**Title**: Energy in the North - Mari Shirazi
**Date**: March 26, 2025
**Participants**: Amanda Byrd, Mari Shirazi


00;00;00;00 - 00;00;19;00 [Mari Shirazi] The leaders are grid-forming and all the other dogs are grid following. They don't decide where to go. The leaders are listening to the musher tell them where to go and everybody else is muscle. They're in line. They're following. They're pulling hard. They're doing their thing. 

00;00;19;02 - 00;00;40;13 [Amanda Byrd] This week on Energy in the North, I speak with Mari Shirazi, a research professor at the ºÚÁÏÉçappCenter for Energy and Power, and Mari leads the Power Systems Integration Program. Her team operates a lab on the UAF campus that emulates a 500 kilowatt remote community microgrid that could support around 200 homes. The lab includes a diesel generator, wind and solar simulators, a battery energy storage system and the control systems to run and connect all of the components, creating a power plant. The lab is used to test new technologies, including control approaches for equipment prior to being deployed in remote communities. Mari and her team have recently been focusing on grid-forming inverters, and I started by asking what is an inverter? 

00;00;54;05 - [Mari Shirazi] Inverters are boxes that take whatever power your resource is contributing - your solar or wind, and they convert it to the kind of power that you want on your grid, which we call fixed frequency 60 hertz. And it's a fixed voltage. And there's two kinds of inverters. One of them is a grid-following inverter. These are what is deployed on almost all wind turbines and solar arrays and many battery energy storage systems. Now, a newer kind of inverter called a grid-forming inverter. And, what a grid-forming inverter does, it behaves just like your diesel generator. It actually creates the nice voltage waveform, fixed frequency, nice fixed voltage, voltage waveform. So one analogy that I like to use for the difference between grid-forming and grid-following inverters is when you are hooking up a dog team, you can hook your dog team up with a gang line hitch, or you can hook your dog team up with a fan hitch. So, grid-following inverters are like every dog in your gang line hitch except the leaders. The leaders are grid-forming and all the other dogs are grid-following. They don't decide where to go. The leaders are listening to the musher tell them where to go and everybody else is muscle. They're in line, they're following, they're pulling hard. They're doing their thing. For a grid-forming inverters, like a fan hitch, every dog kind of has a sense of where they're going. Everybody's kind of going forward. In the meantime, they're also kind of navigating their own little obstacles because every body has a little different path. They have to think. They have to make their own decisions. They have to let go around things and they might slack off a little bit if there's a big snow block in their way, but then they'll come around and they'll pull back in. And so everybody's kind of pulling together. And if somebody stops pulling, all the other dogs, they can make decisions. They're still moving forward. So the other thing with a grid-forming inverter is that you're not relying on a single leader. And so anybody can pick up the slack if you need to. And that really helps. I mean, there are other issues, though, and this is where the lab comes into play.  With a fan-hitch, everybody's got to play nice. There are a lot more opportunities to fight with each other. It's the same thing with grid-forming inverters. There's a lot more opportunities for them to fight with each other or to fight with the diesel generators. So you really need to make sure you have the proper control approaches and the proper tuning. Recently we tested a large system that was prior to it being shipped out to St. Mary's and there were a number of issues in terms of operating that system. It was a grid-forming inverter that we were able to ring out here at the lab before it got sent to St. Mary's.

00;03;09;21 - 00;03;31;05 [Amanda Byrd] That must have been a huge cost saving for the community who would have borne the brunt of that cost. 

00;03;15;28 - 00;03;31;07 [Mari Shirazi] Yeah, and honestly, I'm not actually sure that the level of work that we had to do with that inverter while it was here, it would have been possible out there because we were using pretty sophisticated equipment like Oscilloscope to really look at waveforms and find things, you know, and microsecond level things that were going wrong.

00;03;31;07 - 00;03;52;07 [Amanda. Byrd] So ultimately you're helping communities create a resilient renewable energy system in their communities. 

00;03;38;18 - 00;03;45;22 What I like to think of our role, maybe in particular in this lab, is making sure that we try to do that as responsibly and efficiently as possible. 

00;03;45;22 - 00;03;58;12 [Amanda Byrd] Mari Shirazi is a research professor at the ºÚÁÏÉçappCenter for Energy and Power. And I'm Amanda Byrd, chief storyteller for ACEP.  Find this story and more at uaf.edu/acep.