harder to keep it swinging, just like if you use more electricity for heating, pumping water, running appliances, it’s harder to keep the electrical grid running.
The ride is swinging back and forth once every second (the electricity in the electrical grid swings back and forth at 60 Hz, or _sixty_ times per second, but people move more slowly than electricity, so let’s make it sixty times per _minute_ instead). And, instead of having a big motor swinging the ride back and forth, you have a bunch of carnival workers. When the rides is at one side they all push, and when it’s at the opposite side, they pull, just like pumping on a swing. The carnival workers are the generators tied into the electrical grid, each one contributing a little bit in unison.
Normally, this works fine. You have more carnival workers than you really need to keep the ride moving, so no one of them has to push as hard as they can, and you can have a few more people get on the ride without needing to add more workers. This is like how the electrical grid has more power available than is needed in normal times.
Now, suppose that you have a cold snap that shuts down the other outdoor events, so people want to ride the rides that block out the wind. More people get on the ride, just like more people start turning up the heat. At the same time, the workers start to get cold – some of them may have bad backs or knees, and can’t push when it gets that cold, so they drop off to take a break, and now you _barely_ have enough workers to keep the ride running, pushing and pulling as hard as they can. This is where the ride (and the electrical grid) start to fail – the generators on the electrical grid are running as hard as they can, but people keep needing more and more power.
Next, the generators start to fail – some of them just _break_, like an aging carnival worker who tries to push and pull as hard as they did a decade ago and throws out their back, but it’s more likely they just start to get a bit tired – nobody can work _as hard as they possibly can_ for very long.
Here’s where things start to get “out of phase”. The workers are trying to push and pull once per second, just like the electrical grid is trying to run at 60 Hz. But as they get tired, they slow down a little bit. A tiny bit is okay, because they’re still pushing and pulling _about_ when they need to, at _almost_ the same time as everyone else, but it’s not great, just like a generator running at 59 Hz – it’s still helping, but not as much as it could.
But since they aren’t in sync with everyone else, they aren’t helping as much as they could. Things get even harder, because there are still the same number of people on the ride. If things get _too_ bad, if a worker gets too out of sync with the other workers, then they’ll start pushing when they should be pulling, or pulling when they should be pushing. The ride is so much bigger than them that, well, it’s going to be moving back and forth regardless. So if they don’t stay in sync with it, then it’s either going to smash into them, yank them off their feet, or (best case…) pick them up and start carrying them with it.
As soon as one of those things happen – just like a generator turning into a motor or being damaged and dropping off – the load gets that much worse for the remaining ones, which escalates the problem further until _all_ of the workers (or generators) have been damaged or knocked off, and the ride slows to a halt. This would have been the blackout, and it would have taken months to get everything back online to start the ride moving again – repair the generators, heal the workers, find new ones, etc.
This can happen quickly, because once it starts it goes faster and faster. If you can’t bring on more workers or generators, the only solution is to lighten the load – to kick riders off so that the remaining workers can manage it. That’s what happened in Texas – they were _that_ close to the electrical grid smashing its own generators like a carnival ride hitting the workers who were running it, and they could only stop that by shutting things down.
Latest Answers