Dynapower: Addressing the Frequency Problem with its Grid-forming Software Control solution

Blair Reynold’s extensive background and experience in the solar and advanced energy industry

Kerim: Hi, everyone. This is Kerim, Kerim Baran with SolarAcademy. I am here today with Blair Reynolds of Dynapower, and Blair has a great story in solar, and he has been in every corner of solar that you know, the common people would know about in our industry is. Today, we’re going to talk about some really important issues that concern the grid and the stability of the grid, but before we get into that, we’ll talk a little bit about Blair’s background, Dynapower as a company, and then we’re going to dive into the major problem of frequency regulation or inertia, rotating mass, and some important topics like that.

So Blair, welcome. Thanks for making the time.

Blair: Yeah, thanks for having me, Kerim.

Kerim: Great. So let’s start with your background. Tell us, as far back as you want to go, high school, college, after, how did you end up in solar? I see on LinkedIn, you have a physics undergrad degree.

Blair: Sure.

Kerim: And I see that you’ve worked in one of the oldest San Diego installers. I’m based in San Diego Sullivan Solar Power. And you know, like what drove all those jumps? And you are in North Carolina right now.

Blair: Yeah, that’s right. 

Kerim: And so are you a born and raised, North Carolina person, ended up in San Diego? Tell us.

Blair: Yeah, born and raised in North Carolina or at least, that’s what I tell people. I grew up in Asheville, North Carolina up in the mountains. And yeah, a lovely place to live. It’s very different now than when I grew up there. Of course, it’s been very much discovered by tourism. I went to undergraduate college down in Charlotte area, a little school called Davidson. I was recruited there to go play football, and had a great career there.

Just before the Steph Curry era, if you’re keeping track of sports, he really helped put the school on the map. But yeah, tiny school, and I chose the least popular major there. Like, literally, I was a physics major, and at a school of 1,600 students.

And so my senior year, in our graduating class, there were 3 of us in the physics program. So yeah. In fact, there was a time in my senior year where there was just one other student and I enrolled in a semester-long course, right? So a lot of personal attention, I would say, but yeah, doing that program and being a full-time athlete, which is, you know, essentially a full-time job, plus some, I would say, was quite an experience. And yeah, it definitely put me on a path which, you know, sort of led me into the career that I’m in now, which of course, is renewable energy and large-scale battery storage.

You mentioned San Diego. Yes, it’s a very special place to me, as well. That’s not only where I met my wife. I lived out there for at least up and down the West Coast, but primarily in San Diego for about 6 or 7 years, and that’s where I found the solar industry and this was in the mid-2000s, 2007, I think, is when I first got my first job. But I actually attended a Solar Power International up in 2006. So that was up in San Jose. And I’ve been attending every one ever since.

Kerim: Wow. Yeah.

Blair: But yeah, that was right around this transition that was happening particularly in places like Southern California, where we were seeing an uptake in more energy efficiency and renewable generation and home solar, right? I mean, that was SDGE was doing quite a bit at the time to incentivize homeowners to go solar, including the California Solar Incentive Program, CSI and yeah, so it was really a great time to get into the industry.

My first job was selling to homeowners over a kitchen table, probably, like many of us. But I quickly learned other aspects of the business, including for the technical side, including the design of systems and how to actually get permits through approval, learning the national electric code, learning sort of the practical electrical side of the business, that you don’t learn in college or university.

Kerim: Yup.

Blair: And was yeah, I knew right away that I’ve found my career ran on those. That was obvious.

Kerim: Yeah. Wow. That’s cool. And that took you to a graduate degree in Australia, studying.

Blair: Yeah, yeah. I was working in the industry for a couple of years. In fact, at the time, I got picked up by Sharp Electronics, who was, you might remember, one of the original manufacturers of solar modules in the US.

Kerim: Yeah.

Blair: I was working for them as an applications engineer, and had an opportunity to put that on hold and go back to school and pursue a master’s degree specifically in photovoltaic engineering. That was with a program in Australia, University of New South Wales, made very famous by Professor Martin Green, who was sort of the pioneer of higher efficiency, high-efficiency, silicon solar cell design. In fact, he, I really think can be credited for the PERC technology that we have so much gigawatts deployed around the world. He had, in fact, set the world record, his lab did, back in 1995 for a single junction crystalline silicon efficiency at 25% on a single cell in 1995.

And in fact, it wasn’t until, I think, 2012, 2013 when that record was actually beaten and it was beaten by SunPower, believe it or not. So I did a master’s program down under, had a wonderful time, was working throughout that experience, learned the Australian codes and standards. And yeah, if you haven’t been there, you should go. If it’s far away, I get it. But it is absolutely a wonderful place, and I was just, yes, exposed to gosh, at that time, large deployments of residential solar. I mean, it was every third house. In the cities there, the metropolitan areas had a small, one and a half kilowatt PV array on the roof, and that was primarily driven by not only the economics, but also a rebate program that had a cap on it, so like –

Kerim: Yeah.

Blair: Like 8 modules on every roof. It was great and so yeah. It was a fun time. I went back to work for Sharp after I graduated that program and was sort of kind of right there, until the very end, when they decided to pull out of the U.S. Market and did a little stint over at a German company called SolarWorld, also very well-known for US, manufacturing of solar.

Kerim: Yeah, we sold quite a bit of SolarWorld panels back in the day at my old company, Civic Solar.

Blair: Yeah, and then it’s so funny to see that whole trend come back around full cycle. Yeah, full circle. And, yeah. But really what I was doing was just, it was DC, right? You know, the DC side which eventually led me to batteries. I mean, just not a lot different in terms of the basic principles of current, amps, voltage, short circuits, fusing designs, all this kind of stuff on a PV System versus energy storage system, battery-side.

Blair: So I got into that business around 2013, 2014, with the company that was trying to compete with basically, the Tesla, Tesla Powerwall, making a residential home battery system. And you know, this is really before the lithium stuff really took off in a big way. So I kind of got in on the forefront of that and learned a lot of the tests, technical aspects and practical aspects, too. Like, what does that actually take to get a battery system designed, installed, permitted, and approved by the utility?

And yeah, it was a cool time. I transitioned over to Enphase, believe it or not. I was there. And I helped them launch their AC battery. It’s gone on to be a very successful product line. The Gen 1 battery, I’m not sure if you remember it, it was a grid-following product only, right? So it was not doing backup power. It was really a time-based charging and discharging schedule. That worked really well in markets that had basically been built up around feed and tariff models where you’d be basically get paid for all your generation. And over time, those fee and tariff markets, the value for that generation started to get ratcheted down significantly. And so in those markets, there was definitely an incentivization to install a home battery system and basically store your excess solar, store your solar, and then use it yourself in the evening time.

Kerim: Yeah.

Blair: And so that battery was really the right technical solution for those markets which coincidentally, Australia was one of our biggest fixed markets.

Kerim: Wow.

Blair: Yeah. I’ve since been working in the inverter side of the business after doing the batteries in the stint at Enphase, and that’s really where I got exposed to Dynapower in my current position. I was actually a customer of Dynapower’s for several years with a global solar and energy storage inverter manufacturer called SMA.

I started off on the residential side of their product management division, and then moved over to the utility scale, large scale storage side of the business, and there at SMA, I was the global product manager for their DC-coupled product strategy as well as the global manager for the grid-forming technologies which sort of leads us into the discussion here.

But it was in that role that I found Dynapower. I was interfacing with them almost on a weekly basis. We were white-labeling one of the products that’s been very successful for Dynapower, the DC-to-DC converter product.

And yeah, I really got to know the folks there well, and was fortunate to have an opportunity to come and join them and lead their renewable sales division. So in my current title, I’m the Director of the Renewable Division for Dynapower, primarily responsible for front of the meter solutions like large scale DC-to-DC converters and energy storage inverters. Yeah, that’s a little bit about me.

Kerim: Yeah. Thanks for that background. You definitely have a wealth of experience that I would love to do many more conversations with you, diving into different forks of that path.

Blair: Yeah. Thanks, Kerim.

Kerim: Yeah, hopefully in the future. 

Dynapower’s business overview and key product and solution offerings

Let’s talk a little bit about Dynapower. So you’re responsible for the renewables and e-mobility, I guess, business unit.

Blair: Yeah, that’s right.

Kerim: And driving revenue for that. Can you give us a little bit of a big picture view of Dynapower, and where that division sits kind of like, because from what I understand, it’s a very established large player in the energy power sector.

Blair: Definitely a large competitor in this space. But the company came from a really small kind of grassroots type of organization. Dynarpower is a 60-year-old company. Yeah. Last year, we celebrated the sixtieth anniversary of the company, and the early years of the business, we were really making small volume custom power conversion electronics, primarily rectifiers for C&I and mining applications. We’ve expanded that into more of military and some of these other areas. But it was, like me, in 2017, Dynapower as a company got into renewables, and it was through our very first bi-directional energy storage converter, and that was 2017.

We’re now in 2024. We’re on our fifth generation of the central energy storage inverter product line called CPS. Our smallest is 1.25 megawatt variant. And then I have a 2.5 megawatt variant. But yeah, it’s been a great product for us, that in conjunction with our DC-coupled solutions, so DC-to-DC converters. We have some really innovative approaches to coupling solar and storage together on a DC bus. And that’s really, I think, what put Dynapower on the map and helped us grow into a recognizable competitor in this space.

And two years ago, the company went through another major transition when we were acquired by a publicly-traded global company called Sensata Technologies. And Sensata’s got us beat. They have over a hundred years in the business, and like 21,000 employees, locations in 13 countries around the world, and they do around 4 billion dollars in revenue, just in 2022. So it definitely gave us an injection that we needed to help us scale at a critical time.

Kerim: What’s the synergies between Sensata and Dynapower? Like what are their traditional products versus…

Blair: Yeah. Sensata makes sensors. But they make sensors that go into a lot of automotive and aviation applications. And so I think the typical electric vehicle on the road has something like 20 Sensata parts in it. All of this, like LiDAR and radar stuff that we see out there for the self-driving vehicles with all kinds of yeah, various electronics and sensors. These are high volume, low cost sort of devices. And through the relationships with the EV industry, Sensata saw a real opportunity to grow their clean energy division. They acquired a smaller inverter company, they primarily use in RV applications, mobile applications, a few years before us.

And then yeah, they acquired us, two years back, and really helped bring us up to a more mature level and give us capital injection that we really needed to continue growing and scaling. So yeah, it’s been great to have them supporting us. And they’ve really gotten on board with what we’re doing in our culture. And yeah, it’s a little bit unique. I like it.

Kerim: Yeah. Nice, nice, nice. 

Dynapower’s bi-directional inverter solutions, DC-to-DC converter products

So let’s dive into a little bit of your world then. So can you tell us a little bit about the products, solutions you’re responsible for? And then let’s talk a little bit about the main problem you’re solving in the market.

Blair: Yeah. I mean, it’s primarily inverters, and we don’t make a solar inverter per se. We make a bi-directional inverter. So that’s what you would use in energy storage applications primarily. It also is used in hydrogen electrolysis as a rectifier. So we’re converting the AC to DC, and powering electrolysis with it.

We have a skid where we put a 5 megawatt skid that we make with 2 of our inverters on it along with a medium voltage step-up transformer. And then, yeah, the DC-to-DC converter products that have been really successful for us. We have a 500 and a one-megawatt version of a DC-to-DC converter that allows us to directly couple batteries and solar behind an inverter, behind a single inverter, and in doing so, there’s quite a number of advantages. But it basically comes down to lower cost, higher yield, and easier permitting, faster interconnection applications and so on and so forth. Because you’re generally applying for a smaller interconnection, because it’s a single inverter rather than AC-coupled strategy where you have 2 inverters both sort of competing for that interconnection space.

Kerim: And this is usually coupled with a utility scale solar farm or similar power generation source. 

Blair: Yeah, yeah, yeah. But with the IRA, we’re seeing a whole lot more sort of standalone storage going in.

Kerim: Yeah.

Blair: But yeah, as far as DC coupling, what that really means is, it’s literally connecting solar and batteries. That’s really the primary use case. Yeah.

The frequency problem. Inertia. Rotating Mass. Dynapower’s grid forming technology

Kerim: And one of the major problems you solve is the frequency problem on the grid. So let’s talk a little bit about that. What is the frequency problem? What creates that? And how do you manage that?

Blair: Yeah, Kerim. I think we can both agree that the world is a lot better off with more clean energy sources than not – more clean energy, less pollution. And so there are some fundamental issues that we have when we try to deploy renewable generation at large scale, particularly, when there’s already a high population of renewable generators in a certain section of the utility grid. Think of it thinking about it that way.

The best example I could give you in recent years is Hawaii. They’ve really struggled with growing the amount of renewable penetration on their grids while still not creating a de-balance or a destabilization of the network there.

Kerim: Yeah. That’s why, yeah, I remember it being at 35-40% penetration a few years ago. It’s probably gone past 50 plus now is what I’m assuming, and that was also creating such other dynamics, where all the wealthier folks who could afford it were going almost off grid because they could. I mean, because electricity is so expensive there, 50 plus cents, like it made like you got a 3-year payback putting your own solar on battery, cutting yourself off the grid, and that created less customers for the grid but fixed costs, and like it was a crazy story that the first time I heard it was probably 5, 6 years ago. Can you give us an update, like how things have evolved since then, and like what’s…?

Blair: Well, yeah, what you’re describing a little bit is this, the as-grid defection, where people basically say, “I’m done with being connected to the utility grid. I’m going to be my own power station”, and they connect solar in batteries, and maybe other generation sources like micro hydro or wind, and basically operate their own self-contained microgrid.

And yeah, it’s actually, that kind of segues into some of the technology that we’ll be talking about here is that grid-forming technology. Because when you’re not connected to a power line, you are your own source of the AC wave form. It’s a grid – that’s really the kind of the fundamental roots and background for this grid-forming technology that we’re talking about is it comes from the off-grid space. Because, yeah, you’re generating the sine wave. You’re not like latching onto it and syncing with it as grid-following inverters typically would do. You really are the source of that waveform.

And that it’s really that grid-forming technology that has now evolved to a place where it’s creating stabilization. It’s leaving the electric grid in a better condition than it found it. So I just like to think about it and is solving some of the fundamental problems we have with deploying large volumes of renewables on the grid. So yeah, the example you used earlier, I remember when I first got into the industry 17 so years ago. Yeah, I heard these sort of theoretical limits about how much renewable penetration we could realistically achieve. And it was on the order of 25%. And then I think it kind of crept up to 30%, maybe 35% over time. But it’s always been a talking point in our industry is that renewables are intermittent. They don’t behave like 20th century generators and fossil fuel generators. And they create some stability problems. It’s definitely been a political talking point. And yeah, that’s really what I’m here today to talk about is sort of debunk some of those myths, create a little bit more awareness and education on that area. Yeah.

The relationship b/w frequency & load. How to make inverters behave like conventional power generators

Kerim: So let’s do that because I do believe that in 20 years, grids will be powered. I don’t think the grid is going away. I don’t think we want the grid to go away, necessarily. But I think solar will be the main source of powering the grid, with probably a hundred, if not more times nodes of power production than we have today, and most of that will be solar, stored into local storage or regional storage. So what are the issues along the way? And how do we solve them?

Blair: Yeah, I mean you hit on one earlier, Kerim. You were talking about frequency, but just to kind of like level set, there is a fundamental relationship between frequency and load. And of course, when I’m talking about frequency, I’m talking about the 60 hertz, 60 cycles per second in the U.S. electric grids, 50 hertz in most of world markets. But it’s that yeah, it’s that frequency of the AC wave form that we’re talking about on the electric grid that we build all of our systems around and our electric grids have a very tight tolerance actually, for the level of fluctuations in frequency that we can tolerate.

And this all sort of kind of comes back to how our electric grid was constructed sort of built around 20th century technologies. But the fundamental relationship between frequency and load is an important one to kind of understand. So a sudden increase in load will decrease the overall frequency of the system. And just like a sudden decrease in load, would increase the frequency of the system.

And so, conversely, a sudden decrease in generation will cause the frequency to decrease substantially as well, and drastically, in fact. And that really kind of is the fundamental principle that we’re trying to solve. Or the problem we’re trying to solve is preventing that rapid collapse of frequency. When there is an issue, a major issue on the grid, we lose a generator, and we prevent that crash.

Kerim: Is that the scenario that can crash the whole grid?

Blair: Absolutely. Yeah. Absolutely.

Kerim: Yeah, and what happens if – so I mean, even like just think of a very concentrated huge solar farm. Big Cloud comes over it that could even crash the grid then on a…?

Blair: No, because that’s not really messing enough with the level of frequency drop that we would be concerned about.

Kerim: It’s going to be happening fast enough. Like you would have a failure. 

Blair:  No, we’re really talking about millisecond speeds here. It’s incredibly fast. And so, but you’re right in a sense that inverters, grid-connected inverters have had to sort of devolve over time. We used to, anytime that there was a weird blip on the grid, the inverters used to have to drop, to cut off, and then they would wait 5 minutes before they would come back online and check in, is everything stable now? That was a requirement under the UL Standard 1741.

Kerim: Yeah.

Blair: And we realized that that worked for a period of time, but it wasn’t sustainable to allow us to continue to grow more and more deployments of solar and other types of inverter-based resources on our grids. So we started introducing smart inverter capabilities, things like voltage ride-through, frequency ride-through, these kinds of things, Volt-Var, where we can sort of inject yeah, either active or reactive power into the grid as the conditions would warrant, and that definitely helped to create less instability, for sure. But definitely, didn’t go far enough to solve the frequency problem which, it’s really caused by a massive loss of generator, a generator failure.

And you know, fortunately, these are fairly uncommon, but when they do occur, they can really be a serious problem. There was a recent event in Australia where an entire natural gas generator blew, I mean, it literally blew up. There was shrapnel, hundreds and hundreds of yards away.

And in fact, even it, but it doesn’t necessarily have to be that big of an event. There’s a really interesting report that was published by NERC about well, they call it the Odessa Disturbance. Now, I’m sure there was more than one disturbance in Odessa over the years. But we’re talking about Texas, and this is a particular fault that occurred on a power line there that ended up creating a cascading result that took more than a gigawatt of solar offline. And that’s not how we are supposed to be behaving, fundamentally.

And so NERC did a really good job, doing a deep dive into this. How did this happen? And quite honestly, it comes back to the people that are configuring these systems. Are they actually configured properly, to create that level of stability and ride-through? Are the operators of these plants knowledgeable in how to operate them in a way that’d prevent them from going offline like that after a fairly minor grid disturbance, grid event?

And so yeah, that really kind of leads us into this topic of inertia and sort of how inertia creates stability and strength for the electric grid. Fundamentally, inertia is Newtonian Physics. An object in motion wants to stay in motion. Right? And so it’s incredibly important that we have levels, a certain level of inertia on our electric grids to create this sort of stability that prevents us from experiencing a rapid collapse, a rapid-collapsed frequency.

And maybe I’ll use an analogy here. Imagine going along on a train, and you’re riding along on a train, and all of a sudden, you come to an immediate stop. I mean, I’m having a hard time kind of thinking about how that would happen. I guess, if there was another train with the same velocity and mass, and they both had crashed head on, you’d have a pretty bad day, I would think –

Kerim: Right. Yeah.

Blair: – if you were riding on that train. But of course, that’s not really what happens. When you slam on the brakes on a train, there’s this sort of slow screech that occurs probably over miles of distance.

But if that’s – what we’re talking about here is really creating that slowing down when there is a problem on the grid, and the longer you can sort of maintain that deceleration, the better it is because it allows other systems to come online and correct that problem with backup systems.

But if the trains were to suddenly stop altogether, that would be a very, very big problem. That would be hard to recover from. And so…

Kerim: That would be a massive shutdown of the grid. And then to bring that back up, you would have to do it in like sub sectors slowly. Yeah?

Blair: Yeah, dark-starting little middle nodes of the grid. And it would be a massive problem, not too dissimilar from what we saw in a winter storm in Texas a few years back, too. Right? So yeah, we need to be able to prevent those things from happening. And the problem, the fundamental problem is that inverters, typically, don’t behave like a conventional fossil fuel generator which is actually using –

Kerim: Because they don’t have the rotating –

Blair: – motion. Exactly. There’s a rotating mechanism. That physical mass, there’s literal inertia happening when that turbine is rotating and, of course, what it’s doing is it’s connected to a generator. The generator is creating an AC wave form because it has an electromagnet that’s being rotated through a series of wires. Then that’s creating our AC grid, and so when there is a big disturbance or something that could potentially create a drastic drop in frequency, believe it or not, it is that sort of gradual slowing, that deceleration, we call it dampening that actually creates enough stability to prevent a drastic, sort of instantaneous drop in frequency.

The technical term in our industry is RoCoF, the rate of change of frequency. We really want to try to prevent a sudden drop in frequency. We really want to try to get that slope more gradual, as the frequency declines, so that we allow more time for other backup systems to kick in. That’s really the critical thing.

Kerim: Novice question here, just because I’m a little bit of a numbers, guy. So that frequency of 60 hertz or 50 in the US, or vice versa, US, Europe. Does that go down to like 49, 48, 45? Or are we talking like 49.9 49.8, kind of, or even less?

Blair: Yeah. We’re in serious trouble if we even lose 1 hertz. So if we go from a 60 to a 59, we’re in pretty big trouble. We need to be activating recovery systems right away. And so, yeah, it is a very tight tolerance that we have –

Kerim: Right there. Okay. Got it.

Blair: – around the frequency because fundamentally, it’s the balance between generation and load. And if you have too much of one or the other, yeah, the grid can collapse very quickly. Yeah.

Dynapower’s grid forming software control solution. Fast frequency response. Short Circuit Ratio

Kerim: So what’s the Dynapower solution to this situation, to this scenario?

Blair: We pretend to be like a conventional generator. We behave like a conventional 20th century generator.

Kerim: With a software and battery-coupled solution.

Blair: Yeah, exactly. So we take our bi-directional energy storage inverter. We overlay a very tight software control on top of it, which is actually a grid-forming software control. It is a synchronous grid-forming. And that’s a fairly new term. So I’ll explain it a little more. Rather than being grid-forming in a pure off-grid scenario, like the microgrids that we were talking about, in a synchronous grid-forming scenario, we’re actually constantly operating the inverter in what’s called a voltage source mode. So we are actually contributing and driving that AC wave form rather than being a grid-following inverter, which is just seeing a waveform and latching onto it and injecting current. That’s a current source mode from a grid-following inverter.

In a grid-forming inverter, we’re in a voltage source mode, and we are helping to build upon that waveform and in a virtual, what we call virtual inertia or is basically it’s a software control where we’re emulating the physics, the Newtonian Physics of that rotating mass because with an inverter, it’s basically, you know, we’re digital. The old generators are analog. We have a lot more ways that we can operate in a digital world. We can adjust that waveform between active and reactive power, quite significantly. And in doing so, we can create the same exact behavior that a spinning generator would, conventional, fossil fuel generator. And so it’s a really important technology to help create enough level of inertia on the power grid to prevent catastrophic collapse that can be substantially exacerbated by large-scale deployment of grid-following type inverters, which is mostly, what we have out there these days. So we do it with, yeah, we do it with an inverter, with software controls, and then we need a battery, of course, connected to the inverter as a DC source. So it’s always a captive sort of reserve capacity to create that stability. But that’s how I like to describe it.

The grid-forming, fundamentally, the physics that we’re creating, the problem it’s really solving at the simplest level, it’s basically just acting like a giant shock absorber. So when there is a disturbance on the grid, we can absorb that with basically how we’re building upon the waveform, so that it doesn’t prevent this catastrophic and rapid collapse due to a very sudden drop and rate of change of frequency. And what these systems are really trying to do is buy time. Because there are plenty of other backup types of systems, including fast frequency response that our inverters are capable of delivering, as well as plenty of other inverters, because there’s sort of market mechanisms that incentivize that type of control and behavior.

But fast frequency response, key point, is not instantaneous. It takes time to do fast frequency response. There’ll be less than a second, but still in the amount of time that we’re talking about, the time scale that we’re talking about to prevent a catastrophic collapse, that’s ages.

Kerim: Yeah.

Blair: So what we have to do because fast frequency response is basically, it requires the inverter to measure the signal, process it. There’s computing happening. And then it needs to decide, how am I going to react to the signal? This measurement that I just took? Believe it or not, that cycle to calculate and react is wasting precious, precious milliseconds that we can’t afford to waste when there is a drastic collapse. And so what’s so cool about the synchronous grid-forming and the virtual synchronous inertia is that we are doing that control without any processing time wasted. It’s inherent into how we’re operating the inverter. It literally behaves exactly like a rotating mass would.

There is a slowdown, sure. But with a dampening factor, we can behave like this sort of slower and slower deceleration, buying enough time by continuing to inject inertia into the grid, buying us enough time for these backup power systems to kick on and then take over and bring the frequency back up to a reasonable level. And so, fundamentally, that’s what we’re doing with inertia, but it’s also, we’re able to inject the strength into the electric grid as well. And that’s grid strength. It’s sort of not a well-defined term. But there is a measurement that we use for it called SCR or short circuit ratio. And the short circuit ratio is basically a measurement of the relationship between the short circuit apparent power when there is a line like a triple-line fault on that particular node in the electric grid. I don’t want to get too technical here, but basically, the way that we measure the strength of the electric grid is, if you have an SCR, a short circuit ratio of 3 or higher, that’s a strong grid. Between 2 and 3 is really defined as a weak grid, and less than 2 is a very weak grid.

And so why is this an issue? It’s that in a very weak grid, you couldn’t even connect a solar inverter or an energy storage inverter. It oftentimes won’t even latch. Even the grid-following inverter wouldn’t even be able to connect and inject active/reactive power onto that grid because it is so weak, it’s so unstable.

I mean, I will plug Dynapower’s inverters and say that Dynapower’s inverters are capable of connecting and operating on grids that are less than 2 short circuit ratio which puts us into the very weak range. But it’s tricky and so, yeah. What do we do? With synchronous grid-forming technology, we can actually, because we’re building upon that waveform, we can literally inject strength into the grid at that interconnection point and bolster it, which therefore allows us to connect more and more solar and batteries, other inverter-based resources to that grid.

Case Study: Synchronous grid forming energy storage system at the tip of the Cape Cod Peninsula

And probably the best example I can give you was a project that I was involved with a few years back. It was probably one of the first, if not the first, synchronous grid-forming energy storage system that was connected in the US, anyways, to help solve that exact problem.

It wasn’t envisioned that the project was going to be operated this way from the onset. But what ended up happening was during the interconnection planning studies, the modeling of the energy storage system, it was discovered that this particular part of the electric grid, which, by the way, was at the very, very end of Cape Cod, Massachusetts, at the very, very tip of the peninsula there.

And because it was so far away, just physical, like distance of electric lines to the nearest power generating station that that ended up resulting in a very weak grid, and with all the voltage losses and everything that it experienced along the way.

So when this developer came in and wanted to put a large scale battery system there at this location, they discovered that the short circuit ratio was actually less than 1, and that was fundamentally not possible. We couldn’t even operate the inverter at such a low SCR and so what do we do? We didn’t walk away from the project, that, sorry, tough luck. We actually accelerated development of this technology and got the system interconnected and up and running by operating it in a synchronous grid-forming mode.

So that we actually left the grid in a better condition with more strength than we found it. And that was a really cool story. I mean, I think we really addressed this technical problem in a way that really shows the capabilities of this technology in a way that yeah, it’s going to be increasingly necessary for us to continue deploying gigawatt scale solar and storage across the world.

How to best deploy GW-scale solar & storage and connect inverter-based resources to the grid

Kerim: Storage is growing so fast these days. So I’m assuming most of these deployments are requiring a grid-forming solution like this, coupled with it. Or can you do it without? Or what are you guys seeing? I mean, you guys must have a really strong position in the market and enjoying rapid growth, from what I hear.

Blair: So it is. Everyone, I think, recognizes this. This is the future. We have limited reserves of fossil fuel on this earth. We need more clean energy, and we have fundamental problems with connecting inverter-based resources to an electric grid that was built on 20th century technology.

So what do we do? You can either rebuild the electric grid and upgrade it from an analog to a digital type of grid, to use my example. Or you can just simply operate and behave like a 20th century generator. Essentially, the same outcome. So that’s how we approached it. That’s what we do.

But you’re right. I mean, this is a critical technology. People are aware of it. But it’s one of these funny things where the technology is ahead of the codes and standards. And so we all know that this is coming. We know it’s critically important.

But most of the projects that are happening around the world right now with synchronous grid- forming are either accidental, like the example I told you about, or they are pilot scale to really try to understand, again, the benefits of this technology, how it can replace other 20th century grid stability devices like STATCOMS, for example.

But also to really understand, what’s the value of this technology when connected to the electric grid? Like, basically, how can we build market that incentivizes people to deploy synchronous grid-forming inverters rather than just continuing to push out projects with grid-following inverters? Like, can we create a way to incentivize it through a market-based model? So people are studying this. Meanwhile, codes and standards are continuing to evolve and develop, because, technically, yeah, 1741, the US standard for inverters doesn’t contemplate this kind of operating behavior.

So there’s a little bit of contradiction there in the codes and standards like, if you want to comply with all the UL stuff, you’re in a gray area, when you’re doing synchronous grid-forming. And so yeah, there’s plenty of great committees also working on developing the codes and standards, sort of rewriting the rules, so that allows these kinds of inverter-based technologies to operate in a way that yeah, adds strength, resiliency, bolsters the grid, allows us to create market mechanisms around this technology and ultimately deploy more solar and wind.

Kerim: Right. Blair, thank you so much for this deep wealth of information you shared with us and Dynapower’s grid-forming technology solutions.

Blair: It’s a real pleasure. Thank you.

Kerim: Yeah, thank you for being with us.

Blair: Thanks for having me. Be back anytime. Let me know. Thank you.