What's Really Holding The Grid Together - Fluence

Ed Porter (0:00)

I'm your host, Ed Porter. Welcome back to Transmission.

When something goes wrong on the grid, it needs a sudden surge of electricity to shut the fault off safely. A spinning turbine can throw three to five times its normal output in that instant. Most inverters can only match 1.5 times what they are already producing. And inverters are what are replacing those turbines at scale. As renewable generation grows, that gap becomes a problem. And this mechanism is one of several examples where the grid does more than just move power from A to B. This episode gets technical and I'll make no apology for that. Inertia, fault current, voltage control, the physics that keeps the grid online when something goes wrong. It's the layer sitting underneath every headline about blackouts, data center power deals, and the renewables build out. To get to grips of power markets, you need to get into this detail. Ben Braun, Chief Engineer at Fluence, has spent his career working on the power electronics from batteries to the grid. We explore what's really holding the grid together as old power plants retire and what happens when thousands of inverters all react to the same event in the same preset way.

Want to see what Stability Pathfinder and Inertia Markets are making for batteries? Ask Ko, Modo Energy's AI Analyst. Sign up is free. Link in the description. Let's jump in.

Hello Ben, welcome to Transmission.

Ben Braun (1:38)

Hi Ed, thanks for having me here.

Ed Porter (1:40)

Our pleasure. And as ever, let's get straight into it. So what is one thing that people get wrong about grid forming inverters?

Ben Braun (1:47)

One thing or would I be allowed to list a couple of things?

Ed Porter (1:50)

You can cheat.

Ben Braun (1:51)

All right, let me, I'll try to keep it short. I'll list a couple of them and then maybe we can pick one to go into in more detail. The very first one that I like to point out is that grid forming is so much more than just the power converter controls. A lot of people are naturally drawn to it. That's where it starts, but that's not where it stops. You have to think about the plant holistically if you want to operate in grid forming. And probably throughout the conversation, we'll hit on that more. Another one is that grid forming is not grid forming, is not grid forming, is not grid forming.

I used to joke that I really hope all of the grids and the industry standards organizations, they get together and they harmonize. And there was a bit of that, but we don't have a UL version and an IEC version of grid forming, but we do very much have a NESO version, an AEMO version, a FAUDE, FNN version, and so on.

Ed Porter (2:41)

These are individual, those are system operators, right, that you've just been talking about, and they all have their own specifications.

Ben Braun (2:46)

Yep, they do reference each other quite a lot, and you can kind of follow a paper trail, this one references that one, who references that one, who references, you know, and so on.

Ed Porter (2:54)

But we don't have like an international standard, this is how grid forming works.

Ben Braun (2:58)

No.

Ed Porter (2:58)

Okay, so we've got two so far. The first one is, if you want to do grid forming, it's not just about the inverter itself, it's the whole plan, and the second one is that grid forming standards globally are very different and perhaps shouldn't be.

Ben Braun (3:11)

Correct, and there's even then a subset of the second one, I'm an engineer, where you have people asking for grid forming that aren't even on the grid. And then it's not necessarily that they have their own grid code, but a data center, for example, it's all over the news that they are struggling to get grid connections. Many of them are saying, I don't need a grid connection, I'll bring my own power. But my own power plant will then be subjected to the volatility of my machine learning AI training models, and to cover that, I need a battery. And in that situation, a grid forming battery is very helpful, but it no longer has to adhere to any given grid code. It just has to serve the purpose of protecting the gen sets, whatever they may be, and to make sure that that data center has a high uptime. So you have even within, or let's say parallel to the grid codes, you have a whole other subset of kind of customer specific requirements sometimes. That's the second thing I think that a lot of people get wrong. And the third thing, and this is maybe the most controversial or eyebrow raising. And I bring it up because I think there's a lot of opponents out there, not necessarily only opponents of grid forming, but opponents of converter based generation and you know, let's get the good old synchronous machines back.